267
FXUS02 KWBC 170803
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
303 AM EST MON NOV 17 2025
VALID 12Z THU NOV 20 2025 - 12Z MON NOV 24 2025
..SOUTH-CENTRAL U.S. HEAVY RAIN/RUNOFF THREAT MID-LATE WEEK
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
COMPOSITE OF WELL CLUSTERED GUIDANCE OF THE GFS/ECMWF/CANADIAN
ENSEMBLE MEANS THROUGH MEDIUM RANGE TIME SCALES. WPC CONTINUITY IS
WELL MAINTAINED WITH THIS SOLUTION THAT ALSO SEEMS QUITE COMPATIBLE
WITH THE NATIONAL BLEND OF MODELS DESPITE UNCERTAINTIES. THE
EXTENT OF LATER WEEK SOUTHERN STREAM UPPER TROUGH/SYSTEM DIGGING
ALONG/OFF THE WEST COAST AND RUN TO RUN CONTINUITY HAS BEEN LESS
THAN STELLAR AND TOO VARIED IN GUIDANCE. HOWEVER, RECENT RUNS OF
THE ECMWF THAT HAS BEEN ON THE MORE PROGRESSIVE SIDE OF THE FULL
ENVELOPE OF SOLUTIONS HAS SHIFTED MORE TOWARD THE SLOWER GFS WITH
THE LATEST 00 UTC RUN.
..WEATHER/HAZARDS HIGHLIGHTS
AMPLIFIED UPPER TROUGH ENERGY WITHIN WELL SEPARATED SOUTHERN STREAM
FLOW WILL EJECT FROM THE SOUTHWEST TO THE SOUTH-CENTRAL U.S..
THURSDAY/FRIDAY. HEIGHT FALLS AND LEAD MOISTURE AND INSTABILITY
RETURN FLOW INTO WAVY FRONTAL SYSTEM AND MESO-SCALE FEATURES
FAVORS EMERGENCE OF A GROWING AREA OF HEAVY RAINS AND STRONG
THUNDERSTORMS OVER THE SOUTH-CENTRAL U.S., SHIFTING WITH REDUCED
IMPACT WITH EASTWARD PROGRESSION INTO THE WEEKEND. ACCORDINGLY,
THERE ARE WPC DAY 4/THURSDAY EXCESSIVE RAINFALL OUTLOOK MARGINAL
AND EMBEDDED SLIGHT RISK AREAS FOR THE SOUTH-CENTRAL U.S. GIVEN
HEAVY CONVECTIVE AND REPEAT RAIN POTENTIAL. THIS ACTIVITY LINGERS
INTO A DAY 5/FRIDAY MARGINAL RISK AREA SPREAD INTO THE LOWER
MISSISSIPPI VALLEY WITH GROWING SYSTEM PROGRESSION.
MEANWHILE UPSTREAM, A DIGGING EAST PACIFIC SYSTEM WILL CLOSE-OFF
AND OFFER SOME ENHANCED PRECIPITATION CHANCES TO THE WEST COAST
THURSDAY/FRIDAY AND LATEST GUIDANCE TRENDS SHOW A SUBSEQUENT SLOW
MOTION TO NORTHWEST MEXICO AND THE SOUTHWEST U.S. NEXT WEEKEND.
EXPECT LEAD ORGANIZED PRECIPITATION MAY THEN RE-EMERGE OVER TEXAS.
PRE-FRONTAL TEMPERATURES WILL LINGER MUCH WARMER THAN AVERAGE FOR
PORTIONS OF THE SOUTHERN U.S. INTO LATE WEEK WILL INCLUDE SOME
RECORD TEMPERATURES, WITH WARMING SHIFTING TO THE EAST LATE
WEEK/WEEKEND. MEANWHILE, ROUNDS OF TROUGHING IN CALIFORNIA TO THE
WEST/SOUTHWEST WILL LEAD TO BELOW AVERAGE HIGHS ABOUT 5-10+
DEGREES BELOW CLIMATOLOGY.
SCHICHTEL
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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