936  
FXUS02 KWBC 192034  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
433 PM EDT TUE JUL 19 2022  
 
VALID 12Z FRI JUL 22 2022 - 12Z TUE JUL 26 2022  
 
...DANGEROUS HEAT TO PERSIST OVER THE CENTRAL U.S. THROUGH EARLY  
NEXT WEEK...  
   
..OVERVIEW
 
 
GUIDANCE SHOWS THE AXIS OF A STRONG UPPER RIDGE STRETCHING ACROSS  
MUCH OF THE SOUTH-CENTRAL U.S. DURING THE PERIOD, ALBEIT WITH SOME  
UNCERTAINTY OVER EXACTLY WHERE THE HIGHEST HEIGHTS WILL BE ON A  
DAY-TO-DAY BASIS. THIS RIDGE WILL KEEP HOT AND HUMID WEATHER OVER  
THE CENTRAL/SOUTHERN PLAINS FOR A MAJORITY OF THE PERIOD. SOME  
SOUTHERN LOCATIONS COULD SEE READINGS APPROACH OR BREAK DAILY  
RECORDS FOR HIGHS AND VERY WARM NIGHTTIME LOWS. WITH SOMEWHAT LESS  
EXTREME ANOMALIES, AREAS FROM THE TENNESSEE/OHIO VALLEYS THROUGH  
THE MID-ATLANTIC AND NEW ENGLAND WILL EXPERIENCE MULTIPLE HOT DAYS  
AS WELL. THE WEST SHOULD SEE MODERATE TEMPERATURES RELATIVE TO  
NORMAL LATE WEEK THROUGH THE WEEKEND WITH THE APPROACH/EJECTION OF  
EASTERN PACIFIC UPPER TROUGH ENERGY, FOLLOWED BY HIGHER READINGS  
OVER THE NORTHWEST EARLY NEXT WEEK. THE INITIAL PACIFIC ENERGY AND  
OTHER FEATURES ACROSS SOUTHERN CANADA AND THE NORTHERN TIER U.S.  
WILL FLOW AROUND THE RIDGE AND FEED INTO A BROAD NORTHEASTERN  
U.S./EASTERN CANADA MEAN TROUGH, SUPPORTING ONE OR MORE  
WAVES/FRONTAL SYSTEMS AND EPISODES OF SHOWERS AND THUNDERSTORMS  
FROM THE NORTHERN TIER INTO THE EAST. MONSOONAL MOISTURE OVER THE  
SOUTHWEST/SOUTHERN ROCKIES WILL PROMOTE DAILY CHANCES OF SHOWERS  
AND STORMS, SOME OF WHICH COULD LEAD TO FLASH FLOODING. THIS  
ACTIVITY MAY INCREASE IN COVERAGE AND INTENSITY DURING THE WEEKEND  
AND EARLY NEXT WEEK.  
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
THE OVERALL SYNOPTIC PATTERN OVER THE LOWER 48 WAS CAPTURED WELL  
BY A GENERAL MODEL CONSENSUS THROUGH THE MEDIUM RANGE PERIOD.  
WAVES OF LOW PRESSURE RIDING ALONG THE NORTHERN TIER OF THE  
COUNTRY AND HIGH PRESSURE SETTLED ACROSS THE SOUTH POSED LITTLE IN  
THE WAY OF PATTERN UNCERTAINTY. A GENERAL MODEL BLEND OF THE 00Z  
EC/UK/CMC AND 06Z GFS WERE UTILIZED THROUGH DAY 5 AS THEY HANDLED  
THE EVOLUTION OF A UPPER-LEVEL LOW MOVING ACROSS THE NORTHWEST  
VERY WELL, DESPITE SOME TIMING/INTENSITY DIFFERENCES. HEAVIER  
WEIGHTING WAS GIVEN TO THE 00Z EC AND 06Z GFS ON DAY 3 DUE TO  
NOTABLE DIFFERENCES BETWEEN THE GFS/EC TRENDS AND THOSE OF THE  
UK/CMC WITH RESPECT TO THE TIMING/INTENSITY OF THE NORTHWEST  
TROUGH. BY DAYS 6 AND 7 MORE ENSEMBLE MEAN PRODUCTS WERE  
INCORPORATED INTO THE BLEND WITH SOME 00Z EC AND 06Z GFS TO HELP  
SCALE BACK UNREASONABLE AMPLIFICATION OF A TROUGH OVER THE WEST.  
   
..WEATHER/HAZARDS HIGHLIGHTS
 
 
CONTINUE TO EXPECT MOST OF THE GREATEST TEMPERATURE ANOMALIES TO  
BE OVER AND NEAR THE CENTRAL PLAINS THROUGH THE PERIOD, WITH  
MULTIPLE DAYS OF HIGHS 10-15F ABOVE NORMAL. SOME OF THE HEAT MAY  
ALSO EXTEND INTO PARTS OF THE TENNESSEE VALLEY. BY SUNDAY-MONDAY A  
COLD FRONT MAY SUPPRESS THE HEAT OVER THE NORTH-CENTRAL PLAINS.  
TYPICALLY HOTTER SOUTHERN PLAINS LOCATIONS WILL SEE LESS EXTREME  
ANOMALIES BUT OVERALL THERE WILL BE A BROAD AREA WITH HIGHS  
REACHING OR EXCEEDING 100F FOR HIGHS, WHILE VERY WARM LOWS IN THE  
UPPER 70S TO LOW 80S WILL PROVIDE LITTLE NIGHTTIME RELIEF. THIS  
HEAT WAVE SHOULD BRING SCATTERED RECORDS, MOST LIKELY OVER THE  
SOUTHERN PLAINS TO LOWER/MID MISSISSIPPI VALLEY.  
 
