336
FXUS02 KWBC 131858
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 PM EST WED NOV 13 2024
VALID 12Z SAT NOV 16 2024 - 12Z WED NOV 20 2024
..OVERVIEW
TROUGHING OVER THE WEST BY THIS COMING WEEKEND WILL SPLIT SENDING
NORTHERN STREAM ENERGY THROUGH THE NORTHERN PLAINS/UPPER MIDWEST,
WHILE SOUTHERN STREAM ENERGY DROPS SOUTH AND THEN EASTWARD EARLY
NEXT WEEK. THIS SHOULD HELP INDUCE CYCLOGENESIS IN THE LEE OF THE
ROCKIES WITH A MODESTLY DEEP STORM EJECTING NORTHEASTWARD THROUGH
THE CENTRAL U.S. NEXT TUESDAY AND WEDNESDAY. THE PATTERN WOULD
SUPPORT HEAVY RAINFALL POTENTIAL FROM THE SOUTH-CENTRAL PLAINS INTO
THE MISSISSIPPI VALLEY BY LATE THIS WEEKEND INTO EARLY NEXT WEEK,
WITH SOME SNOW POSSIBLE ON THE BACKSIDE OF THE LOW DEPENDING ON
COLD AIR FILTERING IN BEHIND THIS SYSTEM. ANOTHER ATMOSPHERIC RIVER
WILL BRING A ROUND OF HEAVY RAIN AND MOUNTAIN SNOWS TO THE PACIFIC
NORTHWEST THIS WEEKEND. THIS SHOULD RELOAD AND HELP DEEPEN MEAN
TROUGHING OVER THE WEST RESULTING IN A RATHER ACTIVE AND AMPLIFIED
PATTERN ACROSS THE CONUS BY NEXT WEEK WITH STRONG TROUGHING
SHIFTING THROUGH THE CENTRAL U.S. AND RIDGING OVER THE EAST AND
WEST COASTS. MEANWHILE, GUIDANCE CONTINUES TO SUGGEST SOME SORT OF
TROPICAL DEVELOPMENT EMERGING OUT OF THE CARIBBEAN AND INTO THE
SOUTHERN GULF OF MEXICO NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THERE IS DECENT LARGE-SCALE AGREEMENT OVER THE NEXT WEEK BUT
PLENTY OF UNCERTAINTY IN THE DETAILS AND EVOLUTION OF INDIVIDUAL
SYSTEMS. UNCERTAINTY PERSISTS WITH THE DEEP WESTERN TROUGH WHICH
MAY BRIEFLY CLOSE OFF A LOW IN/AROUND NORTHWEST MEXICO BEFORE IT
MOVES EASTWARD. THE MODELS SHOW BETTER AGREEMENT THIS SHOULD TRACK
NORTHEASTWARD INDUCING STRONG SURFACE LOW PRESSURE THAT TRACKS
THROUGH THE CENTRAL U.S. NEXT WEEK. MORE UNCERTAINTY SURROUNDS THE
NEXT SHORTWAVE INTO THE WEST WHICH SHOULD RELOAD AND DEEPEN THE
MEAN WESTERN TROUGH LEADING TO SOME DIFFERENCES IN EXACTLY HOW
ENERGY GETS INCORPORATED INTO THE TROUGH AND HOW QUICKLY IT MOVES
EASTWARD. FARTHER SOUTH, THE GUIDANCE HAS BEEN TRENDING TOWARDS AN
EMERGING TROPICAL THREAT OUT OF THE CARIBBEAN INTO THE SOUTHERN
GULF, BUT STILL QUITE A BIT OF UNCERTAINTY ON POTENTIAL IMPACTS TO
PARTS OF THE SOUTHEAST. SEE TROPICAL OUTLOOKS FROM THE NATIONAL
HURRICANE CENTER FOR THE LATEST INFORMATION ON THIS POTENTIAL.
THE WPC BLEND WAS COMPRISED OF A COMBINATION OF THE ECWMF/GFS/CMC
FOR THE START OF THE EXTENDED PERIOD AND THEN INCLUDED INCREASING
WEIGHTS OF THE EC AND GEFS ENSEMBLE MEANS FROM THE MIDPOINT TO THE
END OF THE PERIOD. THIS APPROACH MAINTAINED CONTINUITY FROM THE
PREVIOUS FORECAST TO DAMPEN THE INCREASED UNCERTAINTY WITH THE
WEST TO CENTRAL U.S. TROUGH WITH TIME.
..WEATHER/HAZARDS HIGHLIGHTS
THE COVERAGE AND INTENSITY OF PRECIPIATION ACROSS PORTIONS OF THE
FOUR CORNER TO THE SOUTHERN/CENTRAL PLAINS/MID-MISSISSIPPI VALLEY
WILL INCREASE OVER THE WEEKEND; WHICH WILL BOOST THE THREAT FOR
HEAVY RAIN FOR THE PLAINS AND MID-MISSISSIPPI VALLEY FOR THE START
OF THE WEEK. GIVEN THE DEGREE OF SPREAD AMONGST THE GUIDANCE,
SPECIFICS FOR AMOUNTS, LOCATION AND DEGREE OF IMPACTS REMAIN VERY
UNCERTAIN; HOWEVER THERE CONTINUES TO BE A SIGNAL FOCUSING IN THE
VICINITY OF NORTHERN TEXAS INTO OKLAHOMA. AS SUCH, WPC HAS
MAINTAINED A D5 MARGINAL RISK FOR EXCESSIVE RAINFALL FOR THAT
REGION.
DEPENDING ON COLD AIR FILTERING IN BEHIND THE SYSTEM, SOME SNOW
MAY BE POSSIBLE ACROSS THE ROCKIES INTO THE NORTHERN PLAINS EARLY-
MID NEXT WEEK. GENERALLY WET CONDITIONS IS EXPECTED TO ACCOMPANY
THE COLD FRONT LATE PERIOD AS IT PUSHES INTO THE EAST-CENTRAL
STATES AND GREAT LAKES. FOR THE WEST ANOTHER ATMOSPHERIC RIVER IS
EXPECTED TO SUPPORT HEAVY RAIN AND MOUNTAIN SNOWS ACROSS THE
PACIFIC NORTHWEST THIS WEEKEND. WPC IS MAINTAINING THE MARGINAL
RISKS THAT ARE HIGHLIGHTING PORTIONS OF THE COASTAL AND CASCADES
RANGES ON BOTH THE DAY 4 AND 5 EROS.
MOISTURE FROM WHATEVER TROPICAL THREAT EMERGES OUT OF THE
CARIBBEAN MAY BEGIN IMPACTING PARTS OF FLORIDA MID NEXT WEEK, BUT
THERE IS A LOT OF UNCERTAINTY IN EXACT IMPACTS AND AMOUNTS FROM
THIS. BUT THIS WILL NEED TO CONTINUE TO BE WATCHED.
ABOVE SEASONAL NORMAL TEMPERATURES WILL SPREAD FROM THE CENTRAL
U.S. TO THE EAST BY SUNDAY INTO MONDAY LEADING TO DAILY MAXIMUM
TEMPERATURES TO CLIMB 10 TO 15 DEGREES WARMER IN A SOME LOCATIONS.
FOR THE WESTERN U.S., IT WILL BE TRENDING COOLER AS UPPER
TROUGHING AMPLIFIES OVER THE REGION AND PERSISTS INTO NEXT WEEK.
CAMPBELL/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 FORECAST (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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
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