763
FXUS21 KWNC 091747
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 09 2026
SYNOPSIS: RENEWED MID-LEVEL LOW PRESSURE FAVORS THE RETURN OF ANOMALOUS COLD
AIR OVER THE EASTERN CONTIGUOUS U.S. (CONUS), SUPPORTING INCREASED CHANCES FOR
MUCH BELOW NORMAL TEMPERATURES AND FIRST FALL FROSTS AND/OR FREEZES OVER PARTS
OF THE NORTHEAST, NORTHERN MID-ATLANTIC, AND GREAT LAKES. IN THE WAKE OF THE
PREDICTED FRONTAL SYSTEM, A MORE TRANQUIL PATTERN IS EXPECTED, REDUCING THE
RISK OF ADDITIONAL WEATHER RELATED HAZARDS LATER IN THE WEEK-2 PERIOD. OVER
ALASKA, WEAK CYCLONIC FLOW OVER THE GULF OF ALASKA SUPPORTS ABOVE-NORMAL
PRECIPITATION AND PERIODS OF HIGH WINDS FOR PARTS OF THE SOUTHERN MAINLAND AND
SOUTHEAST, THOUGH CONDITIONS ARE EXPECTED TO REMAIN BELOW HAZARD THRESHOLDS.
HAZARDS
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR NORTHEAST, AND PARTS OF THE
GREAT LAKES, APPALACHIANS, AND MID-ATLANTIC, SUN-MON, OCT 18-19.
DETAILED SUMMARY
FOR MONDAY OCTOBER 12 - FRIDAY OCTOBER 16:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY OCTOBER 17 - FRIDAY OCTOBER 23: THE HAZARDS PERSPECTIVE LARGELY
REMAINS ON TRACK SINCE YESTERDAY. THE LATEST 0Z GUIDANCE FROM THE ECENS AND
GEFS ENSEMBLES CONTINUES TO FEATURE 500-HPA TROUGHING SHIFTING EASTWARD AND
DIGGING OVER THE EASTERN U.S., WITH AN AMPLIFIED RIDGE AXIS CENTERED THROUGHOUT
MUCH OF THE WESTERN CONUS AND WESTERN CANADA UPSTREAM. AT THE SURFACE, A MEAN
LOW PRESSURE SYSTEM AND A LARGE FRONTAL BOUNDARY IS EXPECTED TO SWEEP ACROSS
MUCH OF THE EASTERN TWO THIRDS OF THE CONUS, WITH A FAIRLY STRONG MEAN SURFACE
HIGH DESCENDING FROM THE CANADIAN PRAIRIES LATE NEXT WEEK. THE EXTENT OF COLD
AIR ADVECTION FAVORED IS FAIRLY IMPRESSIVE, WHERE THERE IS GOOD ENSEMBLE
AGREEMENT FEATURING DOUBLE DIGIT 24-HOUR TEMPERATURE DROPS FROM THE SOUTHERN
PLAINS TO THE NORTHEAST EARLY IN THE PERIOD. WHILE THIS LOOKS TO BRING A RUSH
OF COLD AIR TO PROMOTE FIRST FALL FROST AND/OR FREEZES FOR THE HIGHER LATITUDES
OF THE CONUS EARLY IN THE PERIOD, THE DRIER AIR LOOKS TO ABATE ANY HEAVY
PRECIPITATION RISKS, AND TEMPERATURES ARE ALSO FAVORED TO MODERATE FAIRLY
QUICKLY AS MUCH OF THE ANOMALOUS HIGH SURFACE PRESSURE LOOKS TO WEAKEN AND
SETTLE OVER MUCH OF THE CENTRAL AND EASTERN U.S. CONCURRENTLY, EXPANDING
MID-LEVEL POSITIVE HEIGHT DEPARTURES ARE FAVORED ALOFT, AND THE PATTERN OVERALL
APPEARS TO BE QUITE TRANQUIL AND FREE OF HAZARDOUS WEATHER RISKS FOR MUCH OF
THE CONUS LATER IN THE WEEK-2 PERIOD.
