079
FXUS21 KWNC 101911
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 10 2025
SYNOPSIS: A MID-LEVEL LOW IS FORECAST TO DEVELOP AND INTRUDE INTO THE
CONTIGUOUS U.S. EARLY IN WEEK-2. THIS FEATURE WILL PROGRESS EAST OVER TIME
TRIGGERING THE NEXT ROUND OF POTENTIAL HAZARDOUS WEATHER. THE ASSOCIATED
FRONTAL SYSTEM ENHANCES THE LIKELIHOOD FOR MULTIPLE HAZARDS INCLUDING HEAVY
PRECIPITATION IN THE SOUTH, SNOW FROM THE ROCKIES INTO THE NORTHEAST, AND HIGH
WINDS ACROSS THE WESTERN AND CENTRAL CONUS. BEHIND THIS SYSTEM, INCREASED RISK
FOR MUCH BELOW NORMAL TEMPERATURES ARE ANTICIPATED TO RETURN ACROSS MOST AREAS
ALONG AND EAST OF THE ROCKY MOUNTAINS.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI
VALLEY AND SOUTHEAST, SAT-SUN, JAN 18-19.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI
VALLEY, SOUTHERN PLAINS, AND TENNESSEE VALLEY AND SOUTHEAST, SAT-MON, JAN 18-20.
SLIGHT RISK OF HEAVY SNOW FOR PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES AND
PLAINS, MIDDLE AND UPPER MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS, GREAT LAKES,
CENTRAL AND SOUTHERN APPALACHIANS, MID-ATLANTIC AND NORTHEAST, SAT-MON, JAN
18-20.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS,
MIDDLE AND LOWER MISSISSIPPI VALLEY, SOUTHEAST, APPALACHIANS, AND NORTHEAST,
SAT-MON, JAN 18-20.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE NORTHERN AND
CENTRAL ROCKIES AND NORTHERN PLAINS, SAT-WED, JAN 18-22.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE CENTRAL AND
SOUTHERN ROCKIES, PLAINS, AND THE UPPER AND MIDDLE MISSISSIPPI VALLEY, SUN-THU,
JAN 19-23.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE SOUTHERN PLAINS,
WESTERN GULF COAST, LOWER MISSISSIPPI VALLEY, TENNESSEE AND OHIO VALLEYS,
SOUTHEAST AND GREAT LAKES, MON-FRI, JAN 20-24.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE NORTHEAST,
MID-ATLANTIC, AND SOUTHEAST TUE-FRI, JAN 21-24.
SLIGHT RISK FOR PERIODS OF HIGH WINDS FOR MUCH OF THE FOUR CORNERS AND
SURROUNDING AREAS, SAT-TUE, JAN 18-21.
DETAILED SUMMARY
FOR MONDAY JANUARY 13 - FRIDAY JANUARY 17:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY JANUARY 18 - FRIDAY JANUARY 24: THERE IS MODERATELY GOOD AGREEMENT
AMONG THE DYNAMICAL MODELS REGARDING THE MID-LEVEL HEIGHT FORECAST DURING THE
WEEK-2 PERIOD. AN AMPLIFIED TROUGH IS FORECAST ACROSS THE CENTRAL CONUS AT THE
START OF THE WEEK-2 PERIOD THAT WILL SLOWLY PROGRESS EAST WITH TIME. THE ECENS
WOULD SUPPORT RELOADING THIS TROUGH IN THE SECOND HALF OF WEEK-2 ACROSS THE
WESTERN CONUS WHILE THE GEFS IS MORE SUPPORTIVE OF MID-LEVEL RIDGING INTRUDING
FROM THE NORTHEASTERN PACIFIC.
