695
FXUS02 KWBC 140702
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
202 AM EST THU NOV 14 2024
VALID 12Z SUN NOV 17 2024 - 12Z THU NOV 21 2024
..HEAVY RAINFALL THREATS FOR PARTS OF THE CENTRAL U.S
...POTENTIAL TROPICAL CYCLONE NINETEEN TO BRING UNCERTAIN TROPICAL
THREATS TO FLORIDA OR THE GULF COAST NEXT WEEK...
..OVERVIEW
TROUGHING OVER THE WEST BY THIS COMING WEEKEND WILL SPLIT SENDING
NORTHERN STREAM ENERGY THROUGH THE NORTHERN PLAINS/UPPER MIDWEST,
WHILE A SOUTHERN STREAM CUTOFF LOW SHIFTS ACROSS THE FOUR CORNERS
REGION AND INTO THE CENTRAL U.S. NEXT WEEK. THE NEXT SHORTWAVE INTO
THE NORTHWEST ON MONDAY WILL INTERACT/COMBINE WITH THE UPPER LOW
AS IT LIFTS NORTHWARD EVENTUALLY RESULTING IN A DEEP AND VERY
AMPLIFIED UPPER LOW/TROUGH SPANNING THE CENTRAL INTO EASTERN U.S.
LATE PERIOD. AT THIS SURFACE, THIS WILL TRANSLATE TO EARLY WEEK
CYCLOGENESIS IN THE LEE OF THE ROCKIES WITH A DEEPENING STORM
SYSTEM TRACKING FROM THE SOUTHERN PLAINS TO THE GREAT LAKES MONDAY-
THURSDAY. THIS 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 ACROSS THE UPPER MIDWEST, BUT DEPENDENT ON THE
QUALITY OF COLD AIR FILTERING IN BEHIND THIS SYSTEM. MEANWHILE,
GUIDANCE SHOWS POTENTIAL TROPICAL CYCLONE NINETEEN EMERGING OUT OF
THE CARIBBEAN AND INTO THE SOUTHERN GULF OF MEXICO NEXT WEEK, WITH
SOME POTENTIAL BUT STILL VERY UNCERTAIN HEAVY RAINFALL THREATS
POSSIBLE FOR PARTS OF FLORIDA OR THE GULF COAST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
CONSIDERING THE INCREASINGLY ACTIVE AND AMPLIFIED PATTERN TO
EVOLVE IN THE MEDIUM RANGE PERIOD, THE GUIDANCE IS IN GENERALLY
GOOD AGREEMENT ON THE LARGE SCALE, BUT STILL WITH PLENTY OF
UNCERTAINTY IN THE DETAILS WHICH WOULD HAVE LARGE IMPLICATIONS ON
SENSIBLE WEATHER. THERE ARE SOME MINOR TIMING DIFFERENCES STILL
WITH THE UPPER LOW AS IT LIFTS THROUGH THE CENTRAL U.S., BUT THE
GREATER UNCERTAINTY COMES EARLY TO MID WEEK WITH REGARDS TO ENERGY
DROPPING INTO THE MEAN TROUGH AND HOW THIS INTERACTS WITH THE
DOWNSTREAM UPPER LOW. REGARDLESS OF THE EVOLUTION DETAILS, BY MID
TO LATE NEXT WEEK, THERE IS GOOD AGREEMENT THAT A VERY AMPLIFIED
AND ACTIVE PATTERN SHOULD BE IN PLACE ACROSS THE CONUS WITH DEEP
TROUGHING OVER THE CENTRAL TO EASTERN U.S. AND STRONG RIDGING OVER
THE WEST.
