272  
FXUS02 KWBC 211946  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
345 PM EDT THU JUL 21 2022  
 
VALID 12Z SUN JUL 24 2022 - 12Z THU JUL 28 2022  
 
...DANGEROUS HEAT WAVE PERSISTS OVER THE SOUTH-CENTRAL U.S. INTO  
MIDWEEK...  
 
...NOTABLE HEAT EXPECTED TO BUILD OVER THE INLAND NORTHWEST NEXT  
WEEK...  
 
   
..OVERVIEW
 
 
THE WESTERN RIDGE WHICH IS CURRENTLY CENTERED OVER THE DESERT  
SOUTHWEST IS EXPECTED TO STEADILY DRIFT EAST THROUGH THE MIDDLE OF  
NEXT WEEK, FOCUSING ON THE SOUTHEAST THROUGH THE MIDDLE OF NEXT  
WEEK WHILE PROGRESSIVE ACTIVITY PERSISTS OVER THE NORTHERN TIER  
STATES. A STRONG RIDGE DEVELOPING OVER THE NORTHEASTERN PACIFIC  
THROUGH EASTERN ALASKA SUNDAY/MONDAY SHIFTS INLAND ACROSS THE WEST  
COAST THROUGH THE MIDDLE OF NEXT WEEK, ESTABLISHING A MULTI-DAY  
PERIOD OF HOT WEATHER OVER THE NORTHWEST (WITH HIGHS LOOKING TO  
REACH 15F ABOVE NORMAL) WHICH LOOKS TO PERSIST PERHAPS THROUGH  
NEXT WEEKEND. AN INITIAL SURFACE FRONT OVER THE CENTRAL CONUS BY  
LATE THIS WEEKEND PERSISTS INTO MIDWEEK, THEN THE NEXT COLD FRONT  
APPROACHES SOON THEREAFTER. THIS LOOKS TO FOCUS HEAVY RAIN  
POTENTIAL OVER PARTS OF THE CENTRAL/EASTERN U.S. AND SUPPORT THE  
MODERATING TEMPERATURE TREND EAST OF THE ROCKIES. A PERIOD OF  
ENHANCED MONSOONAL MOISTURE FROM SUNDAY ONWARD, PROMOTING DAILY  
RISK OF LOCALLY HEAVY SHOWERS AND STORMS THAT MAY PRODUCE  
INSTANCES OF FLASH FLOODING.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE OVERALL PATTERN IS IN DECENT AGREEMENT WITH SOME CONTINUED  
DIFFERENCES FOR LOW-PREDICTABILITY SHORTWAVE DETAILS WITHIN  
NORTHERN U.S./SOUTHERN CANADA, PARTICULARLY BY MIDWEEK. OVERALL  
THE MAJORITY CLUSTER LOOKS GOOD FOR UPPER RIDGING THAT ESTABLISHES  
OVER THE SOUTHEAST AND EXPANDS OVER THE WEST. THE 00Z ECMWF WAS A  
NOTABLE CHANGE FROM ITS PRIOR RUNS WITH A MORE PROLONGED HEAVY  
RAIN PROGGED FOR THE OHIO VALLEY AREA MID TO LATE NEXT WEEK,  
THOUGH CONFIDENCE IN THIS IS LOW GIVEN MODEL VARIABILITY. THAT  
SAID, THE ECENS IS GENERALLY BETWEEN THE MORE PROGRESSIVE 00Z CMCE  
AND THE LESS PROGRESSIVE 06Z GEFS MEANS, SO PERHAPS THE PLACEMENT  
OF RAIN OVER THE OHIO VALLEY IS REASONABLE. THE UPDATED FORECAST  
INCORPORATING THE 00Z/06Z GUIDANCE STARTED WITH AN OPERATIONAL  
MODEL BLEND FAVORING THE 00Z ECMWF/CMC THAT TRANSITIONS TO THE  
ENSEMBLE MEANS OF THE 00Z ECENS/CMCE AND 06Z GEFS.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
A COLD FRONT MOVING INTO NORTHERN SECTIONS OF THE CENTRAL/EASTERN  
U.S. WILL ERODE/END THE HEAT WAVE FROM THE NORTH BY MONDAY-TUESDAY  
BUT NOT REACH FAR ENOUGH SOUTH TO LOWER TEMPERATURES MUCH OVER AND  
NEAR THE SOUTHERN HALF OF THE PLAINS. THE NEXT FRONT THAT REACHES  
THE NORTHERN PLAINS EARLY NEXT WEEK LOOKS TO HAVE A STRONGER  
SOUTHWARD PUSH, BRINGING MODERATELY BELOW NORMAL HIGHS TO THE  
NORTHERN-CENTRAL PLAINS TUESDAY ONWARD, BUT POSSIBLY NOT SOUTH OF  
KANSAS UNTIL THURSDAY AT THE EARLIEST. BOTH FRONTS WILL FOCUS  
EPISODES OF SHOWERS AND STORMS, WITH SOME SEVERE WEATHER AND HEAVY  
RAINFALL POSSIBLE. THE LEADING FRONT HEADING INTO THE EAST MAY  
INITIALLY FAVOR HIGHEST RAINFALL TOTALS FROM THE EASTERN GREAT  
LAKES/OHIO VALLEY INTO THE NORTHEAST/MID-ATLANTIC BUT COULD ALSO  
FOCUS REPEAT ACTIVITY AS FAR WEST AS THE PLAINS AS IT STALLS  
BEFORE LIFTING BACK AS A WARM FRONT. THE SECOND FRONT SHOULD  
PRODUCE NORTHERN PLAINS CONVECTION THAT EXTENDS SOUTH/EAST WITH  
TIME, POTENTIALLY REPEATING ACTIVITY OVER AN ALREADY SOGGY OHIO  
VALLEY. EXPECT PERIODS OF SHOWERS AND THUNDERSTORMS OVER PORTIONS  
OF FLORIDA AND THE GULF COAST REGION. THE FLORIDA PENINSULA MAY  
SEE SOMEWHAT HIGHER RAINFALL TOTALS AROUND MIDWEEK AS AN AREA OF  
ENHANCED MOISTURE PASSES THROUGH FROM EAST TO WEST.  
 
