895  
FXUS02 KWBC 081854  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
253 PM EDT MON AUG 08 2022  
 
VALID 12Z THU AUG 11 2022 - 12Z MON AUG 15 2022  
 
...MONSOONAL MOISTURE/RAINFALL THREAT CONTINUES FOR THE SOUTHWEST  
AND INTERMOUNTAIN WEST/ROCKIES THIS WEEK, WITH SOME LOCALIZED  
HEAVY RAIN POSSIBLE FOR THE GULF COAST STATES AS WELL...  
 
   
..OVERVIEW
 
 
A FAIRLY STAGNANT TROUGH-RIDGE-TROUGH PATTERN IS FORECAST LATER  
THIS WEEK INTO EARLY NEXT WEEK ACROSS THE CONTIGUOUS U.S., AS  
SHORTWAVES COMBINE TO DEEPEN A TROUGH IN THE EAST, AN UPPER LOW  
OFF THE WEST COAST LIFTS NORTHEASTWARD INTO BRITISH COLUMBIA, AND  
AN UPPER HIGH MEANDERS NEAR THE CENTRAL/SOUTHERN HIGH PLAINS. A  
COLD FRONT OR TWO STALLING AND APPROACHING THE GULF COAST WILL  
PROVIDE A FOCUS FOR MOISTURE AND RAIN/THUNDERSTORMS THERE AND  
LINGERING ACROSS MUCH OF FLORIDA INTO EARLY NEXT WEEK. MEANWHILE,  
PERSISTENT MONSOONAL MOISTURE LOOKS TO CONTINUE ACROSS THE  
SOUTHWEST AND EXPANDING INTO THE INTERMOUNTAIN WEST AND ROCKIES  
THIS WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
GUIDANCE HAD STABILIZED FOR THE MOST PART WITH THE EVOLUTION OF AN  
EASTERN PACIFIC UPPER LOW COMING INTO SOUTHWESTERN CANADA, OPENING  
INTO A SHORTWAVE, AND MOVING EASTWARD INTO CANADA EARLY NEXT WEEK,  
BUT TIMING VARIANCE HAS RE-EMERGED. PREFER A SOLUTION ON THE  
SLOWER SIDE OF THE FULL ENVELOPE OF GUIDANCE GIVEN TRENDS AND  
HISTORY. MEANWHILE, THE UPPER HIGH IN THE CENTRAL U.S. APPEARS  
WELL HANDLED IN THE MODELS, THOUGH WITH SOME UNCERTAINTY ON HOW  
MUCH IT COULD BE SUPPRESSED BY ENERGY ROUNDING THE RIDGE,  
ESPECILALY BY THE WEEKEND. THE CMC IN PARTICULAR SUPPRESSED THE  
RIDGE MORE THAN OTHER MODELS IN THE MIDWEST AND SHOWED LESS  
AMPLITUDE OF THE LINGERING EASTERN U.S. UPPER TROUGH. PREFER A  
MORE AMPLIFIED SOLUTION. ACCORDINGLY, THE WPC MEDIUM RANGE PRODUCT  
SUITE THAT WAS PRIMARILY DERIVED FROM A COMPOSITE  
GFS/ECMWF/CANADIAN/UKMET MODEL BLEND AND THE NATIONAL BLEND OF  
MODELS (NBM) FOR THURSDAY/FRIDAY WAS QUICKLY TRANSITIONED TO A  
GFS/ECMWF AND GEFS/ECMWF ENSEMBLE MEAN BLEND ALONG WITH THE NBM  
THROUGH THE WEEKEND INTO EARLY NEXT WEEK. THIS SOLUTION FOLLOWS  
AFOREMENTIONED PREFERENCES. THE MAIN ADJUSTMENT TODAY TO NBM QPF  
WAS TO INCREASE RAINFALL AMOUNTS ALONG THE GULF COAST LATER THIS  
WEEK.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
MOISTURE STREAMING AHEAD OF A COUPLE OF COLD FRONTS MOVING INTO  
THE SOUTHEAST AND TOWARD THE GULF COAST LATE THIS WEEK WILL  
PRODUCE RAIN AND THUNDERSTORMS IN THOSE AREAS, WHICH COULD PRODUCE  
LOCALLY HEAVY RAIN ESPECIALLY ALONG THE COAST. SLOW-MOVING AND  
REPEAT STORMS WILL BE FUELED BY LEAD AND BOUNDARY POOLED DEEP  
MOISTURE AND UPPER DIFFLUENCE/VERTICAL WIND PROFILE. RAIN CHANCES  
ARE LIKELY TO CONTINUE ACROSS MUCH OF FLORIDA INTO THE WEEKEND AS  
THE FRONT STALLS. FARTHER NORTH, THE COLD FRONT SHOULD CLEAR OUT  
MOST RAINFALL FROM THE MID-ATLANTIC, BUT SOME RAIN COULD REMAIN  
ACROSS THE NORTHEAST AS A LOW ALONG THE FRONT MAY LINGER NEARBY.  
MEANWHILE, MONSOONAL MOISTURE (THAT COULD BE ENHANCED DUE TO T.S.  
HOWARD) CONTINUES TO IMPACT THE SOUTHWEST INTO PARTS OF THE GREAT  
BASIN AND INTO THE ROCKIES WITH RAINFALL, WITH SOME LOCALLY HEAVY  
TOTALS POSSIBLE.  
 
VERY WARM TO HOT TEMPERATURES AROUND 10-15F ABOVE AVERAGE, THOUGH  
NOT QUITE TO RECORD-BREAKING LEVELS, ARE FORECAST ACROSS THE  
NORTHERN/CENTRAL PLAINS THROUGH THE LATTER PART OF THE WEEK, WITH  
A SLIGHT EASTWARD TREND AS THE UPPER HIGH DRIFTS THAT DIRECTION.  
HIGHS NEARING 100F ARE FORECAST EARLY NEXT WEEK IN THE  
CENTRAL/SOUTHERN PLAINS. FARTHER EAST, BELOW NORMAL HIGHS ARE  
POSSIBLE IN THE EAST-CENTRAL U.S. BEHIND THE COLD FRONT, WITH THE  
MOST PERSISTENT COOLER THAN AVERAGE WEATHER IN THE OHIO AND  
TENNESSEE VALLEYS. GIVEN THE RAINFALL AND CLOUDINESS OVER THE  
SOUTHWEST AND GREAT BASIN, HIGHS ARE LIKELY TO BE SEVERAL DEGREES  
BELOW NORMAL THERE THROUGH EARLY NEXT WEEK.  
 
TATE/SCHICHTEL  
 
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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