064  
FXUS02 KWBC 101952  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
351 PM EDT WED AUG 10 2022  
 
VALID 12Z SAT AUG 13 2022 - 12Z WED AUG 17 2022  
 
...MONSOONAL MOISTURE/RAINFALL THREAT CONTINUES FOR THE SOUTHWEST  
AND INTERMOUNTAIN WEST/ROCKIES...  
 
...EXCESSIVE HEAT THREAT ACROSS THE PLAINS, WITH WARMING  
TEMPERATURES IN THE NORTHWEST NEXT WEEK...  
 
   
..OVERVIEW
 
 
A FAIRLY STAGNANT TROUGH-RIDGE-TROUGH PATTERN IS FORECAST THIS  
WEEKEND ACROSS THE CONTIGUOUS U.S.. SHORTWAVES WILL DEEPEN AND  
THEN MAINTAIN A TROUGH IN THE EAST, AN UPPER LOW OFF THE WEST  
COAST LIFTS NORTHEASTWARD INTO BRITISH COLUMBIA, AND A WARM UPPER  
HIGH MEANDERS NEAR THE CENTRAL/SOUTHERN HIGH PLAINS. UPPER RIDGING  
IS ALSO FORECAST TO EXPAND INTO THE WEST BY TUESDAY-WEDNESDAY OF  
NEXT WEEK, INCREASING TEMPERATURES TO WELL ABOVE AVERAGE,  
PARTICULARLY IN THE NORTHWEST. THE RIDGE ALOFT WILL ALSO CONTINUE  
TO SUPPORT MONSOONAL MOISTURE STREAMING INTO THE SOUTHWEST,  
INTERMOUNTAIN WEST AND ROCKIES THROUGH MUCH OF NEXT WEEK. A  
LINGERING FRONTAL BOUNDARY OVER FLORIDA WILL PROVIDE A FOCUS FOR  
RAINFALL THERE, WHILE POSSIBLE SHORTWAVE ENERGY ROUNDING THE RIDGE  
COULD LEAD TO ROUNDS OF SHOWERS/THUNDERSTORMS ACROSS THE  
MIDWEST/UPPER GREAT LAKES THIS WEEKEND, WITH RAIN CHANCES  
EXPANDING SOUTH AND EAST INTO EARLY NEXT WEEK.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE LATEST GUIDANCE IS IN GOOD AGREEMENT ON THE BROAD SYNOPTIC  
PATTERN OF DIPOLE TROUGHS ALONG THE COASTS AND RIDGING ACROSS THE  
CENTRAL-WESTERN PART OF THE COUNTRY DURING THE MEDIUM RANGE. THE  
00Z EC/ECE HAD THE LEAST RUN-TO-RUN/ENSEMBLE MEMBER SPREAD WITH  
RESPECT TO THE EASTERN TROUGH AXIS, IN PARTICULAR. ON DAY 3 A  
GENERAL MODEL BLEND OF THE 00Z EC/CMC/UK AND 06Z GFS WERE JOINED  
BY THE 00Z GFS TO ACCOUNT FOR SOME DISCREPANCIES IN THE 00Z EC AND  
06Z GFS. THE GMB WAS CONTINUED ON DAY 4 WITH THE EXCEPTION OF THE  
00Z GFS. THE 00Z ECE AND 06Z GEFS WERE ADDED TO THE BLEND ON DAY 5  
AS THEY SEEMED TO RESOLVE THE EASTERN U.S. TROUGH REASONABLY WELL  
COMPARED TO THE DETERMINISTICS. THE 00Z ECE WAS FAVORED IN THE  
BLEND ON THROUGH DAY 7 AS IT CARRIES LITTLE TO NO SPREAD OVER THE  
LOWER 48 AND DISPLAYS THE OVERALL PATTERN COMPARITIVELY TO MODEL  
CONSENSUS.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
PARTS OF THE WEST HAVE SEEN PERSISTENT MONSOONAL MOISTURE OVER THE  
PAST COUPLE OF MONTHS, AND THE REST OF THIS WEEK AND INTO NEXT  
WEEK WILL CONTINUE THAT PATTERN. IN FACT, NOTABLE MOISTURE  
ANOMALIES ARE FORECAST TO STREAM INTO PARTS OF THE GREAT BASIN AND  
THE ROCKIES AND PRODUCE RAIN AND THUNDERSTORMS. A SLIGHT RISK OF  
EXCESSIVE RAINFALL WAS INTRODUCED TODAY FOR SATURDAY AND SUNDAY  
OVER PORTIONS OF NORTHWESTERN ARIZONA, INCLUDING MOHAVE, YAVAPAI  
AND COCONINO COUNTIES. RAIN TOTALS MAY INCREASE BY MONDAY-TUESDAY  
FOR THE NORTHERN/CENTRAL ROCKIES IN PARTICULAR. MEANWHILE, A MOIST  
AIRMASS AND A LINGERING FRONTAL BOUNDARY WILL CAUSE SHOWERS AND  
THUNDERSTORMS ACROSS THE FLORIDA PENINSULA INTO EARLY NEXT WEEK.  
FARTHER NORTH, SHORTWAVE IMPULSES ROUNDING THE RIDGE COULD LEAD TO  
RAIN AND STORMS ACROSS THE MIDWEST/UPPER GREAT LAKES INTO THE OHIO  
VALLEY THIS WEEKEND, BUT WITH LOW CONFIDENCE ON THE SPECIFICS.  
THEN RAIN CHANCES COULD INCREASE FOR THE OHIO VALLEY TO  
APPALACHIANS AND THE EAST COAST EARLY NEXT WEEK ALONG A COLD  
FRONT, BUT THE DETAILS REMAIN UNCERTAIN THERE AS WELL.  
 
