876  
FXUS01 KWBC 291939  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
238 PM EST TUE JAN 29 2019  
 
VALID 00Z WED JAN 30 2019 - 00Z FRI FEB 01 2019  
 
...ARCTIC AIR PLUNGING SOUTH FROM CANADA WILL DRIVE TEMPERATURES  
DOWN TO AS MUCH AS 30 TO 40 DEGREES BELOW NORMAL OVER THE MIDWEST  
AND OHIO VALLEY BY WEDNESDAY...  
 
...DANGEROUS WIND CHILL VALUES OF AS LOW AS 40 TO 60 DEGREES BELOW  
ZERO ARE EXPECTED OVER PORTIONS OF THE NORTHERN PLAINS, MIDWEST  
AND OHIO VALLEY TONIGHT AND WEDNESDAY...  
 
...VERY HEAVY LAKE-EFFECT SNOW WILL OCCUR DOWNWIND OF THE GREAT  
LAKES...  
 
LOW PRESSURE WILL GRADUALLY PIVOT NORTH ACROSS SOUTHERN ONTARIO  
TONIGHT BEFORE THEN LIFTING INTO WESTERN QUEBEC BY WEDNESDAY  
EVENING. MEANWHILE, LOW PRESSURE DEVELOPING OVER THE CENTRAL  
MID-ATLANTIC REGION THIS EVENING WILL LIFT NORTHEAST ALONG OR JUST  
INLAND OF THE NEW ENGLAND COAST THROUGH WEDNESDAY MORNING. THIS  
REDEVELOPING WAVE WILL BRING A SWATH OF ACCUMULATING SNOW TO THE  
INTERIOR AREAS OF THE NORTHEAST WHERE AS MUCH AS 6 TO 12 INCHES OF  
SNOW CAN BE EXPECTED BEFORE THE LOW CENTER PULLS AWAY INTO  
SOUTHEAST CANADA BY WEDNESDAY NIGHT.  
 
THE STORY IN BEHIND THE DEPARTING LOW PRESSURE OVER NEW ENGLAND  
WILL BE THE ADVANCE OF EXTREMELY COLD AIR COMING DOWN THROUGH THE  
MIDWEST AND THROUGH THE OHIO VALLEY AS AN ARCTIC COLD FRONT  
CROSSES THE REGION. ARCTIC AIR ASSOCIATED WITH A STRONG AREA OF  
HIGH PRESSURE DROPPING SOUTH FROM CANADA WILL ALLOW HIGH  
TEMPERATURES ACROSS THESE AREAS TO BE AS MUCH AS 30 TO 40 DEGREES  
BELOW NORMAL ON WEDNESDAY. THIS COUPLED WITH LOCALLY STRONG WINDS  
WILL RESULT IN WIND CHILL VALUES OF AS MUCH AS 40 TO 60 DEGREES  
BELOW ZERO. THIS BITTERLY COLD AIRMASS WILL MODIFY A BIT AS IT  
ARRIVES ACROSS THE MID-ATLANTIC AND NORTHEAST THROUGH WEDNESDAY  
NIGHT AND THURSDAY, BUT TEMPERATURES WILL BE CONSIDERABLY BELOW  
NORMAL AND WITH DANGEROUSLY COLD WIND CHILLS EXPECTED. WIND CHILL  
ADVISORIES AND WARNINGS ARE IN EFFECT ACROSS A LARGE AREA OF THE  
NORTHERN PLAINS, MIDWEST, OHIO VALLEY AND PARTS OF THE NORTHERN  
MID-ATLANTIC TO ADDRESS THE EXTREMELY LOW WIND CHILLS THAT ARE  
ANTICIPATED.  
 
MEANWHILE, THE FETCH OF DEEP LAYER ARCTIC AIR OVER THE GREAT LAKES  
REGION AROUND THE SOUTH SIDE OF THE AFOREMENTIONED LOW CENTERS  
PULLING AWAY THROUGH SOUTHEAST CANADA WILL SET THE STAGE FOR  
SIGNIFICANT LAKE-EFFECT SNOWFALL OVER THE NEXT COUPLE OF DAYS.  
SNOWFALL AMOUNTS LOCALLY IN EXCESS OF 1 FOOT CAN BE EXPECTED  
DOWNWIND OF LAKE SUPERIOR AND LAKE MICHIGAN INVOLVING AREAS OF THE  
UPPER PENINSULA OF MICHIGAN AND WESTERN LOWER MICHIGAN  
RESPECTIVELY THROUGH THURSDAY. HOWEVER, EVEN HEAVIER SNOW WILL BE  
POSSIBLE DOWNWIND OF LAKE ERIE AND LAKE ONTARIO WHERE A SOMEWHAT  
MORE FAVORABLE LOW LEVEL FETCH OF WIND WILL SUPPORT SOME AREAS  
SEEING IN EXCESS OF 2 FEET OF SNOW. THIS WILL INCLUDE AREAS OF  
WESTERN NEW YORK, AND ESPECIALLY AREAS NEAR AND JUST SOUTH OF  
BUFFALO, NY RELATIVE TO LAKE ERIE, BUT ALSO THE TUG HILL PLATEAU  
REGION DOWNWIND OF LAKE ONTARIO. A LARGE AREA OF WINTER STORM  
WARNINGS ARE IN EFFECT FOR THESE AREAS.  
 
ELSEWHERE, THE WESTERN U.S. WILL SEE CONSIDERABLY MILDER  
TEMPERATURES BY COMPARISON AND GENERALLY DRY WEATHER. ONE  
EXCEPTION WILL BE CALIFORNIA AS A STORM SYSTEM OFFSHORE MOVES EAST  
AND BRINGS RAIN INLAND BY THURSDAY ACROSS CENTRAL AND SOUTHERN  
CALIFORNIA WITH AN EMPHASIS ON THE COASTAL RANGES. RAINFALL  
AMOUNTS ARE NOT EXPECTED TO BE TOO HEAVY, BUT LOCALLY OVER 1 INCH  
OF NEW RAIN IS EXPECTED THROUGH THURSDAY WITH THE HEAVIEST AMOUNTS  
LIKELY FOCUSING ON THE TRANSVERSE RANGES OF SOUTHERN CALIFORNIA.  
TEMPERATURES ASSOCIATED WITH THE RAIN IN CALIFORNIA WILL BE A  
LITTLE BELOW NORMAL, BUT SHOULD BE NORMAL TO SOMEWHAT ABOVE NORMAL  
ACROSS THE REMAINDER OF THE WEST.  
 
ORRISON  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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