806
FOUS30 KWBC 092025
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
425 PM EDT THU APR 9 2026
DAY 1
VALID 16Z THU APR 09 2026 - 12Z FRI APR 10 2026
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PARTS OF THE
CENTRAL PLAINS, LOWER MISSOURI AND MID-MISSISSIPPI VALLEYS AND
ALONG THE EAST COAST OF FLORIDA...
..CENTRAL PLAINS TO MID-MISSISSIPPI VALLEY
16Z UPDATE: THE FORECAST REMAINS ON TRACK FOR A MARGINAL RISK FOR
EXCESSIVE RAINFALL AS MODEST MOISTURE RETURN FROM THE SOUTH AND AN
INCREASE IN INSTABILITY THROUGH THE DAY WILL INTERACT WITH A
STATIONARY FRONT ALIGNED FROM NORTHERN KANSAS EASTWARD TO ILLINOIS.
A DUAL QPF MAXIMA OF 1-2 INCHES IS FORECAST ALONG AND TO THE NORTH
OF A FRONT ACROSS THE I80 CORRIDOR FROM IOWA TO NORTHERN ILLINOIS.
NORTHEAST KANSAS INTO MISSOURI WILL BE ANOTHER FOCAL POINT FOR
POSSIBLE HEAVIER RAINFALL RATES NEAR AND SOUTH OF THE FRONT AND QPF
TOTALS NEARING 1-3 INCHES.
..PREVIOUS DISCUSSION..
THE SURFACE FRONTAL BOUNDARY STRETCHING FROM THE CENTRAL PLAINS
INTO THE MID MISSISSIPPI VALLEY IS EXPECTED TO BE NEARLY STATIONARY
DAY 1, REMAINING ORIENTED IN A GENERAL WEST TO EAST DIRECTION. IN
THE WAKE OF THE STRONG HEIGHT FALLS MOVING NORTHEAST FROM THE UPPER
LAKES INTO SOUTHEAST CANADA, ADDITIONAL SHORTWAVE ENERGY EXPECTED
TO DIVE SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER MS
VALLEY. THESE HEIGHT FALLS WILL HELP STRENGTHEN THE LOW LEVEL SOUTH
SOUTHWESTERLY FLOW INTO THIS BOUNDARY, PUSH PW VALUES TO 1 TO 2+
STANDARD DEVIATIONS ABOVE THE MEAN AND ENHANCE UVVS IN THE ABOVE
AVERAGE PW AXIS IN THE VICINITY OF THE STATIONARY FRONT. THIS WILL
SUPPORT INCREASING CONVECTION LATE THURSDAY AFTERNOON INTO THE
EARLY HOURS OF FRIDAY IN THE VICINITY OF THIS BOUNDARY WITH LOCALLY
HEAVY RAINFALL TOTALS AND ISOLATED RUNOFF ISSUES. ONLY SOME MINOR
CHANGES MADE TO THE PREVIOUS MARGINAL RISK AREA, TRIMMING IT TO THE
NORTHWEST ACROSS NORTHERN IL, AND EXTENDING IT SLIGHTLY FARTHER
SOUTH INTO NORTHEAST KS TO MATCH THE LATEST MODEL QPF CONSENSUS.
THE MARGINAL RISK FITS WELL WITH WHERE THE LATEST HREF NEIGHBORHOOD
PROBABILITIES ARE HIGHEST FOR 1 AND 2"+ TOTALS DURING THE UPCOMING
DAY 1 PERIOD.
..EAST COAST OF FLORIDA
16Z UPDATE: THUNDERSTORMS THIS MORNING WERE MOVING ACROSS THE
SPACE COAST, THE TREASURE COAST, AND THE MIAMI METRO. RADAR
ANALYSIS SHOWED RAINFALL RATES OF AN INCH TO TWO INCHES PER HOUR
OVER SATURATED SOILS FROM PREVIOUS DAYS. SHOWERS AND STORMS WILL
CONTINUE AMID THE STRONG NORTHEASTERLY FLOW ALONG THE EAST COAST OF
FLORID AND THE MARGINAL RISK CONTINUES THIS AFTERNOON.
..PREVIOUS DISCUSSION..
THE STRONG LOW LEVEL EAST NORTHEASTERLY FLOW WILL CONTINUE FOR AT
LEAST THE BEGINNING OF THE DAY 1 PERIOD ALONG THE EAST COAST OF
FLORIDA. PW VALUES WILL REMAIN ABOVE AVERAGE DURING THE DAY ON
THURSDAY, BEFORE BEGINNING TO DECREASE AS THE LOW LEVEL ONSHORE
FLOW WEAKENS AFTER 0000 UTC FRIDAY. THERE WILL CONTINUE TO BE THE
THREAT OF LOCALLY HEAVY RAINS FROM SLOW MOVING TO NEARLY STATIONARY
RAIN BANDS IN THIS STRONG MOIST ONSHORE FLOW REGION. CONFIDENCE IS
NOT GREAT WITH PLACEMENT, LEADING TO LITTLE IN THE WAY OF CHANGES
WITH TO THE PREVIOUS BROAD MARGINAL RISK AREA ALONG THE EAST
CENTRAL TO SOUTHEAST FLORIDA COASTAL REGION, WITH THE GREATEST RISK
OF RUNOFF ISSUES IN MORE URBANIZED REGIONS.
