218
FXUS02 KWBC 100656
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 AM EDT TUE JUN 10 2025
VALID 12Z FRI JUN 13 2025 - 12Z TUE JUN 17 2025
***HEAVY RAIN AND FLASH FLOOD THREAT FOR THE SOUTH-CENTRAL U.S.
THROUGH FRIDAY***
..GENERAL OVERVIEW
A SHORTWAVE TROUGH OVER THE CENTRAL U.S. PAIRED WITH A SURFACE
FRONTAL BOUNDARY WILL CONTINUE TO FOCUS HEAVY RAINFALL AND
POTENTIAL FLASH FLOODING THROUGH AT LEAST FRIDAY, ESPECIALLY
ACROSS PORTIONS OF TEXAS, OKLAHOMA, AND INTO THE LOWER MISSISSIPPI
VALLEY. NORTHERN STREAM ENERGY WILL SUPPORT MODERATE TO HEAVY
RAINFALL ACROSS PORTIONS OF WISCONSIN AND MICHIGAN, WITH RAINFALL
INCREASING IN COVERAGE BY NEXT WEEKEND ACROSS THE OHIO VALLEY INTO
THE EAST AHEAD OF NORTHERN AND SOUTHERN STREAM ENERGY CONVERGENCE.
TROUGHING OVER THE WEST COAST WILL BE PERIODICALLY RENEWED BY
SHORTWAVES ROUNDING THE BASE OF A LARGER UPPER LOW, WITH ABOVE
NORMAL TEMPERATURES EXPECTED TO PREVAIL FOR INTERIOR PORTIONS OF
THE WEST UNDERNEATH UPPER RIDGING.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE IS IN REASONABLY GOOD AGREEMENT FOR
THE END OF THE WEEK AND INTO THE WEEKEND WITH MOST OF THE SYNOPTIC
SCALE FEATURES. ONE OF THE MORE NOTABLE DIFFERENCES IS WITH THE
UKMET SHOWING A FASTER AND STRONGER TROUGH AND SURFACE LOW CROSSING
THE OHIO VALLEY AND THEN THE NORTHEAST THROUGH SATURDAY, WITH
RAINFALL MUCH HIGHER THAN THE OTHER GUIDANCE, SO THE MODEL
PREFERENCE WAS WEIGHTED MORE TOWARDS THE GFS/ECMWF/CMC SOLUTIONS
THROUGH THE WEEKEND, AND A GRADUAL INCREASE OF THE ENSEMBLE MEANS
TO ABOUT HALF BY NEXT TUESDAY AS MESOSCALE DIFFERENCES INCREASED.
..WEATHER/HAZARDS HIGHLIGHTS
AN UNSETTLED WEATHER PATTERN IS EXPECTED TO BE IN PLACE ACROSS A
LARGE PORTION OF THE CENTRAL U.S. TO CLOSE OUT THE WORK WEEK.
ADDITIONAL HEAVY RAINFALL IS LIKELY ACROSS THE ARKLATEX REGION
GOING INTO THE NEW DAY 4 PERIOD FRIDAY WITH A SOUTHERN STREAM
SHORTWAVE POSITIONED OVER TEXAS. THE SLIGHT RISK INHERITED FROM THE
PREVIOUS DAY 5 OUTLOOK WILL BE MAINTAINED FOR FRIDAY, WHERE THE
POTENTIAL EXISTS FOR 1-2 INCHES OF RAINFALL FROM POTENTIAL MCS
ACTIVITY, AND THIS WOULD BE FALLING ATOP SOILS THAT WILL PROBABLY
BE SATURATED OWING TO RAINFALL IN THE DAYS LEADING UP TO THIS.
THERE SHOULD ALSO BE AT LEAST SCATTERED SHOWERS AND STORMS FROM THE
WESTERN GULF COAST AND EXTENDING NORTHWARD ACROSS THE MID-SOUTH, SO
THE MARGINAL RISK AREA HAS BEEN EXPANDED. FARTHER TO THE NORTH
ACROSS THE UPPER MIDWEST AND GREAT LAKES, A WAVE OF LOW PRESSURE
ALONG A QUASI-STATIONARY BOUNDARY SHOULD FUEL THE DEVELOPMENT OF
SCATTERED TO NUMEROUS SHOWERS AND SOME THUNDERSTORMS FROM WISCONSIN
TO LOWER MICHIGAN, AND A MARGINAL RISK OF EXCESSIVE RAINFALL
REMAINS VALID HERE ON THE DAY 4 OUTLOOK. GOING INTO DAY 5 SATURDAY,
A BROAD MARGINAL RISK AREA IS PLANNED FROM THE CENTRAL GULF COAST
TO WESTERN NEW YORK WHERE THE QPF GUIDANCE SHOWS THE BEST SIGNAL
FOR MORE ORGANIZED CONVECTION, ALTHOUGH NOTHING RISES TO THE LEVEL
OF NEEDING A SLIGHT RISK YET. THIS WILL CONTINUE TO BE MONITORED.
TEMPERATURES WILL CONTINUE TO BE QUITE WARM ACROSS MUCH OF THE
INTERMOUNTAIN WEST FOR THE ENTIRE FORECAST PERIOD AS THIS REGION
WILL BE UNDER THE INFLUENCE OF AN UPPER RIDGE, ALTHOUGH A SLOW
MOVING COLD FRONT FROM THE PACIFIC WILL KEEP READINGS CLOSER TO
CLIMATOLOGY FROM THE PACIFIC NORTHWEST TO WESTERN NEVADA/NORTHERN
CALIFORNIA. HEAT WILL ALSO BE BUILDING ACROSS THE DESERT SOUTHWEST
WITH HIGHS MAKING A RUN AT 110 DEGREES FOR THE LOWER ELEVATIONS OF
SOUTHERN ARIZONA AND SOUTHEAST CALIFORNIA, WITH HEAT RISK LIKELY
REACHING THE MAJOR CATEGORY BY SUNDAY INTO MONDAY. MEANWHILE,
SLIGHTLY BELOW AVERAGE TEMPERATURES ARE LIKELY FROM THE UPPER
MIDWEST TO THE GREAT LAKES AND NORTHERN NEW ENGLAND GOING INTO THE
WEEKEND AS THIS REGION WILL BE NORTH OF THE MAIN FRONTAL BOUNDARY.
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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