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FOUS30 KWBC 222002
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
402 PM EDT WED OCT 22 2025
DAY 1
VALID 16Z WED OCT 22 2025 - 12Z THU OCT 23 2025
..16Z UPDATE
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE IS LESS
THAN 5 PERCENT.
WEGMAN
DAY 2
VALID 12Z THU OCT 23 2025 - 12Z FRI OCT 24 2025
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN PLAINS...
..SOUTHERN PLAINS
HEAVY SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP AND EJECT
EAST OUT ACROSS PORTIONS OF WEST-CENTRAL AND NORTHWEST TX BY
THURSDAY EVENING AS THE GRADUAL ARRIVAL OF AN UPSTREAM UPPER-
TROUGH/CLOSED LOW OVER THE SOUTHWEST BEGINS TO INTERACT WITH DEEPER
LAYER AND INCREASINGLY MOIST/UNSTABLE SOUTHERLY FLOW ACROSS THE
RIO GRANDE VALLEY AND TOWARD THE RED RIVER VALLEY. DIVERGENT FLOW
ALOFT, INCREASING LOW TO MID-LEVEL SHEAR, AND MUCAPE VALUES OF 1000
TO 2000+ J/KG WILL FACILITATE BROKEN AREAS OF SEMI-ORGANIZED
CONVECTION THAT WILL BE CAPABLE OF PRODUCING RAINFALL RATES OF UP
TO 1 TO 2 INCHES/HOUR. THE GREATER CONCENTRATIONS OF CONVECTION
THOUGH WILL LIKELY BE THURSDAY NIGHT AND FRIDAY MORNING INTO
PORTIONS OF THE RED RIVER VALLEY INCLUDING NORTHWEST TO NORTH-
CENTRAL TX AND SOUTHWEST OK WHERE STRONGER LOW-LEVEL CONVERGENCE IN
CLOSER PROXIMITY TO DEVELOPING SURFACE LOW PRESSURE AND A SURFACE
WARM FRONT WILL COMBINE WITH A STRENGTHENING LOW-LEVEL JET FOR A
MORE SUSTAINED CONVECTIVE THREAT. THE MODELS SUPPORT ARRIVAL OF AN
UPPER-LEVEL JET STREAK WITH FAVORABLE LEFT-EXIT REGION JET FORCING
THAT WILL FURTHER SUPPORT AN ORGANIZED CONVECTIVE THREAT WHICH WILL
INCLUDE A POLEWARD EXTENSION OF HEAVY RAINFALL THROUGH CENTRAL OK
GIVEN A NOSE OF ELEVATED INSTABILITY HERE NORTH OF THE
AFOREMENTIONED WARM FRONT. SOME LOCALIZED/ISOLATED SWATHS OF 2 TO
4+ INCH RAINFALL TOTALS WILL BE POSSIBLE WHERE SOME SPOTTY AREAS OF
CELL-TRAINING OCCUR GOING INTO THE OVERNIGHT HOURS. WHILE
ANTECEDENT CONDITIONS ARE DRY, SUFFICIENT LEVELS OF RAINFALL MAY
FOSTER AN ISOLATED AND MAINLY URBAN CONCERN FOR FLASH FLOODING. A
MARGINAL RISK OF EXCESSIVE RAINFALL HAS BEEN INTRODUCED AS A
RESULT.
ORRISON
DAY 3
VALID 12Z FRI OCT 24 2025 - 12Z SAT OCT 25 2025
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
SOUTHERN PLAINS...
2030Z UPDATE...
CHANGES TO THE DAY 3 ERO FOR THE 12Z CYCLE ARE RATHER MODEST. THE
LARGER SCALE SYNOPTIC SETUP FOR HEAVY CONVECTIVE RAINFALL ACROSS
THE RED RIVER VALLEY AND STRETCHING SOUTHWARD DOWN INTO THE EDWARDS
PLATEAU IS STILL LARGELY IN PLACE AS STRONG DYNAMIC FORCING/DPVA ASSOCIATED
WITH THE APPROACHING UPSTREAM UPPER-LEVEL TROUGH/CLOSED LOW
INTERACTS WITH A CONVERGENT AND MOIST/UNSTABLE LOW-LEVEL JET AIMING
NORTH ACROSS THE SOUTHERN PLAINS. ENHANCED FRONTAL CONVERGENCE AND
MOISTURE TRANSPORT AIMED INTO THE RED RIVER VALLEY AREA MAY YIELD A
RATHER ORGANIZED CONCERN FOR HEAVY/EXCESSIVE RAINFALL TOTALS WHICH
WILL INCLUDE POTENTIALLY THE GREATER DFW METROPOLITAN AREA. A COLD
FRONT ASSOCIATED WITH THE HEIGHT FALLS WILL ADVANCE RATHER
PROGRESSIVELY EAST ACROSS AREAS OF CENTRAL AND SOUTHERN TX
INCLUDING THE EDWARDS PLATEAU/HILL COUNTRY AREA AND TOWARD THE RIO
GRANGE RIVER, BUT WILL FOSTER LIKELY FAVOR WELL-ORGANIZED AREAS OF
STRONG CONVECTION WITH HEAVY RAINFALL RATES UP TO NEAR 2
INCHES/HOUR. SOME SOUTHWESTWARD ADJUSTMENT TO THE SLIGHT RISK AREA
WAS DONE COMPARED TO CONTINUITY GIVEN THE LATEST MODELS TRENDS FOR
HEAVIER RAINFALL CLOSER INTO THE WARM SECTOR INSTABILITY NEAR AND
SOUTH OF THE RED RIVER VALLEY. SOME LOCALIZED RAINFALL TOTALS
ACROSS PORTIONS OF CENTRAL AND NORTHERN TX MAY APPROACH 3 TO 6
INCHES GIVEN PROXIMITY OF ORGANIZING SURFACE LOW PRESSURE AND
STRONGER FORCING. SCATTERED AREAS OF FLASH FLOODING INCLUDING URBAN
FLOODING IMPACTS WILL BE A CONCERN.
