362  
FXUS01 KWBC 211915  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
314 PM EDT SUN OCT 21 2018  
 
VALID 00Z MON OCT 22 2018 - 00Z WED OCT 24 2018  
   
..HEAVY RAINFALL THREAT CONTINUES FOR SOUTH TEXAS
 
 
...WIDESPREAD FREEZE WARNINGS AND FROST ADVISORIES ARE IN EFFECT  
FROM THE TENNESSEE VALLEY TO THE MID-ATLANTIC OVERNIGHT TONIGHT...  
 
MOISTURE OVERRIDING A STAGNANT FRONTAL BOUNDARY IN THE NORTHERN  
AND WESTERN GULF OF MEXICO WILL KEEP SHOWERS AND THUNDERSTORMS  
ACROSS THE FLORIDA KEYS AND THE GULF COAST THE NEXT SEVERAL DAYS.  
THE BEST SIGNATURE FOR HEAVY RAIN WILL BE ACROSS FAR SOUTH TEXAS,  
WHERE A HANDFUL OF FLASH FLOOD WATCHES ARE IN EFFECT, PARTICULARLY  
IN THE BROWNSVILLE REGION. SHOWERS AND THUNDERSTORMS WILL CONTINUE  
THE NEXT FEW DAYS AS WELL ACROSS SOUTHERN TEXAS AS MOISTURE FROM  
HURRICANE WILLA IN THE EASTERN TROPICAL PACIFIC EVENTUALLY GETS  
PULLED NORTHWARD TOWARDS THE REGION. GIVEN SEVERAL DAYS OF WET  
WEATHER ALREADY, THERE'S A MARGINAL RISK FOR FLASH FLOODING. TO  
THE WEST, EXPECT RAIN ACROSS THE GREAT BASIN THIS EVENING (WITH  
SNOW IN THE HIGHEST ELEVATIONS) SHIFTING SLOWLY EASTWARD BY MONDAY  
AND TUESDAY UNDERNEATH AND AHEAD OF BROAD UPPER LEVEL TROUGHING  
ACROSS THE SOUTHWEST U.S.. LOCALIZED FLASH FLOODING MAY BE A  
THREAT IN REGIONS WHICH ARE SENSITIVE TO HEAVY RAINFALL. FINALLY,  
A SURFACE LOW TRAVERSING THE REGION ON TUESDAY, WILL ALLOW FOR  
MAINLY LIGHT RAIN AND SNOW SHOWERS ACROSS THE GREAT LAKES AND THE  
NORTHEAST.  
 
REGARDING TEMPERATURES ACROSS THE COUNTRY, REINFORCING SHOTS OF  
COLD AIR WILL KEEP TEMPERATURES BELOW NORMAL FROM THE GREAT  
LAKES/NORTHEAST TO THE SOUTHERN PLAINS THROUGH THE SHORT RANGE  
PERIOD. OVERNIGHT LOWS TONIGHT COULD BE NEAR OR BELOW FREEZING  
FROM THE TENNESSEE/LOWER OHIO VALLEY TO THE CENTRAL APPALACHIANS  
AND MID-ATLANTIC WHERE WIDESPREAD FREEZE WARNINGS AND FROST  
ADVISORIES ARE IN EFFECT. IN THE SOUTHERN PLAINS, DAYTIME HIGHS IN  
THE 50S AND 60S ARE POSSIBLE, WHICH WOULD BE AS MUCH AS 10 TO 20  
DEGREES BELOW NORMAL FOR THIS TIME OF THE YEAR. MEANWHILE, OUT  
WEST, TEMPERATURES ABOVE NORMAL ARE EXPECTED TO CONTINUE, AND  
STAGNANT AIRFLOW AND LIGHT WINDS WITHIN THE VALLEYS OF EASTERN  
WASHINGTON AND NORTH-CENTRAL OREGON HAVE PROMPTED AIR QUALITY  
ALERTS.  
 
SANTORELLI  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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