075
FXUS02 KWBC 010658
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
258 AM EDT FRI NOV 1 2024
VALID 12Z MON NOV 04 2024 - 12Z FRI NOV 08 2024
...HEAVY RAIN AND SEVERE WEATHER EXPECTED ACROSS PORTIONS OF THE
CENTRAL U.S. INTO EARLY NEXT WEEK...
..OVERVIEW
THE CENTRAL U.S. WILL BE THE MOST PROMINENT FOCUS FOR ACTIVE
WEATHER DURING PORTIONS OF NEXT WEEK. IN PARTICULAR, CONTINUING
INTO MONDAY EXPECT AN AREA OF HEAVY RAINFALL OVER PARTS OF THE
PLAINS/MIDWEST AS SOUTHERN PLAINS UPPER DYNAMICS EJECT
NORTHEASTWARD WHILE THE LEADING WAVY FRONT INTERACTS WITH ABUNDANT
MOISTURE CONTRIBUTED BY STRONG GULF INFLOW. THEN MOST GUIDANCE
SHOWS SHORTWAVE ENERGY ARRIVING FROM THE PACIFIC AND DROPPING INTO
THE ROCKIES/FOUR CORNERS REGION, POSSIBLY CLOSING OFF AN UPPER LOW
AFTER MIDWEEK. THIS FEATURE MAY PRODUCE ADDITIONAL RAINFALL OVER
THE SOUTHERN PLAINS AND VICINITY LATE IN THE WEEK BUT LIKELY WITH
LIGHTER TOTALS THAN IN THE PRECEDING EVENT. AN AREA OF RAIN AND
HIGHER ELEVATION SNOW SHOULD PASS THROUGH THE PACIFIC NORTHWEST AND
MOVE SOUTH THROUGH THE ROCKIES WITH THE PROGRESSION/EVOLUTION OF
THE ENERGY ALOFT. THIS PATTERN WILL FAVOR VERY WARM TEMPERATURES
(LIKELY INCLUDING SOME DAILY RECORDS) OVER THE EAST AND BELOW
NORMAL READINGS OVER MOST OF THE INTERIOR WEST AND ROCKIES.
MEANWHILE, THE NATIONAL HURRICANE CENTER IS MONITORING POSSIBLE
CARIBBEAN TROPICAL DEVELOPMENT THAT MAY EMERGE INTO THE GULF, WITH
TYPICALLY BROAD GUIDANCE SPREAD FOR TRACK AND TIMING.
..GUIDANCE/PREDICTABILITY ASSESSMENT
WHILE THE AGREEMENT DOES NOT EXTEND TO RAINFALL AMOUNTS OVER THE
MISSISSIPPI VALLY AND VICINITY BY TUESDAY, THERE IS OTHERWISE A
SOLID GUIDANCE CONSENSUS REGARDING THE DETAILS OF EJECTING
SOUTHERN ROCKIES ENERGY AND LEADING WAVY SURFACE FRONT DURING THE
FIRST PART OF THE WEEK. THEN MODELS AND ENSEMBLES DIVERGE FOR
INCOMING PACIFIC ENERGY THAT IS MOST LIKELY TO DIG SOUTHWARD OVER
THE INTERIOR WEST/ROCKIES. WHILE THERE IS A LOT OF SPREAD WITHIN
THE FULL ENSEMBLE ENVELOPE, ENOUGH MEMBERS CLUSTER WELL ENOUGH FOR
THE MEANS TO SUGGEST AN UPPER LOW CLOSING OFF OVER THE FOUR CORNERS
REGION BY NEXT THURSDAY-FRIDAY. THE 18Z GFS/12Z ECMWF/12Z CMC ALL
FIT THIS SCENARIO AS WELL. AMONG NEW 00Z RUNS, THE ECMWF REMAINS A
BIT ON THE WESTERN SIDE WITH THE UPPER LOW WHILE THE GFS/CMC HAVE
SHIFTED EASTWARD. A NUMBER OF 12Z MACHINE LEARNING (ML) MODELS
OFFER POTENTIAL FOR THE UPPER LOW/TROUGH TO REACH THE PLAINS BY
NEXT FRIDAY THOUGH ONE IS SLOW LIKE THE NEW 00Z ECMWF. AS THIS
ENERGY SEPARATES, NORTHERN STREAM FLOW SHOULD TREND TOWARD BROAD
TROUGHING OVER THE NORTHEASTERN U.S. AND EASTERN CANADA WHILE
WESTERN CANADA AND THE NORTHWESTERN U.S. SEE MEAN RIDGING AHEAD OF
A COUPLE STRONG SYSTEMS NEAR ALASKA.
