####018015798#### FXUS05 KWBC 181250 PMD90D FXUS05 KWBC 181244 PMD90D Prognostic Discussion for Long-Lead Seasonal Outlooks NWS Climate Prediction Center College Park MD 830 AM EDT Thu Apr 18 2024 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS During mid-April 2024, an El Niño Advisory remains in effect but the oceanic temperature anomalies associated with El Niño are rapidly fading. There is an 85% chance that ENSO neutral will be in place by the end of the April-May-June (AMJ) season. There is a 60% chance of additional transitioning of the ENSO phase from ENSO Neutral to La Niña by summer (June-July-August, JJA), with La Niña conditions favored to strengthen and continue through boreal autumn and winter. Therefore, a La Niña Watch has also been issued. The May-June-July (MJJ) 2024 temperature outlook favors above-normal seasonal mean temperatures for central and eastern Alaska, the far West excluding southwestern California, and most of the remainder of the Contiguous U.S. (CONUS) with the exception of the north-central states. Maximum probabilities (>50%) favoring above-normal temperatures are indicated over eastern Alaska, parts of the Northwest, the eastern Great Lakes and Northeast, and over New Mexico, southwestern Texas, and southern Florida. For southwestern California, near-normal seasonal mean temperatures are favored. For remaining areas of the CONUS and Alaska, Equal Chances (EC) of below, near, and above-normal seasonal mean temperatures are favored. No areas of favored below-normal temperatures are forecast for the MJJ season. The MJJ 2024 precipitation outlook favors above-normal seasonal total precipitation amounts for approximately the western half of Alaska, and from the southeastern quarter of the CONUS northeastward across the Mid-Atlantic region, southeastern New York state, and southern New England. Below-normal precipitation is favored for parts of the northwestern CONUS, and from eastern sections of Utah and Arizona eastward across Colorado, New Mexico, and much of West Texas. For the remaining areas of the CONUS and Alaska, where seasonal total precipitation amounts are favored to be similar to climatological probabilities, EC is forecast. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS Note: For Graphical Displays of the Forecast Tools Discussed Below See: http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS El Niño is fading rapidly as equatorial Pacific sea surface temperatures (SSTs) continue to cool, associated with upwelling from an oceanic Kelvin wave. The most recent weekly value of the Niño3.4 SST index is a surprisingly high +0.9 degrees C, which is a bit misleading given the very shallow layer of subsurface warmth underlying this area. Relatively cold water (departures ranging from -0.5 degrees C to at least -6 degrees C) is in place from the surface between 120W and 100W longitude, extending westward and deepening across most of the equatorial Pacific, reaching a depth of 150 to 300 meters at 150E longitude (the approximate longitude of the Solomon Islands and Coral Sea). Tropical convection is now slightly suppressed across the vicinity of the Date Line and the equator, and close to average over Indonesia. These anomalies, in addition to the return of low-level easterly wind anomalies to the west-central Pacific Ocean are indicative of the underlying transition from El Niño to ENSO-neutral. As of mid-April 2024, above-normal soil moisture is present in many areas of the CONUS – including many areas west of the Continental Divide, the north-central Plains, from the southern Great Lakes eastward across the Northeast and Mid-Atlantic region, and from the vicinity of the Texas-Oklahoma Panhandles east-southeastward across the Arklatex region and Gulf Coast states. Drier than normal soils are evident over northern North Dakota, northwestern Minnesota, in the vicinity of the Washington Cascades rain shadow and Northern Rockies, and across much of New Mexico and southwestern Texas. Drier than normal soils are also indicated in a wishbone-shaped pattern that extends from the Upper Great Lakes region southwestward across Iowa, southeastern Nebraska, and Kansas, which then largely reverses direction and continues eastward across the Middle Mississippi, southern Ohio, and Tennessee Valleys. Soil moisture anomalies are an important consideration for the Seasonal Outlooks through the warm half of the year. PROGNOSTIC DISCUSSION OF SST FORECASTS Forecasts of the Niño 3.4 SST index from the North American Multi-Model Ensemble (NMME) are generally in good agreement for a nominal La Niña (Oceanic Niño Index or ONI <=-0.5 degrees C) by June. Most participant model predictions are slightly cooler than the NMME average, with the exceptions of the GFDL SPEAR and Canadian CanCM4i models. The former does not reach the La Niña threshold until mid-August. The International Multi-Model Ensemble (IMME, C3S, or Copernicus) average reaches the La Niña threshold by August. Three of the participant models (German DWD, ECMWF, and METEO-France) stay within the confines of ENSO-neutral limits at least into September, while the UKMO and CMCC are considerably cooler and reach marginal La Niña conditions by late May into June. The CFS is the coldest of solutions, exceeding the minimal La Niña threshold even before MJJ, and predicts a strong La Niña (ONI>=-1.5 degrees C) by July-August-September (JAS) 2024. CPC’s SST Consolidation for the Niño 3.4 region passes into La Niña territory by JJA, peaks during the overlapping seasons of September-October-November (SON) and October-November-December (OND) at -1.4 degrees C (just short of a strong cold event), and then retreats into Neutral territory by March-April-May (MAM) 2025. As noted earlier, CPC’s ENSO Team predicts the transition from El Niño to ENSO-neutral should be completed within the AMJ season (85% chance), with the odds of La Niña developing by JJA (60% chance). Historically, La Niña tends to follow strong El Niño events, adding confidence to the forecast. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS Though some remaining El Niño atmospheric response could extend into the very early stages of the MJJ Outlook, it is unlikely to make a significant difference for the season as a whole. Dynamical model forecasts from the NMME and C3S multi-model ensemble systems are utilized, as is the Calibration, Bridging and Merging (CBaM) tool anchored to the NMME forecasts and “bridged” with the Niño 3.4 index – primarily for temperature outlooks. The Constructed Analog (CA) statistical tools based on SST and soil moisture, along with the ENSO-OCN forecast tool that targets impacts from ENSO as predicted by the CPC consolidation Niño 3.4 SST forecast and long-term trends, played a large role in many of the outlooks. La Niña impacts are considered in the outlooks from JJA 2024 through February-March-April (FMA) 2025. PROGNOSTIC DISCUSSION OF OUTLOOKS - MJJ 2024 TO MJJ 2025 TEMPERATURE The MJJ 2024 seasonal temperature outlook favors above-normal seasonal mean temperatures for central and eastern Alaska, the far west excluding southwestern California, and most of the remainder of the CONUS with the exception