051
FXUS21 KWNC 111747
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 11 2024
SYNOPSIS: A GENERALLY QUIET PATTERN IS PREDICTED ACROSS THE CONTIGUOUS U.S.
(CONUS) DURING WEEK-2, WITH MID-LEVEL HIGH PRESSURE SHIFTING INTO THE EAST
FAVORING ABOVE-NORMAL TEMPERATURES. LATE IN WEEK-1 INTO THE OUTSET OF WEEK-2,
MID-LEVEL LOW PRESSURE IS FORECAST TO DIG INTO THE WESTERN CONUS. THIS FEATURE,
COMBINED WITH RETURN FLOW AROUND SURFACE HIGH PRESSURE IN THE EAST, FAVORS AN
UPTICK IN PRECIPITATION CHANCES ACROSS THE GREAT PLAINS WHICH MAY HELP
ALLEVIATE ONGOING DROUGHT CONDITIONS. ENHANCED ONSHORE FLOW MAY BRING ROUNDS OF
HEAVY PRECIPITATION INTO THE PACIFIC NORTHWEST. FLOODING IN THE WAKE OF
HURRICANE MILTON REMAINS A CONCERN OVER PARTS OF FLORIDA.
HAZARDS
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST,
SAT-SUN, OCT 19-20.
POSSIBLE FLOODING FOR THE NORTHERN AND CENTRAL FLORIDA PENINSULA.
RISK OF RAPID ONSET DROUGHT (ROD) ACROSS PORTIONS OF EASTERN TEXAS, NORTHERN
LOUISIANA, AND SOUTHERN ARKANSAS.
DETAILED SUMMARY
FOR MONDAY OCTOBER 14 - FRIDAY OCTOBER 18:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY OCTOBER 19 - FRIDAY OCTOBER 25: TROUGHING OVER THE EAST DURING
WEEK-1 FAVORS A PERIOD OF ANOMALOUSLY COLD TEMPERATURES OVER PARTS OF THE
REGION. THIS FEATURE IS FORECAST TO EXIT BY THE START OF WEEK-2 BUT SURFACE
HIGH PRESSURE ACROSS THE NORTHEAST FAVORS A CHILLY NIGHT LEADING INTO DAY-8,
WITH THE UNCALIBRATED 0Z ECENS DEPICTING MINIMUM TEMPERATURES IN THE 30S DEG F
ACROSS THE APPALACHIANS AND INTERIOR NORTHEAST. THIS IS NOT OUT OF THE ORDINARY
PER LATE OCTOBER CLIMATOLOGY AND THE 0Z GEFS IS GENERALLY A FEW DEGREES WARMER,
PRECLUDING A RELATED TEMPERATURE HAZARD. ANOMALOUS RIDGING AND UNSEASONABLY
WARM TEMPERATURES ARE FORECAST TO BECOME WIDESPREAD ACROSS MUCH OF THE EAST
WITH HIGH TEMPERATURES AT LEAST 10 DEG F ABOVE-NORMAL POSSIBLE OVER THE MIDWEST
AND GREAT LAKES LATE IN WEEK-1 INTO THE START OF WEEK-2. THIS WARMTH IS FAVORED
TO EXPAND EASTWARD WITH TIME, ALTHOUGH THE ECENS IS SLIGHTLY LESS ROBUST
REGARDING THE MAGNITUDE OF THE POSITIVE TEMPERATURE ANOMALIES IN THE EASTERN
CONUS COMPARED TO THE GEFS.
HURRICANE MILTON MADE LANDFALL ON OCT 9 NEAR SIESTA KEY, FLORIDA. WHILE THE
SYSTEM HAS SINCE DEPARTED AND COMPLETED EXTRATROPICAL TRANSITION OVER THE
ATLANTIC, EXTENSIVE FLOODING IS ONGOING AND IS FORECAST TO CONTINUE THROUGH
WEEK-1 AND POSSIBLY INTO WEEK-2. THEREFORE, THE FLOODING POSSIBLE AREA REMAINS
POSTED ACROSS PORTIONS OF THE NORTHERN AND CENTRAL FLORIDA PENINSULA. MODELS
AND THE PROBABILISTIC EXTREMES TOOLS (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.
