224  
FXUS02 KWBC 071827  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
227 PM EDT THU JUL 07 2022  
 
VALID 12Z SUN JUL 10 2022 - 12Z THU JUL 14 2022  
 
...A PROLONGED HEAT WAVE WILL LAST THROUGH EARLY NEXT WEEK ACROSS  
THE SOUTHERN PLAINS AND MID-SOUTH...  
   
..OVERVIEW
 
 
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-THURSDAY. 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-THURSDAY. MEANWHILE SOME MONSOONAL MOISTURE CONTINUES TO  
FLOW INTO THE SOUTHWEST.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
RECENT DETERMINISTIC AND ENSEMBLE GUIDANCE REMAINS IN GOOD  
AGREEMENT FOR THE LARGE SCALE SETUP AND EVOLUTION THROUGH MUCH OF  
THE PERIOD. THERE ARE SOME SMALLER SCALE TIMING DIFFERENCES,  
PARTICULARLY AFFECTING THE SHORTWAVE AS IT DROPS TOWARDS THE GREAT  
LAKES, AND THEN EVOLUTION OF THE DEEPENING TROUGH OVER THE EAST.  
THESE DIFFERENCES, WHICH COULD TAKE INTO THE SHORT RANGE TO FULLY  
RESOLVE, WOULD IMPACT FRONTAL PLACEMENT AND QPF AMOUNTS AS WELL.  
REGARDLESS, THE WPC FORECAST REMAINED VERY CLOSE TO CONTINUITY AND  
WAS COMPRISED OF A BLEND OF LATEST DETERMINISTIC MODEL GUIDANCE  
DAYS 3-5, WITH INCREASING CONTRIBUTIONS FROM THE ENSEMBLE MEANS ON  
DAYS 6-7.  
 
   
..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 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 SUNDAY-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. HOWEVER, THE STORM PREDICTION  
CENTER CURRENTLY DELINEATES PARTS OF THE DAKOTAS INTO MUCH OF  
MINNESOTA IN A SLIGHT RISK FOR SEVERE WEATHER. 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 EVEN 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. 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 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. A BRIEFER PERIOD OF TEMPERATURES 10-20F ABOVE  
AVERAGE IS FORECAST FOR THE CENTRAL/NORTHERN PLAINS ON SUNDAY  
BEFORE APPROACHING CLOSER TO AVERAGE AS THE WORKWEEK BEGINS. 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.  
 
SANTORELLI/TATE  
 
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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