310
FXUS21 KWNC 091809
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 09 2025
SYNOPSIS: STRENGTHENING MID-LEVEL LOW PRESSURE UNDERNEATH A BLOCKING HIGH
FAVORED OVER EASTERN NORTH AMERICA IS EXPECTED TO BRING A RENEWED POTENTIAL FOR
WIDESPREAD FROST AND/OR FREEZES, AS WELL AS PERIODS OF HIGH WINDS OVER PORTIONS
OF THE NORTHEASTERN CONUS DURING THE PERIOD. A RAPID ONSET DROUGHT RISK REMAINS
FOR PARTS OF THE SOUTHERN PLAINS AND THE LOWER MISSISSIPPI VALLEY WHERE
ABOVE-NORMAL TEMPERATURES AND LIMITED PRECIPITATION ARE FORECAST DURING THE
NEXT TWO WEEKS. A STORMY PATTERN REEMERGING OVER ALASKA IS EXPECTED TO BRING
ABOVE-NORMAL PRECIPITATION, WITH AN INCREASED RISK OF HIGH WINDS FOR MOST
SOUTHERN PARTS OF THE STATE.
HAZARDS
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR PARTS OF THE EASTERN CORN
BELT, CENTRAL APPALACHIANS, MID-ATLANTIC, AND THE NORTHEAST, SUN-TUE, OCT 19-21.
SLIGHT RISK OF HIGH WINDS FOR THE MID-ATLANTIC AND NORTHEAST, FRI-MON, OCT
17-20.
SLIGHT RISK OF HIGH WINDS FOR ALEUTIANS, SOUTHERN MAINLAND, AND PARTS OF
SOUTHEAST ALASKA, SAT-TUE, OCT 18-21.
RAPID ONSET DROUGHT (ROD) RISK FOR PORTIONS OF THE SOUTHERN PLAINS AND THE
LOWER MISSISSIPPI VALLEY.
DETAILED SUMMARY
FOR SUNDAY OCTOBER 12 - THURSDAY OCTOBER 16:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY OCTOBER 17 - THURSDAY OCTOBER 23: GOOD AGREEMENT EXISTS BETWEEN THE
GEFS, ECMWF, AND CANADIAN ENSEMBLE MEAN 500-HPA HEIGHT ANOMALY PATTERNS FOR
WEEK-2, CONSISTING OF ANOMALOUS RIDGING ACROSS THE CENTRAL CONUS EXTENDING
NORTHWARD INTO CANADA, BOOKENDED BY A PAIR OF MEAN TROUGHS OVER THE WESTERN AND
EASTERN U.S. CONSISTENT WITH PREVIOUS GUIDANCE, DYNAMICAL MODELS CONTINUE TO
FAVOR BUILDING HEIGHTS NEAR GREENLAND TO FORCE AN AMPLIFYING TROUGH TO THE
SOUTH OVER THE NORTHEASTERN CONUS AND NORTHWESTERN ATLANTIC LATER NEXT WEEK.
THIS MID-LEVEL FEATURE LOOKS TO POTENTIALLY REAMPLIFY BY THE FOLLOWING WEEKEND,
WHICH IS EXPECTED TO BRING SOME PERSISTENCE OF UNSETTLED WEATHER, INCLUDING A
SHOT OF UNSEASONABLY COLD AIR OVERSPREADING PARTS OF THE EASTERN CONUS DURING
THE WEEK-2 PERIOD. BASED ON RAW AND CALIBRATED TEMPERATURE TOOLS, A REDUCTION
IN TEMPERATURES REMAINS FAVORED BY DAY 10 (OCT 19), WHERE THERE ARE INCREASED
CHANCES FOR MINIMUM TEMPERATURES APPROACHING FREEZING LEVELS ACROSS PARTS OF
THE APPALACHIANS, MID-ATLANTIC, GREAT LAKES AND NORTHEAST. ALTHOUGH MANY OF
THESE AREAS TYPICALLY EXPERIENCE THEIR FIRST FREEZES BY MID-OCTOBER (WITH THE
CENTRAL APPALACHIANS FORECAST TO HAVE THEIR FIRST FREEZE IN THE COMING DAYS), A
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES REMAINS POSTED FOR OCT 19-21, AS
ANY RENEWED AUTUMN COLD MAY ADVERSELY IMPACT SENSITIVE VEGETATION WITH FROST
AND/OR FREEZES.
