282
FXUS21 KWNC 091836
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 09 2024
SYNOPSIS: MODELS CONTINUE TO DEPICT MID-LEVEL LOW PRESSURE MOVING THROUGH THE
EASTERN CONTIGUOUS U.S. (CONUS) LATE IN WEEK-1 INTO EARLY WEEK-2. THIS FAVORS A
QUICK SHOT OF COLD AIR INTO THE REGION, WITH OVERNIGHT TEMPERATURES SUPPORTIVE
OF FIRST FROSTS AND FREEZES. HOWEVER, PREVAILING MID-LEVEL HIGH PRESSURE FAVORS
PERSISTENT ABOVE-NORMAL TEMPERATURES ACROSS THE REMAINDER OF THE CONUS, WITH A
MODERATION OF TEMPERATURES LIKELY IN THE EAST BY THE MIDDLE OF THE PERIOD.
FLOODING IN THE WAKE OF HURRICANE MILTON REMAINS A CONCERN FOR PARTS OF FLORIDA.
HAZARDS
MODERATE RISK FOR MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE OHIO
AND TENNESSEE VALLEYS, APPALACHIANS, INTERIOR MID-ATLANTIC, AND NORTHEAST, THU,
OCT 17.
SLIGHT RISK FOR MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE TENNESSEE
AND OHIO VALLEYS, APPALACHIANS, MID-ATLANTIC, AND NORTHEAST., THU-FRI, OCT
17-18.
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS THE PACIFIC NORTHWEST, THU-SUN, OCT
17-20.
POSSIBLE FLOODING FOR PARTS OF THE FLORIDA PENINSULA.
RISK OF RAPID ONSET DROUGHT (ROD) ACROSS PORTIONS OF THE GREAT PLAINS AND
MISSISSIPPI VALLEY.
DETAILED SUMMARY
FOR SATURDAY OCTOBER 12 - WEDNESDAY OCTOBER 16:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY OCTOBER 17 - WEDNESDAY OCTOBER 23: TODAY’S 0Z GEFS, ECENS, AND
CMCE MODELS CONTINUE TO DEPICT A ROBUST SHORTWAVE TROUGH QUICKLY MOVING THROUGH
THE EASTERN CONUS LATE IN WEEK-1 INTO THE EARLY PORTION OF WEEK-2. THIS FEATURE
FAVORS A SHORT BURST OF ANOMALOUSLY COLD TEMPERATURES ACROSS THE REGION, AND
GIVEN THE TIME OF YEAR, IT IS LIKELY THAT SOME LOCATIONS WILL EXPERIENCE THEIR
FIRST FROST OR FREEZE. SURFACE HIGH PRESSURE IS FORECAST TO BE CENTERED OVER
THE TENNESSEE VALLEY AND APPALACHIANS, SETTING UP IDEAL RADIATIONAL COOLING
CONDITIONS. THE GEFS AND ECENS PROBABILISTIC EXTREMES TOOLS (PETS) CONTINUE TO
DEPICT MANY AREAS HAVING A 20-40 PERCENT CHANCE MINIMUM TEMPERATURES FALL BELOW
THE 15TH CLIMATOLOGICAL PERCENTILE. PROBABILITIES INCREASE ABOVE 40 PERCENT IN
THE ECENS PET ACROSS PORTIONS OF THE OHIO AND TENNESSEE VALLEYS, APPALACHIANS,
AND MID-ATLANTIC. BASED ON THE UNCALIBRATED GUIDANCE FROM THE GEFS AND ECENS,
THE HIGHEST LIKELIHOOD OF SUBFREEZING TEMPERATURES IS CONFINED TO THE
APPALACHIANS AND NEW ENGLAND. HOWEVER, A MUCH BROADER AREA OF THE EAST HAS THE
POTENTIAL FOR OVERNIGHT TEMPERATURES TO DIP INTO THE 30S DEG F, WHICH WOULD BE
COLD ENOUGH TO SUPPORT A FIRST FROST OVER MANY AREAS WITH SUSCEPTIBLE
VEGETATION. AS A RESULT, A MODERATE RISK FOR MUCH BELOW NORMAL TEMPERATURES IS
HIGHLIGHTED ACROSS PORTIONS OF THE OHIO AND TENNESSEE VALLEYS, APPALACHIANS,
INTERIOR MID-ATLANTIC, AND NORTHEAST ON OCT 17, WITH A SLIGHT RISK CONTINUING
THROUGH OCT 18. TEMPERATURES ARE PREDICTED TO BE TRENDING UPWARD BY THE START
OF THE PERIOD ACROSS THE MIDWEST AND THEREFORE NOT INCLUDED IN THE BELOW NORMAL
TEMPERATURE HAZARD. THIS WARMING TREND IS FORECAST TO QUICKLY SPREAD EASTWARD
AS ANOMALOUS RIDGING EXPANDS OVER THE CONUS, WITH MANY AREAS OF THE EAST
TRANSITIONING FROM HIGH PROBABILITIES OF BELOW-NORMAL TEMPERATURES DURING THE
6-10 DAY PERIOD TO ENHANCED CHANCES FOR ABOVE-NORMAL TEMPERATURES FOR WEEK-2 AS
A WHOLE.