ESPECIALLY BY THE MEDIUM RANGE PERIOD, THERE IS A TON OF
UNCERTAINTY STILL WITH THE TRACK AND INTENSITY OF CURRENTLY
POTENTIAL TROPICAL CYCLONE NINETEEN. THE LATEST FORECAST FROM THE
NHC HAS THIS SYSTEM MOVING NORTHWARD THROUGH THE YUCATAN PENINSULA
INTO THE GULF AS A TROPICAL STORM. GOOD AGREEMENT IN THE GUIDANCE
THAT THE UPPER TROUGH THROUGH THE CENTRAL U.S. SHOULD HELP STEER
THIS SYSTEM BUT A LOT OF UNCERTAINTY HOW QUICKLY IT MAY GET PULLED
INTO THE APPROACHING COLD FRONT. SOME OF THE LATEST 00Z GUIDANCE IS
SUGGESTING AN EARLIER INTERACTION AND MORE NORTHWARD TRACK TOWARDS
THE CENTRAL GULF COAST AS A WEAKER SYSTEM AS IT BECOMES ABSORBED
INTO THE LARGER SCALE FLOW. BUT ALSO PLENTY OF SUPPORT FOR A MORE
EASTERLY TRACK ACROSS THE FLORIDA PENINSULA. MONITOR PRODUCTS FROM
THE NHC FOR THE LATEST INFORMATION ON PTC NINETEEN.
THE WPC PROGS FOR TONIGHT USED A GENERAL BLEND OF THE GFS, ECMWF,
AND UKMET EARLY PERIOD, AND LEANING INCREASINGLY MORE ON THE
ENSEMBLE MEANS LATE PERIOD TO HELP MITIGATE THE DETAIL DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
THE COVERAGE AND INTENSITY OF PRECIPITATION 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 AND BACK TOWARDS THE
SOUTHERN HIGH PLAINS WHERE A MARGINAL RISK IS IN PLACE ON THE DAY
4/SUNDAY EXCESSIVE RAINFALL OUTLOOK. THE HEAVY RAIN THREAT LIFTS
NORTHWARD ON MONDAY BUT WITH A LOT OF UNCERTAINTY ON EXACTLY WHERE
THE GREATEST THREAT LIES. FOR NOW, THE DAY 5/MONDAY ERO HIGHLIGHTS
A BROAD MARGINAL RISK SPANNING ACROSS MUCH OF THE CENTRAL PLAINS
INTO PARTS OF THE MID TO UPPER MISSISSIPPI VALLEY. DEPENDING ON
COLD AIR FILTERING IN BEHIND THE DEEPENING STORM SYSTEM, SOME
ACCUMULATING 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.
OUT WEST, ANOTHER ATMOSPHERIC RIVER IS EXPECTED TO SUPPORT HEAVY
RAIN AND MOUNTAIN SNOWS ACROSS THE PACIFIC NORTHWEST THROUGH
SUNDAY, WITH LIGHTER PRECIPITATION EXTENDING INLAND ACROSS THE
NORTHERN ROCKIES AND GREAT PLAINS. WPC IS MAINTAINING THE MARGINAL
RISK FOR THE NEW DAY 4 ERO TODAY ACROSS WESTERN WASHINGTON AND
OREGON.
MOISTURE FROM PTC NINETEEN AS IT EMERGES INTO THE GULF OF MEXICO
MAY BEGIN IMPACTING PARTS OF FLORIDA OR THE GULF COAST BY MID NEXT
WEEK, BUT THERE IS A LOT OF UNCERTAINTY IN EXACT IMPACTS AND
AMOUNTS. THERE IS A CLUSTER OF GUIDANCE THAT TAKES THIS ACROSS
FLORIDA AS A POSSIBLE TROPICAL STORM, BUT SOME OF THE NEWEST
GUIDANCE TONIGHT PULLS IT MORE NORTHWARD TOWARDS THE GULF COAST.
THIS SYSTEM WILL NEED TO BE MONITORED.
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. WELL BELOW NORMAL TEMPERATURES AND THE
FIRST COLD SNAP OF THE SEASON WILL SHIFT INTO THE CENTRAL U.S. NEXT
WEEK.
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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