WITH RENEWED NORTHEASTERLY FLOW ALOFT FAVORED DOWNSTREAM OF THE AMPLIFIED RIDGE
AXIS, A SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES IS POSTED OVER
NORTHEASTERN CONUS FOR OCT 18-19. WHILE PROBABILISTIC EXTREME TOOLS (PETS)
FROM THE GEFS AND ECENS SHOW STRONGEST SIGNALS FOR MINIMUM TEMPERATURES FALLING
BELOW THE 15TH CLIMATOLOGICAL PERCENTILE FURTHER SOUTH ACROSS SOUTHERN PLAINS,
THERE IS A LARGE COVERAGE OF 20% CHANCES THAT WELL DELINEATE THE FRONTAL
BOUNDARY EXTENDING INTO THE NORTHEASTERN CONUS, WHERE CHANCES FOR SUBFREEZING
TEMPERATURES ARE HIGHEST. CLIMATOLOGICALLY, FIRST FALL FREEZES GENERALLY OCCUR
BETWEEN LATE SEPTEMBER THROUGH MID-OCTOBER FOR THIS PART OF THE COUNTRY, THOUGH
ANY TEMPERATURES DIPPING TO NEAR FREEZING LEVELS MAY STILL TRIGGER COLD
TEMPERATURE ADVISORIES FOR AREAS THAT HAVE NOT EXPERIENCED THEIR FIRST FROST
AND/OR FREEZES EARLY IN THE PERIOD.
FOR PRECIPITATION, THE SLIGHT RISK OF HEAVY PRECIPITATION IS DISCONTINUED TODAY
BASED ON A REDUCTION OF SIGNALS IN THE RAW AND CALIBRATED PROBABILISTIC TOOLS
FROM BOTH THE GEFS AND ECENS. SOME ENHANCED PRECIPITATION AMOUNTS MAY LINGER
ALONG THE FRONTAL BOUNDARY OVER THE EASTERN U.S., THOUGH IT APPEARS THE
HIGHEST, POTENTIALLY HEAVY AMOUNTS WILL HAVE TIMED OFF BY THE START OF WEEK-2.
DESPITE THE PREDOMINATELY DRIER CONDITIONS FAVORED, IT IS WORTH NOTING THAT ANY
ADDITIONAL PRECIPITATION AMOUNTS DURING WEEK-2 MAY WORSEN ALREADY SATURATED
GROUND CONDITIONS AND TRIGGER LOCALIZED FLOODING FOLLOWING HEAVY RAINFALL FROM
HURRICANE ISAIAS AND ITS REMNANTS OVER MANY PARTS OF THE SOUTHEASTERN CONUS
DURING WEEK-1. PETS ALSO SHOW INCREASED SIGNALS FOR WIND SPEEDS EXCEEDING THE
85TH PERCENTILE ACROSS PARTS OF THE EASTERN U.S., THOUGH WIND SPEEDS ARE
EXPECTED TO REMAIN BELOW HAZARD THRESHOLDS WITH THE MEAN SURFACE HIGH WEAKENING
IN THE WAKE OF THE FRONTAL BOUNDARY.
OVER ALASKA, MUCH OF THE TROUGHING FAVORED LATE IN WEEK-1 REMAINS FAVORED TO
DEAMPLIFY BY THE OUTSET OF WEEK-2. WHILE THERE REMAINS SOME WEAKLY RESIDUAL
CYCLONIC FLOW OVER THE GULF OF ALASKA TO PROMOTE UNSETTLED WEATHER, TOOLS
CONTINUE TO BECOME LESS SUPPORTIVE OF PRECIPITATION AND WINDS EXCEEDING HAZARD
THRESHOLDS, AND THE SLIGHT RISKS OF HEAVY PRECIPITATION AND HIGH WINDS ARE
DISCONTINUED IN THE UPDATED OUTLOOK. GIVEN SOME POTENTIAL FOR ADDITIONAL
TROPICAL CYCLONE ACTIVITY IN THE WESTERN PACIFIC DURING WEEK-2, ANY RECURVING
TROPICAL DISTURBANCES BECOMING ABSORBED IN THE EXTRATROPICAL WESTERLIES AND
AMPLIFYING THE MID-LEVEL PATTERN OVER THE NORTHERN PACIFIC WILL CONTINUE TO BE
MONITORED.
FORECASTER: NICK NOVELLA
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