of the north-central states. Maximum probabilities (>50%) favoring above-normal temperatures are indicated over far eastern Alaska, parts of the Northwest, the eastern Great Lakes and Northeast, and over New Mexico, southwestern Texas, and southern Florida. For southwestern California, near-normal seasonal mean temperatures are favored. The reduced coverage (from last month’s Lead 2 MJJ outlook) of 50%+ probability favoring above-normal temperatures over the Northwest is related to anticipated diminished influences from lagged El Niño impacts, slightly cooler effects of wet soils (through evaporation) over southern Oregon and southern Idaho, and trends. In southwestern California, favored near-normal temperatures is thought to be the best compromise given NMME and C3S SST regional forecasts of near to below-normal in this region extending southward along Baja, during the MJJ season. Near the coast of Southern California, this may be associated with prolonged or more frequent marine layer intrusions, a well-known climatological feature in this region. Across the central portion of the CONUS, anomalous warmth is favored to replace the southern part of the EC region (from last month’s MJJ Outlook), and is favored by statistical and dynamical model guidance. The recent very heavy rainfall (8-10+ inches) and severe weather over the Ark-La-Tex region and Lower Mississippi Valley is the reason behind the slightly lower odds favoring above-normal temperatures in that area. Model guidance and trends (as shown by the OCN tool) favor relative maxima in probabilities for above-normal temperatures across New Mexico and southwestern Texas, and from the eastern Great Lakes region to the Northeast and Mid-Atlantic coasts. Most tools support above-normal temperatures across the Southeast. To the north, the outlook for Alaska is based on a subjective consensus of model guidance, temperature trends, and anticipated residual influences from sea ice. For JJA and JAS 2024, the favored above-normal temperatures in central and eastern Alaska from the preceding MJJ outlook are expected to decrease in coverage and gradually become concentrated over the far northern part of the state. In JJA, favored below-normal temperatures are depicted over the southwest portion of the Mainland and the adjacent Alaska Peninsula, spreading eastward across the southern coast with time. This is partly due to the anticipated emerging effects of La Niña, and supported by the ENSO-OCN tool and the Statistical Consolidation (Stat-CON). For the CONUS, probabilities favoring above-normal temperatures exceed 50% for most of the interior West and south-central states, warranted by the ENSO-OCN, Stat-CON, Dynamical Consolidation (NMME-CON), and a skill-weighted mean of the two CON tools (the Final CON). This is also consistent with most other tools, such as the CBaM tool, the IMME, and longer-term trends. The favored area of EC in the vicinity of the Dakotas in JJA gradually gives way to favored above-normal temperatures in JAS 2024, consistent with emerging influences of La Niña. The three CON tools and trends favor elevated probabilities for above-normal temperatures in the vicinity of the Northeast CONUS. In August-September-October (ASO), the probabilities favoring above-normal temperatures begin to decline over the Pacific Northwest, in preparation for the typical La Niña impacts that set up during boreal autumn and winter. During SON through November-December-January (NDJ) 2024, the temperature outlooks favor a canonical La Niña response, with above-normal temperatures in the Northwest and north-central CONUS giving way to EC, and to below-normal temperatures across the Pacific Northwest by NDJ. Above-normal temperatures are depicted across much of the southern and eastern CONUS, also consistent with a cold event. During this period, SON through NDJ 2024, ENSO composites gradually begin to favor a replacement of the below-normal temperatures across southern Alaska to EC, and the expansion of favored anomalous warmth across northern and western Alaska. SON is the most likely season for high probabilities (>60%) for favored above-normal temperatures across the northwestern coast of Alaska due to the seasonally delayed onset of sea ice formation. From December-January-February (DJF) 2024-25 through MAM 2025, La Niña composites are primarily used in conjunction with model guidance. For the final two leads, AMJ and MJJ 2025, temperature trends are heavily utilized. For remaining areas of the CONUS and Alaska, EC favored. PRECIPITATION The MJJ 2024 seasonal precipitation outlook favors above-normal seasonal total precipitation amounts for approximately the western half of Alaska, and from the southeastern quarter of the CONUS northeastward across the Mid-Atlantic region, southeastern New York state, and southern New England. These anomalies are generally consistent with NMME & C3S multi-model ensemble guidance, CFS, and trends. Below-normal precipitation is favored for parts of the northwestern CONUS, mostly from ENSO-OCN and the last vestiges of lagged El Niño influences. Anomalous dryness is favored from much of the Four Corners region to West Texas. This is consistent with the three CON tools, CFS, C3S, NMME, and to some extent, the SST Constructed Analog (SST-CA) statistical tool. There is also a significant negative correlation between this strong dry signal over the eastern Monsoon region and abundant snowpack over the Central Rockies (Colorado and Utah). Historically, this correlation favors a slow start to, and potential underperformance of, the Southwest Monsoon. For the remaining areas of the CONUS and Alaska, where seasonal total precipitation amounts are favored to be similar to climatological probabilities, EC is forecast. From JJA and JAS 2024, widespread above-normal precipitation is favored in Alaska, consistent with NMME guidance. Afterwards, there is a slight tilt in the odds towards below-normal precipitation for Southeast Alaska for SON through NDJ 2024. From SON 2024 to MAM 2025, the main climate driver/forcing is the anticipated La Niña, which favors an enhanced storm track and above-normal precipitation amounts across the northwestern states, and also (starting with DJF 2024-25) over the Great Lakes and Ohio/Tennessee Valleys. Enhanced dryness and below-normal precipitation amounts are favored across much of the southern CONUS and Eastern Seaboard. For the last two leads, April-May-June (AMJ) and MJJ 2025, the seasonal precipitation outlooks are largely based on trends. FORECASTER: Anthony Artusa The Climatic normals are based on conditions between 1991 and 2020, following the World Meteorological Organization convention of using the most recent 3 complete decades as the climatic reference period. The probability anomalies for temperature and precipitation based on these new normals better represent shorter term climatic anomalies than the forecasts based on older normals. For a description of of the standard forecast tools - their skill- and the forecast format please see our web page at http://www.cpc.ncep.noaa.gov/products/predictions/long_range/tools.html (Use Lower Case Letters) Information on