AS FOR THE POSSIBLE CARIBBEAN TROPICAL DEVELOPMENT TRACKING INTO
THE GULF, LATEST CMC AND ECMWF AIFS RUNS ARE ON THE FAST AND
EASTERN SIDE OF THE SPREAD WITH GULF COAST/SOUTHEAST EFFECTS
ALREADY BY LATE NEXT WEEK. AMONG OTHER GUIDANCE THE MOST COMMON
THEME BY NEXT FRIDAY IS A POSITION OVER THE CENTRAL OR SOUTHWESTERN
GULF. THIS IS IN LINE WITH EXTRAPOLATION OF YESTERDAY'S WPC/NHC
COORDINATED DEPICTION THROUGH THURSDAY.
GUIDANCE COMPARISONS LED TO STARTING THE UPDATED FORECAST WITH A
12Z/18Z OPERATIONAL MODEL COMPOSITE DURING THE FIRST HALF OF THE
PERIOD AND THEN A TRANSITION TOWARD THE 18Z GEFS/12Z ECENS MEANS
AND OPERATIONAL RUNS (MORE GFS/ECMWF THAN CMC).
..WEATHER/HAZARDS HIGHLIGHTS
STRONG DEEP-LAYER FLOW FROM THE GULF OF MEXICO AHEAD OF A WAVY
FRONT PUSHING THROUGH THE CENTRAL U.S. WILL CONTRIBUTE ABUNDANT
MOISTURE TO A HEAVY RAIN EVENT EXPECTED TO CONTINUE FROM THE
WEEKEND INTO THE FIRST PART OF NEXT WEEK. THE STORM PREDICTION
CENTER IS ALSO MONITORING SEVERE WEATHER POTENTIAL OVER PARTS OF
THE CENTRAL/SOUTHERN PLAINS. CURRENTLY THE RELATIVELY HIGHER
POTENTIAL FOR REPEAT AND TRAINING CONVECTION WITH LOCALLY HIGH
RAINFALL RATES EXTENDS FROM AROUND EASTERN OKLAHOMA/WESTERN
ARKANSAS NORTHEASTWARD INTO NORTHERN ILLINOIS, CORRESPONDING TO THE
SLIGHT RISK AREA IN THE DAY 4 EXCESSIVE RAINFALL OUTLOOK. THIS
REGION WILL INITIALLY SEE DRY GROUND CONDITIONS BUT SOME RAINFALL
IS LIKELY IN THE SHORTER TERM LEADING INTO DAY 4. THE COVERAGE OF
SIGNIFICANT RAINFALL WILL LIKELY DECREASE BY DAY 5/TUESDAY AS THE
UPPER DYNAMICS AND PRIMARY FRONTAL WAVE CONTINUE NORTHEASTWARD.
HOWEVER LINGERING MOISTURE/INSTABILITY MAY PROMOTE SOME ADDITIONAL
RAINFALL, WITH CONSIDERABLE SPREAD AMONG GUIDANCE FOR AMOUNTS. THE
DAY 5 ERO DEPICTS A MARGINAL RISK AREA FROM THE LOWER OHIO VALLEY
SOUTHWESTWARD AS A REASONABLE STARTING POINT GIVEN THE FORECAST
UNCERTAINTY.
INCOMING PACIFIC DYNAMICS WILL BRING AN EPISODE OF TERRAIN-ENHANCED
RAIN AND HIGHER ELEVATION SNOW TO THE PACIFIC NORTHWEST EARLY IN
THE WEEK WITH PRECIPITATION THEN DROPPING SOUTH THROUGH THE
ROCKIES, PLUS WITH SOME RAINFALL DEVELOPING OVER THE PLAINS.
SPECIFICS FOR ROCKIES/PLAINS TOTALS WILL BE SENSITIVE TO THE
DETAILS OF FLOW ALOFT.
A BROAD AREA OF WELL ABOVE NORMAL TEMPERATURES WILL DRIFT ACROSS
THE EASTERN HALF OF THE COUNTRY, WITH GRADUAL PROGRESSION OF A
COUPLE FRONTS EVENTUALLY LEADING TO SOME MODERATION BY LATE WEEK.
WARMEST ANOMALIES SHOULD BE FOR MORNING LOWS, WITH SOME AREAS 20F
OR MORE ABOVE NORMAL FOR ONE OR MORE DAYS, BUT DAILY RECORDS WILL
BE POSSIBLE FOR BOTH HIGHS AND WARM LOWS DURING EARLY-MID WEEK. IN
CONTRAST, A MAJORITY OF THE INTERIOR WEST AND ROCKIES SHOULD SEE
CHILLY TEMPERATURES FOR MOST OF NEXT WEEK WITH READINGS TENDING TO
BE 5-15F BELOW NORMAL.
RAUSCH
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.PHPSCHICHTEL/HAMRICK
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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