035  
FXUS02 KWBC 231600  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1159 AM EDT THU MAR 23 2017  
 
VALID 12Z SUN MAR 26 2017 - 12Z THU MAR 30 2017  
   
..OVERVIEW/GUIDANCE EVALUATION/PREFERENCES
 
 
A RATHER ACTIVE MEDIUM RANGE PERIOD PERIOD COMING UP FOR THE  
LATTER PART OF THE WEEKEND INTO NEXT MID WEEK... AS PATTERN  
ADJUSTS TO SPRING. A SERIES OF SPLIT FLOW PAC STORM SYSTEMS WILL  
MOVE INTO THE WEST COAST BEFORE THE SOUTHERN STREAM INTENSIFIES  
AND TAKES CONTROL. THUS A PARADE OF ACTIVE SYSTEMS WILL MOVE FROM  
THE DESERT SW... EJECT INTO THE PLAINS/MS VALLEY AND EVENTUALLY  
REACH THE EAST. THIS COULD SPELL SEVERAL DAYS FOR SEVERE WEATHER  
AND POSSIBLE EXCESSIVE RAINS.  
 
THE FIRST SUCH ACTIVE UPPER JET AND SHORT WAVE TROUGH IS ALREADY  
ADVANCING THROUGH THE FOUR CORNERS REGION TODAY. THIS SYSTEM IS  
PROGGED BY THE GUIDANCE TO BE LOCATED OVER THE MID MS/WESTERN OH  
VALLEYS. THE MODELS HANDLE THIS FEATURE REASONABLY WELL... AS IT  
SLOWLY PRESSES DOWNSTREAM... WEAKENS AND RUNS INTO A RATHER  
FORMIDABLE UPPER RIDGE. THE ADVANCEMENT OF THIS FEATURE INITIALLY  
IS FROM A KICKER SYSTEM UPSTREAM WHICH ON SUN WILL BE OVER THE  
FOUR CORNERS REGION AND EJECTING OUT INTO THE CENTRAL/SRN PLAINS.  
THIS SYSTEM WILL TAKE A SIMILAR STORM PATH FROM THE PLAINS INTO  
THE MID MS VALLEY AND OH VALLEY BEFORE MESHING OR PARTIALLY  
INTERACTING WITH AN ACTIVE NORTHERN STREAM SYSTEM ON TUES. THE  
RESULTING SYSTEM WILL THEN MOVE THROUGH THE EAST TUES/WED. ALSO  
LATE SUN INTO MON... THE NEXT PAC/MARITIME UPPER TROUGH WILL MOVE  
INTO THE WEST COAST. ONCE AGAIN... DIGGING SRN BRANCH WILL DRIVE A  
POTENT SYSTEM THROUGH THE DESERT SW AND FOUR CORNERS REGION INTO  
THE CENTRAL/SRN PLAINS... THOUGH A FAIR AMOUNT OF SPREAD SURROUNDS  
THE PROGRESSION OF THIS FEATURE.  
 
OVERALL WPC PREFERRED TO FOLLOW A MAJORITY BLEND OF THE  
OPERATIONAL 00Z/06Z GFS AND 00Z ECMWF/UKMET WITH SMALL PERCENTAGES  
OF THE GEFS/EC/NAEFS MEAN THROUGH TUES... THOUGH MEANS INCREASING  
EACH DAY. THEN GIVEN THE LARGE PROGRESSION SPREAD... EC FAST AND  
GFS SLOW... ON THE SYSTEM KICKING OUT INTO THE PLAINS/MS VALLEY ON  
WED AND THURS... WHILE NEXT PAC SYSTEM MOVES INTO WEST COAST AND  
DIGS INTO THE DESERT SW. WPC HERE PREFERRED A MAJORITY BLEND OF  
THE GEFS/EC/NAEFS MEANS WITH VERY SMALL PERCENTAGES OF THE  
OPERATIONAL GFS/ECMWF.  
   