ELSEWHERE, NO CHANGES WERE MADE WITH THIS UPDATE TO THE MARGINAL
RISK ACROSS THE PACIFIC NORTHWEST AS THE LATEST GUIDANCE CONTINUES
TO SUPPORT THE ARRIVAL OF A MODERATELY STRONG ATMOSPHERIC RIVER FOR
THIS PERIOD. LOCALLY A FEW INCHES OF RAIN INTO THE COASTAL RANGES
ARE STILL EXPECTED, BUT GIVEN THE EARLY-SEASON NATURE OF THE EVENT,
RUNOFF PROBLEMS SHOULD BE HIGHLY LOCALIZED AND MAINLY CONFINED TO
URBAN AND POOR-DRAINAGE AREAS ALONG WITH THE MORE SENSITIVE BURN
SCAR LOCATIONS.
ORRISON
PREVIOUS DISCUSSION...
..SOUTHERN PLAINS INTO THE WESTERN OZARKS
MODELS CONTINUE TO AMPLIFY THE MID/UPPER TROUGH ACROSS THE SOUTHERN
ROCKIES-SOUTHERN HIGH PLAINS SAT-SAT NIGHT AS A SUBTROPICAL JET
STREAK ROUNDS THE TROUGH BASE. MEANWHILE, THE NORTHERN STREAM JET
STREAK BEGINS TO CURVE ACROSS THE CENTRAL PLAINS-MID MS VALLEY,
WHICH WITHIN A BROAD RIGHT ENTRANCE REGION, WOULD COUPLE WITH THE
INCREASING SOUTHERN STREAM FORCING AND THUS LEAD TO A FAIRLY
SIZABLE AREA OF ROBUST DEEP-LAYER LIFT AND LOW-LEVEL MOISTURE
TRANSPORT. TPWS CLIMB BETWEEN 1.5 TO 2.0" FROM SOUTH TO NORTH ACROSS
THE OUTLOOK AREAS, WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE
NORMAL FOR LATE OCT. MEANWHILE, INCREASING SOUTH-SOUTHWESTERLY LOW
LEVEL FLOW (35-40+ KTS AT 850 MB) WILL BEGIN TO ALIGN WITH WHILE
REACH THE SAME MAGNITUDE OF THE MEAN 850-300 MB FLOW DURING THE
PERIOD, AS THE UPPER TROUGH AMPLIFIES AND APPROACHING SURFACE FRONT
SLOWS DOWN. THIS WILL FAVOR A HIGHER LIKELIHOOD OF MULTIPLE LINEAR
CONVECTIVE SEGMENTS AHEAD OF THE FRONT, WITH CELL TRAINING MOST
LIKELY WITHIN THE SLIGHT RISK AREA.
GUIDANCE SHOWS POCKETS OF 3-6+ INCHES OF RAIN WITHIN THE SLIGHT
RISK AREA, PARTICULARLY ACROSS NORTH TX INTO CENTRAL-NORTHEAST OK.
THERE IS STILL SOME AREAL-SPREAD HOWEVER WITH RESPECT TO THE
HEAVIEST TOTALS. GIVEN THIS ALONG WITH THE THE DRY ANTECEDENT
CONDITIONS (LOW SOIL MOISTURE PERCENTILES FROM NASA SPORT AND HIGH
FFG VALUES FROM THE RFCS), FOR NOW AT LEAST HAVE NOT CONSIDERED AN
UPGRADE TO A MODERATE RISK.
..PACIFIC NORTHWEST INTO NORTHWEST CALIFORNIA
THE MARGINAL RISK AREA FROM YESTERDAY'S DAY 4 ERO WAS MODIFIED ONLY
SLIGHTLY FOR TODAY'S DAY 3 ERO. MODEST ATMOSPHERIC RIVER (AR),
LEVEL 3 ON A 5-LEVEL SCALE PER THE CENTER FOR WESTERN WEATHER AND
WATER EXTREMES (CW3E), WILL PUSH ACROSS THE COASTAL AND CASCADE
RANGES OVER WA/OR FRIDAY, THEN INTO THE NORTHWEST CA COASTAL AND
SHASTA/SISKIYOUS LATE FRI AND FRIDAY NIGHT. IVT VALUES PEAK AROUND
700-750 KG/M/S, HOWEVER ONLY FOR A BRIEF PERIOD OF TIME AT ANY
GIVEN LOCATION AS THE AR IS RATHER TRANSIENT (STEADY SOUTHWARD
PROGRESSION). GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH THE QPF
AMOUNTS, AVERAGING 2-4" ACROSS THE OUTLOOK AREA, WITH LOCAL TOTALS
OF 5+ INCHES. MUCH OF THIS WOULD FALL WITHIN 12 HOURS AS THE AR
TRAVERSES THE AREA, WITH PEAK RATES NEAR 0.50"/HR ALONG AND NEAR
THE AXIS OF MAXIMUM TPW (1.00-1.25") WITH SOME (ALBEIT WEAK)
ELEVATED INSTABILITY (MUCAPES ~100-200 J/KG). THIS RAINFALL MAY
INDUCE SOME LOCALIZED SHORT-TERM RUNOFF ISSUES, PARTICULARLY IN
MORE URBAN/POOR DRAINAGE AREAS AND OVER BURN SCARS.
HURLEY
DAY 1 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/94EPOINTS.TXT
DAY 2 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/98EPOINTS.TXT
DAY 3 THREAT AREA: HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/99EPOINTS.TXT
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