734
FXUS02 KWBC 011853
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 PM 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
UPDATED DETERMINISTIC AND ENSEMBLE GUIDANCE REMAINS IN FAIRLY GOOD
AGREEMENT AND CONSISTENT RUN-TO-RUN ON THE LARGE-SCALE PATTERN
THROUGH MOST OF THE MEDIUM RANGE PERIOD (MONDAY NOV 4 - FRIDAY NOV
8). THE WEEK BEGINS WITH A HIGHLY AMPLIFIED PATTERN WITH STRONG
RIDGING OVER THE EASTERN HALF OF THE COUNTRY AND A DEEP TROUGH OVER
THE WEST, CONTINUING A PERIOD OF MORE MERIDIONAL FLOW ALONG A WAVY
FRONTAL SYSTEM OVER THE CENTRAL PART OF THE COUNTY AIDING IN
MOISTURE RETURN/STORM DEVELOPMENT. THE GUIDANCE THEN INDICATES LEAD
ENERGY WILL LIFT NORTH ALONG THE WESTERN SIDE OF THE RIDGE OVER
THE MIDWEST PROMOTING A SLOW BUT STEADY PROGRESSION OF THE FRONTAL
SYSTEM EASTWARD, WHILE ADDITIONAL NORTHERN/SOUTHERN STREAM ENERGY
REINFORCE MEAN TROUGHING OVER THE WESTERN U.S. BY MID-WEEK. BOTH
DETERMINISTIC AND ENSEMBLE GUIDANCE FROM THE 06Z GFS/GEFS AND 00Z
ECMWF/ECENS THEN INDICATE THE SOUTHERN STREAM ENERGY LEADS TO A
CLOSED LOW OVER THE SOUTHWEST. GUIDANCE DIFFERENCES GROW BETWEEN
THE 06Z GFS/00Z ECMWF ON THE TIMING OF LEAD NORTHERN STREAM ENERGY
COMING OUT OF THE WEST ALONG THE NORTHERN TIER OF THE COUNTRY. THIS
IS REFLECTED WITH A FRONTAL SYSTEM AT THE SURFACE THAT FOLLOWS A
SLOWER, MORE SOUTHERLY TRACK IN THE ECMWF AND THE GFS FURTHER
NORTH. IN ADDITION, THE GFS IS FASTER IN BRINGING THE CLOSED LOW IN
THE WEST OVER THE PLAINS, LEADING TO MORE NORTHERLY/AGGRESSIVE LEE
CYCLOGENESIS AHEAD OF THE WEEKEND WHILE THE ECMWF REMAINS TO THE
SOUTHWEST, FAVORING PRECIPITATION CHANCES OVER THE SOUTHERN
ROCKIES/PLAINS. THE ECMWF FITS WITHIN THE ENVELOPE OF THE
RELATIVELY SIMILAR GEFS/ECENS MEANS, AND THE 12Z GFS CAME IN MORE
SIMILAR TO THE ECMWF.
THE OTHER AREA OF INTEREST IS WITH RESPECT TO POTENTIAL TROPICAL
DEVELOPMENT IN THE SOUTHWESTERN CARIBBEAN THAT MAY EVENTUALLY TRACK
NORTHWARD INTO THE GULF OF MEXICO. THE NATIONAL HURRICANE CENTER
IS CURRENTLY GIVING THIS SYSTEM A 70% CHANCE OF DEVELOPMENT IN THE
NEXT 7 DAYS WITH A FAVORED PATH THAT BRINGS AN AREA OF LOW PRESSURE
INTO THE WESTERN GULF OF MEXICO, WHICH ALIGNS WITH THE 00Z
ECMWF/06Z GFS AND ECENS/GEFS MEANS. THE LATEST CMC WAS MUCH MORE
AGGRESSIVE WITH THE POTENTIAL SYSTEM, BRINGING AN AREA OF LOW
PRESSURE NORTHEASTWARD TOWARDS THE EASTERN GULF OF MEXICO.
DESPITE THE GENERALLY GOOD AGREEMENT ON THE OVERALL PATTERN,
SPECIFICS ON FRONTAL PLACEMENT EARLY IN THE PERIOD OVER THE CENTER
OF THE COUNTRY STILL LEAD TO MUCH HIGHER UNCERTAINTY WITH THE QPF
FORECAST. THE GFS/ECMWF/CMC ALL AGREE ON THE POTENTIAL FOR A
CONTINUATION OF HEAVY RAIN MONDAY SHIFTING EASTWARD FROM THE PLAINS
TOWARDS THE MISSISSIPPI VALLEY, BUT WITH DISAGREEMENT ON THE
LOCATION OF A POTENTIALLY NARROW PRE-FRONTAL AXIS. THIS MAY LINGER
LONGER OVER THE SAME REGION INTO TUESDAY AS WELL, WITH THE ECMWF
FAVORING SLOWER FRONTAL PROGRESSION AND ADDITIONAL RAINFALL.
ADDITIONAL UNCERTAINTY ARISES AROUND THE POTENTIAL FOR HEAVY
RAINFALL IN SOUTH FLORIDA AND THEN AT LEAST SOME RAINFALL ALONG THE
GULF COAST WITH INCREASING MOISTURE FROM THE POTENTIAL TROPICAL
SYSTEM MOVING INTO THE GULF, AS WELL AS WITH ADDITIONAL
PRECIPITATION IN THE SOUTHWEST/PLAINS LATER NEXT WEEK DEPENDING ON
THE PROGRESSION OF THE CLOSED LOW EASTWARD.
THE UPDATED WPC FORECAST USED A COMPOSITE OF THE DETERMINISTIC
GUIDANCE FOR THE FIRST PART OF THE PERIOD GIVEN GOOD AGREEMENT. A
CONTRIBUTION OF THE ECENS/GEFS MEANS WAS USED FOR THE LATTER HALF
OF THE PERIOD, WITH THE CMC REMOVED DUE TO THE DISAGREEMENT IN
HANDLING THE POTENTIAL TROPICAL SYSTEM, AND A HEAVY FAVOR TOWARDS
THE ECMCF OVER THE GFS GIVEN THE CLUSTERING OF THE ECMWF WITH THE
ECENS/GEFS SOLUTIONS. LEANED A BIT HEAVIER ON THE MEANS EARLIER IN
THE PERIOD FOR THE QPF FORECAST GIVEN SPATIAL DIFFERENCES IN THE
DETERMINISTIC GUIDANCE, WITH THE EXPECTATION AMOUNTS MAY INCREASE
AS CERTAINTY IN THE FRONTAL PROGRESSION GROWS.
..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, PARTICULARLY FROM
SOUTHEASTERN OKLAHOMA/NORTHWESTERN ARKANSAS INTO CENTRAL MISSOURI.
A MODERATE RISK MAY EVENTUALLY BE NEEDED HERE WITH MORE CONFIDENCE
IN THE LOCATION OF THE HEAVIEST RAINFALL TOTALS AND HOW MUCH
OVERLAP THERE IS WITH RAINFALL ON DAY 3. 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 AND
LOW CONFIDENCE IN MORE SIGNIFICANT HEAVIER RAINFALL TOTALS. 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 HEAVY, 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. THE SOUTHERN EXTENT OF COOLER AIR WITH
THIS SYSTEM MAY ALSO LEAD TO SOME WINTRY PRECIPITATION OUTSIDE OF
MOUNTAIN AREAS INTO THE CENTRAL/SOUTHERN HIGH PLAINS, BUT AGAIN
WITH LOW CONFIDENCE IN COVERAGE AND ANY ACCUMULATIONS.
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.
PUTNAM/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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