778
FXUS21 KWNC 261951
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 26 2024
SYNOPSIS: A STRONG SURFACE HIGH PRESSURE SYSTEM OFF THE EAST COAST IS EXPECTED
TO CREATE SOUTHERLY SURFACE WINDS FROM THE GULF OF MEXICO AND ATLANTIC OCEAN
INTO THE EAST. UNDER CYCLONIC AND DIFFLUENT MID-LEVEL FLOW, THIS BRINGS AT
LEAST A SLIGHT RISK FOR HEAVY PRECIPITATION INTO THE SOUTHEAST, MID-ATLANTIC
REGION, AND SOUTHERN NEW ENGLAND THROUGH MID-WEEK, WITH A MODERATE RISK
IDENTIFIED ALONG THE CENTRAL GULF COAST AND ADJACENT SOUTHEAST MAR 5-7. FARTHER
NORTH, A SURFACE LOW PRESSURE IS EXPECTED TO PUSH ACROSS THE UPPER MIDWEST
EARLY WEEK-2, AND THE PRESSURE GRADIENT BETWEEN THIS SYSTEM AND THE HIGH
PRESSURE OFF THE EAST COAST INCREASES THE RISK FOR HIGH WINDS FROM THE CENTRAL
PLAINS THROUGH THE GREAT LAKES REGION UNTIL MID-WEEK. ELSEWHERE, UNUSUALLY COLD
AND STORMY WEATHER IS POSSIBLE IN SOUTHERN ALASKA AT TIMES, AND PRECIPITATION
IS EXPECTED TO INCREASE IN CENTRAL AND NORTHERN PORTIONS OF THE WESTERN
CONTIGUOUS U.S. (CONUS) LATER WEEK-2, BUT THESE CONDITIONS ARE NOT FORECAST TO
REACH HAZARDS THRESHOLDS AT THIS TIME.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR THE CENTRAL GULF COAST REGION AND
ADJACENT SOUTHEAST, TUE-THU, MAR 5-7, 2024.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHEAST, MID-ATLANTIC
REGION, AND SOUTHERN NEW ENGLAND TUE-SAT, MAR 5-9, 2024.
SLIGHT RISK OF HIGH WINDS FOR THE CENTRAL PLAINS, UPPER MIDWEST, AND GREAT
LAKES REGION, TUE-WED, MAR 5-6, 2024.
DETAILED SUMMARY
FOR THURSDAY FEBRUARY 29 - MONDAY MARCH 04:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY MARCH 05 - MONDAY MARCH 11: AS WEEK 2 GETS UNDERWAY, A SURFACE
STORM SYSTEM IS EXPECTED TO STRENGTHEN WHILE MOVING FROM THE CENTRAL CONUS INTO
SOUTHERN CANADA. MEANWHILE, SURFACE HIGH PRESSURE SHOULD BE ANCHORED OFF THE
EAST COAST, AND THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS ENHANCES THE
ODDS FOR HIGH WINDS OVER A SWATH EXTENDING FROM THE CENTRAL PLAINS
NORTHEASTWARD THROUGH THE GREAT LAKES. GIVEN THIS POTENTIAL, A SLIGHT RISK FOR
HIGH WINDS IS POSTED OVER THE CENTRAL PLAINS, UPPER MIDWEST, AND GREAT LAKES
REGION FOR MAR 5-6. SOME PRECIPITATION IS EXPECTED IN ASSOCIATION WITH THIS
STORM, BUT THE MOISTURE SUPPLY WILL BE LIMITED, AND HAZARDOUS AMOUNTS OF RAIN
AND/OR SNOW ARE NOT ANTICIPATED. THE STORM IS EXPECTED TO CONTINUE
NORTHEASTWARD AWAY FROM THE CONUS, RELAXING THE PRESSURE GRADIENT AND ENDING
THE HIGH WIND THREAT BY MID-WEEK.
