570  
FXUS01 KWBC 240749  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
348 AM EDT SUN JUN 24 2018  
 
VALID 12Z SUN JUN 24 2018 - 12Z TUE JUN 26 2018  
 
...INCREASING CHANCES FOR SEVERE THUNDERSTORMS ACROSS THE CENTER  
OF THE COUNTRY ON SUNDAY...  
 
...FLASH FLOODING CONCERNS SHOULD GENERALLY FOCUS OVER VAST  
SECTIONS OF THE CENTRAL U.S. INTO THE MIDDLE MISSISSIPPI VALLEY...  
 
...WELL BELOW AVERAGE TEMPERATURES EXPECTED TO FOLLOW AN UPPER LOW  
MOVING FROM THE NORTHERN/CENTRAL ROCKIES INTO THE UPPER MIDWEST...  
 
...LOCALLY HEAVY RAINFALL POSSIBLE ACROSS SOUTH FLORIDA AND THE  
COASTAL CAROLINAS...  
 
A SHARPENING UPPER TROUGH CURRENTLY TRAVERSING ACROSS THE CENTRAL  
ROCKIES WILL EVENTUALLY EMERGE OVER THE ADJACENT HIGH PLAINS BY  
THIS EVENING. WITH A VERY MOIST AND UNSTABLE AIR MASS IN PLACE  
ACROSS THE CENTRAL U.S., WIDESPREAD CONVECTION SHOULD UNFOLD  
DURING THE HEIGHT OF THE DIURNAL HEATING CYCLE. EVOLVING  
THUNDERSTORMS WILL LIKELY BE SEVERE WEATHER PRODUCERS BASED ON THE  
LATEST STORM PREDICTION CENTER OUTLOOK. AS OF EARLY THIS MORNING,  
AN ENHANCED RISK STRETCHES OVER THE OKLAHOMA/TEXAS PANHANDLES INTO  
PARTS OF CENTRAL OKLAHOMA AND KANSAS. ALL SEVERE HAZARDS ARE  
POSSIBLE WITH DAMAGING WINDS AND LARGE HAIL BEING THE MAIN  
CONCERNS ALTHOUGH A FEW TORNADOES CANNOT BE RULED OUT. GRADUALLY A  
BROADER WIND THREAT SHOULD EXTEND OVER LOCATIONS TO THE EAST  
DURING THE OVERNIGHT HOURS AS THE STORMS TAKE ON A MORE  
PROGRESSIVE MODE. BY THE FOLLOWING DAY, THE PARENT SURFACE LOW  
WILL TRACK INTO IOWA WITH THE THREAT FOR SEVERE WEATHER  
ACCOMPANYING THIS RELOCATION.  
 
IN ADDITION TO THE SEVERE ASPECTS OF THIS DYNAMIC UPPER TROUGH,  
FLASH FLOOD CONCERNS WILL BE WIDESPREAD OVER A MAJORITY OF THE  
CENTRAL U.S. SLOW MOVEMENT OF INDIVIDUAL THUNDERSTORM CLUSTERS OR  
AREAS OF REPEAT ACTIVITY SHOULD PROVIDE MECHANISMS TO ENHANCE THE  
FLASH FLOOD POTENTIAL ON SUNDAY. ADDITIONALLY, MANY POCKETS OF THE  
OUTLOOK AREA HAVE SEEN HEAVY RAINFALL THE PAST WEEK WITH RECENT  
TOTALS AROUND 300-600 PERCENT ABOVE NORMAL FOR MID/LATE JUNE. AS A  
RESULT, RAPID RUNOFF WITH THESE HEAVY PRECIPITATION PRODUCING  
THUNDERSTORMS COULD LEAD TO NUMEROUS HYDROLOGIC ISSUES. WHILE THE  
INITIAL THREAT BEGINS ACROSS THE MIDDLE OF THE COUNTRY ON SUNDAY,  
IT SHOULD TRANSLATE INTO THE MIDDLE MISSISSIPPI VALLEY AND BACK  
INTO MISSOURI THEREAFTER.  
 
WITH A SLOW-MOVING UPPER LOW CARRYING A PATH FROM THE  
NORTHERN/CENTRAL ROCKIES TOWARD THE UPPER MIDWEST THE NEXT COUPLE  
OF DAYS, BELOW AVERAGE TEMPERATURES WILL FOLLOW SUIT. EXTENSIVE  
CLOUD COVER UNDERNEATH THE LOW CENTER SHOULD ENSURE HIGHS WILL  
HOLD IN THE 60S ACROSS THE HIGHER TERRAIN AND 70S INTO THE  
NORTH-CENTRAL U.S. WHICH IS ROUGHLY 10 TO 15 DEGREES BELOW  
CLIMATOLOGY. FARTHER EAST, THE GREAT LAKES SHOULD SEE SIMILAR  
DEPARTURES AS A SECONDARY COLD FRONT SAGS SOUTHWARD FROM ONTARIO.  
ON THE FLIP SIDE, THE WARMEST CONDITIONS SHOULD PREVAIL ACROSS THE  
WESTERN U.S. IN ADVANCE OF A POTENT COLD FRONT PUSHING INLAND.  
THIS SHOULD RAISE THE MERCURY TO NEAR THE CENTURY MARK ACROSS THE  
CENTRAL GREAT BASIN ON MONDAY.  
 
ELSEWHERE, A COMBINATION OF ABUNDANT MOISTURE IN PLACE WITH LOCAL  
SEA BREEZE EFFECTS SHOULD SPREAD HEAVY RAINFALL OVER SECTIONS OF  
SOUTH FLORIDA. HEAVIEST AMOUNTS ARE LIKELY TO FOCUS OVER  
SOUTHWESTERN FLORIDA OUT TOWARD THE EVERGLADES. FARTHER NORTH,  
UNSETTLED CONDITIONS ARE FORECAST TO PREVAIL OVER THE COASTAL  
CAROLINAS ON MONDAY. THIS IS IN RESPONSE TO A SERIES OF  
DISTURBANCES OVERRIDING A STALLED FRONTAL ZONE EXTENDING OFFSHORE.  
OTHERWISE, CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE  
NORTHEASTERN U.S. TO START THE WEEK AS A SURFACE RIDGE DROPS DOWN  
FROM ONTARIO.  
 
 
RUBIN-OSTER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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