THE TROUGH FAVORED ACROSS THE WESTERN AND CENTRAL CONUS INCREASES CHANCES FOR
MUCH BELOW NORMAL TEMPERATURES ACROSS THE NORTHERN ROCKIES AND NORTHERN PLAINS
BY THE START OF THE PERIOD. THE ENHANCED CHANCES FOR MUCH BELOW NORMAL
TEMPERATURES THEN DAILY EXPAND SOUTH AND EAST ENVELOPING A LARGE PORTION OF THE
COUNTRY ALONG AND EAST OF THE ROCKY MOUNTAINS FOR MOST OF THE REMAINDER OF THE
WEEK-2 PERIOD. THERE IS GOOD AGREEMENT AMONG THE GEFS AND ECENS PETS FOR A
20-40% CHANCE TEMPERATURES FALL BELOW THE 15TH CLIMATOLOGICAL PERCENTILE IN
MUCH OF THE HIGHLIGHTED AREAS. RAW ENSEMBLE MEANS SHOW DAILY MEAN TEMPERATURES
MORE THAN 10 DEGF BELOW NORMAL. WHILE THESE ANOMALIES ARE FAIRLY SIGNIFICANT
THERE ARE CONCERNS ABOUT THE POTENTIAL FOR THIS COLD AIR TO REACH HAZARDOUS
THRESHOLDS. THE FORECAST SURFACE PATTERN DOES NOT SUPPORT STRONG WINDS
FOLLOWING THE INITIAL COLD AIR ADVECTION THAT WOULD INDUCE MORE ANONYMOUSLY
COLD APPARENT TEMPERATURES. THUS, IT IS DIFFICULT TO ADD A MODERATE RISK FOR
MUCH BELOW NORMAL TEMPERATURES AT THIS TIME. THE BEST AGREEMENT AMONG THE PETS
IS ACROSS PARTS OF THE OHIO VALLEY BEYOND THE DAY 10 TIME FRAME. THEREFORE, A
MODERATE COULD BE ADDED NEXT WEEK IF SIGNALS INCREASE. THEREFORE, FOUR SEPARATE
SLIGHT RISK SHAPES ARE DESIGNATED TODAY TO MATCH THE PROGRESSION OF THE COLD
AIR ADVECTION ACROSS THE COUNTRY. THE FIRST IS FOR PARTS OF THE NORTHERN AND
CENTRAL ROCKIES AND NORTHERN PLAINS, JAN 18-22. THE SECOND IS BROADER ACROSS
MUCH OF THE CENTRAL CONUS, JAN 19-23. THE THIRD COVERS THE GREAT LAKES, OHIO,
TENNESSEE, AND LOWER MISSISSIPPI VALLEYS, JAN 20-24. FINALLY, THE FOURTH
INCLUDES THE NORTHEAST, MID-ATLANTIC, SOUTHEAST, AND GULF COAST, JAN 21-24.
AHEAD OF THE DEVELOPING TROUGH ACROSS THE WEST ONE OR MORE AREAS OF SURFACE LOW
PRESSURE ARE FORECAST TO DEVELOP. THESE SYSTEMS WOULD BRING ELEVATED CHANCES OF
HEAVY RAIN AND SNOW, AND HIGH WINDS TO PARTS OF THE CENTRAL CONUS. IN THE
SOUTHEAST AND SURROUNDING AREAS THE PRECIPITATION HAZARD WOULD LIKELY COME IN
THE FORM OF HEAVY RAIN. THIS IS CONSISTENT WITH THE GEFS AND ECENS PETS SHOWING
INCREASED (30-50%) CHANCES FOR 3 DAY PRECIPITATION AMOUNTS EXCEEDING THE 85TH
PERCENTILE AND 1 INCH IN THE LOWER MISSISSIPPI VALLEY EAST INTO PARTS OF
ALABAMA AND GEORGIA. SOME OF THE RAW ENSEMBLE GUIDANCE SUPPORTS GREATER THAN 2
INCHES OF PRECIPITATION IN 3 DAYS ACROSS THE HIGHLIGHTED REGION. THIS SUPPORTS
A MODERATE RISK OF HEAVY PRECIPITATION WHICH IS POSTED FOR THESE AREAS FOR JAN
18-19. THE PETS AND RAW MODEL GUIDANCE FURTHER SUPPORT A BROADER SLIGHT RISK
AREA FROM EASTERN TEXAS THROUGH LOWER MISSISSIPPI AND TENNESSEE VALLEYS,
SOUTHEAST, AND MID-ATLANTIC FOR JAN 18-20.