FARTHER SOUTH, THE SURFACE HIGH PRESSURE OFF THE EAST COAST SHOULD PRODUCE
SOUTHERLY, MOISTURE-LADEN WINDS FROM THE GULF OF MEXICO AND WESTERN ATLANTIC
OCEAN INTO MUCH OF THE EASTERN CONUS. THIS CONFLUENT MOISTURE FLUX IS EXPECTED
TO INTERACT WITH A TRAILING FRONT FROM THE STORM SYSTEM IN THE UPPER MIDWEST
UNDER CYCLONIC MID-LEVEL FLOW, INCREASING THE ODDS FOR HEAVY PRECIPITATION
THROUGH THE MIDDLE OF WEEK-2 OVER A LARGE PART OF THE EAST. THE PROBABILISTIC
EXTREMES TOOLS (PETS) FROM THE EUROPEAN ENSEMBLES AND THE GEFS SHOW GREATER
THAN 20 PERCENT CHANCES FOR PRECIPITATION TOTALS TO EXCEED ONE INCH AND THE
85TH CLIMATOLOGICAL PERCENTILE DURING MAR 5-7 (DAYS 8-10) FROM THE SOUTHEAST
THROUGH THE MID-ATLANTIC REGION AND LOWER NORTHEAST. HEAVY PRECIPITATION ODDS
IN THE EUROPEAN ENSEMBLE PET ARE SIGNIFICANTLY MORE ROBUST THAN THE GEFS AND
CANADIAN, REACHING 40 TO 60 PERCENT IN A SWATH FROM SOUTHERN SOUTH CAROLINA
THROUGH THE CENTRAL GULF COAST INTO THE LOUISIANA BAYOU, AND ALSO ACROSS PARTS
OF THE MID-ATLANTIC REGION AND SOUTHERN NEW ENGLAND. THE EUROPEAN PETS ALSO
SHOW ODDS OF 20 TO 30 PERCENT FOR 3-DAY RAINFALL TOTALS TO EXCEED 2 INCHES NEAR
THE GULF COAST. IN THESE PARTS OF THE GULF COAST REGION AND ADJACENT SOUTHEAST,
WHERE FAVORABLE CONDITIONS SHOULD BE MAXIMIZED, A MODERATE RISK FOR HEAVY
PRECIPITATION IS POSTED FOR THE FIRST 3 DAYS OF THE PERIOD WHILE A SLIGHT RISK
COVERS A LARGE PART OF THE SOUTHEAST AND ATLANTIC SEABOARD FOR MARCH 5-9.
ONE OR MORE SURFACE STORM SYSTEMS IS EXPECTED TO AFFECT SOUTHERN ALASKA DURING
WEEK-2, BUT MODELS SHOW THE HIGH PRESSURE SYSTEM FARTHER NORTH TO BE SOMEWHAT
WEAKER THAN DURING WEEK-1. THIS SET-UP SHOULD RESULT IN PERIODS OF MODERATE
PRECIPITATION AND GUSTY WINDS NEAR THE SOUTHERN ALASKA COASTLINE, AND WITH
BELOW-NORMAL 500-HPA HEIGHTS PERSISTING, COLDER THAN NORMAL CONDITIONS ARE ALSO
ANTICIPATED ACROSS APPROXIMATELY THE SOUTHERN HALF OF THE STATE. AT THIS TIME,
CONDITIONS DURING WEEK-2 ARE EXPECTED TO REMAIN BELOW HAZARDS THRESHOLDS, AND
NO HAZARDS ARE POSTED. THERE ARE SOME INDICATIONS THAT PRECIPITATION MAY BEGIN
TO INCREASE LATER WEEK-2 IN SOUTHEASTERN ALASKA IN ASSOCIATION WITH A MID-LEVEL
SHORT WAVE THAT MAY IMPACT THE REGION, BUT THE MODELS ARE NOT CONSISTENT IN
THEIR HANDLING OF THIS FEATURE.
THE MID-LEVEL SHORT WAVE THAT MAY AFFECT SOUTHEASTERN ALASKA COULD ALSO BRING
INCREASED PRECIPITATION TO CENTRAL AND NORTHERN SECTIONS OF THE WESTERN CONUS
TOWARD THE END OF WEEK-2. BOTH THE PET TOOLS AND THE ENSEMBLE MEANS FROM THE
EUROPEAN AND THE GEFS POINT TOWARD AN UPTICK IN WETNESS LATER WEEK-2, BUT
TIMING AND INTENSITY ARE BOTH UNCERTAIN, WITH THE GEFS LEANING TOWARD HIGHER
TOTALS THAN THE EUROPEAN ENSEMBLES. THE CANADIAN ENSEMBLES ARE NOT IN AGREEMENT
WITH THIS SCENARIO, KEEPING ANY POTENTIAL SHORTWAVE RELATIVELY WEAK AND THUS
MAINTAINING A RIDGE AXIS INLAND FROM WESTERN NORTH AMERICA, WHICH WOULD NOT
FAVOR HEAVY PRECIPITATION. DUE TO THE UNCERTAINTIES INDICATED BY THE TOOLS, NO
HAZARDS ARE POSTED LATE WEEK-2 FOR SOUTHEASTERN ALASKA AND THE WESTERN CONUS.
FORECASTER: RICH TINKER
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