####018007527#### FXUS06 KWBC 191924 PMDMRD PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 300 PM UTC FRI APR 19 2024 A transient 500-hPa height pattern is forecast across North America during the 6-10 day period. At the outset of the period, troughing and negative height anomalies are predicted across eastern Canada and extending into the Great Lakes and Northeast. Amplified ridging is forecast to shift eastward across the CONUS with troughing developing near the West Coast in its wake. The pattern across Alaska is predicted to quickly transition from enhanced ridging and positive height anomalies at the outset of the period to more influence from troughing over the Bering Sea and Arctic. Near- to above-normal heights are predicted across Hawaii due to increased ridging over the central Pacific. Models are in good agreement regarding near- to below-normal temperatures across much of the western CONUS during the period, consistent with decreasing mid-level heights and increasing troughing in the region. Today’s forecast depicts enhanced probabilities for below-normal temperatures over much of the Northeast and Mid-Atlantic for the period as a whole, along with increased chances for above-normal temperatures across the interior western and central CONUS, and Southeast. Ridging and above-normal 500-hPa heights across Mainland Alaska and Southeast Alaska favor increased chances for above-normal temperatures across southern Mainland Alaska and Southeast Alaska. Elevated probabilities for below-normal temperatures are forecast for the western Aleutians and the northern state, and supported by GEFS temperature reforecast tool. Near-normal temperatures are predicted across the Hawaiian Islands. Return flow around surface high pressure favors increasing precipitation chances across parts of the central and eastern CONUS, except for the eastern seaboard where near- to below-normal precipitation is indicated. Above-normal precipitation probabilities are increased over much of the West due to troughing forecast to develop near the West Coast. Increased southerly flow across Alaska ahead of a developing troughing over the Bering Sea favors enhanced chances for near- to above-normal precipitation across the state. Near- to below-normal precipitation chances are elevated across Hawaii due to increasing ridging over the central Pacific. FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: 3 out of 5, Average, due to general agreement in the models regarding the mid-level pattern evolution, offset by lack of forecast tools due to IT outage. The 500-hPa height pattern during week-2 is forecast to continue to depict amplified ridging and positive 500-hPa height anomalies continuing to expand across the eastern CONUS. Troughs are predicted across the western CONUS and the Aleutians, while ridging and above-normal 500-hPa heights are forecast over Mainland Alaska and Southeast Alaska. Ridging and above-normal 500-hPa heights are forecast over Hawaii. The prevailing mid-level height pattern across the CONUS favors an anomalously warm pattern across much of the CONUS east of the Rockies during week-2. The highest probabilities for above-normal temperatures (greater than 70 percent) are across parts of the south-central CONUS. Near- to below-normal temperatures are favored along the West Coast, Great Basin, and Southwest due to more troughing. Decreasing mid-level heights favor elevated probabilities for below-normal temperatures across portions of northern Mainland Alaska and the Aleutians, with above-normal temperature remaining favored downstream across the southeastern Mainland and Southeast Alaska. Increased chances for near-normal temperatures remain forecast across Hawaii. The trend toward relatively lower mid-level heights across the western CONUS favors increasing chances for above-normal precipitation across a large portion of the CONUS, aided in part by increased southerly return flow over the central CONUS. This pattern sets the stage for multiple episodes of precipitation as ejecting shortwave disturbances promote a favorable environment for enhanced precipitation across much of the region, Below-normal precipitation is likely over northern and central California as well as southern Florida, consistent with the GEFS reforecast precipitation tool. Probabilities for near- to above-normal precipitation remain elevated across Alaska. Near- to below-normal precipitation is favored across Hawaii. FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: 3 out of 5, Average, due to good model agreement regarding amplified ridging across the central CONUS and a subsequent warmer pattern, offset by lack of forecast tools due to IT outage. FORECASTER: Luke He NOTES: AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES. IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT ISSUED. THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS THE SAME AS THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER (ORANGE, "A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N") HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST (DASHES, "F"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY (> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS ALWAYS < 40%. THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WETTER (GREEN, "A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N") HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST (DASHES, "INCHES"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY (> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS ALWAYS < 40%. IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY SEASONS. IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A FORECAST OF LITTLE OR NO PRECIPITATION. THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN THE CLIMATE OUTLOOKS. ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3) FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES: 19621210 - 19851219 - 19601221 - 19561127 - 19531214 ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4) FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES: 19601223 - 19561127 - 19621211 - 20021124 - 19851218 6 TO 10 DAY OUTLOOK TABLE OUTLOOK FOR APR 25 - 29, 2024 8 TO 14 DAY OUTLOOK TABLE OUTLOOK FOR APR 27 - MAY 03, 2024 THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE. FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 - ON AFOS AS NFDPMDMRD. $$