OVER THE WEST, MONSOONAL MOISTURE AND ASSOCIATED DIURNALLY FAVORED  
SHOWERS/STORMS WITH LOCALLY HEAVY RAINFALL MAY KEEP PARTS OF THE  
FOUR CORNERS/GREAT BASIN REGION WITHIN A FEW DEGREES ON EITHER  
SIDE OF NORMAL DURING THROUGH THE PERIOD. THERE IS A GENERAL  
SIGNAL IN THE GUIDANCE THAT RAINFALL SHOULD INCREASE IN COVERAGE  
AND INTENSITY DURING THE WEEKEND AND EARLY NEXT WEEK BUT WITH  
CONSIDERABLE UNCERTAINTY OVER THE SPECIFICS. THE INITIAL SHORTWAVE  
EJECTING FROM THE NORTHWEST AND THEN LINGERING WEAK TROUGH ENERGY  
SHOULD KEEP THAT REGION NEAR OR A TAD BELOW NORMAL THROUGH THE  
WEEKEND. THE MAJORITY SCENARIO OF SOME DEGREE OF UPPER RIDGING  
BUILDING INTO THE NORTHWEST BY NEXT TUESDAY SHOULD LEAD TO A  
WARMING TREND, WITH SOME HIGHS POSSIBLY REACHING UP TO 10-15F  
ABOVE NORMAL.  
 
THE COMBINATION OF SHORTWAVES ALOFT AND SURFACE WAVES/FRONTS WILL  
LIKELY PRODUCE ONE OR MORE EPISODES OF SHOWERS AND STORMS FROM THE  
NORTHERN TIER STATES INTO THE EAST DURING THE PERIOD, WITH SOME  
HEAVY RAINFALL POSSIBLE. CURRENTLY THE BEST SIGNAL FOR ENHANCED  
RAINFALL EXTENDS FROM THE MIDWEST THROUGH THE LOWER GREAT LAKES  
INTO THE MID-ATLANTIC, BUT RECENT GUIDANCE INCONSISTENCY WITH  
IMPORTANT DETAILS AT THE SURFACE AND ALOFT TEMPER CONFIDENCE IN  
THE SPECIFICS FOR NOW. THE MID-ATLANTIC AND NORTHEAST WILL BE ON  
THE VERY WARM TO HOT SIDE FROM LATE WEEK THROUGH THE WEEKEND, WITH  
SOME LOCATIONS POSSIBLY SEEING MORE CONSECUTIVE DAYS OF PLUS 5-10F  
OR SO ANOMALIES FOR HIGHS THAN PREVIOUSLY EXPERIENCED SO FAR THIS  
SUMMER. TEMPERATURES SHOULD TREND CLOSER TO NORMAL FROM NORTH TO  
SOUTH BY EARLY NEXT WEEK AS A COUPLE FRONTS ARRIVE. PERSISTENT  
MOISTURE WILL ALLOW FOR MULTIPLE EPISODES OF SHOWERS/THUNDERSTORMS  
OVER THE SOUTHEAST/FLORIDA AND CENTRAL GULF COAST REGION. BEST  
ORGANIZATION MAY BE LATE THIS WEEK. HIGHS SHOULD STAY NEAR NORMAL  
OVER THE SOUTHEAST.  
 
RAUSCH/KEBEDE  
 
HAZARDS:  
- HEAVY RAIN ACROSS PORTIONS OF THE CENTRAL GREAT BASIN AND THE  
SOUTHWEST, SAT-TUE, JUL 23-JUL 26.  
- HEAVY RAIN ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY, THE  
GREAT LAKES, AND THE UPPER MISSISSIPPI VALLEY, SAT-SUN, JUL 23-JUL  
24.  
- HEAVY RAIN ACROSS PORTIONS OF THE GREAT LAKES, THE CENTRAL  
APPALACHIANS, AND THE OHIO VALLEY, SUN-MON, JUL 24-JUL 25.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL ROCKIES, THE  
CENTRAL GREAT BASIN, AND THE SOUTHWEST, FRI, JUL 22.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE CENTRAL PLAINS, THE LOWER  
MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, THE MIDDLE MISSISSIPPI  
VALLEY, THE SOUTHERN APPALACHIANS, THE SOUTHEAST, THE SOUTHERN  
PLAINS, AND THE OHIO VALLEY, FRI-TUE, JUL 22-JUL 26.  
- EXCESSIVE HEAT ACROSS PORTIONS OF THE SOUTHEAST, THE  
MID-ATLANTIC, THE SOUTHERN APPALACHIANS, AND THE TENNESSEE VALLEY,  
SAT-MON, JUL 23-JUL 25.  
 
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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