213
FXUS02 KWBC 081841
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 PM EDT THU AUG 8 2024
VALID 12Z SUN AUG 11 2024 - 12Z THU AUG 15 2024
...EXCESSIVE HEAT LINGERS OVER PORTIONS OF TEXAS AND THE CENTRAL
GULF COAST INTO NEXT WEEK...
..OVERVIEW
UPPER PATTERN OVER NORTH AMERICA WILL FEATURE STRONG RIDGING OVER
CENTRAL CANADA MOVING SLOWLY EASTWARD INTO HUDSON BAY, A CLOSED
UPPER HIGH OVER TEXAS, AND TROUGHING ALONG BOTH THE WEST AND EAST
COASTS. A FRONTAL BOUNDARY WILL LINGER ACROSS THE SOUTHEAST AND
BACK INTO THE PLAINS WHERE THE FOCUS FOR CONVECTION WILL LIE. IN
ADDITION, WITH A SOUTHEAST FLOW IN THE MID-LEVELS OUT OF MEXICO
INTO THE SOUTHWEST, MONSOONAL RAINS WILL CONTINUE THROUGH THE
PERIOD OVER THE FOUR CORNERS REGION.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00/06Z GUIDANCE SUITE OFFERED REASONABLE CLUSTERING THROUGH
THE PERIOD, AND A BLEND OF THE GFS/ECMWF AND THEIR ENSEMBLES WERE
USED FOR THE STARTING POINT (ALONG WITH SOME OF THE CANADIAN AND
UKMET TO START). THE 13Z NBM WAS USED AS A STARTING POINT FOR THE
SENSIBLE WEATHER GRIDS, WITH MINOR ADJUSTMENTS.
..WEATHER/HAZARDS HIGHLIGHTS
MONSOONAL MOISTURE FLOW ON THE WESTERN SIDE OF THE RIDGE CENTERED
OVER TEXAS WILL KEEP A WET AND UNSETTLED PATTERN IN PLACE FROM THE
FOUR CORNERS REGION NORTHWARD INTO THE CENTRAL ROCKIES/HIGH PLAINS
FOR SUNDAY/MONDAY. MARGINAL EROS ARE IN PLACE HERE FOR DAYS 4/5.
WITH THE SURFACE HIGH SHIFTING EAST TO THE MIDWEST ON SUNDAY, THE
CLOCKWISE FLOW OPENS THE WESTERN GULF TO TRANSPORT MOISTURE UP THE
PLAINS WHERE SOME ISOLATED HEAVY RAIN THREAT EXISTS ANYWHERE FROM
THE ROCKIES ONTO THE PLAINS. A BROAD MARGINAL RISK COVERS MUCH OF
THE PLAINS DUE TO UNCERTAINTY AT THIS TIME RANGE. BY DAY 5,
CONTINUED THE MARGINAL RISK OVER THE CENTRAL PLAINS GIVEN LITTLE
CHANGE IN THE OVERALL PATTERN AND SURFACE FRONT. CONVECTIVE
PROCESSES ARE NOT HANDLED WELL IN GLOBAL MODELS AND WILL LIKELY
CAUSE FURTHER ADJUSTMENT/REFINEMENT TO THESE AREAS WITH POSSIBLE
UPGRADES IN THE COMING DAYS, SO STAY TUNED.
FINALLY, A PERSISTENT FRONT OVER THE SOUTHEAST/CAROLINAS LOOKS TO
PRODUCE WIDESPREAD RAIN WITH EMBEDDED HEAVIER RAIN WHERE RECENT
EXCESSIVE RAINFALL FROM DEBBY HAS RESULTED IN FULLY SATURATED SOILS
THAT MAY ONLY PARTIALLY RECOVER BY THEN. MARGINAL RISKS ARE IN
EFFECT IN THIS PART OF THE SOUTHEAST FOR DAYS 4/5.
ABOVE SEASONAL NORMAL TEMPERATURES PERSIST OVER TEXAS TO THE
CENTRAL GULF COAST INTO NEXT WEEK BENEATH AND DOWNSTREAM OF A RIDGE
AXIS OVER WEST TEXAS. HEATRISK VALUES WILL BE AT MODERATE TO MAJOR
LEVELS WITH SOME ISOLATED EXTREME VALUES. BELOW NORMAL
TEMPERATURES OVER THE CENTRAL U.S. PERSIST BEHIND A COLD FRONT INTO
MONDAY BEFORE RETURN FLOW BRINGS TEMPS BACK TOWARD NORMAL TUES-
THURS.
FRACASSO/JACKSON
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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