740  
FXUS01 KWBC 200748  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
348 AM EDT MON AUG 20 2018  
 
VALID 12Z MON AUG 20 2018 - 12Z WED AUG 22 2018  
 
...HEAVY RAIN AND SEVERE WEATHER EXPECTED ACROSS THE MISSISSIPPI  
VALLEY TODAY...  
   
..ACTIVE WEATHER RETURNS FOR THE EAST COAST THIS WEEK
 
 
   
..AIR QUALITY REMAINS A CONCERN FOR PARTS OF THE WESTERN U.S
 
 
A LOW PRESSURE SYSTEM WILL CONTINUE TO LIFT OUT OF THE PLAINS AND  
MOVE INTO THE MISSISSIPPI VALLEY TODAY. AHEAD OF THE SYSTEM, WARM  
AND MOIST AIR WILL BE TRANSPORTED FROM THE GULF OF MEXICO AHEAD OF  
THE FRONTAL BOUNDARIES ASSOCIATED WITH THIS SYSTEM. SHOWERS AND  
THUNDERSTORMS WILL PERSIST ACROSS THE LOWER AND MIDDLE MISSISSIPPI  
VALLEY, ALONG WITH SCATTERED SHOWERS AND THUNDERSTORMS OCCURRING  
THROUGHOUT THE SOUTHEAST, TENNESSEE AND OHIO VALLEYS. SOME OF  
THESE THUNDERSTORMS HAVE THE CAPABILITY OF PRODUCING SEVERE  
WEATHER WHERE THE STORM PREDICTION CENTER HAS A SLIGHT RISK ALONG  
THE TENNESSEE AND MISSISSIPPI VALLEY. THE HEAVIEST AXIS OF  
RAINFALL WILL FALL ALONG IOWA AND SOUTHERN WISCONSIN TODAY.  
 
BY TUESDAY, THE LOW PRESSURE SYSTEM WILL QUICKLY PROGRESS EASTWARD  
TOWARD THE EAST COAST. AREAS FROM THE NORTHEAST SOUTHWARD INTO THE  
CENTRAL GULF COAST CAN EXPECT CONVECTION ALONG AND AHEAD OF THE  
FRONT. SOME OF THESE STORMS COULD BECOME SEVERE--THUS, SPC HAS  
HIGHLIGHTED A SLIGHT RISK OF SEVERE WEATHER FOR PARTS OF THE OHIO  
VALLEY INTO THE MID-ATLANTIC. MODERATE RAINFALL WILL ALSO BE  
ANTICIPATED FOR THE GREAT LAKES AS THE SURFACE LOW LIFTS OVER THIS  
AREA. BY WEDNESDAY, MOST OF THE PRECIPITATION WILL MOVE OFFSHORE;  
HOWEVER, AS THE FRONT PRESSES ACROSS NEW ENGLAND--SHOWERS AND  
THUNDERSTORMS WILL FOLLOW.  
 
FIRE WEATHER RISKS CONTINUES TO BE ELEVATED ESPECIALLY FOR THE  
PACIFIC NORTHWEST, INTERMOUNTAIN WEST AND PORTIONS OF THE GREAT  
BASIN THROUGH TUESDAY. RED FLAG WARNINGS ARE IN EFFECT FOR PARTS  
OF THESE AREAS. AIR QUALITY ALSO REMAINS A CONCERN DUE TO THE  
SMOKE FROM ONGOING FIRES. AIR QUALITY ALERTS CONTINUE TO BE IN  
EFFECT FOR MUCH OF THE PACIFIC NORTHWEST AND ALL OF MONTANA.  
 
ELSEWHERE, MOISTURE WILL SURGE BACK INTO THE SOUTHWEST BY TUESDAY.  
LATE AFTERNOON AND EARLY EVENING THUNDERSTORMS WILL RETURN ACROSS  
THE SOUTHWEST AND GREAT BASIN ON TUESDAY AND WEDNESDAY. SOME OF  
THESE STORMS COULD PRODUCE FLASH FLOODING ESPECIALLY IN FAVORABLE  
TERRAIN AND URBAN AREAS. ON TUESDAY NIGHT AND INTO WEDNESDAY,  
THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE HIGH PLAINS OF  
COLORADO AND KANSAS AND MOVE INTO THE SOUTHERN PLAINS. SOME OF  
THESE AREAS HAVE RECEIVED ABOVE NORMAL RAINFALL IN THE LAST WEEK,  
ELEVATING THE CHANCES OF LOCALIZED FLASH FLOODING. ADDITIONALLY,  
THERE IS A SLIGHT RISK OF SEVERE WEATHER IN A SMALL AREA OF  
SOUTHEAST COLORADO AND THE OKLAHOMA PANHANDLE.  
 
REINHART  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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