970  
FXUS01 KWBC 090756  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
256 AM EST SAT DEC 09 2017  
 
VALID 12Z SAT DEC 09 2017 - 12Z MON DEC 11 2017  
 
...ACCUMULATING SNOW WILL END ACROSS THE SOUTHEAST WHILE  
INCREASING ACROSS THE MID-ATLANTIC AND NORTHEAST...  
 
...LOCALLY HEAVY LAKE EFFECT SNOWFALL TO CONTINUE DOWNWIND OF THE  
GREAT LAKES...  
   
..CRITICAL FIRE WEATHER PERSISTING ACROSS SOUTHERN CALIFORNIA
 
 
A FRONTAL BOUNDARY IS CURRENTLY OFF THE EAST COAST AND MOVING  
SOUTHWARD ACROSS FLORIDA. HEAVY RAINFALL WILL CONTINUE SOUTHWARD  
TODAY ALONG THE COLD FRONT INTO SOUTH FLORIDA. IN ADDITION, THERE  
IS A MARGINAL RISK OF SEVERE WEATHER FOR SOUTH FLORIDA TODAY--WITH  
THE BIGGEST THREAT BEING STRONG WIND GUSTS FROM THUNDERSTORMS. SEE  
THE STORM PREDICTION CENTER FOR MORE INFORMATION. MEANWHILE, SNOW  
WILL BEGIN TO TAPER OFF ACROSS THE SOUTHEAST AND THE CAROLINAS BY  
THIS MORNING. THE PRIMARY SURFACE LOW WILL TAKE SHAPE BY THIS  
AFTERNOON AND LIFT NORTHWARD OFF THE MID-ATLANTIC COAST. THIS WILL  
BRING PRECIPITATION--IN THE FORM OF SNOW--NORTHWARD INTO THE  
MID-ATLANTIC AND COASTAL NORTHEAST/NEW ENGLAND THIS AFTERNOON. AS  
THE LOW STRENGTHENS AND LIFTS NORTHWARD TOWARD THE CANADIAN  
MARITIMES BY SATURDAY NIGHT, SNOW WILL QUICKLY TAPER OFF THE  
MID-ATLANTIC WHILE INCREASING ACROSS MOST OF THE NORTHEAST. AS THE  
LOW MOVES FARTHER NORTH, SNOW WILL TAPER OFF--AND WILL END BY  
SUNDAY EVENING.  
 
A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE OVER THE UPPER  
MIDWEST AND GREAT LAKES OVER THE NEXT FEW DAYS. REINFORCING SHOTS  
OF COLD AIR OVER THE GREAT LAKES WILL GIVE WAY TO MODERATE TO  
LOCALLY HEAVY SNOWFALL DOWNWIND OF THE LAKES. ON SATURDAY, THE  
HEAVIEST SNOWFALL IS EXPECTED TO OCCUR ALONG THE UP OF MICHIGAN  
AND THE EASTERN SHORE OF LAKE MICHIGAN AS ONE DISTURBANCE MOVES  
OVER THE REGION. THE LAKE EFFECT SNOW ACTIVITY WILL SHIFT TO THE  
LOWER GREAT LAKES ON SUNDAY. BY MONDAY MORNING, ANOTHER  
DISTURBANCE WILL SLIDE SOUTHWARD OVER THE UPPER MIDWEST. WITH  
COLD CONDITIONS IN PLACE, THE PRECIPITATION EXPECTED WITH THIS  
SYSTEM WILL BE SNOW.  
 
AN UPPER RIDGE CONTINUES TO BE CENTERED OVER THE WEST--KEEPING IN  
PLACE THE WARM AND DRY AIRMASS THAT HAS PLAGUED SOUTHERN  
CALIFORNIA IN ADDITION TO STRONG SANTA ANA WINDS GUSTING OVER THE  
REGION. THIS, COMBINED WITH VERY LOW RELATIVE HUMIDITY, IS  
CREATING VERY DANGEROUS FIRE WEATHER CONDITIONS WHICH WILL  
CONTINUE AT LEAST THROUGH THE NEXT FEW DAYS. MOREOVER, AN  
INVERSION WILL KEEP SMOKE TRAPPED ACROSS THE REGION--LEADING TO  
POOR AIR QUALITY. PLEASE CHECK WITH THE LOCAL FORECAST OFFICE FOR  
MORE INFORMATION ON THE WARNINGS AND ADVISORIES ASSOCIATED WITH  
THIS EVENT.  
 
REINHART  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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