FROM THE CENTRAL AND SOUTHERN ROCKIES STRETCHING THROUGH THE PLAINS AND
MISSISSIPPI VALLEY INTO THE GREAT LAKES, CENTRAL APPALACHIANS AND NORTHEAST,
THERE ARE INCREASED CHANCES FOR HEAVY SNOW. THIS IS CONSISTENT WITH THE GEFS
SNOW WATER EQUIVALENT (SWE) PET AND RAW GUIDANCE FROM THE ECENS SHOWING THE
POTENTIAL FOR MULTIPLE CHANCES FOR HEAVY SNOW IN THESE BROAD REGIONS. EARLY IN
THE HAZARD PERIOD, THE MOST LIKELY AREAS FOR HEAVY SNOW ARE ACROSS THE FOUR
CORNERS AND SEPARATELY THE GREAT LAKES. AS THE SYSTEM IN THE ROCKIES DEVELOPS
AND PROGRESSES EAST AND SNOW CHANCES SHIFT INTO THE PLAINS AND MISSISSIPPI
VALLEY. FOLLOWING THE PROGRESSION OF THE SYSTEM INTO THE PLAINS, DYNAMICAL
MODELS THEN BECOME MORE DIFFLUENT WITH CHANCES FOR A SECOND SYSTEM TO DEVELOP
AND BRING ADDITIONAL SNOW TO SIMILAR REGIONS BUT PERHAPS SLIGHTLY FURTHER SOUTH
AND EAST. AT THIS TIME, IT REMAINS DIFFICULT TO DEFINE THE INDIVIDUAL SYSTEM
TRACKS AND TIMING. THEREFORE, A BROAD SLIGHT RISK OF HEAVY SNOW IS POSTED FOR A
LARGE PORTION OF THE CONUS FOR JAN 18-20.
FINALLY, COLD AIR ADVECTION FOLLOWING THE FRONTAL PASSAGE AND STRONG PRESSURE
GRADIENT NEAR THE SURFACE LOW PRESSURE AREAS INCREASES THE RISK FOR HIGH WINDS
ACROSS PARTS OF THE CENTRAL AND SOUTHERN PLAINS, MIDDLE AND UPPER MISSISSIPPI
VALLEY AND WESTERN GREAT LAKES FOR JAN 18-20.
AS MID-LEVEL TROUGHING DEVELOPS ACROSS THE WEST, PERIODS OF EPISODIC HIGH WINDS
ARE FORECAST TO DEVELOP ACROSS THE FOUR CORNERS AND SURROUNDING AREAS SUPPORTED
BY THE WIND PETS FROM THE GEFS AND ECENS. A BROAD SLIGHT RISK OF HIGH WINDS IS
FORECAST FOR THIS AREA FOR JAN 18-21. BY THE END OF THE PERIOD, MID-LEVEL
RIDGING MAY BEGIN DEVELOPING ACROSS THE REGION, REDUCING CHANCES FOR HIGH WINDS.
IN SOUTHERN CALIFORNIA, TOOLS HAVE LOWER CONFIDENCE IN THE DEVELOPMENT OF AN
INVERTED TROUGH OFFSHORE. SURFACE HIGH PRESSURE ACROSS THE GREAT BASIN ALSO
DOES NOT APPEAR TO BE AS ROBUST AS IN PRIOR DAYS. THEREFORE, NO HAZARD IS
POSTED TODAY, BUT THIS AREA WILL CONTINUE TO BE MONITORED AS THERE ARE SOME
INCREASING SIGNALS FOR SURFACE HIGH PRESSURE IN THE GREAT BASIN BY THE SECOND
HALF OF WEEK-2.
IN ALASKA, BY THE MIDDLE THROUGH THE END OF THE WEEK-2 PERIOD, THERE ARE
SIGNALS FOR STRONG HIGH PRESSURE ACROSS NORTHERN ALASKA AND IN THE YUKON.
HOWEVER, THE HIGH MAY BE PROGRESSING TOO RAPIDLY TO INITIATE STRONG GAP WINDS
IN SOUTHERN ALASKA. NO HAZARDS ARE POSTED TODAY DUE TO THIS UNCERTAINTY BUT THE
AREA WILL CONTINUE TO BE MONITORED.
FORECASTER: RYAN BOLT
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