939
FXUS02 KWNH 090628
PREEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
228 AM EDT WED JUL 9 2025
VALID 12Z SAT JUL 12 2025 - 12Z WED JUL 16 2025
*** HEAVY RAIN WITH POTENTIAL FOR FLASH FLOODING FOR
SOUTHERN/CENTRAL PLAINS. ***
..PATTERN OVERVIEW
AN UPPER LOW WITH SEVERAL WAVES OF EMBEDDED SHORTWAVE ENERGY WILL
PROPAGATE ACROSS SOUTH-CENTRAL CANADA AND THE NORTHERN/CENTRAL TIER
OF THE U.S. OVER THE NEXT WEEK. A PAIR OF SURFACE COLD FRONTS WILL
MOVE THROUGH THE PLAINS AND MIDWEST RESPECTIVELY, ACTING AS A FOCUS
FOR STORMS. A RETROGRADING SUBTROPICAL RIDGE WILL KEEP THINGS
WARMER THAN AVERAGE ACROSS THE SOUTHERN TIER.
...GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST GUIDANCE REMAINS IN GOOD AGREEMENT WITH THE BROAD UPPER
LEVEL RIDGING ACROSS THE SOUTHERN TIER OF THE COUNTRY WITH
DIFFERENCES
AROUND TIMING AND PLACEMENT OF SHORTWAVES SPINNING THROUGH THE
BASE OF THE PARENT LOW TO THE NORTH. IT WAS PREVIOUSLY NOTED THAT
THE
06Z ECMWF AIFS WAS MORE EXTREME THAN THE REST OF THE GUIDANCE WHEN
IT COMES TO MAX/MIN TS, WHILE THE 00Z CMC HAS A MUCH HIGHER
MAGNITUDE QPF FOOTPRINT THAN THE GFS/EC/UK SUITE OVER THE PLAINS
AND UPPER MIDWEST THROUGHOUT THE PERIOD. THIS TREND PERSISTED WITH
THE LATEST MODEL RUN.
WPC UTILIZED A STARTING POINT OF THE EC/CMC/GFS/UKMET BEFORE
INCLUDING GEFS MEAN, NAEFS MEAN AND ECMWF ENSEMBLE MEAN BY MID
PERIOD AND INCREASING THE WEIGHTING THROUGH THE LATER PERIODS.
..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 ANTICIPATED HIGHER QPF
AMOUNTS REMAIN A BIT UNCERTAIN GIVEN PERSISTENT MODEL DIFFERENCES,
NEVERTHELESS, THERE IS POTENTIAL FOR ISOLATED INSTANCES OF
EXCESSIVE RAINFALL AND LOCALIZED FLASH FLOODING.
FOR DAY 4, THERE IS A SLIGHT RISK FOR EXCESSIVE RAIN FOR PORTIONS
OF KANSAS AND OKLAHOMA WHERE A MCS WILL LIKELY SETUP AND AN
ENVELOPING BROAD MARGINAL RISK ENVELOPING FROM THE SOUTHERN PLAINS
EAST TO PENNSYLVANIA AND NORTH TO THE MINNESOTA ARROWHEAD. ANOTHER
DAY 4 MARGINAL RISK AREA IS IN EFFECT FOR EASTERN NEW MEXICO INTO
THE TEXAS PANHANDLE. THE POTENTIAL FOR HEAVY RAINFALL NEAR THE
FRONT BOUNDARY OVER THE CENTRAL U.S. WILL PERSIST THEREFORE A
MARGINAL RISK WAS RAISED FOR DAY 5 FOR PORTIONS OF THE SOUTHERN
PLAINS, MIDWEST INTO THE OHIO VALLEY. CONVECTION ALONG THE EASTERN
COAST OF FLORIDA MAY LEAD TO ISOLATED FLASH FLOODING/PONDING IN
URBAN AREAS SO A SMALL MARGINAL RISK AREA WAS RAISED FOR DAY 5 AS
WELL. ALTHOUGH THERE IS FAIR AMOUNT OF SPREAD IN QPF PLACEMENT, A
COUPLE MODEL SOLUTIONS ARE HINTING AT A CONCENTRATION OF QPF NEAR
PARTS OF EASTERN NEW MEXICO/WEST TEXAS AND FOR SOUTHERN PARTS OF
THE HILL COUNTRY. CONFIDENCE IS LOW AT THIS TIME BUT WORTH NOTING
THAT THIS AREA WILL CONTINUE TO BE MONITORED GIVEN THE EXTREME
SENSITIVITY WITH ONGOING FLOODING.
NUMEROUS LOCATIONS WILL HAVE DAILY READING ABOVE 100, WITH SEVERAL
NEARING THE 110S IN THE LOWER ELEVATIONS. CONDITIONS WILL MAINLY BE
DRY ACROSS THE WEST/SOUTHWEST, EXCEPT FOR PERHAPS FAR SOUTHEASTERN
ARIZONA INTO NEW MEXICO WHERE SOME MONSOONAL MOISTURE MAY BE
PRESENT.
CAMPBELL
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page