VERY WARM TO HOT TEMPERATURES AROUND 10-15F ABOVE AVERAGE, THOUGH  
MAINLY NOT TO RECORD-BREAKING LEVELS, ARE FORECAST ACROSS THE  
NORTHERN AND ESPECIALLY THE CENTRAL PLAINS OVER THE WEEKEND, WITH  
SOME GRADUAL MODERATION AND SHIFT SOUTHWARD THROUGH THE WORKWEEK,  
THOUGH HIGHS COULD STILL REACH 100F IN THE SOUTHERN PLAINS. AS THE  
UPPER RIDGE EXPANDS INTO THE NORTHWEST, THIS WILL WARM UP  
TEMPERATURES THERE AND CAUSE HIGHS 10-20F ABOVE NORMAL BY  
TUESDAY-WEDNESDAY. MEANWHILE, 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 TOWARD THE MID-ATLANTIC. GIVEN THE RAINFALL AND CLOUDINESS  
OVER THE SOUTHWEST AND GREAT BASIN INTO THE ROCKIES, HIGHS ARE  
LIKELY TO BE SEVERAL DEGREES BELOW NORMAL THERE THROUGH MUCH OF  
NEXT WEEK.  
 
KEBEDE/TATE  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE SOUTHWEST, THE GREAT BASIN,  
AND THE CENTRAL ROCKIES, SAT-WED, AUG 13-AUG 17.  
- HEAVY RAIN ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES  
AND ADJACENT HIGH PLAINS, MON-WED, AUG 15-AUG 17.  
- HEAVY RAIN ACROSS PORTIONS OF FLORIDA, SAT, AUG 13.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE UPPER  
MISSISSIPPI VALLEY.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS AND MIDDLE  
MISSOURI VALLEY, SAT-SUN, AUG 13-AUG 14.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN  
PLAINS AND LOWER MISSISSIPPI VALLEY, SUN-WED, AUG 14-AUG 17.  
- EXCESSIVE HEAT ACROSS PORTIONS OF TEXAS, TUE-WED, AUG 16-AUG 17.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE PACIFIC NORTHWEST AND  
NORTHERN GREAT BASIN, TUE-WED, AUG 16-AUG 17.  
 
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  
 

 
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page