563  
FXUS01 KWBC 280802  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
402 AM EDT THU JUN 28 2018  
 
VALID 12Z THU JUN 28 2018 - 12Z SAT JUN 30 2018  
 
...SEVERE THUNDERSTORMS AND FLASH FLOODING ARE LIKELY ACROSS THE  
NORTH-CENTRAL U.S. TODAY...  
 
...LOCALLY HEAVY RAINFALL POSSIBLE OVER COASTAL NEW ENGLAND AS  
WELL AS THE SOUTHEASTERN U.S...  
 
...WELL ABOVE AVERAGE TEMPERATURES ARE EXPECTED FROM THE ROCKIES  
EASTWARD TO THE UPPER GREAT LAKES...  
 
...CRITICAL RISK FOR WILDFIRE PRODUCTION OVER THE FOUR CORNERS THE  
NEXT COUPLE OF DAYS...  
 
AN AMPLIFYING UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL  
CONTINUE TO MIGRATE EASTWARD TOWARD THE NORTHERN ROCKIES. AS THIS  
OCCURS, A SURFACE CYCLONE SHOULD RAPIDLY DEEPEN ALONG THE  
MONTANA/WYOMING BORDER WITH EVENTUAL PROGRESSION INTO THE DAKOTAS  
BY LATER TONIGHT. THIS SYSTEM WILL ADVANCE INTO A MOISTURE RICH  
AIR MASS FULL OF INSTABILITY. SUCH A COMBINATION SHOULD FOSTER THE  
DEVELOPMENT OF NUMEROUS SHOWERS AND THUNDERSTORMS DURING THE PEAK  
IN THE DIURNAL HEATING CYCLE. MANY SUCH STORMS COULD BECOME SEVERE  
IN NATURE AS SUGGESTED BY THE STORM PREDICTION CENTER CONVECTIVE  
OUTLOOK. CURRENTLY AN ENHANCED RISK IS IN PLACE ACROSS FAR EASTERN  
MONTANA INTO A MAJORITY OF NORTH DAKOTA WHILE SCRAPING THE  
NORTHERN EXTENT OF SOUTH DAKOTA. LARGE HAIL AND DAMAGING WINDS  
APPEAR TO BE THE PRIMARY THREATS ALTHOUGH A FEW TORNADOES CANNOT  
BE RULED OUT. BESIDES THE SEVERE MODE TO THE CONVECTION, A  
POTENTIAL FOR FLASH FLOODING WILL EXIST OVER A SIMILAR REGION WITH  
1 TO 2 INCHES OF RAINFALL EXPECTED THROUGH EARLY FRIDAY. OF COURSE  
HIGHER AMOUNTS ARE POSSIBLE ON A MORE LOCALIZED SCALE.  
 
A POTENT DISTURBANCE CURRENTLY LIFTING TOWARD UPSTATE NEW YORK  
CONTINUES TO PROVIDE AMPLE LIFT ACROSS THE NORTHEASTERN CORRIDOR  
OF THE U.S. WIDESPREAD MODERATE TO LOCALLY HEAVY RAINFALL IS  
FALLING OVER THE REGION, GENERALLY IN ADVANCE OF A SLOW MOVING  
FRONTAL ZONE. UNTIL THIS BOUNDARY EXITS THE EASTERN SEABOARD, IT  
WILL REMAIN A FOCUS FOR ORGANIZED RAINFALL THROUGH ROUGHLY FRIDAY  
MORNING. DURING THE NEXT 24 HOURS, THE HIGHEST AMOUNTS ARE LIKELY  
ALONG AND EAST OF THE I-95 CORRIDOR EXTENDING FROM CONNECTICUT  
NORTHWARD. THERE REMAINS A THREAT FOR FLASH FLOODING ISSUES,  
PARTICULARLY WHERE CONVECTION TRAINS OR REPEATS. FARTHER SOUTH,  
THE PATTERN WILL ALSO BE QUITE ACTIVE ACROSS THE SOUTHEASTERN  
U.S., ESPECIALLY FLORIDA. AMPLE MOISTURE IN PLACE IN CONJUNCTION  
WITH LOCAL SEA BREEZE CIRCULATIONS SHOULD PROMOTE AMPLE  
THUNDERSTORM GROWTH EACH AFTERNOON AND EVENING. THE HIGHEST  
AMOUNTS WILL LIKELY FOCUS WHERE STORM MERGERS OCCUR WHICH WOULD  
ALLOW HEAVIER RAINFALL TO PERSIST LONGER. GIVEN MUCH OF THE STATE  
TENDS TO RESPOND QUITE WELL TO THE HEAVY PRECIPITATION IN TERMS OF  
DRAINAGE AND ABSORPTION, NO DISCERNIBLE FLASH FLOOD RISKS ARE  
EVIDENT AT THIS TIME.  
 
WITH AN UPPER RIDGE BEGINNING TO TAKE A STRANGLEHOLD ON THE  
CENTRAL U.S. INTO THE MISSISSIPPI RIVER VALLEY, TEMPERATURES WILL  
SOAR CONSIDERABLY THE NEXT COUPLE OF DAYS. LOCAL FORECAST OFFICES  
HAVE ALREADY HOISTED UP WIDESPREAD HEAT ADVISORIES AND EXCESSIVE  
HEAT WATCHES/WARNINGS GENERALLY FROM I-35 ACROSS KANSAS/OKLAHOMA  
TO AS FAR EAST AS LOWER MICHIGAN. HIGH TEMPERATURES THE NEXT  
COUPLE OF DAYS WILL LIKELY BE AROUND 10 TO 15 DEGREES ABOVE  
CLIMATOLOGY WHICH SUPPORTS NUMBERS IN THE MID/UPPER 90S TO  
POSSIBLY NEAR 100 DEGREES. WHILE NO INDIVIDUAL HAZARDS ARE LISTED  
ACROSS EASTERN COLORADO, HIGHS WILL EASILY PUNCH OVER THE CENTURY  
MARK TODAY WITH SOME DAILY RECORDS LIKELY TO BE BROKEN. THE  
EXPECTED HIGH OF 103 DEGREES IN DENVER WOULD BREAK THE PREVIOUS  
RECORD OF 99 DEGREES IF ACHIEVED.  
 
WIDESPREAD RED FLAG WARNINGS REMAIN IN EFFECT OVER VAST SECTIONS  
OF THE DESERT SOUTHWEST INTO THE FOUR CORNERS REGION. HOT, DRY,  
AND WINDY CONDITIONS SHOULD PREVAIL WHICH WILL MAINTAIN RATHER LOW  
RELATIVE HUMIDITY VALUES. MUCH OF THIS REGION HAS BEEN UNDER A  
CONSIDERABLE DROUGHT AS SHOWN BY THE LATEST DROUGHT MONITOR  
PRODUCT. THE COMBINATION OF ALL THESE FACTORS HAS LED TO A  
CRITICAL RISK FOR WILDFIRE PRODUCTION THE NEXT COUPLE OF DAYS OVER  
THE MENTIONED REGION.  
 
RUBIN-OSTER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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