the formation of skill of the CAS forecasts may be found at: http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/Outlook/outlook.shtm l (use lowercase letters) Notes - These climate outlooks are intended for use prior to the start of their valid period. Within any given valid period observations and short and medium range forecasts should be consulted. This set of outlooks will be superseded by the issuance of the new set next month on May 16, 2024 1991-2020 base period means were implemented effective with the May 20, 2021 forecast release. $$ ####018006762#### FXUS07 KWBC 181250 PMD30D FXUS07 KWBC 181948 PMD30D Prognostic Discussion for Monthly Outlook NWS Climate Prediction Center College Park MD 830 AM EST Thu Apr 18 2024 30-DAY OUTLOOK DISCUSSION FOR MAY 2024 El Niño conditions are currently observed, and equatorial sea surface temperatures (SSTs) are above average across the much of the central and eastern equatorial Pacific Ocean, reaching 0.9 degrees Celsius above normal in the Niño3.4 region, 0.6 degrees Celsius above normal in the Niño3 region, but have decreased to -0.2 degrees Celsius below normal in the Niño1+2 region. Above average SSTs have weakened across most of the equatorial Pacific Ocean in the last 4 weeks, and tropical Pacific atmospheric anomalies are weakening as well. Given the weakening signals in the equatorial Pacific, a transition from El Niño to El Niño Southern Oscillation (ENSO)-neutral conditions is likely by April-May-June 2024. The Madden Julian Oscillation (MJO) has continued to weaken recently and though there has been eastward propagation in the past week, the amplitude has dropped. Dynamical model forecasts of the Realtime Multivariate MJO (RMM) index through close to the end of April are weak and incoherent due to an emerging low-frequency feature over the western Indian Ocean which appears to be interfering with the MJO. While we may see some lingering impacts to temperature and precipitation due to El Niño, the influence is expected to weaken throughout the next few months. Moreover, the weak amplitude of the MJO does not support much of a teleconnection response over the Contiguous United States (CONUS). As such, the May 2024 Temperature and Precipitation Outlooks are mainly supported by the lingering influence of El Niño, local SST anomalies, influence of soil moisture anomalies, dynamical model guidance from the North American Multi-Model Ensemble (NMME), Copernicus model suite (C3S), and the Climate Forecast System version 2 (CFSv2), as well as statistical models that include the influence of trend and ENSO. The Week 3-4 Outlook for the early part of May was also considered, as was the expected evolution from the Week 2 forecast period. The May 2024 Temperature Outlook favors above normal temperatures over the Northwest, much of the eastern half of the CONUS, and southeastern Alaska. A relatively small region of near normal temperatures is indicated over parts of California, Arizona, Nevada, and Utah. The highest probabilities of above normal temperatures, 50 to 60 percent, are located over Washington, the Great Lakes, northern New England, southeastern New Mexico and parts of southwestern Texas, the southern tip of Florida, and southeastern Alaska. Probabilities are enhanced over these regions given good consistency among tools on above normal probabilities. Decadal trends also support above normal probabilities over the northwest and northern New England. Anomalously warm Great Lakes temperatures provide additional support for above normal probabilities over the region. Lower than normal soil moisture along with forecasted below normal rainfall in dynamical models, and strong probabilities for above normal temperatures in recent CFSv2 forecasts of May temperatures adds to confidence over the Southwest. Signals were more mixed over western Alaska given cooler SST anomalies and sea ice, but NMME and C3S favor a transition to warmer temperatures over the southeast part of the state. Near normal and equal chances of above, near and below normal temperatures (EC) are indicated over southern California and the Four Corners where there are observed coastal below normal to neutral SSTs, near normal temperature forecasts from NMME and C3S, and a below normal CFSv2 temperature forecast. While tools tilt toward above normal temperatures over the Gulf States (particularly coastal regions), partially supported by warmer Gulf of Mexico SSTs, high amounts of recent rainfall over eastern Texas and Louisiana have resulted in high soil moisture, and as such probabilities are still above normal but damped. EC is favored where models were inconsistent and/or where there was a lack of support from statistical tools. There is more uncertainty in the May 2024 Precipitation Outlook than the Temperature Outlook, as evidenced by lower overall probabilities and larger areas of EC. Models favor above normal precipitation over parts of the central and southern CONUS, including parts of the Mid-Atlantic, Middle Mississippi and Ohio Valley regions. Some lingering influence from El Niño further supports the tilt toward above normal precipitation over the Southeast, as well as enhanced soil moisture. Though El Niño can lead to below normal precipitation over the Great Lakes, Middle Mississippi Valley, and Ohio Valley, this influence is overshadowed by above normal precipitation trend. EC is indicated over the Great Lakes where models had weak or inconsistent signals and trend and El Niño influence are opposite. However, over the Mississippi and Ohio Valley regions C3S and NMME favored above normal rainfall and thus a weak tilt toward above normal is indicated. Dynamical models and dry soil moisture led to the favored probability of below normal precipitation over parts of the southwest, which is also indicated in the Seasonal Outlook for May-July 2024. However, this is at odds with the recent Weeks 3-4 Precipitation Outlook for early May that tilted weakly toward above median precipitation. We expect below normal precipitation over the region by mid- to late- May. Tools were again mixed over the northwest, but influences from El Niño and trend tilt the odds toward below normal. Finally, over Alaska, above normal precipitation is favored over the southwest where there has been recent above normal precipitation, with a weak tilt toward below normal precipitation over southeastern Alaska due to expected influence from El Niño. FORECASTER: Johnna Infanti The climatic normals are based on conditions between 1991 and 2020, following the World Meteorological Organization convention of using the most recent 3 complete decades as the climate reference period. The probability anomalies for temperature and precipitation based on these new normals better represent shorter term climatic anomalies than the forecasts based on older normals. An updated monthly outlook... for May will be issued on Tue Apr 30 2024 These outlooks are based on departures from the 1991-2020 base period. $$ ####018009095#### FXHW40 KWBC 181252 PMDHCO FXHW40 KWBC 181251 PMDHCo Prognostic Discussion for Long-Lead Hawaiian Outlooks NWS Climate Prediction Center College Park MD 830AM EST Thu Apr 