171  
FXUS01 KWBC 150811  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
309 AM EST THU NOV 15 2018  
 
VALID 12Z THU NOV 15 2018 - 12Z SAT NOV 17 2018  
 
...ONGOING WINTER STORM WILL IMPACT THE OHIO VALLEY, APPALACHIANS,  
AND MID-ATLANTIC TODAY AND THE NORTHEAST TONIGHT...  
 
...ANOTHER AREA OF SNOW WILL OVERSPREAD THE NORTHERN ROCKIES AND  
NORTHERN PLAINS ON THURSDAY NIGHT INTO FRIDAY...  
 
A SIGNIFICANT WINTER STORM IS DEVELOPING ACROSS PARTS OF THE  
CENTRAL AND EASTERN U.S. A STRONG UPPER-LEVEL LOW WILL MOVE  
THROUGH THE OHIO VALLEY TODAY, CAUSING THE AREA OF SNOW AND  
FREEZING RAIN THERE TO PERSIST AND MOVE NORTHEASTWARD. PARTS OF  
THE OHIO VALLEY ARE FORECAST TO RECEIVE A FEW ADDITIONAL INCHES OF  
SNOW AND A GLAZE OF FREEZING RAIN. ADDITIONALLY, A SURFACE LOW  
PRESSURE SYSTEM WILL STRENGTHEN OVER THE SOUTHEAST COAST AND MOVE  
NORTHWARD ALONG THE EASTERN SEABOARD ON THURSDAY AND FRIDAY. ON  
THE BACKSIDE OF THIS SURFACE LOW TO THE NORTH AND WEST, MORE  
WINTRY WEATHER IS EXPECTED TODAY. FREEZING RAIN WILL BE THE MAIN  
THREAT ACROSS THE SOUTHERN AND CENTRAL APPALACHIANS AS WARM AND  
MOIST AIR OVERRUNS THE COLD AIR IN PLACE AT THE GROUND. ICE  
ACCUMULATIONS COULD BE OVER A QUARTER OF AN INCH THERE. TONIGHT,  
THE UPPER-LEVEL AND SURFACE LOWS WILL WORK MORE IN CONJUNCTION  
WITH EACH OTHER TO CREATE HEAVY SNOWFALL IN THE NORTHERN  
MID-ATLANTIC AND INTO THE INTERIOR NORTHEAST. SNOW OF OVER A FOOT  
IS POSSIBLE IN PORTIONS OF INTERIOR PENNSYLVANIA AND NEW YORK.  
WIDESPREAD WINTER STORM AND ICE STORM WARNINGS AS WELL AS WINTER  
WEATHER ADVISORIES ARE IN EFFECT, WITH WINTER STORM WATCHES IN  
PLACE IN THE NORTHEAST. THE HEAVIEST OF THIS WINTRY PRECIPITATION  
WILL REMAIN WEST OF THE MAJOR CITIES OF D.C. TO NEW YORK CITY, BUT  
A WINTRY MIX IS POSSIBLE AT THE ONSET OF THIS EVENT ON THURSDAY  
AND COULD CAUSE TRAVEL ISSUES BEFORE TRANSITIONING TO RAIN.  
 
PRECIPITATION DUE TO THIS LOW IS EXPECTED TO STAY ALL RAIN IN THE  
SOUTHEAST AND FROM THE PIEDMONT EASTWARD IN THE CAROLINAS, AS WELL  
AS ALONG THE COASTAL MID-ATLANTIC. LOCALLY HEAVY RAINFALL IS  
POSSIBLE TODAY IN THOSE AREAS, AND A MARGINAL RISK OF EXCESSIVE  
RAINFALL/FLASH FLOODING IS IN PLACE.  
 
A SERIES OF COLD FRONTS DROPPING SOUTHWARD FROM CANADA WILL LEAD  
TO SNOW ACROSS THE NORTHERN TIER OF THE COUNTRY AS WELL. LIGHT  
SNOW IS POSSIBLE IN THE UPPER MIDWEST TODAY AS A SURFACE LOW  
PRESSURE SYSTEM MOVES THROUGH. BY THURSDAY NIGHT, A FRONT WILL  
APPROACH THE NORTHERN ROCKIES INTO NORTHERN PLAINS, AND SNOW WILL  
OVERSPREAD THOSE AREAS. SNOW IS FORECAST TO MOVE SOUTHWARD WITH  
THE COLD FRONT INTO THE CENTRAL ROCKIES AND CENTRAL PLAINS AND  
INTO THE MIDDLE MISSISSIPPI VALLEY BY FRIDAY EVENING. ALTOGETHER,  
THE NORTHERN AND CENTRAL ROCKIES COULD SEE 6 TO 10 INCHES OF SNOW  
IN HIGHER ELEVATIONS, AND A SWATH OF 2 TO 4 INCHES OF SNOW IS  
EXPECTED FROM THE NORTHERN PLAINS INTO PARTS OF THE UPPER AND  
MIDDLE MISSISSIPPI VALLEY BY SATURDAY MORNING.  
 
ONE MORE DAY OF FIRE WEATHER CONCERNS WILL OCCUR THURSDAY IN  
SOUTHERN CALIFORNIA. THE STORM PREDICTION CENTER HAS AN ELEVATED  
RISK DELINEATED IN THEIR FIRE WEATHER OUTLOOK, WITH SOME BRIEF  
HIGH WINDS, LOW RELATIVE HUMIDITIES, AND ONGOING DROUGHT.  
CONDITIONS WILL FINALLY BECOME LESS FAVORABLE FOR FIRES IN  
CALIFORNIA BY FRIDAY.  
 
TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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