HURRICANE MILTON IS FORECAST TO MAKE LANDFALL ALONG THE WEST-CENTRAL FLORIDA
COASTLINE TONIGHT AND BRING VERY HEAVY RAINFALL (LOCALLY UP TO 18 INCHES)
ACROSS NORTHERN AND CENTRAL PORTIONS OF THE FLORIDA PENINSULA. WHILE THIS RAIN
IS FORECAST OVER THE NEXT DAY, THE MAGNITUDE OF RAINFALL MAY RESULT IN FLOODING
CONCERNS LINGERING INTO WEEK-2 SUPPORTING A POSSIBLE FLOODING HAZARD OVER THESE
AREAS. MODELS AND THE PETS INDICATE ENHANCED CHANCES FOR INCREASED RAINFALL
OVER PORTIONS OF SOUTH FLORIDA DURING THE PERIOD, BUT AMOUNTS ARE MARGINAL AND
NO RELATED PRECIPITATION HAZARD IS POSTED AT THIS TIME.
WARM, DRY WEATHER IS FORECAST ACROSS THE WESTERN AND CENTRAL CONUS DURING
WEEK-2. THE RAPID ONSET DROUGHT (ROD) RISK AREA OVER THE GREAT PLAINS AND
WESTERN MISSISSIPPI VALLEY IS MAINTAINED BASED ON THE ANTICIPATED ANOMALOUSLY
WARM TEMPERATURES, 30-DAY PRECIPITATION DEFICITS, LOW SOIL MOISTURE, AND LITTLE
PREDICTED RAINFALL DURING THE NEXT TWO WEEKS. A WEAKENING THERMAL GRADIENT AND
TROUGHING MOVING INLAND ACROSS THE WEST SUPPORTS DISCONTINUING THE HIGH WIND
HAZARD ALONG THE CALIFORNIA COAST.
INCREASED ONSHORE FLOW IS FORECAST ACROSS THE PACIFIC NORTHWEST AND BOTH THE
ECENS AND GEFS PETS DEPICT AT LEAST A 20 PERCENT CHANCE 3-DAY PRECIPITATION
TOTALS EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND 1.5 INCHES. WHILE THIS IS
MARGINAL IN TERMS OF A HAZARD, THERE HAS BEEN A GRADUAL UPTICK IN PRECIPITATION
SIGNALS DURING THE PAST FEW DAYS. THEREFORE, A SLIGHT RISK OF HEAVY
PRECIPITATION IS INTRODUCED ACROSS WESTERN PORTIONS OF WASHINGTON AND OREGON,
OCT 17-20. THE PETS ALSO SHOW AN INCREASED SIGNAL FOR HIGH WINDS, BUT
SYNOPTICALLY THE STRONGEST PRESSURE GRADIENTS ARE ACROSS WESTERN CANADA, AND
THE UNCALIBRATED TOOLS DO NOT DEPICT ANY ENHANCED PROBABILITIES FOR WIND SPEEDS
EXCEEDING 20-MPH. THEREFORE, A RELATED WIND HAZARD IS NOT POSTED. ONSHORE FLOW
IS ALSO FORECAST TO CONTINUE ACROSS SOUTHEASTERN ALASKA, ALTHOUGH PRECIPITATION
AMOUNTS AND WIND SPEEDS ARE UNLIKELY TO REACH HAZARDS THRESHOLDS, WHICH ARE
HIGHER COMPARED TO OVER THE NORTHWESTERN CONUS.
FORECASTER: THOMAS COLLOW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page