423  
FXUS02 KWNH 100650  
PREEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
249 AM EDT THU JUL 10 2025  
 
VALID 12Z SUN JUL 13 2025 - 12Z THU JUL 17 2025  
 
...HEAVY RAIN WITH FLASH FLOODING POTENTIAL FROM THE SOUTHWEST TO  
NORTHEAST, FOR THE UPPER MISSISSIPPI VALLEY/DAKOTAS AND FLORIDA...  
 
   
..OVERVIEW  
 
UPPER RIDGING WILL BE ANCHORED OVER THE WEST/SOUTHWEST WHILE THE  
MAIN JET STREAM PUSHES (ANCHORED BY A NORTH-CENTRAL CANADA UPPER  
LOW) MULTIPLE SHORTWAVES AND FRONTS THROUGH THE NORTHERN TIER  
STATES. MEANWHILE WEAK SHORTWAVES CAUSE MINOR DISTURBANCES IN THE  
LARGE SUBTROPICAL RIDGE ACROSS THE SOUTHERN TIER CAUSING SUMMER  
HEAT. THESE SHORTWAVES, SURFACE FRONTS, AND INSTABILITY CREATED BY  
HOT AND MOIST AIR WILL CAUSE RAIN AND THUNDERSTORM CHANCES FOR THE  
CENTRAL AND EASTERN U.S., WITH A PARTICULAR FOCUS IN THE SOUTHERN  
PLAINS OVER THE WEEKEND.  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT  
 
THE LATEST MODEL GUIDANCE CONTINUES TO HAVE A GOOD GRASP ON THE  
SUBTROPICAL RIDGING AND THE TROUGHING FROM THE NORTH-CENTRAL U.S.  
TO THE NORTHEAST. MODEL VARIANCES PERSIST PER DAY FOR INDIVIDUAL  
SHORTWAVES THEREFORE THE SPECIFICS FOR SENSIBLE WEATHER PARAMETERS  
LIKE FRONTAL PLACEMENT AND QPF REMAIN A BIT UNCERTAIN. AS  
PREVIOUSLY NOTED, THE UKMET CONTINUES TO DEPICT A STRONGER SURFACE  
LOW OVER THE MIDWEST WHEREAS THE REST OF THE GUIDANCE DOES NOT.  
MODELS  
SHOW JUST MINOR TIMING DIFFERENCES WITH THE INITIAL TROUGH AS IT  
TRACKS INTO THE NORTHEAST WITH EVEN GREATER SPREAD WITH THE  
FOLLOWING TROUGH AS IT NEAR THE U.S./CANADIAN BORDER. BY MIDWEEK  
ALL SOLUTIONS HAVE THIS TROUGH OVER THE CENTRAL PORTIONS OF THE  
CONTINENT.  
 
WPC UTILIZED A MULTI-MODEL APPROACH TO INITIALIZE, USING THE 12Z  
ECMWF/CMC AND 12Z/18Z GFS. THROUGH THE MID TO LATE MEDIUM RANGE  
PERIOD, REDUCED THE PROPORTION OF DETERMINISTIC MODELS IN FAVOR OF  
THE GEFS/EC ENSEMBLE MEANS TO MINIMIZE INDIVIDUAL MODEL SPREAD.  
THIS APPROACH MAINTAINED A SENSE OF CONTINUITY FROM THE PREVIOUS  
FORECAST.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS  
 
OVER THE WEEKEND A FRONTAL SYSTEM WILL ADVANCE THROUGH THE MIDWEST  
AND TRAIL ACROSS THE CENTRAL/SOUTHERN PLAINS WHILE CONVECTION FIRES  
UP AHEAD OF IT WHERE MOISTURE AND INSTABILITY POOL. THERE WILL BE A  
BROAD AREA WHERE ISOLATED FLASH FLOODING MAY ARISE, PARTICULARLY  
CENTERED OVER OKLAHOMA AND SURROUNDING AREAS, WHERE AN MCS IS  
LIKELY TO DEVELOP AND TRAIN. A BROAD MARGINAL RISK WAS MAINTAINED  
FOR DAY 4 AND STRETCHES FROM NEW MEXICO NORTHEASTWARD TO UPSTATE  
NEW YORK. SIMILAR CONDITIONS ARE EXPECTED FOR DAY 5 ONLY SHIFTED A  
BIT FURTHER EAST. A SMALL MARGINAL RISK AREA WAS RAISED FOR DAY 5  
IN NEW MEXICO TO COVER SENSITIVE BURN SCARS THERE.  
 
ABUNDANT MOISTURE WILL BE FEEDING INTO FLORIDA THANK TO THE BROAD  
SUBTROPICAL RIDGE. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP  
WITH THE AMPLE INSTABILITY UNDERNEATH THE RIDGE AND MAY LEAD TO  
FLASH PONDING/FLOODING FOR COASTAL AND URBAN LOCATIONS ACROSS THE  
PENINSULA. A MARGINAL RISK WAS MAINTAINED FOR DAY 4 AND RAISED FOR  
DAY 5. CONVECTION MAY INCREASE IN THE SOUTHEASTERN STATES BY  
TUESDAY AS A FRONT MOVES CLOSER.  
 
A SECOND FRONTAL SYSTEM IS ANTICIPATED TO ENTER THE NORTH-CENTRAL  
STATES NEAR THE BEGINNING OF THE WEEK AND WILL BE USHER IN THE  
NEXT ROUND OF RAIN WITH IT. DETAILS IN PLACEMENT AND AMOUNTS WILL  
VARY DEPENDING ON THE EVENTUAL EVOLUTION OF THE TROUGH AND REMAIN  
UNCERTAIN AT THIS TIME. GIVEN THE RECENT RAINS ACROSS PARTS OF THE  
DAKOTAS AND MINNESOTA, SOILS REQUIRE LESS MOISTURE BEFORE RAIN  
BECOMES EXCESSIVE. A MARGINAL RISK AREA IS IN EFFECT FOR THIS PART  
OF THE COUNTRY FOR DAY 5.  
 
HOT WEATHER WILL REMAIN FOR MUCH OF THE WESTERN U.S. AS UPPER  
RIDGING MOSTLY SETS UP TO THE WEST OF ROUNDS OF TROUGHING. DAILY  
MAXIMUMS WILL BE ABOVE NORMAL WITH MANY LOCATIONS CLIMBING INTO  
THE  
100S AND 110S FOR THE DESERT SOUTHWEST, AND NEARING/EXCEEDING 100F  
FARTHER NORTH IN INTERIOR/LOWER ELEVATION AREAS OF THE GREAT  
BASIN. TEMPERATURES COULD BE A FEW DEGREES COOLER THAN AVERAGE  
ESPECIALLY FOR HIGHS FOR THE SOUTH- CENTRAL U.S. THIS WEEKEND AS  
CLOUDS AND RAIN HOLD TEMPERATURES DOWN. THE SOUTHEAST SHOULD BE  
NEAR NORMAL TO A FEW DEGREES ABOVE, FOR TYPICAL SUMMER HEAT AND  
HUMIDITY. TEMPERATURES WILL GENERALLY BE 5-10 DEGREES ABOVE NORMAL  
IN THE GREAT LAKES TO NORTHEAST. INTO NEXT WEEK, DEPENDING ON THE  
EVOLUTION OF THE NORTH- CENTRAL U.S. TROUGH, TEMPERATURES MAY COOL  
NOTABLY, WITH HIGHS PERHAPS ONLY IN THE 70S THROUGH THE NORTH-  
CENTRAL PLAINS FOR TUESDAY/WEDNESDAY.  
 
CAMPBELL/TATE  
 
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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