984  
FXUS01 KWBC 142007  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
406 PM EDT TUE AUG 14 2018  
 
VALID 00Z WED AUG 15 2018 - 00Z FRI AUG 17 2018  
 
...HEAVY RAIN POSSIBLE ACROSS NEW ENGLAND AND THE NORTHERN MID  
ATLANTIC...  
 
...HEAVY RAIN AND THUNDERSTORMS POSSIBLE ACROSS PORTIONS OF THE  
PLAINS THROUGH TONIGHT, SHIFTING EASTWARD INTO THE MISSISSIPPI  
VALLEY FOR WEDNESDAY...  
 
...FIRE WEATHER CONCERNS CONTINUE ACROSS THE WEST WITH THE THREAT  
OF DRY THUNDERSTORMS SPARKING NEW WILDFIRES...  
 
A QUASI-STATIONARY FRONT EXTENDING FROM PARTS OF THE NORTHEAST  
SOUTHWARD ACROSS COASTAL PARTS OF THE MID-ATLANTIC INTO PARTS OF  
THE SOUTHEAST WILL SLOWLY DISSIPATE BY WEDNESDAY MORNING, WITH  
MOST SHOWERS AND THUNDERSTORMS EXPECTED TO TAPER OFF. HOWEVER, THE  
DRIVING SURFACE LOW PRESSURE CENTER WILL REMAIN OVER THE NORTHEAST  
DURING THIS TIME, COUPLING WITH A STRONG UPPER LEVEL LOW. THIS  
WILL ADVECT LARGE AMOUNTS OF MOISTURE INLAND ACROSS THE NORTHEAST,  
RESULTING IN WIDESPREAD RAINFALL. THE WEATHER PREDICTION CENTER  
HAS CONTINUED A SLIGHT RISK OF EXCESSIVE RAINFALL AND FLASH  
FLOODING ACROSS MUCH OF THE NORTHEAST AND INTO THE NORTHERN MID  
ATLANTIC THROUGH TONIGHT. FLASH FLOOD WATCHES AND WARNINGS ARE  
ALSO CURRENTLY IN EFFECT ACROSS THIS AREA.  
 
MEANWHILE, ANOTHER LOW PRESSURE SYSTEM WILL CONTINUE TO GAIN  
STRENGTH ACROSS THE CENTRAL PLAINS AS IT SLOWLY SHIFTS EASTWARD  
TOWARDS THE MIDDLE MISSISSIPPI VALLEY BY WEDNESDAY EVENING. A  
STRONG SURGE OF WARM, MOIST AIR FROM THE GULF OF MEXICO WILL CLASH  
WITH COLDER AIR MOVING IN FROM THE NORTH, RESULTING IN A FRONTAL  
BOUNDARY AND CREATING THE EPICENTER FOR SHOWERS AND THUNDERSTORMS  
OVER THE NEXT SEVERAL DAYS. THE WEATHER PREDICTION CENTER HAS  
OUTLINED A LARGE PORTION OF THE SOUTHERN AND CENTRAL PLAINS,  
EASTWARD INTO THE MID AND LOWER MISSISSIPPI VALLEY AS BEING IN A  
SLIGHT RISK FOR EXCESSIVE RAINFALL THROUGH TONIGHT. THIS RISK AREA  
WILL SHIFT EASTWARD, EXTENDING FROM THE LOW/MIDDLE MISSISSIPPI  
VALLEY AND INTO THE WESTERN OHIO VALLEY DURING THE DAY WEDNESDAY,  
AND THEN INTO THE GREAT LAKES REGION BY THURSDAY. FLASH FLOOD  
WATCHES ARE ALSO CURRENTLY IN EFFECT FOR EASTERN OKLAHOMA AND  
NORTHWEST ARKANSAS.  
 
YET ANOTHER FRONTAL BOUNDARY IS CURRENTLY DRAPED ACROSS THE  
CENTRAL AND NORTHERN PLAINS THIS AFTERNOON. THIS WILL COUPLE WITH  
AN UPPER LEVEL SYSTEM TO BRING FORCING, INSTABILITY AND MOISTURE  
TO PORTIONS OF THIS REGION. THE STORM PREDICTION CENTER HAS  
OUTLINED NORTHEAST WYOMING AND FAR SOUTHEAST MONTANA AS BEING IN A  
SLIGHT RISK FOR SEVERE WEATHER TODAY. THIS SLIGHT RISK REGION WILL  
SHIFT EASTWARD FOR WEDNESDAY, SETTLING ACROSS WESTERN NEBRASKA. A  
MARGINAL RISK OF SEVERE WEATHER IS ALSO IN EFFECT IN THE OUTLYING  
VICINITY.  
 
ELSEWHERE, FIRE WEATHER CONCERNS CONTINUE ACROSS THE WEST. WHILE  
MONSOONAL MOISTURE MOVES INTO THE SOUTHWEST, DRY THUNDERSTORMS  
WILL EXTEND NORTHWARD ACROSS MUCH OF THE WEST, POTENTIALLY  
SPARKING NEW WILDFIRES. A LARGE PORTION OF CENTRAL CALIFORNIA AS  
WELL AS MUCH OF THE PACIFIC NORTHWEST, NORTHERN GREAT BASIN, AND  
NORTHERN ROCKIES ARE UNDER AN AIR QUALITY ALERT DUE TO SMOKE FROM  
ONGOING WILDFIRES. RED FLAG WARNINGS ARE ALSO IN EFFECT ACROSS  
PORTIONS OF NORTHERN CALIFORNIA AND SOUTHERN OREGON, AS WELL AS  
MUCH OF NORTHERN NEVADA AND FAR SOUTHEAST IDAHO AS THE THREAT OF  
DRY THUNDERSTORMS LOOMS THROUGH MID WEEK.  
 
WIX  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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