WITH MEAN SURFACE LOW PRESSURE EXPECTED TO PERSIST OFFSHORE OF THE CANADIAN
MARITIMES TIED TO THE RELOADING MID-LEVEL TROUGH, PERIODS OF STRENGTHENING
NORTHWESTERLY FLOW FAVORED SUPPORTS THE POTENTIAL FOR HIGH WINDS OVER THE
NORTHEASTERN CONUS. BASED ON INCREASED SIGNALS IN THE ECMWF PROBABILISTIC
EXTREMES TOOL (PET), A SLIGHT RISK OF HIGH WINDS REMAINS POSTED, AND IS BOTH
EXPANDED IN COVERAGE OVER THE NORTHEAST AND EXTENDED THROUGH DAY 11 (OCT 20)
WITH THE TROUGHING ALOFT FAVORED TO DEAMPLIFY THEREAFTER. FOR PRECIPITATION,
THE HIGHEST AMOUNTS ARE EXPECTED TO BE OFFSHORE, AND THE ENSEMBLES ARE TRENDING
DRIER ON THE BACKSIDE OF THE MEAN LOW EARLY IN WEEK-2. WHILE THE ECMWF PET
CONTINUES TO SHOW INCREASED CHANCES FOR 3-DAY AMOUNTS EXCEEDING THE 85TH
PERCENTILE AND 1 INCH OVER PARTS OF NEW ENGLAND, OTHER TOOLS ARE LESS
SUPPORTIVE OF THIS POTENTIAL, INCLUDING THE RAW ECMWF WHICH HAS SHOWN BETTER
SKILL THAN ITS CALIBRATED COUNTERPART DURING THE PAST SEVERAL WEEKS. THEREFORE,
THE SLIGHT RISK OF HEAVY PRECIPITATION IS DISCONTINUED OVER NORTHERN NEW
ENGLAND IN THE UPDATED OUTLOOK.
ACROSS THE WESTERN CONUS, MUCH OF THE ANOMALOUS TROUGHING FAVORED IS FAVORED TO
DEAMPLIFY, LEADING TO A MODERATION OF TEMPERATURES ACROSS THE WEST COAST AND
PORTIONS OF THE INTERIOR WEST LATE NEXT WEEK. THIS IS REFLECTED IN BOTH THE
GEFS AND ECMWF PETS INDICATING WEAKER (10-20%) CHANCES FOR MINIMUM TEMPERATURES
FALLING BELOW THE 15TH PERCENTILE. THIS SUPPORTS THE REMOVAL OF MUCH BELOW
NORMAL TEMPERATURE HAZARD IN THE UPDATED OUTLOOK AS THE STRONGEST COLD SIGNALS
ARE EXPECTED TO TIME OFF INTO WEEK-1. FOR PRECIPITATION AND WINDS, THERE IS THE
POTENTIAL FOR ENHANCED ONSHORE TO LINGER AND BRING SOME UNSETTLED WEATHER TO
PORTIONS OF THE WEST. HOWEVER, THE GEFS AND ECMWF ENSEMBLES CONTINUE TO DIFFER
WITH RESPECT TO THE ORIENTATION AND STRENGTH OF THE TROUGH, WITH THE LATTER
FAVORING THE STRONGER SOLUTION EARLY IN WEEK-2. REGARDLESS, DUE TO THE OVERALL
DEAMPLIFICATION OF THE TROUGH HEADING INTO WEEK-2, AND TOOLS BEING UNSUPPORTIVE
OF AMOUNTS EXCEEDING HAZARD THRESHOLDS, NO PRECIPITATION OR WIND HAZARDS ARE
ISSUED.
