485  
FXUS02 KWBC 130654  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
254 AM EDT FRI OCT 13 2017  
 
VALID 12Z MON OCT 16 2017 - 12Z FRI OCT 20 2017  
 
...GUIDANCE EVALUATION/PREFERENCES AND WEATHER  
HIGHLIGHTS/THREATS...  
 
IT REMAINS THE CASE THAT A PROGRESSIVE/WAVY FLOW PATTERN INTO  
EARLY NEXT WEEK TRANSITIONS TO ONE WITH INCREASED WRN US TROUGHING  
AND BUILDING HEIGHTS OVER THE ERN STATES. A COLD FRONT MOVING OFF  
THE EAST COAST MON WILL CONTINUE TO USHER IN COOLED FALL  
TEMPERATURES TO THE ERN HALF OF THE LOWER 48 AND PUSH ASSOCIATED  
RAIN CHANCES OFF THE COAST AND INTO FL.  
UPSTREAM IN THE NORTHWEST...AN UPPER LOW SETTLING INTO ALASKA WILL  
SLOWLY PUSH THE STORM TRACK SOUTHWARD INTO BRITISH COLUMBIA EARLY  
IN THE WEEK...THEN INTO WA/OR THEN CA AND THE INTERIOR WEST INTO  
THU/FRI. THIS WOULD START A RATHER STORMY PERIOD FOR THE NWRN US  
LATER NEXT WEEK. A SERIES OF SHORTWAVES DIGGING INTO THE ENERGETIC  
AND AMPLIFYING MID-UPPER LEVEL WRN US TROUGH ARE EXPECTED TO TAP  
AVAILABLE MOISTURE TO PRODUCE WIDESPREAD SWATHS WITH SOME MODERATE  
TO TERRAIN ENHANCED PCPN FROM THE PAC NW TO THE NRN ROCKIES. THIS  
WILL INCLUDE A THREAT FOR SOME HEAVY MOUNTAIN SNOWS. PLEASE SEE  
WPC WINTER WEATHER OUTLOOK PROBABILITIES FOR DETAILS.  
OTHERWISE...THE REST OF THE COUNTRY LATER NEXT WEEK WILL SEE  
MAINLY DRY CONDITIONS AND NEAR TO ABOVE AVERAGE TEMPERATURES.  
 
LATEST MODELS AND ENSEMBLES CONTINUE TO CONVERGE UPON A MORE WELL  
CLUSTERED LARGER SCALE FLOW EVOLUTION WITH THE MAIN DIFFERENCE  
RELATED TO LESS PREDICTABLE TIMING/STRENGTH OF EMBEDDED  
SHORTWAVES. A COMPOSITE SOLUTION DERIVED FROM A BLEND OF THE  
LATEST GFS/ECMWF AND GEFS/ECMWF ENSEMBLES SEEMS A REASONABLE WAY  
TO MITIGATE ERROR AS MUCH OF FEASIBLE.  
 
SCHICHTEL  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page