573
FXUS02 KWBC 240658
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 AM EST FRI JAN 24 2025
VALID 12Z MON JAN 27 2025 - 12Z FRI JAN 31 2025
..GENERAL OVERVIEW
THE FORECAST PERIOD FOR NEXT WEEK BEGINS WITH A SLOW MOVING CLOSED
LOW OVER CALIFORNIA AND BROAD CYCLONIC FLOW ALOFT FROM THE NORTHERN
PLAINS TO THE NORTHEAST STATES, WITH A SPLIT UPPER LEVEL FLOW
PATTERN IN PLACE FOR THE BEGINNING OF THE WEEK. THE CLOSED LOW
MAKES SLOW EASTWARD PROGRESS THROUGH THE MIDDLE OF THE WEEK, WITH A
RIDGE AXIS BUILDING NORTH TO THE PACIFIC NORTHWEST REGION, AND A
TROUGH REMAINING OVER THE NORTHEASTERN QUADRANT OF THE COUNTRY. IT
APPEARS LIKELY THAT SURFACE CYCLOGENESIS WILL TAKE PLACE OVER THE
SOUTHERN PLAINS IN RESPONSE TO THE APPROACHING UPPER LOW, AND THIS
WILL LIKELY FUEL AN INCREASE IN RAIN FROM TEXAS TO PORTIONS OF THE
DEEP SOUTH FOR THE END OF THE WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE IS INITIALLY IN GOOD OVERALL SYNOPTIC
SCALE AGREEMENT ACROSS THE CONTINENTAL U.S. FOR THE BEGINNING OF
THE WEEK, BUT THE CMC STARTS TO DIFFER ACROSS ONTARIO AND QUEBEC
GOING INTO TUESDAY, AND DEPICTS A SURFACE LOW OVER WESTERN ONTARIO
THAT DOES NOT HAVE MUCH MODEL SUPPORT. THE GUIDANCE BECOMES MUCH
MORE MURKY WITH LOCATION AND EXTENT OF SURFACE CYCLOGENESIS OVER
TEXAS AND VICINITY BY THURSDAY. GIVEN THE OVERALL UPPER AIR PATTERN
AND AI GUIDANCE, THE ECMWF PROBABLY HAS THE MOST REASONABLE
DEPICTION, WHEREAS THE CMC AND GFS ARE MUCH MORE SUPPRESSED. WITH
FORECAST CONFIDENCE DROPPING TO BELOW AVERAGE BY THURSDAY INTO
FRIDAY, THE ENSEMBLE MEANS ACCOUNTED FOR ABOUT 2/3RDS OF THE
FORECAST BLEND BY THAT TIME.
..WEATHER/HAZARDS HIGHLIGHTS
THE SLOW MOVING UPPER LOW THROUGH CALIFORNIA SUNDAY AND INTO MONDAY
WILL CONTINUE TO ALLOW FOR MUCH NEEDED RAIN TO SOUTHERN CALIFORNIA.
MOST OF THE NOTEWORTHY RAINFALL WITH THIS EVENT SHOULD BE TAPERING
OFF MONDAY MORNING, WITH JUST A FEW LINGERING SHOWERS REMAINING
DURING THE 12Z MONDAY TO 00Z TUESDAY TIME PERIOD. THEREFORE, NO
RISK AREAS APPEAR WARRANTED IN THE DAY 4 OR DAY 5 EXCESSIVE
RAINFALL OUTLOOKS AT THIS TIME.
THE UPPER LOW THAT SLOWLY APPROACHES THE SOUTHERN PLAINS BY LATE
WEDNESDAY IS LIKELY TO RESULT IN NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS DEVELOPING FROM CENTRAL TEXAS TO THE LOWER
MISSISSIPPI RIVER VALLEY THROUGH FRIDAY MORNING. THERE HAS BEEN A
GENERAL UPWARD TREND IN EXPECTED RAINFALL TOTALS COMPARED TO THE
PREVIOUS WPC FORECAST OVER THE ARKLATEX REGION TO THE WESTERN GULF
COAST, WITH THE POTENTIAL FOR 1 TO 3 INCHES FOR THIS REGION. MODELS
STILL DON'T AGREE ON THE MAIN QPF AXIS, SO THERE WILL BE UPDATES ON
THIS AS WE GET CLOSER IN TIME.
MUCH OF THE EAST SHOULD FINALLY BE BACK UP TOWARDS NORMAL
TEMPERATURES EARLY NEXT WEEK, THOUGH READINGS A FEW DEGREES BELOW
NORMAL ARE POSSIBLE ACROSS THE SOUTHEAST ON MONDAY. ANOMALOUSLY
COLD TEMPERATURES WILL ALSO DEVELOP ACROSS THE SOUTHWESTERN U.S.
UNDER THE INFLUENCE OF UPPER TROUGHING/CLOSED LOW. THE NORTHEAST
U.S. SHOULD ALSO COOL BACK DOWN TO SLIGHTLY BELOW AVERAGE BY THE
END OF NEXT WEEK AFTER ANOTHER COLD FRONTAL PASSAGE.
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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