876  
FXUS02 KWBC 080644  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
243 AM EDT FRI JUL 08 2022  
 
VALID 12Z MON JUL 11 2022 - 12Z FRI JUL 15 2022  
 
...A PROLONGED HEAT WAVE WILL LAST THROUGH EARLY NEXT WEEK ACROSS  
THE SOUTHERN PLAINS AND MID-SOUTH...  
   
..OVERVIEW
 
 
IT REMAINS THE CASE THAT A PERSISTENT AND STRONG UPPER LEVEL HIGH  
DRIFTING WEST FROM THE SOUTHERN HIGH PLAINS AND THEN MEANDERING  
ATOP THE FOUR CORNERS STATES NEXT WEEK WILL KEEP VERY HOT  
TEMPERATURES IN PLACE ACROSS MUCH OF THE CENTRAL U.S. PARTICULARLY  
THROUGH AROUND TUESDAY. COMBINED WITH THE HUMIDITY, OPPRESSIVE  
HEAT INDICES ARE LIKELY IN PLACES AND WITH VERY LITTLE NIGHTTIME  
RELIEF IN TEMPERATURES, A PROLONGED HEAT WAVE IS EXPECTED TO  
CONTINUE ACROSS THE SOUTHERN HALF OF THE PLAINS AND MISSISSIPPI  
VALLEY. ON THE PERIPHERY OF THE UPPER RIDGE, TROUGHING IS FORECAST  
OVER THE NORTHEAST THIS WEEKEND WHILE ANOTHER TROUGH ACROSS THE  
NORTHWEST SUNDAY WILL TRACK QUICKLY ACROSS THE NORTH-CENTRAL U.S.  
AND REDEVELOP TROUGHING CENTERED IN THE NORTHEAST QUADRANT OF THE  
LOWER 48 BY TUESDAY-FRIDAY. RAIN AND THUNDERSTORMS ARE FORECAST  
FOR THE SOUTHEAST NEAR A COLD FRONT THAT SHOULD STALL AND  
DISSIPATE THROUGH THE FIRST HALF OF THE WEEK. THE NORTHERN PLAINS  
TO UPPER MIDWEST SHOULD ALSO SEE CHANCES OF RAIN AND POTENTIALLY  
SEVERE THUNDERSTORMS AHEAD OF ANOTHER COLD FRONT, AND SOME SHOWERS  
AND STORMS COULD SHIFT SOUTHEASTWARD WITH THE FRONT STRETCHING  
FROM THE NORTHEAST BACK INTO THE CENTRAL/SOUTHERN PLAINS  
TUESDAY-LATER NEXT WEEK. MEANWHILE, A PERSISTENT MONSOONAL  
MOISTURE FLOW INTO THE SOUTHWEST OFFERS MULTI-DAY CHANCES FOR  
PERIODS OF LOCALLY ENHANCED RAINFALL.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A  
COMPOSITE BLEND OF THE SEEMINGLY REASONABLE AND WELL CLUSTERED  
MODEL GUIDANCE OF THE 18 UTC GFS AND 12 UTC ECMWF/UKMET/CANADIAN  
ALONG WITH COMPATIBLE 01 UTC NATIONAL BLEND OF MODELS (NBM) DATA  
MONDAY INTO WEDNESDAY. INCREASING FORECAST SPREAD AND DECREASING  
RUN-RUN CONTINUITY INTO DAYS 6/7 (THURSDAY/NEXT FRIDAY) PROMPTED A  
PREFERENCE TRANSITION TO THE MORE COMPATIBLE 18 UTC GEFS MEAN AND  
12 UTC ECMWF ENSEMBLE MEAN ALONG WITH THE NBM. LARGEST MODEL  
DIFFERENCES MAINLY CONCERN RUN TO RUN CONSISTENCY WITH THE LATER  
PERIOD AMPLITUDE OF UPPER TROUGH ENERGY OFF THE PACIFIC NORTHWEST  
AND THE ENSEMBLE MEANS SHOW MODERATE AMPLIFICATION WITH NEAR  
NEUTRAL TILT. THIS FORECAST STRATEGY MAINTAINS GOOD WPC PRODUCT  
CONTINUITY IN A PATTERN WITH OVERALL ABOVE NORMAL PREDICTABILITY  
AND NEWER 00 UTC GUIDANCE GENERALLY REMAINS IN LINE.  
 