18 2024 MONTHLY FORECAST DISCUSSION VALID APRIL 2024 Sea surface temperature (SST) anomalies were near-average over the Hawaiian islands (Kauai, Oahu, Maui and the Big Island) during the previous week, with slightly negative SST anomalies near the southeastern islands including the Big Island. For January through March 2024, rainfall total accumulations were: -Lihue Airport 4.41 inches (37 percent of normal) -Honolulu Airport 3.17 inches (52 percent of normal) -Kahului Airport 6.70 inches (95 percent of normal) -Hilo Airport 24.78 inches (81 percent of normal) The NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) predict below average SSTs around the southeastern islands including the Big Island through May 2024 and near average SSTs near northwestern islands. Based primarily on these SST forecasts, surface temperatures are also favored to be below normal for the Big Island, while Equal Chances (EC) for above, near or below normal temperatures are forecast for Maui, Kauai and Oahu in May 2024. For the May 2024 precipitation outlook, below normal precipitation chances are elevated for all of the island chain, as indicated by most dynamical model forecasts, and consistent with El Niño conditions over the tropical Pacific. TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV Hilo B40 72.6 0.7 B55 7.4 8.9 11.2 Kahului EC 74.1 0.6 B55 0.5 0.9 1.3 Honolulu EC 76.3 0.5 B50 0.3 0.5 0.7 Lihue EC 74.0 0.6 B50 1.6 1.9 2.8 SEASONAL FORECAST DISCUSSION VALID MJJ 2024 - MJJ 2025 Refer to the prognostic discussion of the long-lead seasonal outlooks for the CONUS and Alaska for a description of the ENSO outlook and other climate conditions relevant to the seasonal outlook. El Niño conditions are observed over the tropical Pacific Ocean. Equatorial sea surface temperatures (SSTs) are above average across the central and east-central Pacific Ocean. Positive subsurface temperature anomalies have weakened across the equatorial Pacific but remain close to the surface in the central Pacific. Negative subsurface temperature anomalies expanded across the equatorial Pacific and below-average temperatures have reached the surface in the far eastern Pacific Ocean. Low-level (850-hPa) wind anomalies were easterly over a small region in the west-central tropical Pacific Ocean, while upper-level wind anomalies (200-hPa) were near average over most of the equatorial Pacific. Convection and precipitation were near average in the central and eastern equatorial Pacific, and slightly suppressed around the Philippines and Malaysia. While atmospheric and oceanic conditions over the tropical Pacific are generally consistent with El Niño conditions, atmospheric anomalies are weakening. There is a 85% chance of transition from El Niño to ENSO-neutral during April-June 2024, with about a 60% chance of La Niña developing in June-August 2024. Enhanced probabilities for above normal temperatures are forecast for Kauai, Oahu and Maui and Equal Chances (EC) for above, near or below normal temperatures are forecast for the Big Island in MJJ (May-June-July) 2024, consistent with most dynamical model forecasts from the NMME. Enhanced probabilities for above normal temperatures are forecast for the Big Island, Kauai, Oahu and Maui in JJA (June-July-August) 2024 through ASO (August-September-October) 2023, consistent with the NMME forecast. The forecast signal weakens at longer leads, therefore EC is indicated for Hawaii beginning in SON (September-October-November) 2024 and extending through all longer leads thereafter. Enhanced probabilities for below normal precipitation are forecast over the Hawaiian Islands (Kauai, Oahu, Maui and the Big Island) from MJJ 2024 to SON 2024, consistent with most dynamical and statistical model forecasts. Due to considerable uncertainty in the precipitation forecasts from dynamical and statistical models, EC is indicated over the Hawaiian Islands beginning in OND (October-November-December) 2024 through longer leads. Hilo TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 EC 74.0 0.4 B60 20.2 27.5 29.1 JJA 2024 A40 75.2 0.4 B60 19.4 27.2 31.4 JAS 2024 A40 76.1 0.4 B50 25.2 28.6 33.4 ASO 2024 A40 76.4 0.4 B45 26.1 28.8 33.3 SON 2024 EC 76.2 0.4 B40 24.3 30.2 40.8 OND 2024 EC 75.5 0.4 EC 28.3 34.5 42.0 NDJ 2024 EC 74.2 0.4 EC 26.4 36.6 43.0 DJF 2025 EC 72.8 0.4 EC 19.6 30.2 33.3 JFM 2025 EC 71.8 0.4 EC 22.0 32.0 44.5 FMA 2025 EC 71.7 0.4 EC 24.6 34.1 45.5 MAM 2025 EC 72.0 0.5 EC 22.5 28.4 34.0 AMJ 2025 EC 72.9 0.5 EC 21.4 23.7 29.0 MJJ 2024 EC 74.0 0.4 EC 20.2 27.5 29.1 Kahului TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 EC 76.0 0.5 B60 0.7 1.1 1.8 JJA 2024 A40 77.7 0.4 B55 0.7 1.1 1.5 JAS 2024 A45 79.0 0.4 B50 0.8 1.1 1.6 ASO 2024 A45 79.4 0.4 B45 0.8 1.6 2.5 SON 2024 EC 79.1 0.4 B40 2.1 3.3 4.8 OND 2024 EC 77.8 0.4 EC 4.2 5.3 8.1 NDJ 2024 EC 75.9 0.4 EC 5.2 7.6 9.5 DJF 2025 EC 73.8 0.4 EC 4.6 6.9 8.7 JFM 2025 EC 72.5 0.4 EC 4.2 6.2 8.2 FMA 2025 EC 72.3 0.4 EC 3.2 4.1 6.4 MAM 2025 EC 73.0 0.4 EC 2.5 3.5 4.6 AMJ 2025 EC 74.3 0.5 EC 1.2 1.6 2.2 MJJ 2024 EC 76.0 0.5 EC 0.7 1.1 1.8 Honolulu TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 EC 78.2 0.4 B50 0.8 1.4 1.6 JJA 2024 A40 79.9 0.4 B50 0.7 0.8 1.3 JAS 2024 A45 81.3 0.4 B45 1.0 1.4 1.7 ASO 2024 A45 81.7 0.4 B45 1.6 2.4 3.1 SON 2024 EC 81.4 0.4 B40 2.5 4.0 5.6 OND 2024 EC 80.0 0.4 EC 4.4 6.4 8.5 NDJ 2024 EC 77.7 0.5 EC 3.9 5.6 8.8 DJF 2025 EC 75.3 0.5 EC 3.7 5.6 8.6 JFM 2025 EC 73.9 0.4 EC 2.1 4.6 7.8 FMA 2025 EC 73.8 0.4 EC 1.9 3.2 4.7 MAM 2025 EC 74.8 0.4 EC 1.8 2.6 3.0 AMJ 2025 EC 76.3 0.4 EC 1.2 1.6 1.8 MJJ 2024 EC 78.2 0.4 EC 0.8 1.4 1.6 Lihue TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 A40 76.0 0.5 B50 4.9 5.4 5.9 JJA 2024 A40 77.7 0.4 B50 4.4 5.3 6.9 JAS 2024 A45 79.0 0.3 B45 5.3 6.1 7.8 ASO 2024 A45 79.4 0.3 B40 6.2 7.9 8.4 SON 2024 EC 79.1 0.3 B40 9.2 10.0 11.2 OND 2024 EC 77.8 0.3 EC 9.2 11.7 15.6 NDJ 2024 EC 75.7 0.3 EC 8.6 12.1 16.9 DJF 2025 EC 73.6 0.4 EC 7.5 8.4 14.0 JFM 2025 EC 72.2 0.4 EC 6.5 8.8 13.8 FMA 2025 EC 72.1 0.5 EC 5.8 8.4 9.9 MAM 2025 EC 72.8 0.5 EC 5.3 6.6 8.0 AMJ 2025 EC 74.2 0.5 EC 4.7 5.5 6.0 MJJ 2024 EC 76.0 0.5 EC 4.9 5.4 5.9 FORECASTER: Dan Collins Anomalies are based on the 1991-2020 means. CLARIFICATION: EC indicated equal chances that the predicted parameter will fall into any one of the three categories, whose boundaries are specific in the tables above. A forecast specification of EC means there is no particulate tilt of the odds toward above normal or below normal conditions in the outlook. For example A40 means a 40% chance that the average temperature or total precipitation will be in the above normal class, B40 means a 40% chance that the average temperature or total precipitation will be in the below normal class, and N35 means a 35% probability that the average temperature or total precipitation will be in the near normal class. When EC is specified, all categories are equally likely. NOTE - These outlooks are intended for use prior to the start of the valid periods. Within any valid period, observations and shorter range forecasts should be consulted. Also, this set of outlooks will be superseded by the issuances of the new set next month, on Thu May 16, 