876
FXUS02 KWBC 030658
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 AM EDT SUN SEP 03 2023
VALID 12Z WED SEP 06 2023 - 12Z SUN SEP 10 2023
...IMPRESSIVE HEAT TO SHIFT FROM THE EAST/SOUTH PAST MIDWEEK BACK
TO THE SOUTH-CENTRAL U.S AND SOUTHWEST LATER WEEK/WEEKEND...
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
BROAD COMPOSITE BLEND OF BEST CLUSTERED OVERALL GUIDANCE FROM THE
18 UTC GFS/GEFS MEAN AND THE 12 UTC ECMWF/CANADIAN/ECMWF ENSEMBLE
MEAN ALONG WITH THE COMPATIBLE 01 UTC NATIONAL BLEND OF MODELS IN
A PATTERN WITH SEEMINGLY ABOVE NORMAL MID-LARGER SCALE
PREDICTABILITY. THIS BLEND TENDS TO MITIGATE WIDESPREAD SMALLER
SCALE WARM SEASON GUIDANCE DIFFERENCES GENERALLY CONSISTENT WITH
SYSTEM PREDICTABILITY AND MAINTAINS GOOD WPC CONTINUITY. A
COMPOSITE OF FAVORABLY TRENDING GUIDANCE FROM THE LATEST 00 UTC
GUIDANCE CYCLE REMAINS IN LINE WITH THIS AFOREMENTIONED FORECAST
PLAN.
..WEATHER/HAZARDS HIGHLIGHTS
HOT LATE SUMMER TEMPERATURES LINGERING ACROSS THE EAST AND SOUTH
PAST MIDWEEK WILL THEN REFOCUS TO THE SOUTH-CENTRAL U.S. AND THE
SOUTHWEST LATER WEEK INTO NEXT WEEKEND WITH RE-DIRECTION/BUILDING
OF A MAIN SUPPORTING/AMPLIFIED UPPER RIDGE. TEMPERATURE ANONALIES
IN THE 10-15 DEGREES ABOVE NORMAL RANGE OFFERS POTENTIAL FOR
WIDESPREAD RECORD VALUES IN WHAT HAS PROVEN TO BE A SWELTERING
SUMMER.
THE STEADY DOWNSTREAM EJECTION OF A MAIN UPPER TROUGH AND
ENTRAINING LEAD IMPULSES FROM THE NORTHERN PLAINS THROUGH THE
NORTHEAST MIDWEEK INTO NEXT WEEKEND WILL SUPPORT A SWATH OF
PRECIPITATION ADDITIONALLY FUELED POOLING MOISTURE AND INSTABILITY
INTO A LEADING SURFACE LOW/FRONTAL SYSTEM. SOME LOCALIZED HEAVY
CONVECTIVE DOWNPOURS WILL ALSO OCCUR IN SCATTERED CONVECTION BACK
ACROSS THE EASTERN TO CENTRAL STATES NEAR A TRAILING FRONT IN A
PATTERN WITH FAVORABLE UPPER DIFFLUENCE AND DIGGING IMPULSES.
WHILE NO WPC EXCESSIVE RAINFALL AREAS HAVE BEEN ISSUED FOR THE DAY
4/5 PERIOD WED/THU GIVEN UNCERTAINTIES AT THESE LONGER TIME FRAMES
FOR SUMMER CONVECTION, THERE IS A BUILDING GUIDANCE SIGNAL THAT A
FEW SLOWER CELLS ALONG WITH TRAINING COULD PRODUCE SOME RUNOFF
ISSUES OVER THE MID-SOUTH AND VICINITY. A SERIES OF ADDITIONAL
SHORTWAVES WILL ALSO UNCERTAINLY WORK FROM THE PACIFIC THROUGH THE
WEST/NORTHWEST AND INLAND ACROSS THE INTERMOUNTAIN WEST/ROCKIES,
ALBEIT IN A PATTERN WITH LIMITED PRECIPITATION BUT LOCALIZED
CONVECTION THAT MAY BECOME BEST ORGAINZED LATER WEEK ACROSS THE
NORTHERN ROCKIES AND DOWNSTREAM INTO THE NORTHERN PLAINS WITH
SYSTEM ADVANCE.
SCHICHTEL
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, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES 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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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