   
..SENSIBLE WEATHER AND HAZARDS
 
 
AS THE EASTERN PART OF A COLD FRONT CONTINUES TO DROP SOUTHWARD  
AND THEN STALL EARLY NEXT WEEK IN THE SOUTHEAST/CENTRAL GULF  
COAST/FLORIDA, IT WILL PROVIDE A FOCUS FOR ANOMALOUSLY HIGH  
MOISTURE TO POOL AND LEAD TO RAIN AND THUNDERSTORMS CHANCES  
CONTINUING FROM THE SHORT RANGE PERIOD. WHILE RAIN TOTALS ARE  
EXPECTED TO GRADUALLY DROP AS THE FRONT SLOWLY DISSIPATES,  
LOCALIZED AREAS OF FLASH FLOODING CANNOT BE RULED OUT ESPECIALLY  
IF MULTIPLE ROUNDS OF HEAVY RAIN AFFECT THE SAME AREAS. FARTHER  
NORTH, SHORTWAVE ENERGY AND A FRONTAL SYSTEM OR TWO ARE FORECAST  
TO LEAD TO RAIN AND THUNDERSTORMS ACROSS THE NORTHERN PLAINS AND  
UPPER MIDWEST INTO MONDAY. ALTHOUGH MOISTURE AND INSTABILITY  
LEVELS WILL BE SUFFICIENT, THE POSSIBLY QUICKER STORM MOTIONS AND  
THE UNCERTAINTY IN THE DETAILS OF THE SHORTWAVES/FRONTAL PLACEMENT  
PRECLUDE SLIGHT RISK ISSUANCE IN THE WPC EXPERIMENTAL EXCESSIVE  
RAINFALL OUTLOOK AT THIS POINT. THE STORM PREDICTION CENTER  
CURRENTLY SHOWS A SLIGHT RISK FOR SEVERE WEATHER FROM THE EASTERN  
DAKOTAS TO THE UPPER MIDWEST. RAINFALL ACTIVITY SHOULD SHIFT  
TOWARD THE GREAT LAKES REGION AND THEN THE NORTHEAST  
MONDAY-WEDNESDAY, WITH SCATTERED STORMS ALSO POSSIBLE ALONG THE  
TRAILING COLD FRONT IN THE OHIO VALLEY AND EVEN BACK INTO CENTRAL  
AND THEN SOUTHERN PARTS OF THE PLAINS AND MISSISSIPPI VALLEY.  
ELSEWHERE, MONSOONAL MOISTURE COULD PERSIST INTO NEXT WEEK WITH  
MOIST SOUTHWESTERLY FLOW/EMBEDDED SHORTWAVES LEADING TO MAINLY  
DIURNALLY DRIVEN SHOWERS AND STORMS OVER THE FOUR CORNERS STATES.  
AN UPPER LEVEL WEAKNESS NEAR THE CENTRAL GULF COAST EARLY TO MID  
NEXT WEEK COULD BRING SOME LOCALLY HEAVY RAINFALL TO COASTAL  
LOCATIONS. THIS SYSTEM HAS POTENTIAL FOR FOCUS SLOW MOVING/REPEAT  
CELLS WITH VERY HEAVY DOWNPOURS THAT OFFER A LOCAL RUNOFF RISK.  
THE WEST COAST SHOULD BE THE MOST CONSISTENTLY DRY AREA THROUGH  
THE PERIOD.  
 
VERY HOT WEATHER IS EXPECTED TO PERSIST ACROSS THE SOUTHERN HALF  
OF THE PLAINS/MISSISSIPPI VALLEY UNDERNEATH THE STRONG UPPER  
RIDGE/HIGH EARLY NEXT WEEK, BEFORE FINALLY SOME SLIGHT MODERATION  
AROUND NEXT MIDWEEK. HIGH TEMPERATURES NEAR OR EXCEEDING 100F ARE  
EXPECTED, WHICH IS BETWEEN 5 AND 15 DEGREES ABOVE NORMAL. COMBINED  
WITH THE HUMIDITY, DAILY MAXIMUM HEAT INDICES 105-110F+ ARE LIKELY  
AT TIMES ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY  
THROUGH EARLY NEXT WEEK. THE REPEATING DAYS OF HIGH HEAT/HUMIDITY  
AND LACK OF ANY APPRECIABLE NIGHTTIME RELIEF (LOWS IN THE UPPER  
70S TO LOW 80S FOR SOME AREAS) WILL INCREASE THE POTENTIAL FOR  
IMPACTS FROM THIS PROLONGED HEATWAVE TO THE MORE SENSITIVE AND  
VULNERABLE POPULATIONS. SEVERAL DAILY RECORD HIGH TEMPERATURES ARE  
POSSIBLE, PARTICULARLY FOR WARM LOWS BUT A FEW HIGHS MAY BE CLOSE  
TO RECORDS IN TEXAS. AS THE UPPER RIDGE DRIFTS WESTWARD, THE WEST  
SHOULD SEE TEMPERATURES WARMING FROM SLIGHTLY BELOW NORMAL TO  
ABOVE NORMAL (BY 10+ DEGREES IN THE NORTHWEST) AS NEXT WEEK  
PROGRESSES. THE EAST CAN EXPECT SLIGHTLY COOLER THAN NORMAL  
TEMPERATURES EARLY IN THE WEEK BEHIND THE COLD FRONT, BEFORE  
WARMING TO NEAR/JUST ABOVE NORMAL.  
 
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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