115
FOUS30 KWBC 071934
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
334 PM EDT TUE JUL 7 2026
DAY 1
VALID 16Z TUE JUL 07 2026 - 12Z WED JUL 08 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE NORTHERN PLAINS/MID-ATLANTIC/NORTHWEST LOUISIANA...
16Z EXCESSIVE RAINFALL OUTLOOK UPDATE...
INTRODUCED A TARGETED SLIGHT RISK IN NORTHWEST LOUISIANA WHERE
RAINFALL FROM THE OVERNIGHT HOURS INTO THIS MORNING HAS LOWERED
FLASH FLOOD GUIDANCE. RADAR IMAGERY HAS SHOWN CONTINUED DEVELOPMENT
CLOSE TO...IF NOT LOCATED OVER...THE SAME AREA. GIVEN LATEST
MODELS...THE EXPECTATION IS THAT THE RISK WILL DIMINISH WITH TIME
THIS AFTERNOON BUT THE POTENTIAL FOR RAINFALL RATES TO EXCEED FLASH
FLOOD GUIDANCE IS HEIGHTENED FOR THE TIME BEING.
THE SLIGHT RISK AREA WAS EMBEDDED WITHIN A BROAD MARGINAL RISK AREA
EXTENDING NORTHEASTWARD ACROSS PARTS OF THE TENNESSEE VALLEY INTO
THE MID-ATLANTIC WHERE THE RISK OF EXCESSIVE RAINFALL RESULTS FROM
SLOW MOTION OF CELLS THAT PRODUCE DOWNPOURS.
ELSEWHERE...FEW CHANGES WERE NEEDED BASED ON A QUICK LOOK AT LATEST
GUIDANCE.
BANN
0830Z EXCESSIVE RAINFALL DISCUSSION...
..NORTHERN PLAINS
DURING THIS PERIOD A SHORTWAVE ROUNDING THE RIDGE ANCHORED OVER THE
FOUR CORNERS WILL MAKE ITS WAY THROUGH CENTRAL MONTANA TO WESTERN
MINNESOTA. THIS SHORTWAVE WILL DRIVE DOWNSTREAM PVA AND HEIGHT
FALLS WHILE CONCURRENT BUT MODEST RRQ DIFFLUENCE IN THE TAIL OF A
DISTANT JET STREAK HELPS ENHANCE SYNOPTIC LIFT. AT THE SURFACE, A
WAVERING BOUNDARY WITH A WAVE OF LOW PRESSURE MOVING ALONG IT WILL
TRY TO SHIFT NORTH IN RESPONSE TO SUBTLY INCREASING SOUTHERLY LOW-
LEVEL FLOW, WITH THE RESULTING ISENTROPIC ASCENT AIDING LIFT ACROSS
THE REGION. THIS ROBUST ASCENT WILL ACT UPON PWS THAT WILL SURGE
TO 1.25 TO 1.75 INCHES, OR AROUND +2 SIGMA, COLLOCATED WITH A PLUME
OF MUCAPE EXCEEDING 2000 J/KG.
THROUGH THE DAY CONVECTION IS EXPECTED TO INCREASE IN AREAL
COVERAGE FROM WEST TO EAST. THE ENVIRONMENT WILL BE FAVORABLE FOR
BACKBUILDING OR TRAINING. HOURLY RAINFALL AS MUCH AS 0.75"-1.0"+ IS
LIKELY, WHICH COULD CREATE LOCALLY 2-3" OF RAINFALL AS REFLECTED
BY MODEST (5-15% CHANCE) OF 3"/24 HRS. SOILS ACROSS THIS PART OF
THE COUNTRY HAVE BEEN RECENTLY WET THUS INCREASING SENSITIVITY. A
SLIGHT RISK REMAINS IN EFFECT FROM THE EASTERN DAKOTAS TO WESTERN
WISCONSIN. A BROAD MARGINAL RISK EXTENDS FROM EASTERN MONTANA TO
NORTH-CENTRAL WISCONSIN.
..MID-ATLANTIC
GUIDANCE CONTINUES TO SHOW HEAVY RAINFALL POTENTIALLY EXCEEDING 3
INCHES LOCALLY FROM SOUTHWEST PENNSYLVANIA INTO CENTRAL VIRGINIA
AND NORTHEAST NORTH CAROLINA WITH MERGING CELLS NEAR A BACKDOOR
FRONT. THIS PART OF THE REGION COULD SEE ISOLATED TO SCATTERED
AREAS OF FLASH FLOODING, THUS A SLIGHT RISK WAS MAINTAINED. A
MARGINAL RISK AREA REMAINS IN EFFECT FOR MUCH OF THE LOWER
MISSISSIPPI VALLEY, TENNESSEE VALLEY AND THE MID-ATLANTIC WHERE
LINGERING HIGH MOISTURE AND INSTABILITY SHOULD SUPPORT HEAVY
RAINFALL RATES AND LOCALIZED FLASH FLOODING CONCERNS.
