069
FXUS21 KWNC 282011
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 28 2024
SYNOPSIS: MULTIPLE MODEL ENSEMBLES DEPICT AN ENHANCED FLOW OF GULF OF MEXICO
MOISTURE MOVING OVER MUCH OF THE EASTERN CONTIGUOUS U.S. (CONUS) AT THE OUTSET
OF WEEK-2, BRINGING THE INCREASED POTENTIAL FOR HEAVY PRECIPITATION TO THE
REGION. A PREDICTED STALLED FRONTAL SYSTEM PROLONGS THE RISK FOR HEAVY
PRECIPITATION OVER THE SOUTHEAST U.S. INTO THE MIDDLE OF THE FORECAST PERIOD.
PASSING MID-LEVEL DISTURBANCES BRING THE ENHANCED POTENTIAL FOR HEAVY RAIN AND
HIGH WINDS TO THE WEST COAST, AS WELL AS HEAVY SNOW TO HIGHER ELEVATIONS IN
PORTIONS OF THE WESTERN CONUS DURING WEEK-2. MODELS DEPICT A DEEP SURFACE LOW
PRESSURE MOVING OVER THE GREAT PLAINS AND GREAT LAKES REGIONS DURING WEEK-2,
BRINGING WITH IT THE POTENTIAL FOR HIGH WINDS.
HAZARDS
SLIGHT RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF THE TENNESSEE, OHIO, AND
LOWER AND MIDDLE MISSISSIPPI VALLEYS, SOUTHERN APPALACHIANS, MID-ATLANTIC, AND
SOUTHEASTERN U.S., THU-SUN, MAR 7-10.
SLIGHT RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF THE CENTRAL APPALACHIANS,
MID-ATLANTIC, AND NORTHEAST U.S., THU-FRI, MAR 7-8.
SLIGHT RISK FOR HEAVY PRECIPITATION FOR PORTIONS OF CALIFORNIA, SUN-TUE, MAR
10-12.
SLIGHT RISK FOR HIGH WINDS FOR PORTIONS OF THE GREAT PLAINS, MIDDLE AND UPPER
MISSISSIPPI VALLEY,
THU-MON, MAR 7-11.
SLIGHT RISK FOR HIGH WINDS FOR PORTIONS OF THE OHIO VALLEY AND GREAT LAKES
REGION, SAT-MON, MAR 9-11.
SLIGHT RISK FOR HIGH WINDS FOR COASTAL PORTIONS OF THE WEST COAST, SUN-TUE, MAR
10-12.
SLIGHT RISK FOR HEAVY SNOW FOR THE KLAMATH AND SIERRA NEVADA MOUNTAINS,
SUN-TUE, MAR 10-12.
SLIGHT RISK FOR HEAVY SNOW FOR PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES AND
HIGHER ELEVATIONS OF THE CENTRAL GREAT BASIN, THU-SAT, MAR 7-9.
DETAILED SUMMARY
FOR SATURDAY MARCH 02 - WEDNESDAY MARCH 06:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY MARCH 07 - WEDNESDAY MARCH 13: THERE ARE SEVERAL AREAS OF ACTIVE
WEATHER DEPICTED IN TODAY’S MODEL SOLUTIONS AT THE OUTSET OF WEEK-2, HOWEVER
THERE IS SIGNIFICANT MODEL SPREAD PARTICULARLY OVER THE WESTERN CONUS, LEADING
TO INCREASED UNCERTAINTY IN TODAY’S WEEK-2 HAZARDS OUTLOOK. THE MOST ACTIVE
WEATHER DEPICTED IN TODAY’S SOLUTIONS REMAINS OVER THE EASTERN HALF OF THE
CONUS, WITH AMPLE MOISTURE FLOWING INTO A SERIES OF FAST-MOVING SURFACE LOW
PRESSURE SYSTEMS MOVING OFF THE ROCKIES AND TRIGGERING WIDESPREAD ENHANCED
PRECIPITATION WITH THE POTENTIAL FOR THUNDERSTORM ACTIVITY OVER THE SOUTHEAST,
PARTICULARLY AT THE OUTSET OF WEEK-2. THE GEFS AND ECMWF PRECIPITATION
PROBABILISTIC EXTREMES TOOLS (PETS) BOTH INDICATE AT LEAST A 20% CHANCE OF
3-DAY PRECIPITATION TOTALS EXCEEDING THE 85TH PERCENTILE AND 1 INCH FOR MUCH OF
THE TENNESSEE, OHIO, AND LOWER AND MIDDLE MISSISSIPPI VALLEYS, SOUTHERN
APPALACHIANS, MID-ATLANTIC, AND SOUTHEASTERN U.S. FOR MARCH 7-10. THE ECMWF
CONTINUES TO BE VERY BULLISH ON THE POTENTIAL FOR HEAVY PRECIPITATION, BUT RAW
ECMWF OUTPUT IS LESS SUPPORTIVE OF THESE HIGHER PROBABILITIES THAN YESTERDAY,
THUS THE MODERATE RISK OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE SOUTHEAST
U.S. HAS BEEN DISCONTINUED. THE ECMWF ALSO CONTINUES TO FAVOR THE POTENTIAL FOR
HEAVY PRECIPITATION TO EXTEND NORTH ALONG THE EAST COAST EARLY IN THE FORECAST
PERIOD, THEREFORE A SLIGHT RISK FOR HEAVY PRECIPITATION CONTINUES FOR PORTIONS
OF THE MID-ATLANTIC AND NORTHEAST U.S. FOR MARCH 7-8.
