812
FXUS02 KWBC 100701
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST THU NOV 10 2022
VALID 12Z SUN NOV 13 2022 - 12Z THU NOV 17 2022
..OVERVIEW
AMPLIFIED TROUGHING OVER THE EAST ON SUNDAY SHOULD LIFT OUT BY
MONDAY WITH SOME WEAK RIDGING RETURNING EARLY NEXT WEEK OVER THE
SOUTHEAST. MEANWHILE, A STRONG AND BLOCK RIDGE OVER THE EASTERN
PACIFIC WILL FORCE VARIOUS SYSTEMS SOUTHWARD INTO THE NORTH TO
NORTH-CENTRAL CONUS WHICH PROMOTES OVERALL CYCLONIC FLOW AND BELOW
NORMAL TEMPERATURES OVER MUCH OF THE LOWER 48 THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK. CONFIDENCE IN EMBEDDED DETAILS IS STILL ON
THE LOWER SIDE, WITH PARTICULAR FOCUS ON AN UPPER
SHORTWAVE/SURFACE SYSTEM THAT COULD SPREAD PRECIPITATION OF
VARYING TYPES OVER PARTS OF THE CENTRAL/EASTERN U.S. IN THE
EARLY-MID WEEK TIME FRAME.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
IN GENERAL, THERE IS OVERALL DECENT AGREEMENT ON THE LARGE SCALE
BRAODLY CYCLONIC FLOW EXPECTED TO MAINTAIN OVER THE CONUS DURING
THE MEDIUM RANGE PERIOD (SUNDAY-THURSDAY). HOWEVER, THERE REMAIN
SOME SIGNIFICANT DIFFERENCES IN THE DETAILS, PARTICULARLY
SURROUNDING NORTHERN AND SOUTHERN STREAM SHORTWAVES DIVING INTO
THE WESTERN/CENTRAL U.S. ON THE EAST SIDE OF A BUILDING RIDGE OVER
THE EAST PACIFIC. THE GUIDANCE CONTINUES TO SHOW QUITE A BIT OF
RUN TO RUN VARIABILITY, BUT THERE MAY BE SOME SORT OF TREND
TOWARDS A CONSENSUS GIVEN THE DECREASE IN OVERALL SPREAD OF THE
VARIOUS ENSEMBLE SOLUTIONS. ONE PARTICULARLY IMPACTFUL FEATURE
INVOLVES A SOUTHERN STREAM CLOSED LOW DIVING ACROSS THE GREAT
BASIN ON SUNDAY INTO THE SOUTHERN PLAINS ON MONDAY. THERE IS A LOT
OF UNCERTAINTY BY TUESDAY-WEDNSEDAY NEXT WEEK ON DETAILS
SURROUNDING PHASING OF THIS SYSTEM WITH A NORTHERN STREAM
SHORTWAVE INTO THE NORTH-CENTRAL STATES AT THE SAME TIME. ANOTHER
SYSTEM DIVES INTO THE NORTHWEST MID NEXT WEEK WITH AGAIN A LOT OF
QUESTIONS ON BOTH SPEED AND AMPLIFICATION. THE WPC FORECAST USED A
BLEND OF DETERMINISTIC SOLUTIONS EARLY ON, AMIDST BETTER
AGREEMENT, BUT THEN TRENDED MORE TOWARDS THE ENSEMBLE MEANS THE
SECOND HALF OF THE PERIOD IN AN ATTEMPT TO MITIGATE THE
DIFFERENCES.
..WEATHER/HAZARD HIGHLIGHTS
AN UPPER TROUGH CROSSING THE EAST ALONG WITH COOL LOW LEVEL
CYCLONIC FLOW WILL SUPPORT SOME LAKE EFFECT SNOW WITHIN THE
TYPICAL SNOW BELTS OVER THE UPPER AND LOWER GREAT LAKES, MAINLY
EARLY IN THE WEEK. THE WEST MAY SEE SOME LIGHT PRECIPITATION
ACCOMPANYING THE UPPER LOW EXPECTED TO TRACK FROM OREGON
SOUTHEASTWARD THIS WEEKEND. LATEST CONSENSUS IS MAINTAINING
STRONGER DEFINITION OF THIS FEATURE AS IT OPENS AND CONTINUES
EAST-NORTHEAST FROM THE SOUTHERN ROCKIES EARLY-MID WEEK, LEADING
TO MORE SURFACE WAVINESS FROM THE GULF COAST TO EAST COAST. THIS
YIELDS BROADER COVERAGE OF PRECIPITATION FROM THE SOUTHERN HALF OF
THE PLAINS THROUGH THE EAST. RAIN COULD BE LOCALLY HEAVY ALONG THE
GULF COAST AND IT WILL BE POSSIBLE FOR SOME WINTRY PRECIPITATION
TO EXIST IN THE NORTHERN FRINGE OF THE MOISTURE SHIELD. IT WILL
TAKE ADDITIONAL TIME TO RESOLVE IMPORTANT SYSTEM DETAILS THAT WILL
DETERMINE THE COVERAGE/INTENSITY/TYPE OF PRECIPITATION.
BROAD UPPER TROUGHING IN RESPONSE TO THE STRONG RIDGE OFFSHORE THE
WEST COAST SHOULD KEEP A COLD PATTERN IN PLACE SUNDAY-THURSDAY,
AND LIKELY BEYOND PER THE CLIMATE PREDICTION CENTER WEEK 2
FORECAST. THE COLDEST AIR SHOULD BE OVER PARTS OF MONTANA AND THE
PLAINS SUNDAY-TUESDAY WITH SOME READINGS AT LEAST 20-30F BELOW
NORMAL, INCLUDING LOCALLY SUBZERO MORNING LOWS. COLDEST ANOMALIES
OVER THE WEST SHOULD TEND TO BE OVER THE GREAT BASIN WITH MULTIPLE
DAYS OF HIGHS 10-25F BELOW NORMAL. MAINE AND FLORIDA COULD BE
EXCEPTIONS WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES.
SANTORELLI
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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