..EASTERN MASSACHUSETTS & RHODE ISLAND
A WAVE OF LOW PRESSURE WILL BE TRACKING SOUTH OF RHODE ISLAND
DURING THIS PERIOD KEEPING SOME SHOWERS AND THUNDERSTORMS IN PLACE
ACROSS SOUTHERN NEW ENGLAND. ALTHOUGH NEW ACCUMULATIONS ARE
EXPECTED TO BE MODEST HOURLY RATES OF 1+ INCHES/HR WILL BE
POSSIBLE. A MARGINAL RISK AREA WAS MAINTAINED FOR THIS PERIOD.
CAMPBELL
DAY 2
VALID 12Z WED JUL 08 2026 - 12Z THU JUL 09 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES...
20Z UPDATE...
THE PREVIOUSLY ISSUED OUTLOOK STILL IN GOOD SHAPE. EVEN THOUGH
THERE WERE A COUPLE OF MINOR ADJUSTMENTS...THERE WAS NO FUNDAMENTAL
SHIFT IN THE FORECAST REASONING.
BANN
PREVIOUS EXCESSIVE RAINFALL DISCUSSION...
..CENTRAL PLAINS TO THE UPPER GREAT LAKES
SEVERAL LOCATIONS REMAIN SENSITIVE GIVEN RECENT RAINS AND LOWERED
FFGS, PARTICULARLY FOR PORTIONS OF THE UPPER MISSISSIPPI VALLEY AND
UPPER GREAT LAKES. A SLIGHT RISK AREA REMAINS WARRANTED FOR THIS
PART OF THE COUNTRY WHERE AREAL AVERAGES OF 1-2 INCHES ARE EXPECTED
WITH LOCALIZED SWATHS OF 3+ INCHES. CONVECTION FROM OVERNIGHT MAY
BE WEAKENING DURING THE MORNING HOURS HOWEVER REDEVELOPMENT NEAR
THE FRONTAL BOUNDARY MIDDAY SHOULD OCCUR OVER MINNESOTA AND
WISCONSIN. APPROACHING SHORTWAVE ENERGY AND AN UPPER LEVEL JET
WILL HELP DRIVE THIS UPTICK IN ACTIVITY, WITH PWS ABOVE THE
CLIMATOLOGICAL 90TH PERCENTILE AND CAPE APPROACHING 2000 J/KG
SUPPORTING HEAVY RAINFALL RATES. WHILE A PROGRESSIVE SQUALL LINE
SHOULD EVENTUALLY EVOLVE, THERE WILL BE AN OPPORTUNITY FOR SOME
TRAINING AND BACKBUILDING DURING THE DEVELOPMENT AND INITIAL
UPSCALE GROWTH PHASE OF CONVECTION. A MARGINAL RISK SPANS FROM THE
CENTRAL PLAINS TO THE GREAT LAKES AND SURROUNDING AREA.
..TENNESSEE/OHIO VALLEY TO THE MID-ATLANTIC
A MARGINAL RISK WAS MAINTAINED FOR THIS REGION. A SHORTWAVE MOVING
ACROSS KENTUCKY/TENNESSEE AND A LINGERING BACKDOOR FRONT OVER
WEST VIRGINIA/VIRGINIA SHOULD BOTH ACT AS A FOCUS FOR CONVECTIVE
DEVELOPMENT. NOT EXPECTING ANYTHING TOO ORGANIZED OR WIDESPREAD,
BUT ENOUGH MOISTURE AND INSTABILITY WILL BE AROUND TO SUPPORT
LOCALLY HEAVY RAINFALL RATES.
CAMPBELL
DAY 3
VALID 12Z THU JUL 09 2026 - 12Z FRI JUL 10 2026
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE NORTHERN/CENTRAL PLAINS, MIDWEST, OHIO/TENNESSEE VALLEYS
AND GREAT LAKES REGION...
20Z UPDATE...
THE PREVIOUSLY ISSUED OUTLOOK STILL IN GOOD SHAPE. EVEN THOUGH
THERE WERE A COUPLE OF MINOR ADJUSTMENTS...THERE WAS NO FUNDAMENTAL
SHIFT IN THE FORECAST REASONING.
BANN
PREVIOUS EXCESSIVE RAINFALL DISCUSSION...
