062  
FXUS01 KWBC 201959  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
258 PM EST TUE NOV 20 2018  
 
VALID 00Z WED NOV 21 2018 - 00Z FRI NOV 23 2018  
 
...UNSETTLED WEATHER IN THE WESTERN U.S. WITH RAIN IN LOWER  
ELEVATIONS AND SNOW IN HIGHER ELEVATIONS...  
 
...LAKE ENHANCED SNOW LIKELY ON WEDNESDAY IN THE GREAT LAKES  
REGION...  
 
...RECORD LOWS AND RECORD LOW MAXIMUM TEMPERATURES LIKELY FOR  
THANKSGIVING IN THE NORTHEAST...  
 
A SERIES OF FRONTS AND A STRENGTHENING JET STREAM WILL LEAD TO AN  
INCREASE IN PRECIPITATION CHANCES FOR THE WESTERN U.S. OVER THE  
NEXT COUPLE OF DAYS. THIS WILL BE A RELIEF TO FIRE-STRICKEN AREAS  
OF CALIFORNIA, AND HELP CLEAR OUT AIR STAGNATION ADVISORIES THAT  
ARE IN EFFECT ACROSS PARTS OF THE NORTHWEST. HOWEVER, HAZARDOUS  
CONDITIONS COULD BE CREATED AS WELL. HEAVY RAIN IS POSSIBLE IN  
LOWER ELEVATIONS IN THE WEST COAST. ON WEDNESDAY AND WEDNESDAY  
NIGHT, THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL IN PARTS OF  
CALIFORNIA, WITH EMBEDDED SLIGHT RISKS WHERE THE RECENT FIRES HAVE  
CREATED BURN SCARS, WHICH CAN FLASH FLOOD QUICKLY AS WATER RUNS  
OFF. IN HIGHER ELEVATIONS, SNOW IS EXPECTED, RAMPING UP WEDNESDAY  
NIGHT AND THURSDAY. SNOW OF OVER A FOOT IS FORECAST THROUGH  
THURSDAY EVENING IN THE SIERRA NEVADA, WITH SNOW OF 6 TO 10 INCHES  
IN THE CASCADES.  
 
A SURFACE LOW PRESSURE SYSTEM WILL MOVE ACROSS THE GREAT LAKES  
REGION TUESDAY NIGHT AND INTO THE NORTHEAST ON WEDNESDAY. THE LOW  
COMBINED WITH LAKE ENHANCEMENT IS FORECAST TO PRODUCE SNOW IN  
THOSE REGIONS. DOWNWIND OF THE UPPER AND LOWER GREAT LAKES, 4 TO 6  
INCHES OF SNOW IS EXPECTED TUESDAY NIGHT INTO WEDNESDAY, AND 1 TO  
3 INCHES IS FORECAST FOR NORTHERN NEW ENGLAND. THIS COULD CREATE  
SLICK TRAVEL CONDITIONS.  
 
A COLD SURFACE HIGH WILL BUILD INTO THE NORTHEAST AND MID-ATLANTIC  
ON THURSDAY, THANKSGIVING DAY. VERY COLD CONDITIONS ARE EXPECTED  
BECAUSE OF THIS, WITH LOW TEMPERATURES IN THE SINGLE DIGITS IN  
NORTHERN NEW ENGLAND, AND HIGH TEMPERATURES BELOW FREEZING IN THE  
NORTHEAST AND NORTHERN MID-ATLANTIC. SETTING NEW RECORD LOW  
MINIMUM AND MAXIMUM TEMPERATURES WILL BE WIDESPREAD ACROSS THOSE  
REGIONS. IN CONTRAST, THE NORTHERN AND CENTRAL PLAINS WILL BE 10  
TO 20 DEGREES ABOVE NORMAL ON WEDNESDAY AND THURSDAY.  
 
ELSEWHERE, RAIN SHOWERS ARE POSSIBLE ACROSS THE WESTERN GULF COAST  
ON WEDNESDAY AND SPREADING INTO THE CENTRAL GULF COAST ON  
THURSDAY, AS AN UPPER-LEVEL DISTURBANCE MOVES THROUGH. FLORIDA  
COULD SEE SHOWERS OVER THE NEXT COUPLE OF DAYS AS WELL. THE  
CENTRAL U.S. WILL REMAIN DRY THROUGH THANKSGIVING.  
 
TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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