..SENSIBLE WEATHER/HIGHLIGHTS
 
 
CONCERNING THE SYSTEM STARTING OVER THE MID MS VALLEY AND OH/TN  
VALLEYS... EXPECT SCATTERED SHOWERS/STORMS FROM THE OH/TN VALLEYS  
AND APPALACHIANS INTO THE MID-ATL AND NORTHEAST ON SUN AND MON...  
WITH A LOCALIZED MAX FOR QPF OF WARM SECTOR AND OVERRUNNING INTO  
COLD SECTOR FROM THE EASTERN OH VALLEY INTO PA TO THE  
NORTHEAST/SRN NEW ENGLAND COAST COAST... WHILE VERY NRN EDGE OF  
THIS SYSTEM COULD DELIVER MORE WINTER WEATHER FOR NRN NEW ENGLAND  
AND MAINE.  
 
FOR THE STORM SYSTEM EMERGING FROM THE CENTRAL/SRN ROCKIES INTO  
THE PLAINS ON SUN AND PROCEEDING THROUGH THE MIDWEST AND EAST SUN  
THROUGH WED. EXPECT SCATTERED SHOWERS/STORMS FROM IA/KS/MO SOUTH  
AND WEST INTO TX WITH SOME SEVERE AND LOCALLY HEAVY RAINS ON SUN.  
PRECIPITATION CHANCES INCREASING ON MON WITH SHOWERS/STORMS  
EXTENDING FROM WESTERN GREAT LAKES/OH VALLEY AND MID MS VALLEY TO  
THE SOUTH/CENTRAL GULF COAST REGION... SEVERE THREAT FROM SR/LA  
EAST TO SRN APPALACHIANS WITH LOCALLY HEAVY RAIN AND A  
LOCAL/ISOLATED THREAT FROM MO/IA INTO IL AND OH VALLEY FOR  
SEVERE/HEAVY RAIN. THEN TUES AND WED... A POSSIBLE THREAT  
ORGANIZED PRECIP FROM THE MID-ATL REGION TO THE NERN QUAD OF THE  
COUNTRY BUT THIS REMAINS HIGHLY UNCERTAIN.  
 
THE SYSTEM ARRIVING INTO THE WEST COAST LATE SUN INTO MON...  
EXPECT LOCALLY HEAVY RAINS FROM THE PAC NW TO NRN CA AND PERHAPS  
CENTRAL CA WITH MTN SNOW. WIDESPREAD PRECIP ON MON ACROSS MUCH OF  
THE WEST... ESPECIALLY INVOF NV/UT INTO AZ... AND MOISTURE  
CONTINUING ACROSS THE FOUR CORNERS REGION ON TUES WITH POSSIBLE  
DRY LINE CONVECTION/HEAVY RAINS ERN CO/NM INTO OK/TX PANHANDLES.  
THEN ON WED AND THURS... POSSIBLE WIDESPREAD CONVECTION AND HEAVY  
RAINS FROM THE CENTRAL/SRN PLAINS AND ADVANCING DOWNSTREAM BUT DUE  
TO SPREAD TO DETERMINE HOW FAR DOWNSTREAM... WHILE MOISTURE  
RETURNS UPSTREAM ACROSS THE PAC NW INTO THE INTER-MOUNTAIN WEST  
THESE DAYS.  
 
OVERALL 5 DAY MEAN MAX TEMP ANOMALIES SUGGEST NEAR AVG TO SLIGHTLY  
BELOW AVG ACROSS THE PAC NW/INTERIOR NW INTO CA AND FOR THE  
NORTHEAST DUE TO THE BACK DOOR COLD FRONT. FOR THE REST OF THE  
COUNTRY FROM THE FRONT RANGE OF THE ROCKIES TO THE EASTERN  
SEABOARD MINUS NEW ENGLAND COULD BE AS MUCH AS 5 TO 15 DEG ABOVE  
AVG.  
 
MUSHER  
 

 
 
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