MODEL DEPICTIONS OF LEE CYCLOGENESIS OVER THE GREAT PLAINS DURING WEEK-2 ARE
MORE ROBUST RELATIVE TO YESTERDAY, WITH STRONGER PRESSURE GRADIENTS DEVELOPING
AND EXTENDING FURTHER SOUTH. THE ECMWF PET FOR HIGH WINDS CONTINUES TO INDICATE
AT LEAST A 20% CHANCE FOR WINDS SPEEDS EXCEEDING THE 85TH PERCENTILE FOR
PORTIONS OF THE GREAT PLAINS AND GREAT LAKES REGION. THEREFORE A SLIGHT RISK
FOR HIGH WINDS REMAINS POSTED AND EXPANDED SOUTHWARD TO COVER MUCH OF THE GREAT
PLAINS, AS WELL AS THE LOWER AND MIDDLE MISSISSIPPI VALLEYS FOR MARCH 7-11, AND
FOR PORTIONS OF THE OHIO VALLEY AND GREAT LAKES FOR MARCH 9-11 AS SURFACE LOW
PRESSURE TRACKS EAST AWAY FROM THE ROCKIES.
A SHORTWAVE TROUGH IS FAVORED TO MOVE ASHORE OVER THE WEST COAST LATE IN
WEEK-1, BRINGING THE CHANCE FOR HEAVY SNOW TO HIGHER ELEVATIONS OF THE INTERIOR
WEST. A SLIGHT RISK FOR HEAVY SNOW IS POSTED FOR PORTIONS OF THE CENTRAL AND
SOUTHERN ROCKIES AND HIGHER ELEVATIONS OF THE CENTRAL GREAT BASIN FOR MARCH
7-9, WHERE GEFS PET FOR SNOW WATER EQUIVALENT (SWE) INDICATES AT LEAST A 20%
PROBABILITY OF 3-DAY SWE ACCUMULATION TO EXCEED THE 85TH PERCENTILE AND AT
LEAST HALF AN INCH. IN THE SECOND HALF OF WEEK-2 MODELS FAVOR A RELOADING OF
MID-LEVEL TROUGHING AND INCREASED STORMINESS AFFECTING THE WEST COAST. MODEL
SPREAD IS QUITE HIGH, BUT THE GEFS AND ECMWF PETS FOR HEAVY PRECIP INDICATE AT
LEAST A 20% PROBABILITY OF 3-DAY PRECIPITATION TOTALS EXCEEDING 1 INCH ALONG
THE WEST COAST. THE ECMWF ONCE AGAIN FAVORS A WETTER SOLUTION BOTH IN TIME AND
SPACE THAN THE GEFS, BUT AGAIN THE RAW OUTPUT SUGGESTS A MORE CONSERVATIVE
ESTIMATE. THE BEST AGREEMENT AMONG THE MODELS LIES OVER MUCH OF WESTERN
CALIFORNIA, WHERE A SLIGHT RISK FOR HEAVY PRECIPITATION IS POSTED FOR MARCH
10-12. A SLIGHT RISK FOR HEAVY SNOW IS ALSO POSTED FOR THE SIERRA NEVADA AND
KLAMATH MOUNTAINS FOR MARCH 10-12. ENSEMBLE SOLUTIONS ARE MORE EXPANSIVE WITH
REGARD TO THE POTENTIAL FOR HIGH WINDS ALONG THE COAST, WARRANTING A SLIGHT
RISK FOR HIGH WINDS FOR COASTAL AREAS FOR THE ENTIRE WEST COAST.
FORECASTER: DANNY BARANDIARAN
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