2024. $$ ####018015765#### FXUS05 KWBC 181252 PMD90D Prognostic Discussion for Long-Lead Seasonal Outlooks NWS Climate Prediction Center College Park MD 830 AM EDT Thu Apr 18 2024 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS During mid-April 2024, an El Niño Advisory remains in effect but the oceanic temperature anomalies associated with El Niño are rapidly fading. There is an 85% chance that ENSO neutral will be in place by the end of the April-May-June (AMJ) season. There is a 60% chance of additional transitioning of the ENSO phase from ENSO Neutral to La Niña by summer (June-July-August, JJA), with La Niña conditions favored to strengthen and continue through boreal autumn and winter. Therefore, a La Niña Watch has also been issued. The May-June-July (MJJ) 2024 temperature outlook favors above-normal seasonal mean temperatures for central and eastern Alaska, the far West excluding southwestern California, and most of the remainder of the Contiguous U.S. (CONUS) with the exception of the north-central states. Maximum probabilities (>50%) favoring above-normal temperatures are indicated over eastern Alaska, parts of the Northwest, the eastern Great Lakes and Northeast, and over New Mexico, southwestern Texas, and southern Florida. For southwestern California, near-normal seasonal mean temperatures are favored. For remaining areas of the CONUS and Alaska, Equal Chances (EC) of below, near, and above-normal seasonal mean temperatures are favored. No areas of favored below-normal temperatures are forecast for the MJJ season. The MJJ 2024 precipitation outlook favors above-normal seasonal total precipitation amounts for approximately the western half of Alaska, and from the southeastern quarter of the CONUS northeastward across the Mid-Atlantic region, southeastern New York state, and southern New England. Below-normal precipitation is favored for parts of the northwestern CONUS, and from eastern sections of Utah and Arizona eastward across Colorado, New Mexico, and much of West Texas. For the remaining areas of the CONUS and Alaska, where seasonal total precipitation amounts are favored to be similar to climatological probabilities, EC is forecast. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS Note: For Graphical Displays of the Forecast Tools Discussed Below See: http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS El Niño is fading rapidly as equatorial Pacific sea surface temperatures (SSTs) continue to cool, associated with upwelling from an oceanic Kelvin wave. The most recent weekly value of the Niño3.4 SST index is a surprisingly high +0.9 degrees C, which is a bit misleading given the very shallow layer of subsurface warmth underlying this area. Relatively cold water (departures ranging from -0.5 degrees C to at least -6 degrees C) is in place from the surface between 120W and 100W longitude, extending westward and deepening across most of the equatorial Pacific, reaching a depth of 150 to 300 meters at 150E longitude (the approximate longitude of the Solomon Islands and Coral Sea). Tropical convection is now slightly suppressed across the vicinity of the Date Line and the equator, and close to average over Indonesia. These anomalies, in addition to the return of low-level easterly wind anomalies to the west-central Pacific Ocean are indicative of the underlying transition from El Niño to ENSO-neutral. As of mid-April 2024, above-normal soil moisture is present in many areas of the CONUS – including many areas west of the Continental Divide, the north-central Plains, from the southern Great Lakes eastward across the Northeast and Mid-Atlantic region, and from the vicinity of the Texas-Oklahoma Panhandles east-southeastward across the Arklatex region and Gulf Coast states. Drier than normal soils are evident over northern North Dakota, northwestern Minnesota, in the vicinity of the Washington Cascades rain shadow and Northern Rockies, and across much of New Mexico and southwestern Texas. Drier than normal soils are also indicated in a wishbone-shaped pattern that extends from the Upper Great Lakes region southwestward across Iowa, southeastern Nebraska, and Kansas, which then largely reverses direction and continues eastward across the Middle Mississippi, southern Ohio, and Tennessee Valleys. Soil moisture anomalies are an important consideration for the Seasonal Outlooks through the warm half of the year. PROGNOSTIC DISCUSSION OF SST FORECASTS Forecasts of the Niño 3.4 SST index from the North American Multi-Model Ensemble (NMME) are generally in good agreement for a nominal La Niña (Oceanic Niño Index or ONI <=-0.5 degrees C) by June. Most participant model predictions are slightly cooler than the NMME average, with the exceptions of the GFDL SPEAR and Canadian CanCM4i models. The former does not reach the La Niña threshold until mid-August. The International Multi-Model Ensemble (IMME, C3S, or Copernicus) average reaches the La Niña threshold by August. Three of the participant models (German DWD, ECMWF, and METEO-France) stay within the confines of ENSO-neutral limits at least into September, while the UKMO and CMCC are considerably cooler and reach marginal La Niña conditions by late May into June. The CFS is the coldest of solutions, exceeding the minimal La Niña threshold even before MJJ, and predicts a strong La Niña (ONI>=-1.5 degrees C) by July-August-September (JAS) 2024. CPC’s SST Consolidation for the Niño 3.4 region passes into La Niña territory by JJA, peaks during the overlapping seasons of September-October-November (SON) and October-November-December (OND) at -1.4 degrees C (just short of a strong cold event), and then retreats into Neutral territory by March-April-May (MAM) 2025. As noted earlier, CPC’s ENSO Team predicts the transition from El Niño to ENSO-neutral should be completed within the AMJ season (85% chance), with the odds of La Niña developing by JJA (60% chance). Historically, La Niña tends to follow strong El Niño events, adding confidence to the forecast. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS Though some remaining El Niño atmospheric response could extend into the very early stages of the MJJ Outlook, it is unlikely to make a significant difference for the season as a whole. Dynamical model forecasts from the NMME and C3S multi-model ensemble systems are utilized, as is the Calibration, Bridging and Merging (CBaM) tool anchored to the NMME forecasts and “bridged” with the Niño 3.4 index – primarily for temperature outlooks. The Constructed Analog (CA) statistical tools based on SST and soil moisture, along with the ENSO-OCN forecast tool that targets impacts from ENSO as predicted by the CPC consolidation Niño 3.4 SST forecast and long-term trends, played a large role in many of the outlooks. La Niña impacts are considered in the outlooks from JJA 2024 through February-March-April (FMA) 2025. PROGNOSTIC DISCUSSION OF OUTLOOKS - MJJ 2024 TO MJJ 2025 TEMPERATURE The MJJ 2024 seasonal temperature outlook favors above-normal seasonal mean temperatures for central and eastern Alaska, the far west excluding southwestern California, and most of the remainder of the CONUS with the exception of the north-central