OVER THE WEST, PERSISTENT MONSOONAL MOISTURE AND VARIOUS SHORTWAVE  
IMPULSES WILL SUPPORT DIURNALLY FAVORED SHOWERS/STORMS WITH SOME  
LOCALLY HEAVY RAINFALL OVER THE FOUR CORNERS/GREAT BASIN REGION  
FROM SUNDAY THROUGH AT LEAST THURSDAY. GUIDANCE CONTINUES TO  
SUGGEST THAT THE PATTERN EVOLUTION WILL SUPPORT A MORE ACTIVE  
PERIOD WITH GREATER COVERAGE AND INTENSITY OF RAINFALL VERSUS THE  
SHORT RANGE TIME FRAME. POTENTIAL STILL EXISTS FOR SOME OF THIS  
MOISTURE TO INTERACT WITH CENTRAL PLAINS FRONTS (ONE DURING  
SUNDAY/EARLY NEXT WEEK AND THE SECOND ARRIVING AROUND MIDWEEK) TO  
ENHANCE RAINFALL TOTALS. UPPER RIDGING THAT BUILDS OVER THE  
NORTHWEST NEXT WEEK WILL BRING MULTIPLE DAYS OF HOT WEATHER TO  
THAT REGION, WITH SOME LOCATIONS LIKELY TO SEE HIGHS REACH UP TO  
10-15F OR SO ABOVE NORMAL. SOME DAILY RECORDS FOR HIGHS/WARM LOWS  
WILL BE POSSIBLE, PARTICULARLY OVER INLAND PORTIONS OF THE  
NORTHWEST SUCH AS THE COLUMBIA BASIN.  
 
JACKSON  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE CENTRAL PLAINS, THE CENTRAL  
ROCKIES, THE CENTRAL GREAT BASIN, THE SOUTHERN ROCKIES, THE  
SOUTHERN PLAINS, AND THE SOUTHWEST, SUN-THU, JUL 24-JUL 28.  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE  
CENTRAL APPALACHIANS, THE TENNESSEE VALLEY, THE MIDDLE MISSISSIPPI  
VALLEY, THE SOUTHERN APPALACHIANS, AND THE OHIO VALLEY, MON-THU,  
JUL 25-JUL 28.  
- HEAVY RAIN ACROSS PORTIONS OF THE GREAT LAKES, THE MID-ATLANTIC,  
THE NORTHEAST, THE CENTRAL APPALACHIANS, AND THE OHIO VALLEY, SUN,  
JUL 24.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE NORTHERN  
PLAINS.  
- EXCESSIVE HEAT ACROSS PORTIONS OF CALIFORNIA, THE CENTRAL GREAT  
BASIN, THE PACIFIC NORTHWEST, THE NORTHERN ROCKIES, AND THE  
NORTHERN GREAT BASIN, MON-THU, JUL 25-JUL 28.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE SOUTHEAST, THE MIDDLE  
MISSISSIPPI VALLEY, THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN  
PLAINS, AND THE TENNESSEE VALLEY, SUN-THU, JUL 24-JUL 28.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS, THE LOWER  
MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, THE MIDDLE MISSISSIPPI  
VALLEY, THE SOUTHERN PLAINS, AND THE OHIO VALLEY, SUN-WED, JUL  
24-JUL 27.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE NORTHEAST, THE CENTRAL  
APPALACHIANS, THE TENNESSEE VALLEY, THE MIDDLE MISSISSIPPI VALLEY,  
THE MID-ATLANTIC, THE SOUTHERN APPALACHIANS, THE SOUTHEAST, AND  
THE OHIO VALLEY, SUN, JUL 24.  
 
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, EXPERIMENTAL EXCESSIVE RAINFALL  
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES 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  
 

 
 

 
 
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