..SOUTH-CENTRAL TEXAS
A SUB-MARGINAL RISK FOR EXCESSIVE RAINFALL IS POSSIBLE FROM THE
HILL COUNTRY WESTWARD TO THE RIO GRANDE. THE QPF FORECAST CALLS FOR
A GENERAL 1.0-2.0 INCHES ACROSS THE REGION TODAY AS ENOUGH
MOISTURE AND INSTABILITY WILL BE PRESENT FOR SCATTERED
THUNDERSTORMS. A DISTURBANCE MOVING ACROSS THE MEXICAN PLATEAU
COULD ENHANCE LOCALLY HEAVIER RAINFALL TOTALS ACROSS THE RIO
GRANDE, WITH SOME UNCERTAINTY IF THE STORMS CAN MAINTAIN ACROSS THE
U.S./MEXICO BORDER LATE THIS AFTERNOON INTO THE EVENING. DRY
ANTECEDENT CONDITIONS AND LOW SIGNALS FROM THE HREF NEIGHBORHOOD
PROBABILITIES EXCEEDING 2 INCHES PRECLUDES A MARGINAL RISK FOR
EXCESSIVE RAINFALL AS OF THIS FORECAST PACKAGE.
ORAVEC/WILDER
DAY 2
VALID 12Z FRI APR 10 2026 - 12Z SAT APR 11 2026
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE CENTRAL TO SOUTHERN PLAINS...
20Z UPDATE: THE MARGINAL RISK FOR EXCESSIVE RAINFALL HAD A MINOR
SHIFT SOUTH INTO NORTHERN OKLAHOMA BASED ON LATEST CAM CONSENSUS.
THE MARGINAL RISK WAS EXTENDED FARTHER SOUTH INTO NORTHERN
OKLAHOMA, INCLUDING THE TULSA METRO, AS MODELS SHOW A SOUTHWARD
TREND OF THE MAXIMUM QPF WHERE THE FRONT ALIGNS. THE WEST TO EAST
FRONT STRETCHING FROM THE CENTRAL PLAINS INTO THE MID-MISSISSIPPI
VALLEY TODAY WILL BEGIN TO PUSH SOUTHWARD EARLY TOMORROW. THIS
FRONT WILL THEN MEANDER ACROSS THE CENTRAL PLAINS, EAST INTO THE
LOWER MO VALLEY AND MID- MISSISSIPPI VALLEY. PWAT VALUES SHOULD
INCREASE IN THE VICINITY OF THIS FRONT IN RESPONSE TO STRENGTHENING
SOUTHERLY LOW LEVEL INFLOW. SHORTWAVE ENERGY PUSHING NORTHEASTWARD
INTO THIS HIGH PW AXIS IN THE VICINITY OF THIS FRONT WILL SUPPORT
AREAS OF SLOW MOVING CONVECTION ALONG THIS FRONT,LOCALLY HEAVY
RAINS AND ISOLATED RUNOFF ISSUES. HREF NEIGHBORHOOD PROBABILITIES
SHOW 40-70% FOR 2 INCHES AND 20-40 % FOR 3 INCHES OF RAINFALL
ACROSS THESE AREAS.
WILDER/ORAVEC
DAY 3
VALID 12Z SAT APR 11 2026 - 12Z SUN APR 12 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHERN PLAINS...
20Z UPDATE: UPGRADED TO A SLIGHT RISK ACROSS WEST TEXAS INTO THE
RED RIVER VALLEY.
AN AXIS OF ABOVE AVERAGE PWATS IS EXPECTED TO MOVE ACROSS THE
SOUTHERN AND CENTRAL PLAINS ON SATURDAY. UPPER DYNAMICS WILL
SUPPORT ASCENT AHEAD OF A LONGWAVE TROUGH ENTERING THE WEST COAST,
AS WELL AS A SHORTWAVE TROUGH TRAVERSING THE HIGH PLAINS. AS
RIDGING BUILDS IN ACROSS THE EAST, THIS WILL ALSO PROMOTE STRONG
SOUTHERLY FLOW AND A LOW LEVEL JET OVER THE SOUTHERN PLAINS AND
TEXAS TO ADVECT MOISTURE AND INSTABILITY IN THE AREA. AT THE
SURFACE, A DRY LINE ACROSS WEST TEXAS WILL HELP SERVE AS AN
INITIATING MECHANISM FOR CONVECTION. THE QPF FOOTPRINT IN THE
AFTERNOON CYCLE HAS A SIGNAL FOR 2-4 INCHES POSSIBLE FROM THE
CONCHO VALLEY IN WEST TEXAS TO THE RED RIVER VALLEY IN SOUTHERN
OKLAHOMA. RAINFALL RATES COULD ALSO BE AS HIGH AS AN INCH OR TWO
PER HOUR WITH ORGANIZED CONVECTION LIKELY AS NOTED WITH SPC'S
SLIGHT RISK ACROSS THE REGION. A SLIGHT RISK FOR EXCESSIVE RAINFALL
WAS INTRODUCED FROM WEST TEXAS TO THE RED RIVER VALLEY ON SATURDAY
FOR THE POTENTIAL OF SCATTERED FLASH FLOODING.
WILDER/ORAVEC
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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