893
FXUS02 KWBC 090658
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 AM EST FRI FEB 9 2024
VALID 12Z MON FEB 12 2024 - 12Z FRI FEB 16 2024
..GENERAL OVERVIEW
AN ACTIVE WEATHER PATTERN WILL INITIALLY BE IN PLACE ACROSS THE
SOUTHEASTERN U.S. AND THE MID-ATLANTIC/NORTHEAST AS A POTENT UPPER
TROUGH SUSTAINS A WELL DEVELOPED SURFACE LOW, AND THIS SHOULD EXIT
THE EAST COAST TUESDAY MORNING WITH WIDESPREAD RAIN AND INTERIOR
NORTHEAST SNOWFALL. A QUASI-ZONAL FLOW PATTERN DEVELOPS ACROSS
MUCH OF THE NATION IN THE WAKE OF THIS STORM SYSTEM, WITH A
MODIFIED ARCTIC AIRMASS LIKELY REACHING MONTANA AND THE DAKOTAS
LATER IN THE WEEK BUT NOTHING TOO EXTREME. MEANWHILE, AN UPPER
LEVEL RIDGE IS LIKELY TO BECOME ESTABLISHED OVER THE WEST COAST
STATES AND THIS WILL TEND TO LIMIT THE PROGRESSION OF OFFSHORE
PACIFIC STORM SYSTEMS. ELSEWHERE, SOME LIGHT SNOW SHOWERS ARE
POSSIBLE FROM THE NORTHERN ROCKIES TO THE UPPER MIDWEST WITH WEAK
SHORTWAVE PASSAGES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE MODELS AND ENSEMBLES ARE IN RELATIVELY GOOD OVERALL AGREEMENT
ACROSS MOST OF THE U.S. ON MONDAY, WITH THE EXCEPTION OF THE
SOUTHEAST STATES. AT THE TIME OF FRONTS/PRESSURES COMPILATION,
THE 18Z GFS WAS CONSIDERABLY SLOWER WITH THE TRACK OF THE SURFACE
LOW ACROSS THE MID-ATLANTIC REGION FOR THE EARLY WEEK STORM
SYSTEM. THE 18Z ICON MODEL INDICATED A SOLUTION MORE IN LINE WITH
THE 12Z UKMET/ECMWF/CMC CONSENSUS FOR THE MONDAY THROUGH TUESDAY
NIGHT TIME PERIOD, SO A NON-GFS BLEND WAS USED FOR THE FIRST HALF
OF THE FORECAST PERIOD TO ACCOUNT FOR THIS. THE 00Z GFS CONTINUES
TO BE SLOWER THAN THE OTHER GUIDANCE WITH THIS EVENT. HOWEVER,
THE GFS WAS MORE IN LINE WITH THE ENSEMBLE MEANS FOR THE WEDNESDAY
THROUGH FRIDAY TIME PERIOD, SO IT WAS A PART OF THE MODEL BLEND BY
THIS TIME AFTER THE LOW EXITED THE EAST COAST. MODEL SPREAD FOR
THE THURSDAY-FRIDAY TIME IS WORSE THAN NORMAL OWING TO COMPLICATED
FLOW INTERACTIONS AND TIMING DIFFERENCES, AND THE BEST AGREEMENT
IS ACROSS THE WEST COAST REGION WITH THE UPPER RIDGE AXIS, AND
MORE WEIGHTING WAS APPLIED TO THE ENSEMBLE MEANS DURING THIS TIME.
..OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
THE LOW PRESSURE SYSTEM CROSSING THE MID-ATLANTIC MONDAY NIGHT
INTO EARLY TUESDAY WILL LIKELY HAVE ENOUGH MOISTURE TO FUEL AN
AXIS OF HEAVY RAINFALL IN THE WARM SECTOR OF THE LOW ACROSS THE
EASTERN CAROLINAS. THERE HAS BEEN A SLIGHT INCREASE IN MODEL QPF
DURING THE NEW DAY 4 PERIOD ACROSS EASTERN NC AND CENTRAL/EASTERN
SC, AND THEREFORE THE MARGINAL RISK AREA INHERITED FROM THE
PREVIOUS DAY 5 WAS EXTENDED NORTH TO THE NC/VA BORDER. FARTHER TO
THE NORTH, THERE IS AN INCREASING POTENTIAL FOR THE SPREAD OF
WRAP-AROUND ACCUMULATING SNOWS AND WINDY CONDITIONS ACROSS THE
MARGINALLY COOL APPALACHIANS/INTERIOR NORTHEAST MONDAY NIGHT AND
INTO TUESDAY BEFORE THE WHOLE SYSTEM EXITS THE COAST AS A
CONTINUED MARITIME HAZARD. BEHIND THIS SYSTEM, CONDITIONS ACROSS
MUCH OF THE CONTINENTAL U.S. SHOULD DRY OUT MID NEXT WEEK BESIDES
PERIODIC INTRUSIONS FROM THE PACIFIC TO BRING SOME MODEST
PRECIPITATION TO PARTS OF THE NORTHWEST AND NORTH-CENTRAL PLAINS.
NO EXCESSIVE RAINFALL AREAS ARE CURRENTLY NECESSARY FOR THE DAY 5
PERIOD ON TUESDAY-TUESDAY NIGHT.
TEMPERATURES ARE EXPECTED TO BE GENERALLY 5 TO 15 DEGREES ABOVE
MID-FEBRUARY AVERAGES ACROSS MUCH OF THE MIDWEST AND THE SOUTHEAST
U.S. ON MONDAY WITH SLIGHTLY BELOW AVERAGE READINGS OVER THE
DESERT SOUTHWEST TO THE SOUTHERN PLAINS. GOING INTO WEDNESDAY, A
COLD FRONT DROPPING SOUTH FROM WESTERN CANADA IS EXPECTED TO BRING
A RETURN TO BELOW AVERAGE TEMPERATURES ACROSS MONTANA AND NORTH
DAKOTA WHERE A MODIFIED ARCTIC AIRMASS IS EXPECTED TO MOVE INTO
THE REGION. THERE IS CERTAINLY THE POTENTIAL FOR THINGS TO TREND
COLDER IN FUTURE FORECASTS. MEANWHILE, MUCH OF THE REMAINDER OF
THE U.S. SHOULD HAVE TEMPERATURES GENERALLY WITHIN 5 DEGREES OF
CLIMATOLOGICAL AVERAGES.
HAMRICK
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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