STRONGER FLOW WILL INITIALLY REMAIN ALONG THE NORTHERN TIER OF THE
CONUS EARLY TO MID-WEEK WITH MEAN UPPER-RIDGING ACROSS THE WESTERN
TO CENTRAL UNITED STATES. EMBEDDED SHORTWAVES ROUNDING THE UPPER-
RIDGE WILL EVENTUALLY LEAD TO DEEPENING TROUGHING ACROSS THE THE
MIDWEST AND ADJACENT AREAS ON THURSDAY. THE SOUTHWARD SHIFT OF
STRONGER FLOW ALOFT INTO THE CENTRAL PLAINS EAST THROUGH THE MIDDLE
MISSISSIPPI/OHIO/TENNESSEE VALLEYS AND LOWER GREAT LAKES WILL
BRING A BETTER CHANCE FOR SCATTERED THUNDERSTORMS ACROSS THE
REGION.
SEASONABLY HIGH INSTABILITY AND MOISTURE POOLING SOUTHWARD OF A WAVY
COLD FRONT WILL SUPPORT LOCALLY HEAVY RAINFALL RATES WITH TRAINING
POTENTIAL OVER THE REGION. THAT WILL COMPOUND IMPACTS FROM
CONVECTION THE PREVIOUS FORECAST PERIOD. A LARGE AREA OF 1-2 INCH AREAL
AVERAGE TOTALS WITH EMBEDDED HIGHER AMOUNTS POSITIONED OVER THE
SOUTHERN-THIRD OF ILLINOIS/INDIANA/OHIO THROUGH MUCH OF KENTUCKY
INTO WEST VIRGINIA. THIS IS COINCIDENT WITH THE PROGRESSION OF BOTH
THE FRONT AND A STRENGTHENING SHORTWAVE TROUGH MIGRATING OUT OF
THE CENTRAL PLAINS INTO THE REGION AS WE MOVE INTO FRIDAY. MACHINE
LEARNING OUTPUT IS ALSO FAVORING THE OHIO RIVER BASIN INTO THE
CENTRAL APPALACHIANS EXTENDED FROM SOUTHWESTERN PENNSYLVANIA DOWN
THROUGH WEST VIRGINIA AS TERRAIN INFLUENCES ALONG WITH THE SYNOPTIC
EVOLUTION WILL COUPLE INTO A TARGETED THREAT FOR HEAVY RAINFALL
AND LOCAL MAXIMA SUFFICIENT FOR SCATTERED FLASH FLOOD PROSPECTS.
PUTNAM/CAMPBELL
DAY 4 AND DAY 5
VALID 12Z FRI JUL 10 2026 - 12Z SUN JUL 12 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE OHIO/MID-MISSISSIPPI VALLEYS AND CENTRAL APPALACHIANS ON
FRIDAY AND SATURDAY...
..OHIO AND MID-MISSISSIPPI VALLEY'S
20Z UPDATE: THE PREVIOUS FORECAST WAS GENERALLY MAINTAINED WITH THE
OVERALL SYNOPTIC PATTERN STILL MAINTAINING CONTINUITY IN THE
PROPOSED EVOLUTION AT BOTH THE UPPER LEVELS AND AT THE SURFACE.
ENSEMBLES CONTINUE TO INDICATE A MULTI-DAY BOUT OF HEAVY RAINFALL
ACROSS THE MID-MISSISSIPPI TO OHIO VALLEY IN CONJUNCTION WITH BOTH
MID-LEVEL ASCENT AND THE PROXY OF A COLD/QUASI-STATIONARY FRONT
THAT WILL AID IN SCATTERED TO WIDESPREAD CONVECTIVE ACTIVITY IN-OF
A VERY MOIST ENVIRONMENT POSITIONED OVER THE REGION. THE TRENDS IN
GUIDANCE INDICATE A BIT MORE EMPHASIS FURTHER WEST INTO MO WITH
EVEN THE D4 SHOWING AN EXTENSION OF HEAVY RAIN PROSPECTS BACK INTO
THE SOUTHERN HIGH PLAINS THANKS TO A LIKELY CONVECTIVE COMPLEX
DEVELOPING AROUND THE EASTERN FLANK OF A STRENGTHENING RIDGE OVER
THE FOUR CORNERS. CLASSIC SUMMER PATTERN MATERIALIZING FOR AREAS
WEST OF THE MISSISSIPPI, SO THE THREAT FOR ISOLATED FLASH FLOODING
WILL LIKELY HAVE SOME FOOTING IN THE EXTENDED WITH D4 THE FIRST
PROSPECTUS DAY FOR THE THREAT. THE SLGT RISK INHERITED WAS EXPANDED
INTO THE MID-MISSISSIPPI AREA OF EASTERN MO ON D4 AND ACROSS
SOUTHERN MO ON D5 GIVEN THE TRENDS. THE MRGL RISK EXPANDS WESTWARD
INTO THE SOUTHERN HIGH PLAINS ON D4.
