118
FXUS21 KWNC 081813
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 08 2024
SYNOPSIS: MODELS CONTINUE TO TREND TOWARD A STRONGER AREA OF 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,
WED-THU, OCT 16-17.
SLIGHT RISK FOR MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE MIDWEST,
TENNESSEE AND OHIO VALLEYS, APPALACHIANS, MID-ATLANTIC, AND NORTHEAST.,
WED-FRI, OCT 16-18.
SLIGHT RISK FOR HIGH WINDS ACROSS COASTAL PORTIONS OF CALIFORNIA, WED-THU, OCT
16-17.
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 FRIDAY OCTOBER 11 - TUESDAY OCTOBER 15:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY OCTOBER 16 - TUESDAY OCTOBER 22: 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. THERE IS A STRONGER SIGNAL IN THE GEFS AND ECENS PROBABILISTIC
EXTREMES TOOLS (PETS) COMPARED TO YESTERDAY, WITH MORE AREAS HAVING AT LEAST A
20-40 PERCENT CHANCE MINIMUM TEMPERATURES FALL BELOW THE 15TH CLIMATOLOGICAL
PERCENTILE. PROBABILITIES INCREASE ABOVE 40 PERCENT 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 16-17, WITH A SLIGHT RISK CONTINUING THROUGH OCT 18. COLD
OVERNIGHT TEMPERATURES ALSO REMAIN POSSIBLE OVER PARTS OF THE UPPER MIDWEST AT
THE OUTSET OF WEEK-2. HOWEVER, THIS REGION WAS EXCLUDED GIVEN THAT THE INITIAL
IMPACTS OF A FIRST FROST/FREEZE ARE MORE LIKELY TO OCCUR IN WEEK-1, WITH
TEMPERATURES BEGINNING TO TREND UPWARD BY THE START OF THE PERIOD. 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
NEAR- TO ABOVE-NORMAL TEMPERATURES FOR WEEK-2 AS A WHOLE.
HURRICANE MILTON IS A POWERFUL CATEGORY-4 HURRICANE LOCATED TO THE NORTH OF THE
YUCATAN PENINSULA. THE NATIONAL HURRICANE CENTER (NHC) FORECASTS SOME WEAKENING
OF THE SYSTEM PRIOR TO STRIKING THE WEST COAST OF FLORIDA LATE WEDNESDAY INTO
EARLY THURSDAY. MILTON IS FORECAST TO BRING VERY HEAVY RAINFALL (LOCALLY UP TO
18 INCHES) ACROSS NORTHERN AND CENTRAL PORTIONS OF THE FLORIDA PENINSULA. WHILE
THIS RAIN IS FORECAST DURING THE WEEK-1 PERIOD, THE FLOODING CONCERNS ARE
LIKELY TO LINGER INTO WEEK-2 SUPPORTING A POSSIBLE FLOODING HAZARD OVER THESE
AREAS. WEEK-1 RAINFALL TOTALS ARE LOWER ACROSS THE SOUTHERN FLORIDA PENINSULA
AND THE FLOODING HAZARD IS REMOVED FROM THIS REGION. THERE IS ALSO MORE
UNCERTAINTY REGARDING ANOTHER NORTHWARD PUSH OF TROPICAL MOISTURE OUT OF THE
CARIBBEAN DURING WEEK-2, WITH TODAY’S GUIDANCE TRENDING STRONGER WITH THE
SURFACE HIGH OVER THE EAST. THEREFORE, THE SLIGHT RISK OF HEAVY PRECIPITATION
IS DISCONTINUED.
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. AN ENHANCED THERMAL GRADIENT MAY
RESULT IN INCREASED WIND SPEEDS ALONG COASTAL CALIFORNIA. WHILE THERE IS NO
SIGNAL IN THE PETS, THE UNCALIBRATED 0Z GEFS AND ECENS DEPICT ELEVATED CHANCES
FOR WIND SPEEDS GREATER THAN 20-KNOTS OFF THE CALIFORNIA COAST EARLY IN THE
PERIOD. THEREFORE, A SLIGHT RISK FOR HIGH WINDS IS POSTED FOR OCT 16-17.
NO HAZARDS ARE FORECAST ACROSS ALASKA AS IMPACTFUL WEATHER RELATED TO A SURFACE
LOW OVER THE GULF OF ALASKA HAS SHIFTED INTO THE WEEK-1 PERIOD. ANOTHER STORM
SYSTEM MAY BRING ENHANCED ONSHORE FLOW AND AN ASSOCIATED INCREASE IN
PRECIPITATION CHANCES ACROSS PORTIONS OF SOUTHEASTERN ALASKA AND THE PACIFIC
NORTHWEST DURING WEEK-2, BUT TOOLS DO NOT INDICATE ANY WIDESPREAD HAZARDOUS
WEATHER.
FORECASTER: THOMAS COLLOW
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