888
FXUS02 KWBC 072035
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
435 PM EDT MON JUL 7 2025
VALID 12Z THU JUL 10 2025 - 12Z MON JUL 14 2025
***HEAVY RAIN AND STORMS EXPECTED FOR THE MIDWEST AND PORTIONS OF
THE EAST COAST, AND HIGH HEAT CONTINUES FOR THE SOUTHWEST
STATES***
..PATTERN OVERVIEW
A WELL DEFINED UPPER LEVEL TROUGH IS FORECAST TO TRACK FROM
SOUTHWESTERN CANADA EASTWARD TO THE NORTHERN GREAT LAKES FOR THE
END OF THE WEEK AND INTO THE WEEKEND. THIS WILL BRING A COLD FRONT
THAT WILL CROSS THE CENTRAL AND NORTHERN ROCKIES, AND THEN ACROSS
THE NORTH-CENTRAL U.S. TO CLOSE OUT THE WORK WEEK. MEANWHILE, A
STATIONARY FRONTAL BOUNDARY WILL BE IDLING ACROSS THE MID-ATLANTIC
REGION WITH COPIOUS MOISTURE TO FUEL DAILY SHOWERS AND STORMS. A
SEPARATE COMPLEX OF ORGANIZED CONVECTION IS ALSO LIKELY FOR THE
UPPER MIDWEST THURSDAY INTO FRIDAY AHEAD OF THE FRONT. UPPER LEVEL
RIDGING CONTINUES OVER THE SOUTHWEST STATES AND THIS WILL LEAD TO A
CONTINUATION OF THE VERY HOT CONDITIONS.
...GUIDANCE/PREDICTABILITY ASSESSMENT
THE 12Z MODEL GUIDANCE STARTS OFF IN EXCELLENT AGREEMENT ACROSS
THE CONTINENTAL U.S. ON THURSDAY, WITH A MULTI-DETERMINISTIC MODEL
BLEND WORKING WELL AS A STARTING POINT IN THE FORECAST PROCESS.
THE MODELS AGREE ON A STRONGER SHORTWAVE TROUGH AND PROBABLE
CLOSED LOW OVER THE DAKOTAS AND MINNESOTA TO CLOSE OUT THE WORK
WEEK. THE CMC IS NOW MORE IN LINE WITH THE MODEL CONSENSUS, AND
ALSO FITS IN WELL WITH THE AIFS GUIDANCE, SO IT WAS INCLUDED
THROUGH THE END OF THE FORECAST PERIOD. MODEL DIFFERENCES BECOME
MORE PRONOUNCED WITH TRAILING SHORTWAVE ENERGY ACROSS THE WESTERN
HIGH PLAINS AND INTO SOUTH-CENTRAL CANADA BY SUNDAY AND MONDAY.
THE ENSEMBLE MEANS WERE GRADUALLY INCREASED TO ABOUT HALF BY THIS
TIME TO ACCOUNT FOR THE MODEL DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
SCATTERED CONVECTION ANTICIPATED TO FIRE AHEAD OF, AND ALONG PROGRESSIVE
COLD FRONTS, STALLED BOUNDARIES AND ROUND THE UPPER HIGH IN THE
SOUTHERN ROCKIES. THE EXACT LOCATION OF HIGHER QPF IS LESS CERTAIN
HOWEVER THERE IS THE POTENTIAL FOR ISOLATED INSTANCES OF FLASH
FLOODING-- INCLUDING AREAS FROM THE CORN BELT INTO THE MIDWEST AND
OHIO VALLEY, APPALACHIANS, MID-ATLANTIC, AND NORTHEAST. IN TERMS OF
THE EXCESSIVE RAINFALL OUTLOOKS, THE BROAD MARGINAL RISK AREA IS
MAINTAINED ACROSS THE UPPER MIDWEST FOR BOTH DAYS 4 AND 5. UPON
EXAMINATION OF THE 12Z MODEL GUIDANCE SUITE, A SMALL SLIGHT RISK
AREA HAS BEEN INTRODUCED FOR EXTREME EASTERN NEBRASKA AND WEST-
CENTRAL IOWA FOR DAY 4. THERE IS A GOOD OVERALL MODEL SIGNAL FOR
ORGANIZED MCS ACTIVITY TO DEVELOP WITH THE POTENTIAL FOR 1+ INCH
PER HOUR RAINFALL RATES. ELSEWHERE, A BROAD MARGINAL RISK REMAINS
FROM INTERIOR PORTIONS OF THE DEEP SOUTH TO THE SOUTHERN
APPALACHIANS TO THE MID-ATLANTIC COAST, AND A SLIGHT RISK WAS ALSO
ADDED FOR PORTIONS OF CENTRAL NORTH CAROLINA INTO SOUTH-CENTRAL
VIRGINIA FOR DAY 4. THIS REGION WILL BE SOUTH OF A QUASI-STATIONARY
FRONT WITH COPIOUS MOISTURE IN PLACE, AND THE COMBINATION OF
SATURATED GROUNDS FROM BOTH RECENT AND SHORT RANGE PREDICTED
RAINFALL WILL INCREASE THE POTENTIAL FOR FLOODING.
MANY LOCATIONS WILL HAVE DAILY MAXIMUMS CLIMBING WELL INTO THE
100S AT LOWER ELEVATIONS ACROSS THE SOUTHWEST AND MAINLY DRY
CONDITIONS, EXCEPT FOR PERHAPS FAR SOUTHEASTERN ARIZONA INTO NEW
MEXICO WHERE SOME MONSOONAL MOISTURE MAY BE PRESENT. EXPERIMENTAL
HEATRISK VALUES MAY RISE TO MAJOR OR EXTREME LEVELS (3 OUT OF 4 OR
4 OUT OF 4) FROM THE CALIFORNIA DESERTS INTO SOUTHERN NEVADA, UTAH,
AND ARIZONA. EXTREME HEAT WATCHES HAVE BEEN RAISED FOR PARTS OF
ARIZONA THROUGH AT LEAST THURSDAY.
CAMPBELL/HAMRICK
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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