516
FXUS02 KWBC 070719
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
219 AM EST TUE FEB 07 2023
VALID 12Z FRI FEB 10 2023 - 12Z TUE FEB 14 2023
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS AND ENSEMBLES OFFER A REASONABLY SIMILAR LARGER SCALE
PATTERN EVOLUTION THROUGH MED-RANGE TIME SCALES, BUT HAVE BEEN
HAVING SOME DIFFICULTIES WITH EVEN THE MAIN EMBEDDED SYSTEMS.
OVERALL, THE WPC MEDIUM RANGE PRODUCT SUITE WAS EARLIER PREPARED
FROM A COMPOSITE BLEND OF THEN BEST CLUSTERED GUIDANCE FROM THE 12
UTC ECMWF/CANADIAN/UKMET AND ECMWF/NAEFS ENSEMBLE MEANS
FRIDAY/SATURDAY BEFORE REPLACING THE CANADIAN/UKMET WITH A MORE
HEALTHY DOSE OF THESE ENSEMBLES SUNDAY AND EARLY NEXT WEEK AMID
GROWING FORECAST SPREAD. AS SUCH, FORECAST SPREAD REMAINS AN ISSUE
WITH THE PROGRESSION OF AN EMERGING SOUTHERN STREAM UPPER TROUGH
TRACKING FROM THE SOUTH TO UP THE EAST COAST ALONG WITH A COMPLEX
SURFACE SYSTEM REFLECTION. LATEST 00 UTC GUIDANCE HAS OVERALL
TRENDED SLOWER WITH PROGRESSION AND THAT SEEMS GENERALLY SEEMS
REASONABLE GIVEN SOUTHERN STREAM SEPARATION. WELL UPSTREAM,
COMPARED TO THE ECMWF/CANADIAN/UKMET AND ECMWF ENSEMBLES THAT DROP
ALONG/JUST OFF THE WEST COAST, RECENT GFS/GEFS RUNS OFFER MORE ON
AN INLAND SLIDER INTO THE WEST THEN SOUTHWEST CLOSED LOW WITH THE
DIGGING OF UPPER TROUGH ENERGIES, BUT THE 00 UTC VERSIONS HAVE
TRENDED PARTIALLY WESTWARD. MEANWHILE, THE 12 UTC UKMET AND
CANADIAN WERE MILD OUTLIERS INTO NEXT WEEK WITH MORE PROGRESSIVE
NORTHERN STREAM THAN THE GFS/ECMWF AND THE BULK OF ENSEMBLES, BUT
THEIR NEWER 00 UTC RUNS HAVE TRENDED MORE IN LINE.
..WEATHER/HAZARD HIGHLIGHTS
LEAD UPPER SHORTWAVE TROUGH EJECTION THROUGH THE NORTHEAST WILL
BRING A COMPLEX SURFACE LOW/FRONTAL SYSTEM THROUGH THE REGION INTO
THE CANADIAN MARITIMES FRIDAY. THIS WILL OCCUR AS A POTENT UPPER
TROUGH WORKS DOWN ACROSS THE SOUTH, AMPLIFYING DOWNSTREAM OF AN
AMPLIFIED UPPER RIDGE OVER THE WEST. GUIDANCE HAS TRENDED SLOWER
WITH THIS LATTER FEATURE ALLOWING FOR A LINGERING HEAVY RAINFALL
POTENTIAL ALONG WITH SOME RISK OF RUNOFF ISSUES WITH
REPEAT/TRAINING OF CELLS ALONG A SLOW MOVING AND GULF MOISTURE
POOLING FRONT OVER THE MOIST SOILS OF THE SOUTHEAST. RAIN RATES
COULD BE HIGH GIVEN THE POTENTIAL FOR INSTABILITY TO BE IN PLACE
SO THE WPC EXPERIMENTAL DAY 4 EXCESSIVE RAINFALL OUTLOOK (ERO) HAS
COLLABORATED THE ISSUANCE OF A "MARGINAL" RISK AREA FROM THE FL
PANHANDLE/SOUTHERN GA TO THE EASTERN CAROLINAS FRIDAY. MEANWHILE,
COLD AIR DRAPED TO THE NORTH OF THE SYSTEM AND COLD CANADIAN AIR
IN THE WAKE OF SYSTEM PASSAGE WILL ALSO OFFER A THREAT FOR
SNOW/ICE ON THE NORTHERN PERIPHERY OF THE PRECIPITATION SHIELD
THROUGH NORTHERN PORTIONS OF THE NORTHEAST AND SOUTHEAST CANADA.
EXPECT TRAILING LAKE-EFFECT SNOWS INTO THE WEEKEND GIVEN LINGERING
COLD/WINDY FLOW. THE DEEP UPPER TROUGH THEN SLATED TO LIFT FROM
THE SOUTHEAST TO UP THE EAST COAST FOR THE WEEKEND OFFERS MODERATE
COASTAL LOW GENESIS AND ATLANTIC INFLOW POTENTIAL TO LIFT ENHANCED
LATE WEEK RAINS UP THE EASTERN CAROLINAS/MID-ATLANTIC BEFORE
RENEWING SOME MAINLY INTERIOR NORTHEAST WEEKEND SNOWS. COLD FRONTS
PASSING AHEAD OF THE TROUGH IN THE EAST SHOULD MEANWHILE LEAD TO A
TRANSITION FROM MUCH ABOVE NORMAL TEMPERATURES THROUGH LATE
WORKWEEK TO NEAR NORMAL CONDITIONS FOR THE WEEKEND.
WHILE THERE IS A GROWING GUIDANCE SIGNAL FOR THE AMPLIFICATION OF
THE OVERALL FLOW SIGNIFICANTLY LATER WEEK ACROSS THE NATION AND
ADJOINING OCEANS, SUBSEQUENT PRECIPITATION RE-EMERGENCE MAY
OTHERWISE BE LIMITED THROUGH THE WEEKEND. NORTHERN STREAM
SHORTWAVE TROUGH PASSAGE SHOULD SUPPORT SEVERAL SHOTS FOR MODEST
PRECIPITATION, MAINLY FOR THE PACIFIC NORTHWEST AND INLAND TO THE
NORTHERN ROCKIES. MEANWHILE, UNCERTAIN EASTERN PACIFIC/WEST COAST
UPPER TROUGH/LOW AMPLIFICATION IN A DEFINING SOUTHERN STREAM COULD
LEAD TO MODEST PRECIPITATION SOUTHWARD ALONG THE CALIFORNIA COAST
AND EVENTUALLY INTO THE SOUTHWEST. BUT WITH GUIDANCE POINTING
TOWARD AN UPPER LOW IN THE SOUTHWEST BY AROUND MONDAY, GULF
MOISTURE STREAMING AHEAD OF IT COULD RENEW A RAINFALL THREAT IN
THE SOUTHERN PLAINS TO LOWER MS VALLEY BY MONDAY-TUESDAY.
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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