states. Maximum probabilities (>50%) favoring above-normal temperatures are indicated over far eastern Alaska, parts of the Northwest, the eastern Great Lakes and Northeast, and over New Mexico, southwestern Texas, and southern Florida. For southwestern California, near-normal seasonal mean temperatures are favored. The reduced coverage (from last month’s Lead 2 MJJ outlook) of 50%+ probability favoring above-normal temperatures over the Northwest is related to anticipated diminished influences from lagged El Niño impacts, slightly cooler effects of wet soils (through evaporation) over southern Oregon and southern Idaho, and trends. In southwestern California, favored near-normal temperatures is thought to be the best compromise given NMME and C3S SST regional forecasts of near to below-normal in this region extending southward along Baja, during the MJJ season. Near the coast of Southern California, this may be associated with prolonged or more frequent marine layer intrusions, a well-known climatological feature in this region. Across the central portion of the CONUS, anomalous warmth is favored to replace the southern part of the EC region (from last month’s MJJ Outlook), and is favored by statistical and dynamical model guidance. The recent very heavy rainfall (8-10+ inches) and severe weather over the Ark-La-Tex region and Lower Mississippi Valley is the reason behind the slightly lower odds favoring above-normal temperatures in that area. Model guidance and trends (as shown by the OCN tool) favor relative maxima in probabilities for above-normal temperatures across New Mexico and southwestern Texas, and from the eastern Great Lakes region to the Northeast and Mid-Atlantic coasts. Most tools support above-normal temperatures across the Southeast. To the north, the outlook for Alaska is based on a subjective consensus of model guidance, temperature trends, and anticipated residual influences from sea ice. For JJA and JAS 2024, the favored above-normal temperatures in central and eastern Alaska from the preceding MJJ outlook are expected to decrease in coverage and gradually become concentrated over the far northern part of the state. In JJA, favored below-normal temperatures are depicted over the southwest portion of the Mainland and the adjacent Alaska Peninsula, spreading eastward across the southern coast with time. This is partly due to the anticipated emerging effects of La Niña, and supported by the ENSO-OCN tool and the Statistical Consolidation (Stat-CON). For the CONUS, probabilities favoring above-normal temperatures exceed 50% for most of the interior West and south-central states, warranted by the ENSO-OCN, Stat-CON, Dynamical Consolidation (NMME-CON), and a skill-weighted mean of the two CON tools (the Final CON). This is also consistent with most other tools, such as the CBaM tool, the IMME, and longer-term trends. The favored area of EC in the vicinity of the Dakotas in JJA gradually gives way to favored above-normal temperatures in JAS 2024, consistent with emerging influences of La Niña. The three CON tools and trends favor elevated probabilities for above-normal temperatures in the vicinity of the Northeast CONUS. In August-September-October (ASO), the probabilities favoring above-normal temperatures begin to decline over the Pacific Northwest, in preparation for the typical La Niña impacts that set up during boreal autumn and winter. During SON through November-December-January (NDJ) 2024, the temperature outlooks favor a canonical La Niña response, with above-normal temperatures in the Northwest and north-central CONUS giving way to EC, and to below-normal temperatures across the Pacific Northwest by NDJ. Above-normal temperatures are depicted across much of the southern and eastern CONUS, also consistent with a cold event. During this period, SON through NDJ 2024, ENSO composites gradually begin to favor a replacement of the below-normal temperatures across southern Alaska to EC, and the expansion of favored anomalous warmth across northern and western Alaska. SON is the most likely season for high probabilities (>60%) for favored above-normal temperatures across the northwestern coast of Alaska due to the seasonally delayed onset of sea ice formation. From December-January-February (DJF) 2024-25 through MAM 2025, La Niña composites are primarily used in conjunction with model guidance. For the final two leads, AMJ and MJJ 2025, temperature trends are heavily utilized. For remaining areas of the CONUS and Alaska, EC favored. PRECIPITATION The MJJ 2024 seasonal precipitation outlook favors above-normal seasonal total precipitation amounts for approximately the western half of Alaska, and from the southeastern quarter of the CONUS northeastward across the Mid-Atlantic region, southeastern New York state, and southern New England. These anomalies are generally consistent with NMME & C3S multi-model ensemble guidance, CFS, and trends. Below-normal precipitation is favored for parts of the northwestern CONUS, mostly from ENSO-OCN and the last vestiges of lagged El Niño influences. Anomalous dryness is favored from much of the Four Corners region to West Texas. This is consistent with the three CON tools, CFS, C3S, NMME, and to some extent, the SST Constructed Analog (SST-CA) statistical tool. There is also a significant negative correlation between this strong dry signal over the eastern Monsoon region and abundant snowpack over the Central Rockies (Colorado and Utah). Historically, this correlation favors a slow start to, and potential underperformance of, the Southwest Monsoon. For the remaining areas of the CONUS and Alaska, where seasonal total precipitation amounts are favored to be similar to climatological probabilities, EC is forecast. From JJA and JAS 2024, widespread above-normal precipitation is favored in Alaska, consistent with NMME guidance. Afterwards, there is a slight tilt in the odds towards below-normal precipitation for Southeast Alaska for SON through NDJ 2024. From SON 2024 to MAM 2025, the main climate driver/forcing is the anticipated La Niña, which favors an enhanced storm track and above-normal precipitation amounts across the northwestern states, and also (starting with DJF 2024-25) over the Great Lakes and Ohio/Tennessee Valleys. Enhanced dryness and below-normal precipitation amounts are favored across much of the southern CONUS and Eastern Seaboard. For the last two leads, April-May-June (AMJ) and MJJ 2025, the seasonal precipitation outlooks are largely based on trends. FORECASTER: Anthony Artusa The Climatic normals are based on conditions between 1991 and 2020, following the World Meteorological Organization convention of using the most recent 3 complete decades as the climatic reference period. The probability anomalies for temperature and precipitation based on these new normals better represent shorter term climatic anomalies than the forecasts based on older normals. For a description of of the standard forecast tools - their skill- and the forecast format please see our web page at http://www.cpc.ncep.noaa.gov/products/predictions/long_range/tools.html (Use Lower Case Letters) Information on the formation of