555  
FXUS01 KWBC 112000  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EST SAT NOV 11 2017  
 
VALID 00Z SUN NOV 12 2017 - 00Z TUE NOV 14 2017  
   
..HEAVY RAIN POSSIBLE FOR PARTS OF THE PACIFIC NORTHWEST
 
 
WEST TO EAST UPPER-LEVEL FLOW WITH LOW AMPLITUDE TO UPPER-LEVEL  
IMPULSES IS CONTRIBUTING TO DIFFICULTY IN MAINTAINING COHERENT  
SURFACE FEATURES. ONE UPPER-LEVEL FEATURE OVER THE NORTHERN  
PLAINS WILL MOVE EASTWARD TO THE MID-ATLANTIC/CENTRAL APPALACHIANS  
BY MONDAY. THE SYSTEM PRODUCES RAIN OVER PARTS OF THE CENTRAL  
PLAINS/MIDDLE MISSISSIPPI VALLEY THAT WILL MOVE EASTWARD TO THE  
MID-ATLANTIC/LOWER GREAT LAKES/CENTRAL APPALACHIANS BY MONDAY,  
TOO. A SECOND FEATURE OVER THE UPPER GREAT LAKES WILL MOVE  
EASTWARD TO NORTHERN MAINE BY SUNDAY EVENING. THE ENERGY WILL  
PRODUCE LIGHT SNOW OVER PARTS OF THE UPPER GREAT LAKES THROUGH TO  
SUNDAY AFTERNOON.  
 
MEANWHILE, MOISTURE FROM THE GULF OF MEXICO WILL FLOW NORTHWARD  
OVER  
 
THE COLDEST WEATHER OF THE SEASON IS MAKING ITS PRESENCE KNOWN  
ACROSS MUCH OF THE EASTERN U.S. AFTER THE PASSAGE OF AN ARCTIC  
FRONT EARLIER ON FRIDAY. HIGH TEMPERATURES 15 TO 25 DEGREES BELOW  
AVERAGE BY EARLY NOVEMBER STANDARDS ARE MAKING IT FEEL MORE LIKE  
JANUARY, AND NUMEROUS FREEZE WARNINGS ARE IN EFFECT FROM SOUTH  
CAROLINA TO LONG ISLAND, NEW YORK, FOR OVERNIGHT LOWS IN THE 20S  
TO LOW 30S. RECORD LOWS WILL BE POSSIBLE ACROSS PARTS OF THE OHIO  
VALLEY, GREAT LAKES, NORTHERN MID ATLANTIC, AND NORTHEAST  
INCLUDING MANY OF THE MAJOR CITIES IN THE REGION ON SATURDAY  
MORNING AND AGAIN ON SUNDAY MORNING ACROSS THE NORTHEAST.  
 
ACROSS THE WEST, A FRONT APPROACHING THE REGION FROM THE PACIFIC  
WILL BRING A PERIOD OF WIDESPREAD RAIN TO WESTERN WASHINGTON,  
OREGON, AND ALSO NORTHERN CALIFORNIA, AND SNOW FOR THE HIGHEST  
ELEVATIONS. THE SOUTHWESTERN U.S. WILL BE UNDER THE INFLUENCE OF  
A STRONG UPPER LEVEL RIDGE PROVIDING WARM AND DRY WEATHER THROUGH  
THE WEEKEND. SCATTERED SHOWERS ARE POSSIBLE ALONG THE EAST COAST  
OF FLORIDA WITH MOIST EASTERLY FLOW BEHIND THE COLD FRONT. GIVEN  
THE LACK OF INSTABILITY AND DEEP MOISTURE, LITTLE IN THE WAY OF  
THUNDERSTORM ACTIVITY IS EXPECTED NATIONWIDE.  
 
KREKELER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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