006
FXUS02 KWBC 060701
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST MON FEB 06 2023
VALID 12Z THU FEB 09 2023 - 12Z MON FEB 13 2023
...GUIDANCE/PREDICTABILITY ASSESSMENT AND WEATHER/HAZARD
HIGHLIGHTS...
AN INITIALLY POTENT SOUTHERN STREAM UPPER TROUGH WILL EJECT
NORTHEASTWARD FROM THE MS VALLEY THROUGH THE NORTHEAST
THURSDAY/FRIDAY AS A KICKER UPPER TROUGH DIGS SOUTHEASTWARD
THROUGH THE ROCKIES TO THE SOUTH-CENTRAL U.S., AMPLIFYING
DOWNSTREAM OF A BUILDING UPPER RIDGE OVER THE WEST. IN THIS
PATTERN, A LEAD SURFACE LOW WILL DEEPEN AND TRACK ACROSS THE
MIDWEST/OH VALLEY THURSDAY BEFORE EXITING THROUGH THE NORTHEAST
FRIDAY. GULF MOISTURE INFLOW/INSTABILITY AND RIGHT ENTRANCE REGION
UPPER JET/HEIGHT FALLS SUPPORT WILL COMBINE WITH THE ASSOCIATED
FRONTAL SYSTEM TO PRODUCE A WIDESPREAD SWATH OF RAINFALL ACROSS
THE APPALACHIANS AND EASTERN SEABOARD. HEAVIEST POTENTIAL AND SOME
RISK OF RUNOFF ISSUES WITH REPEAT/TRAINING OF CELLS TO MONITOR IN
THE COMING DAYS MAY BE ALONG A TRAILING FRONT TO SLOW OVER THE
MOIST SOILS OF THE SOUTHEAST AS THE UPSTREAM UPPER TROUGH IS
CARVED OUT OVER THE SOUTH-CENTRAL U.S. AND SUBSEQUENTLY WORKS
SLOWLY EASTWARD. MEANWHILE, COLD AIR DRAPED TO THE NORTH OF THE
SYSTEM AND SEVERAL POTENT SHOTS OF CANADIAN AIR IN THE WAKE OF
SYSTEM PASSAGE WILL ALSO OFFER A THREAT FOR WRAPBACK AND LEAD FLOW
SNOW/ICE ON THE NORTHERN PERIPHERY OF THE EXPANDING PRECIPITATION
SHIELD OUT FROM THE CENTRAL PLAINS THROUGH THE GREAT LAKES AND
INTERIOR NORTHEAST AND SOUTHERN CANADA. EXPECT LAKE-EFFECT SNOWS
INTO THE WEEKEND GIVEN LINGERING COLD/WINDY FLOW. UPPER TROUGH
ENERGY SLATED TO LIFT FROM THE SOUTHEAST TO UP THE EAST COAST FOR
THE WEEKEND AND MODEST COASTAL LOW GENESIS AND ATLANTIC INFLOW
COULD RENEW A MAINLY INTERIOR NORTHEAST SNOW THREAT TO MONITOR.
LATEST 00 UTC GUIDANCE HAS CONVERGED A BIT MORE ON A MORE COMMON
SYSTEM EVOLUTION AND TIMINGS, BUT THERE IS A WAYS FURTHER TO GO.
WHILE THERE IS A GROWING GUIDANCE SIGNAL FOR THE AMPLIFICATION OF
THE OVERALL FLOW SIGNIFICANTLY BY LATER WEEK ACROSS THE NATION AND
ADJOINING OCEANS, SUBSEQUENT PRECIPITATION RE-EMERGENCE MAY
OTHERWISE BE LIMITED. NORTHERN STREAM SHORTWAVE TROUGH PASSAGE
SHOULD SUPPORT MODEST PRECIPITATION SHOTS REPEATLY OVER MAINLY THE
PACIFIC NORTHWEST. MODEST PRECIPITATION WITH UNCERTAIN EASTERN
PACIFIC/WEST COAST UPPER TROUGH/LOW AMPLIFICATION MAY ORGANIZE
OVER SOUTH-CENTRAL CA AND THE SOUTHWEST BY THE WEEKEND WITH
EXPECTED CARVING OUT OF A CLOSED LOW TO MONITOR GIVEN GUIDANCE
UNCERTAINTIES, BUT FORECAST SPREAD IS REDUCED WITH LATEST 00 UTC
GUIDANCE BOLSTERING FORECAST CONFIDENCE COMPARED TO EARLIER
ECMWF/CANADIAN/ECENS RUNS THAT WERE SLOWER AND GFS/UKMET/GEFS RUNS
THAT WERE MORE PROGRESSIVE.
OVERALL NOW, A COMPOSITE BLEND OF 00 UTC MODEL AND ENSEMBLE
GUIDANCE SEEMS TO PROVIDE A REASONABLE FORECAST BASIS OVERALL FOR
THE PATTERN EVOLUTION AND MAIN SYSTEMS THROUGH MEDIUM RANGE TIME
SCALES.
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, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES 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
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