550
FXUS02 KWNH 210759
PREEPD
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
359 AM EDT TUE OCT 21 2025
VALID 12Z FRI OCT 24 2025 - 12Z TUE OCT 28 2025
***HEAVY RAIN AND STRONG STORMS BECOMING MORE LIKELY FOR THE
SOUTHERN PLAINS LATE THIS WEEK***
..GENERAL OVERVIEW
THE LARGE SYNOPTIC SCALE TROUGH THAT WILL BE IN PLACE ACROSS THE
GREAT LAKES AND NORTHEAST THROUGH MID-WEEK WILL BE LIFTING OUT
ACROSS EASTERN CANADA BY FRIDAY. A SOUTHERN STREAM SHORTWAVE
CROSSING FROM THE ROCKIES TO THE CENTRAL/SOUTHERN PLAINS WILL
SUPPORT A SURFACE LOW AND WARM FRONT WITH PLENTY OF MOISTURE FROM
KANSAS TO THE ARKLATEX REGION, WITH NUMEROUS SHOWERS AND STORMS.
OUT WEST, A PATTERN CHANGE WILL TAKE PLACE GOING INTO THE WEEKEND
AS AN UPPER TROUGH AMPLIFIES OVER THE REGION AND LEADS TO COLDER
WEATHER AND WIDESPREAD MOUNTAIN SNOW. THIS SAME TROUGH IS EXPECTED
TO SPUR SURFACE CYCLOGENESIS OVER THE CENTRAL/NORTHERN PLAINS BY
EARLY NEXT WEEK WITH ADDITIONAL SHOWERS AND STORMS EXPECTED.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE IS IN GOOD OVERALL AGREEMENT ACROSS
THE CONTINENTAL U.S. FOR THE BEGINNING OF THE PERIOD FRIDAY, AND
THIS ALSO HOLDS TRUE GOING INTO SATURDAY, WITH MAINLY MINOR
MESOSCALE DIFFERENCES, SO A MULTI-DETERMINISTIC MODEL BLEND WAS
USED THROUGH SATURDAY NIGHT. OVERALL, THERE HAS BEEN A SLIGHTLY
SLOWER TREND WITH THE SOUTHERN STREAM SHORTWAVE THAT SPURS SURFACE
CYCLOGENESIS OVER TEXAS AND OKLAHOMA LATE THIS WEEK, AND ALSO A
STRONGER TREND IN THE GUIDANCE OVERALL WITH THIS LOW AS IT REACHES
THE MID-SOUTH THIS WEEKEND. THE SHORTWAVE EJECTING FROM THE ROCKIES
TO THE CENTRAL PLAINS HAS ALSO TRENDED A LITTLE STRONGER IN THE
MODEL GUIDANCE OVER THE PAST FEW CYCLES BY EARLY NEXT WEEK. THERE
IS A GROWING SIGNAL OVERALL FOR A CLOSED UPPER LOW OVER THE MIDWEST
BY TUESDAY, WITH DIFFERENCES IN PLACEMENT. IN TERMS OF QPF, AMOUNTS
HAVE TRENDED DOWN SOME ACROSS THE PACIFIC NORTHWEST AND UP FOR THE
CENTRAL GULF COAST REGION, ALTHOUGH THE NBM IS LIKELY A LITTLE TOO
HIGH WITH COVERAGE OF HIGHER QPF ACROSS THE ARKLATEX REGION, SO
THIS WAS REDUCED A LITTLE UNTIL THE OVERALL MODEL SIGNAL BECOMES
MORE REFINED IN FUTURE FORECASTS. THE ENSEMBLE MEANS WERE INCREASED
TO ABOUT HALF BY NEXT TUESDAY.
..WEATHER/HAZARDS HIGHLIGHTS
THE SURFACE LOW THAT IS FORECAST TO EVOLVE OVER KANSAS AND OKLAHOMA
LATER THIS WEEK, ALONG WITH STRONG WARM AIR ADVECTION AND
INCREASING INSTABILITY, WILL LIKELY FUEL THE DEVELOPMENT OF
WIDESPREAD SHOWERS AND THUNDERSTORMS, SOME OF WHICH WILL BE STRONG
AND SLOW MOVING. THERE WILL LIKELY BE PATCHY QPF MAXIMA ON THE
ORDER OF 2 TO 4 INCHES FROM EASTERN OKLAHOMA TO CENTRAL LOUISIANA
THROUGH SATURDAY, AND HIGHER RAINFALL RATES WITH THE STORMS THAT
DEVELOP COULD LEAD TO SOME INSTANCES OF FLASH FLOODING. THEREFORE
A SLIGHT RISK AREA IS VALID ON FRIDAY ACROSS PORTIONS OF CENTRAL
OKLAHOMA INTO NORTH-CENTRAL TEXAS WHERE THE MODEL SIGNAL IS
GREATEST FOR INSTABILITY AND QPF. RAIN AND MOUNTAIN SNOW ALSO
INCREASES FROM NORTHERN CALIFORNIA TO WESTERN WASHINGTON GOING
INTO
FRIDAY AND THE WEEKEND, AND A MARGINAL RISK OF EXCESSIVE RAIN WILL
BE VALID FROM NEAR EUREKA, CA TO THE COASTAL RANGES AND THE
CASCADES OF WASHINGTON AS AN ATMOSPHERIC RIVER ADVECTS COPIOUS
MOISTURE INLAND.
ELSEWHERE ACROSS THE NATION, LAKE ENHANCED SHOWERS FROM MICHIGAN TO
UPSTATE NEW YEAR WILL BE PREVALENT AS COLDER AIR ALOFT MOVES ACROSS
THE WARMER LAKE WATERS LATE THIS WEEK, BUT LIKELY TOO WARM FOR ANY
SNOW THIS TIME. BY THE WEEKEND, WIDESPREAD SNOW DEVELOPS ACROSS
THE HIGHER TERRAIN OF THE INTERMOUNTAIN WEST AND THE
CENTRAL/NORTHERN ROCKIES AS MULTIPLE SHORTWAVES PASS THROUGH THE
AMPLIFYING UPPER TROUGH, WITH OVER A FOOT OF ACCUMULATION POSSIBLE
FOR THE HIGHER RANGES. A NEW SURFACE LOW IS LIKELY TO DEVELOP BY
MONDAY ACROSS THE CENTRAL/NORTHERN PLAINS AS A POTENT SHORTWAVE
EJECTS EASTWARD FROM THE ROCKIES, SUPPORTING AN INCREASE IN
SHOWERS/STORMS AND GUSTY WINDS FROM THE DAKOTAS TO MISSOURI.
WARM TO HOT CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE SOUTHERN
PLAINS THROUGH THE WEEKEND WITH HIGHS RUNNING ABOUT 5 TO 15
DEGREES ABOVE AVERAGE, EQUATING TO READINGS TOPPING OUT FROM THE
MIDDLE 80S TO MIDDLE 90S. IT SHOULD ALSO BE RATHER MILD FOR THIS
TIME OF YEAR ACROSS THE DAKOTAS THROUGH SATURDAY WITH THE UPPER
RIDGE IN PLACE. MUCH COLDER WEATHER MAKES ITS ARRIVAL FOR THE WEST
COAST AND INTO THE INTERMOUNTAIN WEST BY THE WEEKEND AS THE UPPER
TROUGH BUILDS IN ALONG WITH WIDESPREAD CLOUD COVER. TEMPERATURES
SHOULD BE NEAR TO SLIGHTLY BELOW AVERAGE FOR MOST OF THE EAST COAST
STATES.
HAMRICK
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page