440
FXUS02 KWBC 221941
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
341 PM EDT WED OCT 22 2025
VALID 12Z SAT OCT 25 2025 - 12Z WED OCT 29 2025
...HEAVY RAIN FORECAST FROM THE SOUTHERN PLAINS TO THE LOWER
MISSISSIPPI VALLEY THIS WEEKEND...
..GENERAL OVERVIEW
A SPLIT UPPER LEVEL FLOW PATTERN WILL BE IN PLACE ACROSS THE
CONTINENTAL U.S. FOR THIS UPCOMING WEEK, WITH A SOUTHERN STREAM
SHORTWAVE/CLOSED LOW BRINGING HEAVY RAIN AND STRONG THUNDERSTORMS
TO THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. MEANWHILE, AN
AMPLIFYING UPPER TROUGH OVER THE WESTERN U.S. WILL HERALD A
PATTERN CHANGE ACROSS THE REGION THIS WEEKEND, WITH COLDER
CONDITIONS AND WIDESPREAD PRECIPITATION CHANCES, SNOW FOR THE
HIGHER TERRAIN AND MODERATE TO HEAVY RAIN FOR THE COAST AND LOW
ELEVATIONS. THIS TROUGH WILL LIKELY PUSH A FRONTAL SYSTEM ACROSS
THE WEST AND INTO THE PLAINS, WHICH SHOULD BRING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS TO THE CENTRAL U.S. EARLY NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS REMAIN IN FAIRLY GOOD AGREEMENT ON THE OVERALL PATTERN
ACROSS THE U.S. THIS WEEKEND, BUT THERE IS SIGNIFICANT SPREAD AND
UNCERTAINTY IN THE FORECAST FOR EARLY NEXT WEEK. MODELS HAVE BEEN
STRUGGLING TO RESOLVE INTERACTIONS BETWEEN NORTHERN AND SOUTHERN
STREAM FEATURES, WHICH WILL ULTIMATELY AFFECT THE EVOLUTION OF
SURFACE FRONTAL SYSTEMS AND SENSIBLE WEATHER.
FOR WPC'S AFTERNOON FORECAST, A NEAR EVEN BLEND OF THE AVAILABLE
DETERMINISTIC MODELS WAS USED THROUGH THE WEEKEND. FOR EARLY NEXT
WEEK, ENSEMBLE MEANS WERE ADDED IN INCREASING AMOUNTS TO HELP
SMOOTH OUT DIFFERENCES AMONG THE DETERMINISTIC MODEL RUNS. SOME
INFLUENCE FROM THE DETERMINISTIC MODEL SOLUTIONS FROM THE
ECMWF/GFS/CMC WAS RETAINED TO MAINTAIN DETAIL IN INDIVIDUAL
SYSTEMS, BUT THE FORECAST TRENDED CLOSELY TOWARDS THE ENSEMBLE MEAN
SOLUTIONS GIVEN HIGH UNCERTAINTY. THIS BLEND MAINTAINED GOOD
CONTINUITY WITH THE PREVIOUS FORECAST.
..WEATHER/HAZARDS HIGHLIGHTS
A LOW PRESSURE SYSTEM IS FORECAST TO MOVE EAST ACROSS THE SOUTHERN
PLAINS AND LOWER MISSISSIPPI VALLEY THIS WEEKEND, WHICH WILL BRING
STRONG WARM AIR ADVECTION AND INCREASING INSTABILITY TO THESE
REGIONS. WIDESPREAD SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS
SYSTEM, AND HEAVY RAINFALL IS EXPECTED. THE CURRENT FORECAST CALLS
FOR RAINFALL TOTALS OF 2-4 INCHES, WITH LOCALLY HIGHER AMOUNTS
POSSIBLE, FOR EASTERN TEXAS AND LOUISIANA. THIS AMOUNT OF RAINFALL
COULD RESULT IN SCATTERED INSTANCES OF FLASH FLOODING FRIDAY INTO
SATURDAY, WHICH IS REPRESENTED BY A SLIGHT RISK OF EXCESSIVE
RAINFALL IN THE EXCESSIVE RAINFALL OUTLOOK. IN ADDITION TO HEAVY
RAINFALL, SOME THUNDERSTORMS MAY BE STRONG TO SEVERE.