PRECIPITATION DEFICITS OVER THE PAST 30 DAYS RANGE FROM 3 TO 5 INCHES FOR MANY
PARTS OF THE SOUTHERN PLAINS AND INTO THE LOWER MISSISSIPPI VALLEY. THIS
ANTECEDENT DRYNESS COMBINED WITH THE INCREASED LIKELIHOOD OF LITTLE TO NO
PRECIPITATION AND DAILY HIGHS IN THE 80S TO LOWER 90S (DEGREES F) SUPPORT THE
CONTINUATION OF A RAPID ONSET DROUGHT RISK, WITH ITS COVERAGE EXPANDED INTO
SOUTHCENTRAL TEXAS AND INTO PORTIONS OF SOUTHEASTERN OKLAHOMA AND WESTERN
ARKANSAS IN THE UPDATED OUTLOOK.
AMPLIFIED TROUGHING REMAINS FAVORED TO SHIFT EASTWARD FROM THE BERING SEA AND
INTO THE GULF OF ALASKA WHICH IS EXPECTED TO SPAWN ONE OR MORE SURFACE LOWS
DURING WEEK-2. BASED ON THE EVOLUTION OF THE MID-LEVEL PATTERN, AND BETTER
SUPPORT IN THE ENSEMBLES FOR STRONGER MEAN LOW PRESSURE AND IN THE PETS, A
SLIGHT RISK OF HIGH WINDS IS HIGHLIGHTED COVERING THE ALEUTIANS, THE SOUTHERN
MAINLAND, AND PARTS OF THE SOUTHEAST, VALID FROM OCT 18- 21. ABOVE-NORMAL
PRECIPITATION IS ALSO FAVORED ASSOCIATED WITH THE ENHANCED ONSHORE FLOW, THOUGH
TOOLS DO NOT INDICATE AMOUNTS WILL EXCEED HAZARDOUS THRESHOLDS AT THIS TIME.
IN THE TROPICAL ATLANTIC, THE NATIONAL HURRICANE CENTER (NHC) CONTINUES TO
MONITOR TROPICAL STORM JERRY LOCATED TO THE EAST OF THE LESSER ANTILLES AND IS
FORECAST TO TURN NORTH AND BEGIN TO RECURVE. WHILE NO IMPACTS TO THE U.S. ARE
EXPECTED WITH JERRY, ATTENTION REMAINS DRAWN TO THE SOUTHERN CARIBBEAN WHERE
WEEK-2 GUIDANCE CONTINUES TO POINT TO THE DEVELOPMENT OF A CENTRAL AMERICAN
GYRE (CAG) EVENT WHICH IS LIKELY BEING DRIVEN BY REORGANIZING MADDEN-JULIAN
OSCILLATION (MJO) ACTIVITY IN THE TROPICS. SUCH A BROAD SCALE CYCLONIC
ENVIRONMENT EMERGING, ACCOMPANIED BY REDUCED SHEAR, WOULD BECOME QUITE
CONDUCIVE FOR DEVELOPMENT OVER THIS PART OF THE TROPICS, THOUGH MODELS AND
PROBABILISTIC GENESIS TOOLS REMAIN FAIRLY MODEST IN TERMS OF THIS POTENTIAL AT
THIS TIME. THE ECMWF ENSEMBLE FAVORS A NUMBER OF DEVELOPING LOWS IN THE GULF OF
HONDURAS, BUT GENERALLY KEEPS ANY TRACKS AND ANY ASSOCIATED ENHANCED
PRECIPITATION CONFINED TO THE LOWER LATITUDES. THIS POTENTIAL WILL CONTINUE TO
BE MONITORED IN UPCOMING HAZARD OUTLOOKS.
FORECASTER: NICK NOVELLA
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