KLEEBAUER
..PREVIOUS DISCUSSION..
STRONGER FLOW WILL INITIALLY REMAIN ALONG THE NORTHERN TIER OF THE
CONUS THROUGH MID-WEEK WITH MEAN UPPER-RIDGING ACROSS THE WESTERN
TO CENTRAL U.S. EMBEDDED SHORTWAVES ROUNDING THE UPPER-RIDGE WILL
EVENTUALLY LEAD TO DEEPENING TROUGHING ACROSS THE THE MIDWEST AND
ADJACENT AREAS BY THURSDAY. THE SOUTHWARD SHIFT OF STRONGER FLOW
ALOFT WILL BRING INCREASINGLY WIDESPREAD STORM CHANCES FROM THE
CENTRAL PLAINS EAST THROUGH THE MISSISSIPPI VALLEY INTO THE
OHIO/TENNESSEE VALLEYS AND CENTRAL APPALACHIANS. SEASONABLY HIGH
INSTABILITY AND MOISTURE POOLING ALONG A SOUTHWARD PROGRESSING,
WAVY COLD FRONT WILL LEAD TO MULTIPLE ROUNDS OF HEAVY RAIN-
PRODUCING STORMS LATER THIS WEEK AND INTO THE WEEKEND. MEAN FLOW
GENERALLY PARALLEL TO THE EAST-WEST ORIENTED FRONT WILL SUPPORT
CLUSTERING/TRAINING STORMS INCREASING THE THREAT FOR LONGER-
DURATION RAINFALL AND HIGHER TOTALS. THE EMBEDDED WAVES WILL HELP
TO SLOW THE FRONTAL PROGRESSION AT TIMES ALSO HELPING TO INCREASE
THE CHANCE FOR REPEATED ROUNDS/TRAINING OF STORMS. FOR FRIDAY (DAY
4), THE LATEST GUIDANCE SHOWS WIDESPREAD AREAL AVERAGE RAINFALL OF
1-2" WITH GOOD OVERLAP BETWEEN THE ENSEMBLE MEANS AND AI GUIDANCE
FAVORING THE OHIO/TENNESSEE VALLEYS INTO THE CENTRAL APPALACHIANS,
WHERE A SLIGHT RISK HAS BEEN MAINTAINED. WHILE THE GUIDANCE IS NOT
QUITE AS BULLISH ON AMOUNTS YET ON SATURDAY (DAY 5), A SIMILAR SET
UP WILL SUPPORT ADDITIONAL LOCALLY HEAVY RAINFALL, WITH THE CONCERN
BEING THAT MUCH OF THE MEAN/AI GUIDANCE OVERLAPS SIMILAR REGIONS
TO FRIDAY, FAVORING THE MIDDLE TO UPPER OHIO/TENNESSEE VALLEYS INTO
THE CENTRAL APPALACHIANS. GIVEN THE INCREASINGLY WET ANTECEDENT
CONDITIONS EXPECTED FROM THE PRIOR DAYS WITH ADDITIONAL STORMS
LIKELY, ANOTHER SLIGHT RISK HAS BEEN INTRODUCED.
PUTNAM
..SOUTHWEST U.S
MONSOONAL ACTIVITY WILL FINALLY MAKE AN APPEARANCE BY THE END OF
THE WEEK WITH THE THREAT RAMPING UP INTO SOME MORE APPRECIABLE IN
REGARDS TO MAGNITUDE AND COVERAGE ACROSS THE TERRAIN OF
SOUTHEASTERN AND CENTRAL AZ, MAINLY FOLLOWING THE HUACHUCAS UP
THROUGH THE MOGOLLON RIM IN EAST-CENTRAL AZ. PWATS WILL SURGE NORTH
ALONG PREVAILING SOUTHERLY FLOW ON THE WESTERN SIDE OF THE BROAD
UPPER RIDGE CENTERED OVER THE FOUR CORNERS. QPF SIGNATURES ARE
TEXTBOOK IN MONSOONAL CONVECTION BILLOWING UP ACROSS THE TERRAIN AT
LEAD WHICH IS A GOOD INDICATOR OF AT LEAST THE ISOLATED THREAT OF
FLASH FLOODING TO KICK OFF THE MONSOON SEASON ACROSS THE SOUTHWEST.
A MRGL RISK HAS BEEN ADDED TO ACCOUNT FOR THE THREAT ON D5 WITH
PERHAPS AN UPGRADE PLAUSIBLE ON D4, BUT SIGNALS ARE NOT AS PROLIFIC
ON FRIDAY COMPARED TO SATURDAY ON BOTH THE GLOBAL DETERMINISTIC AND
THEIR ENSEMBLES.
KLEEBAUER
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page