267  
FXUS01 KWBC 191959  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
359 PM EDT WED SEP 19 2018  
 
VALID 00Z THU SEP 20 2018 - 00Z SAT SEP 22 2018  
 
...SEVERE THUNDERSTORMS AND FLASH FLOODING ARE FORECAST FOR THE  
UPPER MIDWEST...  
 
...MOISTURE FROM NEWLY FORMED TROPICAL DEPRESSION NINETEEN-E WILL  
CAUSE HEAVY RAIN IN THE SOUTHWEST AND SOUTHERN PLAINS...  
 
...MUCH ABOVE NORMAL TEMPERATURES FOR THE MIDDLE MISSISSIPPI  
VALLEY EASTWARD...  
 
AN UPPER-LEVEL TROUGH IS FORECAST TO MOVE THROUGH THE NORTHERN  
U.S. THROUGH THE END OF THE WORKWEEK. AT THE SURFACE, A FRONT  
STRETCHED ACROSS THE INTERMOUNTAIN WEST, CENTRAL PLAINS, AND  
MIDDLE MISSISSIPPI TO OHIO VALLEY WILL MOVE MINIMALLY THROUGH  
THURSDAY, BUT FINALLY MOVE MORE ON FRIDAY AS A SURFACE LOW  
STRENGTHENS AND MOVES THROUGH THE CENTRAL PLAINS, UPPER MIDWEST,  
AND INTO ONTARIO, CANADA. THE UPPER-LEVEL TROUGH TO THE WEST AND  
THE FRONT WILL BOTH SUPPORT RAIN AND STORMS FORMING ACROSS THE  
NORTHERN GREAT BASIN TO THE NORTHERN AND CENTRAL PLAINS AND INTO  
THE UPPER MIDWEST. THE HEAVIEST RAIN WILL BE ACROSS PARTS OF THE  
NORTHERN PLAINS TO UPPER MIDWEST. THROUGH TONIGHT, THERE IS A  
MODERATE RISK OF EXCESSIVE RAINFALL/FLASH FLOODING IN THOSE AREAS,  
WITH A SLIGHT RISK FOR PARTS OF THE UPPER MIDWEST TOMORROW. FLASH  
FLOOD WATCHES ARE IN EFFECT. ADDITIONALLY, THE STORM PREDICTION  
CENTER HAS OUTLOOKED AN ENHANCED RISK OF SEVERE WEATHER FOR  
PORTIONS OF THE UPPER MIDWEST TOMORROW.  
 
TROPICAL DEPRESSION NINETEEN-E HAS FORMED IN THE GULF OF  
CALIFORNIA, AND EXPECTED TO MOVE INTO NORTHWESTERN MEXICO  
WEDNESDAY EVENING. THE MOISTURE PLUME FROM THIS SYSTEM WILL LEAD  
TO HEAVY RAIN ACROSS THE SOUTHWEST, PARTICULARLY THROUGH WEDNESDAY  
NIGHT BUT INTO THURSDAY AS WELL. A MODERATE RISK OF EXCESSIVE  
RAINFALL IS IN PLACE THROUGH WEDNESDAY NIGHT, AND FLASH FLOOD  
WATCHES ARE IN EFFECT. A COLD FRONT DEVELOPING FROM THE  
STRENGTHENING LOW ACROSS THE PLAINS, PLUS THE VERY MOIST AIR  
CONTINUING TO STREAM IN, WILL LEAD TO RAIN AND THUNDERSTORMS FOR  
THE SOUTHERN PLAINS BY THURSDAY NIGHT.  
 
TEMPERATURE-WISE, THE AFOREMENTIONED FRONT WILL DELINEATE WHERE  
ABOVE AND BELOW AVERAGE TEMPERATURES WILL OCCUR. THE MIDDLE  
MISSISSIPPI TO OHIO VALLEYS AND SOUTHWARD WILL SEE HIGH  
TEMPERATURES IN THE 90S ON THURSDAY, AROUND 10 TO 15 DEGREES ABOVE  
NORMAL FOR THIS TIME OF YEAR. WARM TEMPERATURES ARE EXPECTED TO  
SPREAD INTO THE EASTERN U.S. ON FRIDAY. ON THE OTHER SIDE OF THE  
FRONT, TEMPERATURES ARE FORECAST TO BE 10 TO 20 DEGREES COLDER  
THAN NORMAL ACROSS THE NORTHERN HIGH PLAINS ON THURSDAY. THESE  
COLDER TEMPERATURES WILL EVEN SUPPORT SOME SNOW FALLING IN THE  
HIGHER ELEVATIONS OF THE ROCKIES.  
 
TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page