007   
FXUS02 KWBC 170700  
PMDEPD  
  
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT SAT AUG 17 2024  
  
VALID 12Z TUE AUG 20 2024 - 12Z SAT AUG 24 2024  
  
...HAZARDOUS HEAT TO PERSIST FROM THE SOUTHERN PLAINS TO THE   
WEST-CENTRAL GULF COAST NEXT WEEK...  
  
   
..OVERVIEW  
  
AN OMEGA-STYLE BLOCKY UPPER PATTERN WILL DEVELOP AND LINGER NEXT   
WEEK. THIS WILL BE HIGHLIGHTED BY A BUILDING UPPER HIGH CENTERED   
OVER THE SOUTHERN HIGH PLAINS THAT WILL PROMOTE HAZARDOUS HEAT FROM  
THE SOUTHERN PLAINS TO THE CENTRAL GULF COAST. UPSTREAM, AMPLIFIED  
UPPER TROUGHING IS FORECAST TO MEANDER NEAR/OFF THE WEST COAST.   
DOWNSTREAM, AN AMPLIFIED MEAN UPPER TROUGH WILL WORK INTO AND   
PERSIST OVER AN UNSETTLED EAST-CENTRAL TO EASTERN U.S..  
   
..GUIDANCE/PREDICTABILITY ASSESSMENT  
  
FORECAST SPREAD AND UNCERTAINTY IN GUIDANCE CONTINUES TO HOLD AT   
BELOW NORMAL THRESHHOLDS THROUGH MEDIUM RANGE TIME SCALES FOR NEXT  
WEEK OVER MUCH OF OUR FINE NATION. A FULLY INCLUSIVE MODEL AND   
ENSEMBLE MEAN COMPOSITE BLEND ALONG WITH THE NATIONAL BLEND OF   
MODELS SEEMS TO PROVIDE A SOLID DETERMINISTIC FORECAST BASE AND   
RANGES OF SOLUTIONS AND POTENTIAL HAZARDS, ALBEIT WITH TYPICALLY   
LESS PREDICTABLE SMALLER SCALE WARM SEASON FEATURES AND LOCAL   
WEATHER FOCUS TO BETTER ADDRESS AT CLOSER TIME SCALES.  
   
..WEATHER/HAZARDS HIGHLIGHTS  
  
AN EAST-CENTRAL TO EASTERN U.S. UPPER TROUGH OFFERS SOME LINGERING  
UNSETTLED CONDITIONS, BUT MUCH OF EARLIER PERIOD RAINS ARE   
EXPECTED TO TAPER OFF BY MIDWEEK AS SURFACE HIGH PRESSURE BUILDS   
IN BEHIND THE COLD FRONT(S) AND IN THE WAKE OF ERNESTO AS LIFTED   
WELL OFFSHORE. HOWEVER, TRAILING FRONTS SLATED TO STALL FARTHER   
SOUTH ACROSS FLORIDA AND VICINITY WILL MAINTAIN PERIODIC   
THUNDERSTORM CHANCES THERE. FLOODING ISSUES ARE A POSSIBILITY IF   
HEAVY RAIN FALLS IN URBAN AREAS. THIS FRONT MOVES SLOWLY AS IT   
BENDS BACK TO THE WEST ATOP THE CENTRAL GULF COAST AND BACK NORTH   
INTO THE PLAINS. SCATTERED STORMS ARE POSSIBLE NEAR THE FRONT AS   
IMPULSES "RIDE THE RIDGE" ALOFT, BUT WITH GENERALLY LOW CONFIDENCE   
IN PLACEMENT STILL AT THIS TIME.  
  
MEANWHILE, MONSOONAL CONVECTION WILL AFFECT THE SOUTHWEST/FOUR   
CORNERS STATES NEXT WEEK WITH MOIST SOUTHERLY FLOW WEST OF THE   
UPPER RIDGE AXIS. THE WPC DAY 4/5 EXCESSIVE RAINFALL OUTLOOKS HAVE  
MARGINAL RISKS AREAS ISSUED FOR TUESDAY AND WEDNESDAY OVER   
PORTIONS OF ARIZONA, UTAH, SOUTHEAST CALIFORNIA, SOUTHERN NEVADA   
AND COLORADO. STORMS WITH EMBEDDED HEAVY RAIN COULD CAUSE ISOLATED   
FLOODING, PARTICULARLY IN VULNERABLE AREAS.   
  
MEANWHILE, UPPER TROUGH AMPLIFICATION PROXIMITY ALONG/OFF THE WEST  
COAST PORTENDS A COOLER AND WETTER PATTERN FOR THE NORTHWEST. SOME  
RAINS ARE ALSO FORECAST TO BROADLY FOCUS DOWNSTREAM ACROSS THE U.S.   
NORTHERN TIER AS THE WEEK PROGRESSES. SOME CONVECTION MAY BREAK OUT  
ALONG/AHEAD OF RELATIVELY SLOW MOVING FRONTAL SYSTEMS ACROSS THE   
NORTH-CENTRAL U.S. AS NEXT WEEK PROGRESSES, BUT FOCUS IS UNCERTAIN.  
  
UPPER RIDGING OVER THE SOUTH-CENTRAL U.S. WILL MAINTAIN ABOVE   
NORMAL TEMPERATURES BY 5-15 DEGREES FROM THE HIGH PLAINS EAST INTO   
THE WEST-CENTRAL GULF COAST. HIGHS WELL INTO THE 100S IN MUCH OF   
TEXAS COULD SET DAILY RECORDS AND HIGH DEWPOINTS SHOULD PRODUCE   
HEAT INDICES LIKELY ABOVE 110 DEGREES. LOW TEMPERATURES IN THE   
UPPER 70S TO LOW 80S WILL EXACERBATE HEAT STRESS AND COULD SET   
RECORDS FOR WARM MINIMUM TEMPERATURES. EXPERIMENTAL HEATRISK   
CONTINUES TO SHOW MAJOR TO EXTREME IMPACTS FROM THIS HEAT WAVE.  
  
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 FORECAST (QPF), EXCESSIVE RAINFALL   
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT   
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:  
  
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  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW  
  
  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.


The Nexlab HPC Page

Main Text Page