987  
FXUS02 KWBC 011935  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
335 PM EDT MON AUG 01 2022  
 
VALID 12Z THU AUG 04 2022 - 12Z MON AUG 08 2022  
 
...THE SOUTHWEST MONSOON RESUMES A VERY ACTIVE PHASE LATE THIS  
WEEK...  
...HEAVY RAIN LIKELY FROM THE OHIO VALLEY THROUGH THE NORTHEAST  
LATE THIS WORK WEEK***  
 
   
..GENERAL OVERVIEW
 
 
ACTIVE UPPER LEVEL FLOW PATTERN WILL CONTINUE ACROSS SOUTHERN  
CANADA/NEAR THE U.S. BORDER OVER THE NEXT WEEK AS THE PERSISTENT  
HUDSON BAY LOW IS DISLODGED EAST AROUND THURSDAY. A WELL DEFINED  
COLD FRONT WILL SLOW/STALL AS IT TRACKS EAST ACROSS THE EASTERN  
GREAT LAKES THURSDAY AND CROSS NEW ENGLAND ON FRIDAY. THE NEXT  
COLD FRONT CROSSES THE NORTHERN GREAT PLAINS THURSDAY NIGHT/FRIDAY  
AND THE UPPER MIDWEST/GREAT LAKES THIS WEEKEND. MEANWHILE, THE  
CORE OF THE UPPER RIDGE INTENSIFIES AS IT DRIFTS EAST TO THE  
CENTRAL PLAINS THURSDAY INTO FRIDAY FRIDAY BEFORE DRIFTING BACK  
WEST THIS WEEKEND. AS A RESULT THE MONSOONAL PATTERN ACROSS THE  
FOUR CORNERS REGION RE-INTENSIFIES THURSDAY WITH A RATHER ACTIVE  
PERIOD THROUGH AT LEAST THE WEEKEND.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
ABOVE AVERAGE FORECAST CONFIDENCE CONTINUES FOR LATE THIS WEEK  
INTO THE WEEKEND AMONG GLOBAL DETERMINISTIC GUIDANCE ON THE UPPER  
FLOW PATTERN. A GENERAL DETERMINISTIC MODEL BLEND IS USED FOR THE  
DAYS 3-5 PROGS. THE TIMING OF THE EJECTION OF THE LOW FROM BC WAS  
IN QUESTION WITH THE 06Z GFS BEING SLOWER THAN THE PREFERRED 00Z  
ECMWF/CMC, THOUGH THE 12Z GFS HAS SLOWED TO BE MUCH LIKE THE  
EC/CMC, SO WE WILL SEE IF THAT AGREEMENT CONTINUES. DAYS 6/7 OF  
THE FORECAST HAVE INCREASING USAGE OF ENSEMBLE MEANS FROM THE  
CMCE/GEFS/ECENS WHICH IS TYPICAL, PARTICULARLY AFTER THE END OF  
THE 5-DAY UKMET OUTPUT. FOR QPF, THE NBM WAS ENHANCED WITH THE 06Z  
GFS AND 00Z ECMWF/CMC OVER THE SOUTHWEST FOR MONSOONAL PRECIP.  
CONSIDERABLE INCREASES IN QPF OVER THE NBM WERE DONE MAINLY FROM  
THE 00Z ECMWF/CMC FOR THE EASTERN HALF OF THE CONUS DAYS 5-7 DUE  
TO THEIR SIMILARITIES WITH COLD FRONTAL TIMING OVER THE  
NORTHEASTERN QUADRANT (LESS PROGRESSIVE THAN THE 06Z GFS). THE 12Z  
GFS DID SLOW IN THE NORTHEAST AND WAS AN INFLUENCE ON THE SLIGHT  
RISK OF EXCESSIVE RAINFALL FOR THE NORTHEASTERN URBAN CORRIDOR  
ENDING 12Z SATURDAY.  
 
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
ANOTHER EASTWARD MOVING WAVE OF ANOMALOUS HEAT IS EXPECTED TO  
CROSS THE NORTHERN PLAINS THURSDAY - SATURDAY WHICH WILL BE  
SIMILAR TO THE WAVE CROSSING THE FIRST HALF OF THIS WEEK. THIS  
WITH MEANWHILE, MAXIMUM TEMPERATURES WILL LIKELY BE NEAR TO  
SLIGHTLY BELOW NORMAL ACROSS MUCH OF THE WESTERN U.S. FOR MOST OF  
THE FORECAST PERIOD. THIS WAVE LOOKS TO REACH THE NORTHEAST BY  
SUNDAY WITH ANOTHER BRIEF WAVE OF HIGH TEMPERATURES EXPECTED TO  
CONTINUE AHEAD OF A COLD FRONT INTO MONDAY. MEANWHILE, MONSOONAL  
CLOUDS AND RAIN OFFER BELOW NORMAL MAX TEMPS FOR THE DESERT  
SOUTHWEST TO THE GREAT BASIN TO SOUTHERN ROCKIES.  
 
FOR PRECIPITATION, TWO GENERAL ROUNDS OF HEAVY RAIN ARE EXPECTED  
AHEAD OF THE TWO COLD FRONTS OVER THE CENTRAL AND NORTHERN  
PORTIONS OF THE EASTERN CONUS - THUR/FRI AND SUN/MON. A SECOND  
SLIGHT RISK OF EXCESSIVE RAINFALL WAS ADDED TO THE DAY 4 OUTLOOK  
OVER THE EASTERN GREAT LAKES AND ONE WAS ADDED FOR THE BOS-WASH  
MEGALOPOLIS FOR DAY 5 - BOTH HAVE DECENT AGREEMENT AMONG GLOBAL  
DETERMINISTIC GUIDANCE FOR HEAVY RAIN FOCUS THERE AHEAD OF A SLOW  
MOVING COLD FRONT. THE MONSOON REINVIGORATES IN THE SOUTHWEST AS  
THE RIDGE STRENGTHENS AFTER A MIDWEEK PERIOD OF MORE DIFFUSE  
MONSOON. SLIGHT RISKS WERE EXPANDED OVER THE SOUTHWEST FOR BOTH  
DAYS 4 AND 5 FOR THIS INCREASED THREAT.  
 
JACKSON  
 
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  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE CENTRAL ROCKIES, THE CENTRAL  
GREAT BASIN, CALIFORNIA, AND THE SOUTHWEST, THU-MON, AUG 4-AUG 8.  
- HEAVY RAIN ACROSS PORTIONS OF THE LOWER GREAT LAKES, AND THE  
OHIO VALLEY, THU, AUG 4.  
- HEAVY RAIN ACROSS PORTIONS OF THE NORTHEAST, THE MID-ATLANTIC,  
AND THE CENTRAL APPALACHIANS, FRI, AUG 5.  
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE OHIO  
VALLEY AND THE NORTHERN PLAINS.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE THE LOWER MISSISSIPPI  
VALLEY, AND THE SOUTHERN PLAINS, THU-MON, AUG 4-AUG 8.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS, AND THE  
MIDDLE MISSISSIPPI VALLEY, SAT-SUN, AUG 6-AUG 7.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE NORTHEAST, THE CENTRAL  
APPALACHIANS, AND THE NORTHERN PLAINS, THU-FRI, AUG 4-AUG 5.  
- HEAVY RAIN ACROSS PORTIONS OF THE ALASKA PANHANDLE AND SOUTHEAST  
MAINLAND ALASKA, FRI-SAT, AUG 5-AUG 6.  
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF NORTHERN  
MAINLAND ALASKA, SAT-MON, AUG 6-AUG 8.  
 
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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