479
FOUS30 KWBC 140039
QPFERD
EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
839 PM EDT SAT SEP 13 2025
DAY 1
VALID 01Z SUN SEP 14 2025 - 12Z SUN SEP 14 2025
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
SOUTHERN HIGH PLAINS...
..CENTRAL & SOUTHERN HIGH PLAINS
UPPER TROUGH OVER THE GREAT BASIN WILL CONTINUE TO EDGE EASTWARD
AND TAKE ON A NEGATIVE TILT, WITH A CONTINUED INFLUX OF MOISTURE
(PW ANOMALIES +2 SIGMA) INTO THE SOUTHERN ROCKIES AND POINTS
NORTHWARD. THE LLJ (WHICH IS ON THE INCREASE) WILL SUPPORT
CONVECTION OVER EASTERN NM THAT PUSHES INTO WEST TEXAS. STORMS MAY
HAVE ENOUGH FORWARD SPEED TO LIMIT FLASH FLOODING POTENTIAL, BUT
THERE WAS ENOUGH OF A SIGNAL IN THE RECENT HIGH-RESOLUTION GUIDANCE
PROBABILITIES AND RECENT RADAR REFLECTIVITY TRENDS TO MAINTAIN THE
SLIGHT RISK NEAR THE TX/NM BORDER.
..NORTHERN PLAINS
SOUTHERLY FLOW THROUGH THE COLUMN WILL MAINTAIN A SURGE OF
MOISTURE (PW ANOMALIES +3 SIGMA / 1.50") INTO THE NORTHERN PLAINS
AS WEAKER SHORTWAVES RACE NORTHWARD AHEAD OF THE MAIN UPPER LOW
OVER MT, SUCH AS THE ONE TRANSITING CENTRAL ND CURRENTLY. IT
APPEARS THAT THE CONVECTION ACROSS ND HAS REACHED ITS PEAK FOR THE
DAY, SO LOWERED THE RISK TO MARGINAL. SLIGHT RISK IMPACTS ARE
POSSIBLE IN THE NEAR TERM ACROSS A COUPLE COUNTIES IN WESTERN ND.
..IN AND NEAR INDIANA
WHILE THE PRIMARY SHORTWAVE HAS LEFT THE SCENE, SOME OF THE
MESOSCALE GUIDANCE SHOWS A MODEST OVERNIGHT UPTICK, SO LEFT THE
MARGINAL RISK IN PLACE AND SHIFTED IT SLIGHTLY SOUTHEAST.
..EAST-CENTRAL FLORIDA
WHILE DAYTIME CONVECTION IS BEGINNING TO WANE ACROSS SOUTHERN FL,
ACTIVITY OFFSHORE EASTERN FL IS POISED TO MOVE INLAND IN THE SHORT
TERM WITHIN WHAT APPEARS TO BE A COMMA HEAD PATTERN AROUND THE
PERIPHERY OF AN UPPER LEVEL LOW. PRECIPITABLE WATER VALUES REMAIN
1.5"+, THE LOW-LEVEL FLOW REMAINS ONSHORE IN THIS REGION WHICH IS
KEEPING 2000+ J/KG OF ML CAPE AROUND, AND EFFECTIVE BULK SHEAR IS
HIGH ENOUGH TO WORRY ABOUT CONVECTIVE ORGANIZATION, WHICH CONTINUES
CONCERNS ABOUT SHORT TRAINING BANDS LEADING TO HEAVY RAIN CONCERNS
IN URBAN AREAS BEFORE THE SYSTEM MOVES OUT TO SEA SUNDAY.
MESOSCALE GUIDANCE KEEPS CONVECTIVE ACTIVITY CLOSE ENOUGH TO THE
SPACE & TREASURE COASTS TO HAVE A MARGINAL RISK FOR THE REGION OVERNIGHT.
ROTH
DAY 2
VALID 12Z SUN SEP 14 2025 - 12Z MON SEP 15 2025
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN THE WESTERN DAKOTAS...
20Z UPDATE...
EXTENDED THE MARGINAL RISK FURTHER SOUTH FROM THE CENTRAL PLAINS
INTO WESTERN OKLAHOMA AND THE EASTERN TEXAS PANHANDLE, WHERE
CONVECTION IS EXPECTED TO DEVELOP DURING THE AFTERNOON/EVENING
AHEAD OF A LOW LEVEL CONFLUENCE AXIS AND WITHIN A STRIPE OF DEEPER
MOISTURE. WHILE NOT ANTICIPATING A WIDESPREAD HEAVY RAINFALL
EVENT, SOME MODELS DO INDICATE THE POTENTIAL FOR SLOW-MOVING OR
BACKBUILDING CELLS, RESULTING IN LOCALLY HEAVY AMOUNTS AND PERHAPS
ISOLATED FLASH FLOODING CONCERNS.
OTHERWISE, NO SIGNIFICANT CHANGES TO THE PREVIOUS OUTLOOK.
PEREIRA
PREVIOUS DISCUSSION...
..CENTRAL AND NORTHERN PLAINS
UPPER TROUGH EXITING THE ROCKIES WILL SPLIT OFF ITS SOUTHERN
PORTION INTO AN UPPER LOW OVER WESTERN NEBRASKA MIDDAY SUNDAY, WITH
SOUTHERLY FLOW CONTINUING ACROSS THE NORTHERN PLAINS (AND AMPLE
MOISTURE -- PW ANOMALIES STILL +2 TO +3 SIGMA). THIS MID-LEVEL LOW
WILL LIFT NORTHWARD AND ACT AS A FOCUS FOR CONVERGENCE TOWARD THE
NOSE OF THE SFC- BASED INSTABILITY GRADIENT JUST TO THE EAST.
STORMS MAY REPEAT OVER THE SAME AREA AS D1, WITH THE POTENTIAL FOR
ANOTHER 1-2"+ OF RAIN. MAINTAINED THE SLIGHT RISK OUTLINE HERE WITH
A BROADER MARGINAL RISK EXTENDING TO THE SOUTH WHERE THE GUIDANCE
SHOWS POTENTIAL FOR 2-4" OF RAINFALL, BUT OVER AREAS WITH HIGHER
FFG VALUES (ESP. THE SAND HILLS).
FRACASSO
DAY 3
VALID 12Z MON SEP 15 2025 - 12Z TUE SEP 16 2025
THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE IS LESS
THAN 5 PERCENT.
PEREIRA
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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