980
FXUS02 KWBC 140701
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST TUE NOV 14 2023
VALID 12Z FRI NOV 17 2023 - 12Z TUE NOV 21 2023
...PATTERN OVERVIEW AND GUIDANCE EVALUATION/PREDICTABILITY
ASSESSMENT...
A SPLIT FLOW PATTERN SHOULD REMAIN ESTABLISHED OVER MUCH OF NOTH
AMERICA FOR THE NEXT WEEK AND GUIDANCE OVERALL CONTINUES TO TREND
TOWARD AMPLIFICATION WITH GREATER SYSTEM DIGGING AND SLOWER
PROGRESSIONS WITHIN WELL DEFINED NORTHERN AND SOUTHERN STREAM
FLOWS. THIS SEEMS REASONABLE CONSIDERING INCREASING TRENDS TOWARD
AMPLITUDE UPSTREAM OVER THE PACIFIC AS WELL AS AT HIGHER LATITUDES
WITH DEEP FORCING SYSTEMS FROM NORTHEAST ASIA TOWARD ALASKA.
ACCORDINGLY, THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY
DERIVED FROM A COMPOSITE BLEND OF BEST CLUSTERED AND
AMPLIFIED/STREAM SEPARATED GUIDANCE FROM THE 18 UTC GFS AND 12 UTC
ECMWF/UKMET VALID FOR FRIDAY INTO SUNDAY. GEFS/ECMWF ENSEMBLE AND
NATIONAL BLEND OF MODEL SUPPORT HAS ALSO INCREASED FOR THIS
SCENARIO IN THIS TIME FRAME AND THE LATEST 00 UTC CYCLE GUIDANCE
OVERALL REMAINS IN LINE, BOLSTERING FORECAST CONFIDENCE. AT LONGER
TIME FRAMES INTO EARLY NEXT WEEK, THE GUIDANCE CAMP THAT CONTINUES
TO BEST EXTEND PREFERENCE FOR SLOWED/AMPLIFIED FLOW/TRENDS SEEMS
TO BEST FIT REASONABLY CLUSTERED GUIDANCE FROM THE 18/00 UTC GFS
AND 12/00 UTC ECMWF/ECMWF ENSEMBLE MEAN VERSUS THE SOMEWHAT MORE
PROGRESSIVE RECENT RUNS OF THE GEFS/CANADIAN ENSEMBLES AND THE
CANADIAN MODEL.
..WEATHER/HAZARDS HIGHLIGHTS
THE SLOW AND STEADY MARCH OF AN AMPLIFIED AND DYNAMIC UPPER TROUGH
AND ASSOCIATED WAVY FRONTAL SYSTEM ACROSS THE GREAT LAKES/MIDWEST
AND NORTHEAST/MAINE SHOULD FAVOR INCREASING PRECIPITATION CHANCES
ACROSS THE REGION FRIDAY INTO THE WEEKEND, ESPECIALLY AS MOISTURE
FEED POTENITALLY INCREASES MORE SUBSTANTAILLY OVER THE NORTHEAST
AND AS PER INTERACTION WITH A LEAD COASTAL LOW.
FOR THE WEST/SOUTHWEST, THE SLOW APPROACH OF THE CLOSED SOUTHERN
STREAM UPPER LOW WILL ONLY GRADUALLY BRING IN BOUTS OF LIGHT TO
MODERATE/TERRAIN ENHANCED RAIN AND MOUNTAIN SNOW THAT EXPAND
EASTWARD IN TIME. THE DELAY IN THE HEIGHT FALLS LIKELY LESSENS THE
STRONGER MOISTURE FLUX INTO THE AREA AS THE SYSTEM FILLS BEFORE
MOVING ASHORE, BUT MOST AREAS OF CALIFORNIA INTO THE SOUTHWEST
WILL SEE AT LEAST MEASURABLE RAINFALL (ESPECIALLY COASTAL AREAS)
OUTSIDE SOME OF THE SHADOWED DESERTS. GIVEN THE CONSISTENT SLOWER
AND DRIER TREND IN THE GUIDANCE, NO EXCESSIVE RAINFALL RISK AREAS
ARE IN PLACE. AS THE AMPLIFIED UPPER SYSTEM FINALLY CROSSES THE
DIVIDE, RETURN FLOW OUT OF THE GULF OF MEXICO WILL HELP INCREASE
MOISTURE OVER THE PLAINS THEN MISSISSIPPI VALLEY, WITH RAIN
EXPANDING IN COVERAGE LATE WEEKEND INTO EARLY NEXT WEEK. LEAD
CYCLOGENSIS AND FRONTGENESIS MAY INCREASINGLY SUPPORT A RENEWED
HEAVY RAINFALL PATTERN WITH FOCUS OVER THE LOWER MISSISSIPPI
VALLEY IN ABOUT A WEEK TO MONITOR. MEANWHILE IN THE WAKE OF THIS
SYSTEM, RENEWED PACIFIC SYSTEM ENERGY WITHIN NORTHERN STREAM FLOW
IS EXPECTED TO DIG MORE SHARPLY INLAND/SOUTHEASTWARD FROM THE
NORTHWEST THROUGH THE ROCKIES THIS WEEKEND INTO EARLY NEXT WEEK TO
FOCUS A SWATH OF RAIN AND TERRAIN ENHANCED MOUNTAIN SNOWS GIVEN
UPPER DYNAMIC SUPPORT.
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page