912
FXUS02 KWBC 011851
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
151 PM EST SAT MAR 1 2025
VALID 12Z TUE MAR 04 2025 - 12Z SAT MAR 08 2025
...NUMEROUS SEVERE THUNDERSTORMS AND HEAVY RAINFALL EXPECTED FROM
EASTERN TEXAS TO THE DEEP SOUTH STATES MIDWEEK...
..GENERAL OVERVIEW
THE WEATHER PATTERN ACROSS THE CONTINENTAL U.S. WILL BE QUITE
ACTIVE NEXT WEEK WITH TWO BIG STORM SYSTEMS OF INTEREST. THE FIRST
AND STRONGEST LOW PRESSURE SYSTEM WILL BE GATHERING STRENGTH ACROSS
THE CENTRAL PLAINS ON TUESDAY IN RESPONSE TO AN AMPLIFYING UPPER
LEVEL SHORTWAVE EXITING THE ROCKIES. HEAVY RAINFALL, SEVERE
THUNDERSTORMS, AND STRONG WINDS WILL BE MAKING WEATHER HEADLINES
ACROSS THE SOUTH-CENTRAL U.S. THROUGH MIDWEEK, AND THE STORM SYSTEM
REACHES THE EAST COAST BY WEDNESDAY NIGHT. A SECOND AND SLIGHTLY
WEAKER STORM SYSTEM DEVELOPS OVER THE ROCKIES ON THURSDAY AND
LIKELY REACHES THE CENTRAL PLAINS ON FRIDAY, WITH ADDITIONAL
SHOWERS AND THUNDERSTORMS EXPECTED. THIS SHOULD REACH THE EAST
COAST STATES BY NEXT SATURDAY AS THE FLOW PATTERN ALOFT REMAINS
RATHER PROGRESSIVE.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS TENDED TO BE IN GOOD AGREEMENT REGARDING THE SYNOPTIC
PATTERN ON DAY 3. DETERMINISTIC GUIDANCE BEGINS TO DIVERGE
NOTICEABLY BEGINNING ON DAY 5 OVER THE CENTRAL U.S.. THE 00Z EURO
AND CANADIAN ARE NOTICEABLE OUTLIERS, THUS WERE REDUCED IN
WEIGHTING CONSIDERABLY BEYOND BEGINNING ON DAY 5. THE DAYS 3 AND 4
BLENDS CONSISTED OF EQUAL PARTS DETERMINISTIC 00Z ECMWF AND 06Z GFS
WITH SOME 00Z CMC/UKMET INCLUDED. UNCERTAINTY REGARDING AN INCOMING
PACIFIC TROUGH PROMPTED A MORE ENSEMBLE MEAN AND DETERMINISTIC GFS-CENTRIC
BLEND ON DAY 5 FOLLOWED BY ENSEMBLE MEAN FAVORED BLENDS ON DAYS 6
AND 7.
..WEATHER/HAZARDS HIGHLIGHTS
AN AMPLIFIED UPPER LEVEL TROUGH REACHES THE WESTERN HIGH PLAINS BY
TUESDAY MORNING, ALONG WITH A RAPIDLY DEVELOPING SURFACE LOW THAT
WILL TRACK EASTWARD ACROSS THE MIDWEST AND THEN ACROSS THE GREAT
LAKES. ABUNDANT GULF MOISTURE AND INSTABILITY WILL BE ADVECTED
NORTHWARD TO FUEL WIDESPREAD HEAVY RAINFALL FROM THE SOUTHERN
PLAINS TO THE EASTERN U.S. THROUGH EARLY THURSDAY. THE LATEST
GUIDANCE CONTINUES TO SIGNAL THE HEAVIEST RAINFALL TOTALS FROM THE
ARKLATEX TO THE WESTERN OHIO VALLEY ON TUESDAY/TUESDAY NIGHT. SOME
AREAS HAVE WET ANTECEDENT SOIL CONDITIONS, WHICH WOULD EXACERBATE
FLOOD POTENTIAL. THE SLIGHT RISK AREA IS MAINTAINED ON THE DAY 4
EXCESSIVE RAINFALL OUTLOOK ACROSS ARKANSAS AND SOUTHERN MISSOURI,
AND A NEW SLIGHT RISK AREA WILL BE ADDED FOR PORTIONS OF SOUTHERN
IOWA AND NORTHERN MISSOURI. ONCE THIS STORM SYSTEM REACHES THE
NORTHEAST U.S. WEDNESDAY, A MARGINAL RISK IS PLANNED FOR THE NEW
DAY 5 OUTLOOK FROM NEW JERSEY TO SOUTHERN MAINE WHERE 1-2 INCHES OF
RAINFALL IS POSSIBLE.
ANOTHER FACET OF THIS LOW PRESSURE SYSTEM WILL BE THE ELEVATED
POTENTIAL FOR WIDESPREAD SEVERE WEATHER FROM EASTERN TEXAS TO THE
LOWER MISSISSIPPI RIVER VALLEY THROUGH TUESDAY NIGHT. A FAVORABLE
COMBINATION OF KINEMATICS AND DEEP MOISTURE INCREASES THE THREAT OF
DAMAGING WINDS, LARGE HAIL, AND TORNADOES. THE STORM PREDICTION
CENTER HAS ADDITIONAL INFORMATION PERTAINING TO THIS.
A SECOND STORM SYSTEM IS EXPECTED TO FOLLOW BEHIND THIS, AND BRING
ADDITIONAL ROUNDS OF SHOWERS AND THUNDERSTORMS TO MANY OF THESE
SAME AREAS, BUT THE CURRENT THINKING IS THAT IT WILL NOT BE AS
INTENSE AS THE MIDWEEK STORM SYSTEM. SOME STRONG TO SEVERE
THUNDERSTORMS WILL ALSO BE POSSIBLE WITH THIS EVENT LATE IN THE
WEEK, DEPENDING ON HOW LOW LEVEL BOUNDARIES EVOLVE.
KEBEDE/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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