ON SUNDAY, THE LOW PRESSURE SYSTEM WILL BE WEAKENING WHILE
CONTINUING TO MOVE EAST. THE INGREDIENTS SHOULD STILL BE IN PLACE
FOR SHOWERS AND THUNDERSTORMS TO PRODUCE LOCALLY HEAVY RAINFALL
FROM THE CENTRAL GULF COAST THROUGH MISSISSIPPI AND ALABAMA AND
INTO WESTERN TENNESSEE. GIVEN THIS POTENTIAL, ISOLATED INSTANCES OF
FLASH FLOODING MAY BE POSSIBLE, AND THERE IS A MARGINAL RISK OF
EXCESSIVE RAINFALL IN EFFECT FOR THESE AREAS.
OUT WEST, AN AMPLIFYING UPPER TROUGH WILL DIRECT AN ATMOSPHERIC
RIVER AT THE PACIFIC NORTHWEST THIS WEEKEND. STEADY MODERATE TO
OCCASIONALLY HEAVY RAIN IS EXPECTED ALONG THE COAST AND OVER LOW
ELEVATION AREAS, WHICH COULD RESULT IN ISOLATED INSTANCES OF FLASH
FLOODING. A MARGINAL RISK OF EXCESSIVE RAINFALL REMAINS IN EFFECT
FOR THIS AREA ON SATURDAY. IN ADDITION TO HEAVY PRECIPITATION, THIS
PACIFIC SYSTEM WILL LIKELY BRING ELEVATED WINDS AND WAVES TO
COASTAL WASHINGTON AND OREGON FRIDAY AND SATURDAY. BY SUNDAY,
PRECIPITATION RATES SHOULD DECREASE AS THE SURFACE FRONTAL SYSTEM
PUSHES INLAND. AS MOISTURE SPREADS INLAND OVER THE WEEKEND,
PRECIPITATION WILL FALL AS SNOW IN THE HIGHER ELEVATIONS OF THE
CASCADES AND NORTHERN ROCKIES, AND 1 TO 2 FEET OF SNOW IS BECOMING
MORE LIKELY FOR THE HIGHER RANGES.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED ACROSS THE
CENTRAL U.S. EARLY NEXT WEEK AS THE FRONTAL SYSTEM MOVING ACROSS
THE WEST EMERGES IN THE PLAINS, WITH THE POTENTIAL TO SPAWN A NEW
LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS. AS THE POTENTIAL LOW
DEVELOPS, IT MAY SUPPORT GUSTY WINDS ACROSS THE NORTHERN AND
CENTRAL PLAINS.
THE PATTERN CHANGE COMING OUT WEST WILL RESULT IN COLDER WEATHER
ACROSS THE NORTHWEST THROUGH MONDAY. HIGHS ARE EXPECTED TO BE 5 TO
15 DEGREES BELOW AVERAGE, PERHAPS LOCALLY MORE, BUT OVERNIGHT LOWS
SHOULD BE CLOSER TO AVERAGE OWING TO INCREASED CLOUD COVER AND
PRECIPITATION. LATE SEASON WARMTH IS EXPECTED FOR MUCH OF THE
CENTRAL U.S. THIS WEEKEND INTO EARLY NEXT WEEK THANKS TO BROAD
SOUTHERLY FLOW AHEAD OF THE AMPLIFYING TROUGH, BUT TEMPERATURES
SHOULD COOL DOWN MID-NEXT WEEK. THE EAST COAST REGION WILL
GENERALLY BE SLIGHTLY BELOW AVERAGE FOR BOTH HIGHS AND LOWS THROUGH
MOST OF THE FORECAST PERIOD.
DOLAN/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
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