273
FXUS02 KWBC 101900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 PM EST SAT FEB 10 2024
VALID 12Z TUE FEB 13 2024 - 12Z SAT FEB 17 2024
...NORTHEAST COASTAL STORM HEAVY SNOW/GUSTY WIND IMPACTS TO LINGER
INTO TUESDAY...
..GENERAL OVERVIEW
A DEVELOPING AND WET STORM SYSTEM ACROSS THE SOUTHERN TO EASTERN
U.S. IN THE SHORT TERM IS FORECAST TO EXIT THE MID-ATLANTIC COAST
AND DEEPEN INTO A POTENT COASTAL STORM INTO TUESDAY, WITH
IMPACTFUL WRAP-BACK SNOW NOW LIKELY CONTINUING INTO TUESDAY
AFTERNOON ACROSS SOUTHERN NEW ENGLAND BEFORE TAPERING OFF. A
QUASI-ZONAL FLOW PATTERN DEVELOPS ACROSS MUCH OF THE NATION IN THE
WAKE OF THIS STORM SYSTEM, AND A PATTERN CHANGE IS EXPECTED TO
EVOLVE ACROSS THE NORTH-CENTRAL U.S. AS AN ARCTIC AIRMASS DROPS
SOUTHWARD FROM WESTERN CANADA WITH A RETURN TO BELOW NORMAL
TEMPERATURES. MEANWHILE, AN UPPER LEVEL RIDGE IS LIKELY TO BECOME
ESTABLISHED OVER THE WEST COAST STATES BY THE END OF THE WEEK, AND
THIS WILL TEND TO LIMIT THE PROGRESSION OF OFFSHORE PACIFIC STORM
SYSTEMS UNTIL ABOUT SATURDAY WHEN THE NEXT ROUND OF ORGANIZED
PRECIPITATION MOVES INLAND ACROSS CALIFORNIA. ELSEWHERE, SOME
LIGHT SNOW SHOWERS ARE POSSIBLE FROM THE NORTHERN ROCKIES TO THE
UPPER MIDWEST WITH WEAK SHORTWAVE PASSAGES, AND LAKE EFFECT SNOW
ACROSS THE GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY.
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST MODELS AND ENSEMBLES REMAIN IN REASONABLY GOOD AGREEMENT
ACROSS THE CONTINENTAL U.S. FOR TUESDAY, WITH A SLIGHTLY SLOWER
TREND RECENTLY WITH THE MAIN SYSTEM EXITING THE EAST COAST THAT
WOULD EXTEND WRAPBACK SNOW/WIND POTENTIAL A BIT ACROSS SOUTHERN
PORTIONS OF THE NORTHEAST THAT DAY. DIFFERENCES BECOME MORE
EVIDENT WEDNESDAY WITH THE EXTENT OF TROUGH AMPLIFICATION OVER THE
NORTH-CENTRAL U.S. AND THE TIMING OF SHORTWAVE FEATURES IN THE
NORTHERN STREAM FLOW, AND ALSO WITH THE EXTENT OF PACIFIC SYSTEM
ENERGIES AND MOISTURE TO UNDERCUT AMD WORK ONSHORE INTO THE WEST
COAST. HOWEVER, THERE IS DECENT MODEL AGREEMENT WITH THE
DEVELOPING SOUTHERN STREAM TROUGH NEAR THE GULF COAST LATE IN THE
FORECAST PERIOD. ACCORDINGLY, A COMPOSITE MODEL BLEND FOR BEST
DETAIL ON TUESDAY WAS QUICKLY SUBSTITUTED BY GEFS/ECMWF ENSEMBLE
USAGE WEDNESDAY INTO NEXT WEEKNED TO ACCOUNT FOR THE GROWING
MESOSCALE MODEL DIFFERENCES.
IN TERMS OF THE NBM, TEMPERATURES WERE REDUCED ACROSS MUCH OF THE
NORTH-CENTRAL U.S. GIVEN THE ONGOING SIGNAL FOR AN ARCTIC SURFACE
HIGH TO SETTLE IN. QPF WAS REDUCED INLAND INTO THE WEST COAST
STATES INTO AT LEAST LATE NEXT WEEK GIVEN MODEL UNCERTAINTIES WITH
ONSHORE SYSTEM ONSET IN COMPLEX FLOW OVER THE EASTERN PACIFIC
UNDERCUTTING HIGHER LATITUDE BLOCKING FLOW. THE ENSEMBLE MEAN
PATTERN DOES SUPPORT AN EVENTUAL WETTER PATTERN INTO NEXT WEEKEND
TO MONITOR. THE QPF WAS ALSO RAISED ACROSS THE GENERAL VICINITY OF
THE GREAT LAKES THURSDAY INTO FRIDAY FROM THE NBM GIVEN THE DECENT
OVERALL SIGNAL FOR SOME LAKE EFFECT SNOWS.
..OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
WIDESPREAD SNOW WILL LIKELY BE ONGOING TUESDAY MORNING ACROSS MUCH
OF THE NORTHEAST U.S. AS THE SURFACE LOW CONTINUES TO
RE-DEVELOP/DEEPEN UPON EXITING THE COAST. IMPACTFUL SNOW IS
EXPECTED, ESPECIALLY ACROSS INTERIOR PORTIONS OF THE NORTHERN
MID-ATLANTIC THROUGH SOUTHERN NEW ENGLAND WHERE SNOW IS THE
PRIMARY PRECIPITATION TYPE THROUGHOUT THE EVENT. THE RAIN/SNOW
LINE COMES CLOSE TO THE MAJOR METROPOLITAN AREAS ALONG INTERSTATE
95 FROM PHILADELPHIA THROUGH NEW YORK AND SOUTHERN NEW ENGLAND,
AND THERE THE FORECAST IS MORE UNCERTAIN WHERE A CHANGEOVER FROM
RAIN TO SNOW SHOULD TEND TO LIMIT OVERALL ACCUMULATIONS. RAIN
WILL BE THE MAIN PRECIPITATION TYPE ACROSS EASTERN PORTIONS OF THE
MID-ATLANTIC. THE QUICK PROGRESSION OF THE SYSTEM SHOULD BRING AN
END TO MOST OF THE HEAVIER RAINS BY TUESDAY, SO NO WPC EXCESSIVE
RAINFALL AREAS SEEM WARRANTED AT THIS TIME.
ELSEWHERE AND LOOKING AHEAD TO FRIDAY AND NEXT SATURDAY, A LOW
PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE WESTERN GULF AND
ADVECT INCREASING MOISTURE NORTHWARD AND OVER A DEVELOPING WARM
FRONT, AND THIS WILL LIKELY RESULT IN WIDESPREAD SHOWERS AND
THUNDERSTORMS ACROSS SOUTHERN TEXAS THAT MAY THEN QUICKLY
OVERSPREAD THE GULF COAST STATES AND THE SOUTHEAST IN AN EMERGING
ENHANCED RAINFALL PATTERN TO MONITOR. WHILE THERE IS QUITE A BIT
UNCERTAINTY IN THE MODELS ALL NEXT WEEK OVER THE EASTERN PACIFIC,
THE NEXT MAIN ROUND OF ORGANIZED MOISTURE IS EXPECTED TO REACH THE
WEST COAST HEADING INTO NEXT WEEKEND. THE STRONGEST ENSEMBLE
SIGNAL FAVORS AN EMERGING RAIN SIGNATURE FOR THE NORTHERN HALF OF
CALIFORNIA, WITH SNOW FOR THE HIGHER TERRAIN. FARTHER EAST, THE
PROSPECTS FOR LAKE EFFECT SNOW ARE INCREASING TO CLOSE OUT NEXT
WEEK AS MUCH COLDER AIRMASS CROSSES THE REGION.
TEMPERATURES ARE EXPECTED TO BE GENERALLY 5 TO 15 DEGREES ABOVE
MID-FEBRUARY AVERAGES ACROSS MUCH OF THE MIDWEST REGION ON TUESDAY
AND WEDNESDAY WITH SLIGHTLY BELOW AVERAGE READINGS OVER THE DESERT
SOUTHWEST AND THE NORTHERN ROCKIES. GOING INTO LATE WEDNESDAY, A
STRONG COLD FRONT DROPPING SOUTH FROM WESTERN CANADA IS EXPECTED
TO HERALD THE ARRIVAL OF AN ARCTIC AIRMASS ACROSS THE NORTHERN
PLAINS AND BRING A RETURN TO BELOW AVERAGE TEMPERATURES FROM
MONTANA TO THE DAKOTAS AND NORTHERN MINNESOTA THROUGH THE END OF
THE WEEK, PERHAPS UP TO 20 DEGREES BELOW AVERAGE. MEANWHILE, MUCH
OF THE REMAINDER OF THE U.S. SHOULD HAVE TEMPERATURES GENERALLY
WITHIN 5 DEGREES OF CLIMATOLOGICAL AVERAGES TO CLOSE OUT THE WORK
WEEK, FOLLOWED BY COLDER CONDITIONS ACROSS MUCH OF THE CENTRAL AND
SOUTHERN PLAINS THROUGH LATER NEXT WEEK WITH THE SOUTHWARD MARCH
OF THE COLD AIRMASS.
HAMRICK/SCHICHTEL
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES ARE AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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