skill of the CAS forecasts may be found at: http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/Outlook/outlook.shtm l (use lowercase letters) Notes - These climate outlooks are intended for use prior to the start of their valid period. Within any given valid period observations and short and medium range forecasts should be consulted. This set of outlooks will be superseded by the issuance of the new set next month on May 16, 2024 1991-2020 base period means were implemented effective with the May 20, 2021 forecast release. $$ ####018006732#### FXUS07 KWBC 181252 PMD30D Prognostic Discussion for Monthly Outlook NWS Climate Prediction Center College Park MD 830 AM EST Thu Apr 18 2024 30-DAY OUTLOOK DISCUSSION FOR MAY 2024 El Niño conditions are currently observed, and equatorial sea surface temperatures (SSTs) are above average across the much of the central and eastern equatorial Pacific Ocean, reaching 0.9 degrees Celsius above normal in the Niño3.4 region, 0.6 degrees Celsius above normal in the Niño3 region, but have decreased to -0.2 degrees Celsius below normal in the Niño1+2 region. Above average SSTs have weakened across most of the equatorial Pacific Ocean in the last 4 weeks, and tropical Pacific atmospheric anomalies are weakening as well. Given the weakening signals in the equatorial Pacific, a transition from El Niño to El Niño Southern Oscillation (ENSO)-neutral conditions is likely by April-May-June 2024. The Madden Julian Oscillation (MJO) has continued to weaken recently and though there has been eastward propagation in the past week, the amplitude has dropped. Dynamical model forecasts of the Realtime Multivariate MJO (RMM) index through close to the end of April are weak and incoherent due to an emerging low-frequency feature over the western Indian Ocean which appears to be interfering with the MJO. While we may see some lingering impacts to temperature and precipitation due to El Niño, the influence is expected to weaken throughout the next few months. Moreover, the weak amplitude of the MJO does not support much of a teleconnection response over the Contiguous United States (CONUS). As such, the May 2024 Temperature and Precipitation Outlooks are mainly supported by the lingering influence of El Niño, local SST anomalies, influence of soil moisture anomalies, dynamical model guidance from the North American Multi-Model Ensemble (NMME), Copernicus model suite (C3S), and the Climate Forecast System version 2 (CFSv2), as well as statistical models that include the influence of trend and ENSO. The Week 3-4 Outlook for the early part of May was also considered, as was the expected evolution from the Week 2 forecast period. The May 2024 Temperature Outlook favors above normal temperatures over the Northwest, much of the eastern half of the CONUS, and southeastern Alaska. A relatively small region of near normal temperatures is indicated over parts of California, Arizona, Nevada, and Utah. The highest probabilities of above normal temperatures, 50 to 60 percent, are located over Washington, the Great Lakes, northern New England, southeastern New Mexico and parts of southwestern Texas, the southern tip of Florida, and southeastern Alaska. Probabilities are enhanced over these regions given good consistency among tools on above normal probabilities. Decadal trends also support above normal probabilities over the northwest and northern New England. Anomalously warm Great Lakes temperatures provide additional support for above normal probabilities over the region. Lower than normal soil moisture along with forecasted below normal rainfall in dynamical models, and strong probabilities for above normal temperatures in recent CFSv2 forecasts of May temperatures adds to confidence over the Southwest. Signals were more mixed over western Alaska given cooler SST anomalies and sea ice, but NMME and C3S favor a transition to warmer temperatures over the southeast part of the state. Near normal and equal chances of above, near and below normal temperatures (EC) are indicated over southern California and the Four Corners where there are observed coastal below normal to neutral SSTs, near normal temperature forecasts from NMME and C3S, and a below normal CFSv2 temperature forecast. While tools tilt toward above normal temperatures over the Gulf States (particularly coastal regions), partially supported by warmer Gulf of Mexico SSTs, high amounts of recent rainfall over eastern Texas and Louisiana have resulted in high soil moisture, and as such probabilities are still above normal but damped. EC is favored where models were inconsistent and/or where there was a lack of support from statistical tools. There is more uncertainty in the May 2024 Precipitation Outlook than the Temperature Outlook, as evidenced by lower overall probabilities and larger areas of EC. Models favor above normal precipitation over parts of the central and southern CONUS, including parts of the Mid-Atlantic, Middle Mississippi and Ohio Valley regions. Some lingering influence from El Niño further supports the tilt toward above normal precipitation over the Southeast, as well as enhanced soil moisture. Though El Niño can lead to below normal precipitation over the Great Lakes, Middle Mississippi Valley, and Ohio Valley, this influence is overshadowed by above normal precipitation trend. EC is indicated over the Great Lakes where models had weak or inconsistent signals and trend and El Niño influence are opposite. However, over the Mississippi and Ohio Valley regions C3S and NMME favored above normal rainfall and thus a weak tilt toward above normal is indicated. Dynamical models and dry soil moisture led to the favored probability of below normal precipitation over parts of the southwest, which is also indicated in the Seasonal Outlook for May-July 2024. However, this is at odds with the recent Weeks 3-4 Precipitation Outlook for early May that tilted weakly toward above median precipitation. We expect below normal precipitation over the region by mid- to late- May. Tools were again mixed over the northwest, but influences from El Niño and trend tilt the odds toward below normal. Finally, over Alaska, above normal precipitation is favored over the southwest where there has been recent above normal precipitation, with a weak tilt toward below normal precipitation over southeastern Alaska due to expected influence from El Niño. FORECASTER: Johnna Infanti The climatic normals are based on conditions between 1991 and 2020, following the World Meteorological Organization convention of using the most recent 3 complete decades as the climate reference period. The probability anomalies for temperature and precipitation based on these new normals better represent shorter term climatic anomalies than the forecasts based on older normals. An updated monthly outlook... for May will be issued on Tue Apr 30 2024 These outlooks are based on departures from the 1991-2020 base period. $$ ####018009065#### FXHW40 KWBC 181252 PMDHCO Prognostic Discussion for Long-Lead Hawaiian Outlooks NWS Climate Prediction Center College Park MD 830AM EST Thu Apr 18 2024 MONTHLY FORECAST DISCUSSION VALID APRIL 2024 Sea surface temperature (SST) anomalies were near-average over the Hawaiian islands (Kauai, Oahu, Maui and the Big Island) during the previous week, with slightly negative SST anomalies near the southeastern islands including the Big Island. For January through March 2024, rainfall total accumulations were: -Lihue Airport 4.41 inches (37 percent of normal) -Honolulu Airport 3.17 inches (52 percent of normal) -Kahului Airport 6.70 inches (95 percent of normal) -Hilo Airport 24.78 inches (81 percent of normal) The NCEP Climate Forecast System (CFS) and other climate models of the North American Multi-Model Ensemble (NMME) predict below average SSTs around the southeastern islands including the Big Island through May 2024 and near average SSTs near northwestern islands. Based primarily on these SST forecasts, surface temperatures are also favored to be below normal for the Big Island, while Equal Chances (EC) for above, near or below normal temperatures are forecast for Maui, Kauai and Oahu in May 2024. For the May 2024 precipitation outlook, below normal precipitation chances are elevated for all of the island chain, as indicated by most dynamical model forecasts, and consistent with El Niño conditions over the tropical Pacific. TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV Hilo B40 72.6 0.7 B55 7.4 8.9 11.2 Kahului EC 74.1 0.6 B55 0.5 0.9 1.3 Honolulu EC 76.3 0.5 B50 0.3 0.5 0.7 Lihue EC 74.0 0.6 B50 1.6 1.9 2.8 SEASONAL FORECAST DISCUSSION VALID MJJ 2024 - MJJ 2025 Refer to the prognostic discussion of the long-lead seasonal outlooks for the CONUS and Alaska for a description of the ENSO outlook and other climate conditions relevant to the seasonal outlook. El Niño conditions are observed over the tropical Pacific Ocean. Equatorial sea surface temperatures (SSTs) are above average across the central and east-central Pacific Ocean. Positive subsurface temperature anomalies have weakened across the equatorial Pacific but remain close to the surface in the central Pacific. Negative subsurface temperature anomalies expanded across the equatorial Pacific and below-average temperatures have reached the surface in the far eastern Pacific Ocean. Low-level (850-hPa) wind anomalies were easterly over a small region in the west-central tropical Pacific Ocean, while upper-level wind anomalies (200-hPa) were near average over most of the equatorial Pacific. Convection and precipitation were near average in the central and eastern equatorial Pacific, and slightly suppressed around the Philippines and Malaysia. While atmospheric and oceanic conditions over the tropical Pacific are generally consistent with El Niño conditions, atmospheric anomalies are weakening. There is a 85% chance of transition from El Niño to ENSO-neutral during April-June 2024, with about a 60% chance of La Niña developing in June-August 2024. Enhanced probabilities for above normal temperatures are forecast for Kauai, Oahu and Maui and Equal Chances (EC) for above, near or below normal temperatures are forecast for the Big Island in MJJ (May-June-July) 2024, consistent with most dynamical model forecasts from the NMME. Enhanced probabilities for above normal temperatures are forecast for the Big Island, Kauai, Oahu and Maui in JJA (June-July-August) 2024 through ASO (August-September-October) 2023, consistent with the NMME forecast. The forecast signal weakens at longer leads, therefore EC is indicated for Hawaii beginning in SON (September-October-November) 2024 and extending through all longer leads thereafter. Enhanced probabilities for below normal precipitation are forecast over the Hawaiian Islands (Kauai, Oahu, Maui and the Big Island) from MJJ 2024 to SON 2024, consistent with most dynamical and statistical model forecasts. Due to considerable uncertainty in the precipitation forecasts from dynamical and statistical models, EC is indicated over the Hawaiian Islands beginning in OND (October-November-December) 2024 through longer leads. Hilo TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 EC 74.0 0.4 B60 20.2 27.5 29.1 JJA 2024 A40 75.2 0.4 B60 19.4 27.2 31.4 JAS 2024 A40 76.1 0.4 B50 25.2 28.6 33.4 ASO 2024 A40 76.4 0.4 B45 26.1 28.8 33.3 SON 2024 EC 76.2 0.4 B40 24.3 30.2 40.8 OND 2024 EC 75.5 0.4 EC 28.3 34.5 42.0 NDJ 2024 EC 74.2 0.4 EC 26.4 36.6 43.0 DJF 2025 EC 72.8 0.4 EC 19.6 30.2 33.3 JFM 2025 EC 71.8 0.4 EC 22.0 32.0 44.5 FMA 2025 EC 71.7 0.4 EC 24.6 34.1 45.5 MAM 2025 EC 72.0 0.5 EC 22.5 28.4 34.0 AMJ 2025 EC 72.9 0.5 EC 21.4 23.7 29.0 MJJ 2024 EC 74.0 0.4 EC 20.2 27.5 29.1 Kahului TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 EC 76.0 0.5 B60 0.7 1.1 1.8 JJA 2024 A40 77.7 0.4 B55 0.7 1.1 1.5 JAS 2024 A45 79.0 0.4 B50 0.8 1.1 1.6 ASO 2024 A45 79.4 0.4 B45 0.8 1.6 2.5 SON 2024 EC 79.1 0.4 B40 2.1 3.3 4.8 OND 2024 EC 77.8 0.4 EC 4.2 5.3 8.1 NDJ 2024 EC 75.9 0.4 EC 5.2 7.6 9.5 DJF 2025 EC 73.8 0.4 EC 4.6 6.9 8.7 JFM 2025 EC 72.5 0.4 EC 4.2 6.2 8.2 FMA 2025 EC 72.3 0.4 EC 3.2 4.1 6.4 MAM 2025 EC 73.0 0.4 EC 2.5 3.5 4.6 AMJ 2025 EC 74.3 0.5 EC 1.2 1.6 2.2 MJJ 2024 EC 76.0 0.5 EC 0.7 1.1 1.8 Honolulu TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 EC 78.2 0.4 B50 0.8 1.4 1.6 JJA 2024 A40 79.9 0.4 B50 0.7 0.8 1.3 JAS 2024 A45 81.3 0.4 B45 1.0 1.4 1.7 ASO 2024 A45 81.7 0.4 B45 1.6 2.4 3.1 SON 2024 EC 81.4 0.4 B40 2.5 4.0 5.6 OND 2024 EC 80.0 0.4 EC 4.4 6.4 8.5 NDJ 2024 EC 77.7 0.5 EC 3.9 5.6 8.8 DJF 2025 EC 75.3 0.5 EC 3.7 5.6 8.6 JFM 2025 EC 73.9 0.4 EC 2.1 4.6 7.8 FMA 2025 EC 73.8 0.4 EC 1.9 3.2 4.7 MAM 2025 EC 74.8 0.4 EC 1.8 2.6 3.0 AMJ 2025 EC 76.3 0.4 EC 1.2 1.6 1.8 MJJ 2024 EC 78.2 0.4 EC 0.8 1.4 1.6 Lihue TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV MJJ 2024 A40 76.0 0.5 B50 4.9 5.4 5.9 JJA 2024 A40 77.7 0.4 B50 4.4 5.3 6.9 JAS 2024 A45 79.0 0.3 B45 5.3 6.1 7.8 ASO 2024 A45 79.4 0.3 B40 6.2 7.9 8.4 SON 2024 EC 79.1 0.3 B40 9.2 10.0 11.2 OND 2024 EC 77.8 0.3 EC 9.2 11.7 15.6 NDJ 2024 EC 75.7 0.3 EC 8.6 12.1 16.9 DJF 2025 EC 73.6 0.4 EC 7.5 8.4 14.0 JFM 2025 EC 72.2 0.4 EC 6.5 8.8 13.8 FMA 2025 EC 72.1 0.5 EC 5.8 8.4 9.9 MAM 2025 EC 72.8 0.5 EC 5.3 6.6 8.0 AMJ 2025 EC 74.2 0.5 EC 4.7 5.5 6.0 MJJ 2024 EC 76.0 0.5 EC 4.9 5.4 5.9 FORECASTER: Dan Collins Anomalies are based on the 1991-2020 means. CLARIFICATION: EC indicated equal chances that the predicted parameter will fall into any one of the three categories, whose boundaries are specific in the tables above. A forecast specification of EC means there is no particulate tilt of the odds toward above normal or below normal conditions in the outlook. For example A40 means a 40% chance that the average temperature or total precipitation will be in the above normal class, B40 means a 40% chance that the average temperature or total precipitation will be in the below normal class, and N35 means a 35% probability that the average temperature or total precipitation will be in the near normal class. When EC is specified, all categories are equally likely. NOTE - These outlooks are intended for use prior to the start of the valid periods. Within any valid period, observations and shorter range forecasts should be consulted. Also, this set of outlooks will be superseded by the issuances of the new set next month, on Thu May 16, 2024. $$