####018005534#### FXUS02 KWBC 141900 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EDT Sun Apr 14 2024 Valid 12Z Wed Apr 17 2024 - 12Z Sun Apr 21 2024 ...Overview... A low pressure system exiting the Upper Midwest/Great Lakes early in the period will continue to bring a threat for at least locally heavy rainfall to parts of the Great Lakes/Ohio Valley Wednesday into Thursday. Behind this, another upper trough/low will skirt the northern tier states but fight with a southern stream ridge to determine how far south it may reach across the Ohio Valley to Northeast late this week. At least a brief period of upper ridging looks to build over the Northwest by next weekend ahead of another amplified trough across the northern Pacific and the overall pattern across the CONUS turns more zonal/relatively quiet. ...Guidance/Predictability Assessment... Model guidance remains reasonably agreeable on the large scale pattern through the period, but still some differences in the smaller scale details and timing of systems. As the first Midwest- Great Lakes low exits, the second broader upper low across south- central to southeastern Canada shows variations especially with troughing along its periphery. There are some timing inconsistencies with the surface front swinging through the East and its associated generally light precipitation as shortwave energy may swing through the Ohio Valley/Northeast during the latter part of the week. Farther south than the Ohio Valley/Northeast, models seem to be gradually trending toward less amplification of the trough, favoring more southern stream ridging. On the western side of the upper low center, there is uncertainty with how much energy is held back across the Northwest. GFS runs have shown more energy there while the non-NCEP camp has more ridging across the Northwest Friday-Saturday. The latter was favored. Then upstream energy also shows model variations especially by Sunday with potentially additional energy coming into the Northwest. The WPC forecast maintained a multi-model deterministic blend early in the period, and increased the proportion of the GEFS and EC ensemble means to over half while phasing out the GFS in particular by late period. ...Weather/Hazards Highlights... Precipitation will be ongoing from the Upper Midwest into the Ohio Valley associated with a deep low (both at the surface and in the upper levels) moving through the Upper Midwest on Wednesday. Given ample moisture and instability and a low threat for locally heavy rainfall, a broad Marginal Risk remains in place for the Day 4 Excessive Rainfall Outlook (Wednesday-Thursday morning) for portions of the Great Lakes and Ohio Valley. The Storm Prediction Center is also watching severe potential near the Ohio River on Wednesday. Gusty winds are possible for the Great Lakes region as well as behind the low in the Rockies and the north-central Plains. The next upper trough right on its heels could bring some notable snow to mainly the higher elevations of the northern/central Rockies midweek. As systems progress, rain and convection are forecast to move into the eastern U.S. into late week, while lingering across the south-central U.S. as the frontal system stalls briefly. Then renewed moisture into Texas in particular ahead of weak shortwave energy sliding into the Southwest could create some enhanced rainfall totals there into the weekend, while some rain could extend across the Southeast while the Northeast dries out. Expect a broad area of above normal temperatures by 5-15 degrees over the southern half of the country Wednesday-Thursday, while the northeastern quadrant of the U.S. gradually cools behind a cold front. Meanwhile the upper trough across the northern tier states will bring below normal temperatures (with greater anomalies for highs than lows) starting in the northern Rockies/Plains midweek. Cooler temperatures gradually expand farther south and east behind the secondary cold front late week into the weekend, with near to below average temperatures expected to reach everywhere but Florida by next weekend. Meanwhile, above normal temperatures across the Southwest should gradually expand northward underneath a building Western U.S. ridge. Tate/Santorelli Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$ ####018006026#### FXUS06 KWBC 141903 PMDMRD Prognostic Discussions for 6 to 10 and 8 to 14 day outlooks. NWS Climate Prediction Center, College Park, MD 300 PM EDT Sun April 14 2024 There is no forecaster message written on weekends. 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 1991-2020 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: 20020327 - 19610417 - 20080412 - 20020420 - 19860415 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: 20010402 - 20080412 - 20020326 - 19610419 - 20020422 6 TO 10 DAY OUTLOOK TABLE Outlook for Apr 20 - 24, 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A B SRN CALIF A B IDAHO A B NEVADA A B W MONTANA A B E MONTANA N B WYOMING A B UTAH A B ARIZONA A B COLORADO A A NEW MEXICO A A N DAKOTA N B S DAKOTA N B NEBRASKA B N KANSAS B N OKLAHOMA B A N TEXAS B A S TEXAS B A W TEXAS B A MINNESOTA N B IOWA B B MISSOURI B N ARKANSAS B N LOUISIANA B A WISCONSIN B B ILLINOIS B B MISSISSIPPI B A MICHIGAN B B INDIANA B B OHIO B B KENTUCKY B B TENNESSEE B N ALABAMA B N NEW YORK B B VERMONT B N NEW HAMP B N MAINE B N MASS B N CONN B N RHODE IS B N PENN B B NEW JERSEY B N W VIRGINIA B B MARYLAND B N DELAWARE B N VIRGINIA B N N CAROLINA B N S CAROLINA B A GEORGIA A A FL PNHDL A A FL PENIN A N AK N SLOPE B A AK ALEUTIAN B N AK WESTERN B A AK INT BSN N A AK S INT N A AK SO COAST N A AK PNHDL A A 8 TO 14 DAY OUTLOOK TABLE Outlook for Apr 22 - 28, 2024 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A A OREGON A A NRN CALIF N A SRN CALIF N A IDAHO A A NEVADA A A W MONTANA A A E MONTANA A A WYOMING A A UTAH A A ARIZONA A A COLORADO A A NEW MEXICO A A N DAKOTA A A S DAKOTA A A NEBRASKA A A KANSAS A A OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA A A IOWA A A MISSOURI A N ARKANSAS A N LOUISIANA A N WISCONSIN A A ILLINOIS A N MISSISSIPPI A N MICHIGAN A N INDIANA A N OHIO N N KENTUCKY A N TENNESSEE A N ALABAMA A N NEW YORK N B VERMONT N B NEW HAMP B B MAINE N B MASS B B CONN B B RHODE IS B B PENN N B NEW JERSEY B B W VIRGINIA N B MARYLAND B B DELAWARE B B VIRGINIA N B N CAROLINA N N S CAROLINA N N GEORGIA N N FL PNHDL A N FL PENIN A A AK N SLOPE B A AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A AK S INT B A AK SO COAST B A AK PNHDL B A LEGEND TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN B - BELOW B - BELOW 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. $$