623
FXUS02 KWBC 221726
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
126 PM EDT SAT OCT 22 2022
VALID 12Z TUE OCT 25 2022 - 12Z SAT OCT 29 2022
...MODEL AND PREDICTABILITY ASSESSMENT AND WEATHER/HAZARD
HIGHLIGHTS...
MODEL AND ENSEMBLE SOLUTIONS CONTINUE TO TREND TOWARDS BETTER
AGREEMENT ON THE OVERALL PATTERN, BUT DO STILL SHOW SOME RUN TO
RUN VARIABILITY AND FORECAST SPREAD ON THE SMALL-MID SCALE
INTERACTIONS/DETAILS THROUGH NEXT WEEK. THE WPC PRODUCT SUITE WAS
PRIMARILY DERIVED FROM A COMPOSITE BLEND OF THE GFS/ECMWF/UKMET
TUESDAY AND WEDNESDAY. BY DAY 5/THURSDAY, INCORPORATED INCREASING
PARTS OF THE ENSEMBLE MEANS ALONG WITH REASONABLY COMPATIBLE
GFS/ECMWF THURSDAY-SATURDAY TO SMOOTH OUT SOME OF THE LINGERING
DIFFERENCES. THIS ALSO MAINTAINED GOOD CONTINUITY WITH THE
PREVIOUS WPC FORECAST.
A POTENT UPPER TROUGH/CLOSED LOW IS SLATED TO LIFT/SHEAR
NORTHEASTWARD ACROSS THE CENTRAL U.S. AND MIDWEST/GREAT
LAKES/NORTHEAST THOUGH EARLY-MID WEEK. TIMING AND AMPLITUDE ISSUES
REMAIN IN THE GUIDANCE, BUT FORECAST SPREAD HAS STEADILY DECREASED
OVER THE PAST FEW DAYS. THE 00Z CMC SEEMS TOO QUICK TO LIFT THE
SYSTEM NORTH AND WAS NOT INCLUDED IN TODAYS BLEND. THE ECMWF/UKMET
ARE A NICE COMPROMISE, WITH THE 06Z GFS A LITTLE SLOW (BUT THE 12Z
RUN CAME IN FASTER). THE PATTERN SHOULD FOCUS GULF MOISTURE AND
INSTABILITY INTO THE DEVELOPING LEAD FRONTAL SYSTEM WHERE STRONG
TO SEVERE THUNDERSTORMS ARE POSSIBLE ALONG WITH INCREASINGLY
PROGRESSIVE CONVECTIVE RAINS OVER TIME. THE BEST POTENTIAL FOR
MULTIPLE INCHES OF RAINFALL MAY BE OVER THE PARTS OF THE MIDDLE
MISSISSIPPI VALLEY/MIDWEST ON TUESDAY INTO WEDNESDAY COINCIDENT
WITH ANY CLOSED SIGNATURE ALOFT. THIS AREA HAS BEEN VERY DRY
RECENTLY AND SO MUCH OF THIS RAINFALL MAY BE MORE BENEFICIAL THAN
PARTICULARLY HAZARDOUS. NEEDED A NOTICEABLE INCREASE FROM THE 13Z
NBM QPF ACROSS THIS REGION, AND NORTH INTO MICHIGAN, WHERE THE NBM
SEEMED UNDERDONE WITH AFTERNOON/EVENING TRAILING COLD FRONTAL
CONVECTIVE RAINFALL POTENTIAL IN DEEPER MOISTURE AND FAVORABLE
SUPPORT ALOFT. LIGHT AND MORE SCATTERED PRECIPITATION SHOULD
QUICKLY RACE OFF INTO THE GREAT LAKES AND NORTHEAST BY LATER
WEDNESDAY AND INTO THURSDAY, WITH SOME LAKE ENHANCEMENT POSSIBLE
AFTER THE UPPER LOW MOVES THROUGH.
PERIODIC UPPER TROUGH ENERGY FLOW INTO THE WEST COAST BY EARLY
NEXT WEEK AND AS RENEWED LATER IN THE WEEK CONTINUE TO EXHIBIT
SOME DIFFERENCES MAINLY WITH AMPLITUDE/TIMING ALTHOUGH WITH SOME
RECENT IMPROVING AGREEMENT. EVEN SO, THE PATTERN DOES SHOW A GOOD
SIGNAL FOR A PERIOD OF MUCH BELOW NORMAL COLD OVER THE
WEST/ROCKIES AND COMPOSITE SYSTEM AMPLITUDES SHOULD STILL FAVOR A
DECENT AND REPEATABLE MODERATE QPF COVERAGE RESPONSE TO INCLUDE
ADDITIONAL HIGHER TERRAIN HEAVY SNOW THREATS FROM THE WEST COAST
STATES THROUGH THE GREAT BASIN AND THE ROCKIES. A MAIN AND
POSSIBLY CLOSED SOUTHERN STREAM SYSTEM REMAINS SLATED TO AGAIN
EMERGE OVER THE SOUTH-CENTRAL TO SOUTHERN U.S. LATE NEXT WEEK INTO
NEXT WEEKEND TO RENEW RAIN/CONVECTION, ALTHOUGH UNCERTAINTY ON
PLACEMENT/AMOUNTS REMAIN HIGHLY VARIABLE.
ELSEWHERE, THE EVOLUTION ASSOCIATED WITH PESKY/LINGERING WEAK
UPPER TROUGHING OVER THE NORTHEAST THROUGH AT LEAST EARLY NEXT
WEEK REMAINS UNCERTAIN AND RUN TO RUN INCONSISTENT IN GUIDANCE.
HOWEVER, THE PATTERN DOES OFFER SUPPORT FOR COASTAL EFFECTS AND
BROAD SCALE MODEST QPF WITH PROTRACTED INFLOW, ALBEIT WITH
DIMINISHING INFLUENCE THROUGH MEDIUM RANGE TIME SCALES.
SANTORELLI/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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