TROUGHING IS FORECAST OVER THE WEST-CENTRAL CONUS AT THE START OF THE PERIOD
FAVORING ENHANCED PRECIPITATION CHANCES ACROSS THE GREAT PLAINS TIED TO A COLD
FRONT AND ALSO AIDED BY SOUTHERLY RETURN FLOW AROUND SURFACE HIGH PRESSURE OVER
THE EAST. BOTH THE GEFS AND ECENS PETS DEPICT SOME AREAS OF THE SOUTHERN PLAINS
HAVING AT LEAST A 20 PERCENT CHANCE 3-DAY PRECIPITATION TOTALS EXCEED THE 85TH
CLIMATOLOGICAL PERCENTILE AND 1-INCH. HOWEVER, NO RELATED PRECIPITATION HAZARD
IS DESIGNATED AS ANY PRECIPITATION WOULD BE BENEFICIAL CONSIDERING THE ONGOING
DROUGHT CONDITIONS. BEHIND THE FRONT, ELEVATED WIND SPEEDS ARE POSSIBLE ACROSS
PORTIONS OF THE NORTHERN ROCKIES AND PLAINS, WITH THE ECENS PET DEPICTING AT
LEAST A 20 PERCENT CHANCE WIND SPEEDS EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE
AND 20-MPH. HOWEVER, NO HAZARD IS POSTED DUE TO THE LACK OF A SIGNIFICANT
SIGNAL IN THE UNCALIBRATED GEFS OR ECENS. GIVEN THE UPTICK IN THE PRECIPITATION
SIGNALS OVER THE CENTRAL CONUS, THE RAPID ONSET DROUGHT (ROD) RISK IS CONFINED
TO PORTIONS OF EASTERN TEXAS, NORTHERN LOUISIANA, AND SOUTHERN ARKANSAS. THESE
AREAS REMAIN FAVORED TO HAVE LESS PRECIPITATION COMPARED TO FARTHER NORTH AND
WEST, AND THE POTENTIAL FOR TEMPERATURES IN THE 80S DEG F SUPPORTS HIGHER
EVAPOTRANSPIRATION RATES.
THE MID-LEVEL PATTERN IS FORECAST TO REMAIN CONDUCIVE FOR ENHANCED ONSHORE FLOW
ACROSS THE NORTHWESTERN CONUS EARLY IN WEEK-2, WITH THE POTENTIAL FOR ANOTHER
WEAKNESS IN THE MID-LEVEL HEIGHT FIELD MOVING INTO THE REGION. 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 OVER THE PACIFIC
NORTHWEST EARLY IN THE PERIOD. WHILE THIS IS MARGINAL IN TERMS OF A HAZARD,
THERE HAS BEEN A CONSISTENT PRECIPITATION SIGNAL OVER THE PAST FEW DAYS.
THEREFORE, A SLIGHT RISK OF HEAVY PRECIPITATION IS HIGHLIGHTED ACROSS WESTERN
PORTIONS OF WASHINGTON AND OREGON, OCT 19-20, CORRESPONDING WITH THE STRONGEST
SIGNALS IN THE DAILY GUIDANCE. THE UNCALIBRATED GEFS AND ASSOCIATED PET DEPICT
MUCH STRONGER COLD SIGNALS ACROSS THE WEST EARLY IN WEEK-2 COMPARED TO THE
ECENS GUIDANCE. DUE TO THESE DIFFERENCES, ALONG WITH THE COLDEST TEMPERATURES
ALIGNED WITH CLIMATOLOGY, NO RELATED TEMPERATURE HAZARD IS POSTED. HOWEVER,
SOME SNOW CANNOT BE RULED OUT ACROSS HIGHER ELEVATIONS OF THE CASCADES AND
ROCKIES. RIDGING FORECAST ACROSS ALASKA FAVORS DECREASING PRECIPITATION TOTALS
ACROSS THE SOUTHEASTERN PART OF THE STATE RELATIVE TO WEEK-1.
FORECASTER: THOMAS COLLOW
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