761  
FXUS02 KWBC 271538  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1038 AM EST TUE FEB 27 2018  
 
VALID 12Z FRI MAR 02 2018 - 12Z TUE MAR 06 2018  
 
...SIGNIFICANT WESTERN STORM LATE THIS WEEK THROUGH THE WEEKEND  
WILL MOVE INTO THE HIGH PLAINS NEXT WEEK...  
 
   
..PATTERN OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
AN UPPER LOW WILL SWING THROUGH THE WESTERN CONUS FRI/SAT/SUN  
WHILE ANOTHER SYSTEM OFF THE EAST COAST SLOWLY MOVES OUT TO SEA.  
IN BETWEEN THE TWO, UPPER RIDGING WILL SLIDE EASTWARD OUT OF THE  
PLAINS INTO THE MIDWEST AND THE THE NORTHEAST BY NEXT WEEK.  
SIGNIFICANT SNOW IS LIKELY FOR THE SIERRAS EASTWARD THROUGH  
NEVADA/UTAH AND WESTERN WYOMING. AS THE SYSTEM MOVES  
NORTHEASTWARD, SNOW WILL SPREAD OUT OVER THE HIGH PLAINS INTO THE  
UPPER MIDWEST WITH WIND-DRIVEN SNOW AND HAZARDOUS CONDITIONS  
POSSIBLE EARLY NEXT WEEK. RAIN AND CONVECTION WILL EXPAND OVER THE  
LOWER MISSISSIPPI VALLEY NEXT WEEK AS THE COLD FRONT MOVES  
EASTWARD THROUGH TEXAS. LATEST GFS/ECMWF SOLUTIONS WERE VIABLE  
OPTIONS THROUGH THE PERIOD WITH SOME DIFFERENCES IN  
TIMING/LOCATION OF THE SYSTEM AS IT EXITS THE ROCKIES. A BLEND  
WITH THEIR ENSEMBLE MEANS OFFERED A GOOD MIDDLE GROUND POSITION  
INTO NEXT WEEK AS THE SFC LOW LIFTS THROUGH MINNESOTA.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
IN THE EAST, A POTENT COASTAL STORM WILL PULL AWAY FROM THE  
NORTHEASTERN US FRIDAY WITH SOME ENHANCED WRAPAROUND PRECIP ACROSS  
THE NORTHERN MID-ATLANTIC INTO THE NORTHEAST/NEW ENGLAND. SOME  
SNOW IS POSSIBLE IN ESPECIALLY HIGHER ELEVATIONS ON THE NORTHERN  
SIDE OF THE PRECIPITATION SHIELD. STRONG WINDS AND COASTAL  
FLOODING (ALONG WITH HIGH SEAS) ARE PROBABLE WITH THIS SYSTEM --  
PLEASE CONSULT THE LATEST GUIDANCE FROM THE OCEAN PREDICTION  
CENTER FOR COASTAL/MARITIME EFFECTS.  
 
IN THE WEST, UPPER LOW AND SURFACE FRONT WILL BRING IN COLDER  
TEMPERATURES, WINDY CONDITIONS, AND MODEST TO LOCALLY HEAVY  
RAIN/SNOW TO AREAS NORTH OF ABOUT 35N (SOUTHERN  
CALIFORNIA/NORTHERN ARIZONA). SNOW LEVELS WILL LOWER AS THE UPPER  
TROUGH SWINGS THROUGH. TEMPERATURES WILL BE WELL BELOW AVERAGE (BY  
ABOUT 10-25 DEGREES) AND SOME RECORD LOWS WILL BE POSSIBLE (BOTH  
LOW MAXIMA AND LOW MINIMA). CONVERSELY, AHEAD OF THE FRONT,  
TEMPERATURES WILL WARM ABOVE AVERAGE BY ABOUT 10-20 DEGREES EAST  
OF THE ROCKIES THROUGH THE PLAINS FRI/SAT/SUN. PRECIPITATION  
INCREASINGLY DEVELOPS FOR THE CENTRAL TO EAST-CENTRAL US AHEAD OF  
THE UPPER TROUGH AND SFC FRONT NEXT WEEK AS GULF MOISTURE  
INCREASES OVER THE LOWER MS/TN VALLEYS AND CENTRAL GULF COAST  
STATES. TO THE NORTH, POTENTIAL EXISTS FOR A HAZARDOUS SNOWSTORM  
IN THE COLDER AIR NORTH OF THE LOW WITH WINDY CONDITIONS AROUND  
THE LOW CENTER FROM THE DAKOTAS INTO MINNESOTA.  
 
FRACASSO  
 

 
 
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