087
FXUS02 KWBC 091900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EST FRI FEB 09 2024
VALID 12Z MON FEB 12 2024 - 12Z FRI FEB 16 2024
...DEEP COASTAL STORM GENESIS THREAT EARLY NEXT WEEK MAY PRODUCE
IMPACTFUL WRAP-BACK SNOWS AND GUSTY WINDS OVER THE NORTHEASTERN
U.S....
..GENERAL OVERVIEW
AN ACTIVE WEATHER PATTERN WILL INITIALLY BE IN PLACE ACROSS THE
SOUTHEASTERN U.S. AND THE MID-ATLANTIC/NORTHEAST AND MARITIME
CONCERNS AS A POTENT UPPER TROUGH SUSTAINS A WELL DEVELOPED INLAND
SURFACE LOW WITH WIDESPREAD PRECIPITATION. THE LOW SHOULD EXIT THE
EAST COAST AND RE-DEVELOP AS A DEEPENING ATLANTIC COASTAL STORM
INTO TUESDAY. THIS OFFERS A THREAT FOR IMPACTFUL WRAP-BACK SNOWS
AND GUSTY WINDS FROM THE APPALACHIANS/NORTHERN MID-ATLANTIC
THROUGH SOUTH-CENTRAL AREAS OF THE NORTHEAST, ESPECIALLY INLAND
FROM COASTAL AREAS GIVEN LIKELY STORM TRACK, BUT CONSIDERING A
RELATIVE LACK OF COLD AIR OVER AND SET TO FEED INTO THE AREA WITH
SYSTEM DEVELOPMENT AND PASSAGE.
ELSEWHERE, A QUASI-ZONAL MEAN FLOW PATTERN DEVELOPS ACROSS MUCH OF
THE NATION IN THE WAKE OF THIS STORM SYSTEM, WITH A MODIFIED
ARCTIC AIRMASS LIKELY DIGGING INTO THE NORTH-CENTRAL U.S. LATER
NEXT WEEK, BUT NOTHING TOO EXTREME OR WINTRY AT THIS POINT.
MEANWHILE, AN UPPER LEVEL MEAN RIDGE IS LIKELY TO BECOME
ESTABLISHED OVER THE WEST COAST STATES AND THIS WILL TEND TO LIMIT
THE PROGRESSION OF OFFSHORE PACIFIC STORM SYSTEMS, BUT NEAR
COASTAL AREAS FROM PACIFIC NORTHWEST TO NORTHERN CALIFORNIA MAY
GRADUALLY SEE AN UPTICK IN PRECIPITATION INTO LATER NEXT WEEK THAT
MAY BE LEADING INTO A WETTER WEEK 2 FORECAST AS PER CPC. IN THIS
PATTERN, SOME LIGHT SNOW SHOWERS ARE POSSIBLE DOWNSTREAM FROM THE
NORTHERN ROCKIES TO THE UPPER MIDWEST/GREAT LAKES WITH WEAK
SHORTWAVE PASSAGES. LATER PERIOD, THERE IS A GROWING GUIDANCE
SIGNAL FOR AN EMERGING RAIN AREAS OVER THE SOUTHERN ROCKIES/PLAINS
IN ABOUT A WEEK CONTINGENT OF THE EXTENT OF RETURN FLOW IN
SOUTHEASTERLY LOWER LEVEL FLOW UP FROM THE GULF OF MEXICO IN
ADVANCE OF UNCERTAIN APPROACH OF SOUTHERN STREAM SYSTEM ENERGIES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL AND ENSEMBLE SOLUTIONS SEEM REASONABLY CLUSTERED MONDAY AND
A COMPOSITE ALONG WITH INPUT FROM THE NATIONAL BLEND OF MODELS
(NBM) AND WPC CONTINUITY SEEMS TO MITIGATE LINGERING SMALL SCALE
VARIANCE. THE BROADER STORY STILL SEEMS DECENTLY SHOWED BY
GUIDANCE INTO LATER NEXT WEEK, BUT LOCAL FOCUS/FORECAST SPREAD
INCREASES BY TUESDAY BOTH WITH DEVELOPMENT OF THE DEEPENING
COASTAL STORM UP/OFF THE EAST COAST AND WITH SUBSEQUENT AND
UNCERTAIN SHORTWAVES WITH EXPECTED DEVELOPMENT OF FLATTER UPSTREAM
FLOW ACROSS MUCH OF THE REST OF THE LOWER 48 THROUGH LATER NEXT
WEEK, ALBEIT IN A MUCH LESS ACTIVE WEATHER PATTERN. THE WPC
PRODUCT SUITE WAS MAINLY BASED ON GEFS/ECMWF ENSEMBLE MEAN
GUIDANCE AND THE NBM AT THESE LONGER TIME FRAMES. LATEST 12 UTC
GUIDANCE REMAINS GENERALLY IN LINE WITH EARLIER GUIDANCE, BUT HAS
TRENDED A TAD LESS PROGRESSIVE/DEEPER WITH COASTAL STORM
DEVELOPMENT. THIS NEEDS TO BE MONITORED, BUT SEEMS CONSISTENT WITH
STANDARD BIAS WITH A SEPARATED SOUTHERN STREAM FLOW SYSTEM,
PENDING UNCERTAIN PHASING.
..OVERVIEW AND WEATHER/HAZARDS HIGHLIGHTS
UPPER SUPPORT AND DEEPENED MOISTURE WITH THE MAIN LOW FRONTAL
SYSTEM WORKING ACROSS THE EAST MONDAY MAY FUEL AN AXIS OF HEAVY
RAINFALL IN THE WARM SECTOR OF THE LOW AND WITH THE TRAILING COLD
FRONT OVER THE SOUTHEAST/CAROLINAS. A WPC EXCESSIVE RAINFALL
OUTLOOK MARGINAL RISK AREA WAS MAINTAINED. 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/NORTHERN MID-ATLANTIC THROUGH SOUTH-CENTRAL AREAS OF
THE NORTHEAST MONDAY NIGHT AND TUESDAY INTO EARLY WEDNESDAY AS THE
WHOLE SYSTEM EXITS THE COAST AS A CONTINUED MARITIME HAZARD.
BEHIND THIS SYSTEM, CONDITIONS ACROSS MUCH OF THE CONTINENTAL U.S.
SHOULD OVERALL DRY OUT MID WEEK BESIDES PERIODIC INTRUSIONS FROM
THE PACIFIC INTO THE WEST COAST/NORTHWEST. NO EXCESSIVE RAINFALL
AREAS ARE CURRENTLY NECESSARY FOR THE DAY 5 PERIOD ON
TUESDAY-TUESDAY NIGHT. THERE IS A GROWING GUIDANCE SIGNAL FOR AN
EMERGING RAIN AREAS OVER THE SOUTHERN ROCKIES/PLAINS IN ABOUT A
WEEK CONTINGENT OF THE EXTENT OF RETURN FLOW IN SOUTHEASTERLY
LOWER LEVEL FLOW UP FROM THE GULF OF MEXICO IN ADVANCE OF
UNCERTAIN APPROACH OF SOUTHERN STREAM SYSTEM ENERGIES.
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,
HIGH PRESSURE AND LEADING EDGE COLD FRONT DIGGING SOUTH FROM
WESTERN CANADA IS EXPECTED TO BRING A RETURN TO BELOW AVERAGE
TEMPERATURES DOWN THROUGH THE NORTH-CENTRAL U.S. WHERE A MODIFIED
ARCTIC AIRMASS IS EXPECTED TO MOVE INTO THE REGION, BUT THERE IS
CERTAINLY 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/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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