Winter Storm Warning 5, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
1207 PM AKDT MON OCT 27 2008

.SHORT TERM...SATELLITE IMAGERY SHOWS THE REMNANTS OF A LOW
WEAKENING AS IT MOVES INLAND TO THE W OF PAYA. THE REMAINING
FRONTAL BAND IS SLOWLY MOVING N WITH RAIN OVER THE SOUTHERN AND
CENTRAL PANHANDLE WITH SHOWERS OVER THE NORTHERN PANHANDLE. WINDS
ARE DIMINISHING OVER MUCH OF THE REGION WITH PAGY AND PAHN
RETAINING SOME GUSTY WINDS WITH A LEE TROUGH OVER THE YUKON.
SHOULD SEE THE WINDS DIMINISH THROUGH OUT THE DAY.

 THE NEXT BIG QUESTION IS THE NEXT SHORT WAVE LOW TRAVELING UP
THE FRONTAL BAND. EARLY FORECASTS HAD THIS AS A WEAKER SYSTEM BUT
WITH SUBSEQUENT MODEL RUNS IT IS FORECASTED TO BE MUCH STRONGER.
12Z AK-GFS HAS A 990MB LOW WITH A NW TRAJECTORY COMPARED TO THE
12Z NAM12 WHICH IS WEAKER AT 999MB. 12Z UKMET IS A BIT WEAKER
THAN BOTH WITH A TRAJECTORY SIMILAR TO THE GFS. DECIDED TO GO
WITH A 50/50 BLEND OF THE 12Z AK-GFS AND 12Z NAM12, WHICH WAS
AGREED UPON BY PAFC. THIS DID MAKE SOME SIGNIFICANT CHANGES TO
THE SHORT TERM GRIDS...SPECIFICALLY THE WINDS OVER THE SOUTHER
PANHANDLE. THE LLJ TUE MORNING HAS 50 TO 60 KT WINDS WHICH BRINGS
US TO NEAR WIND ADVISORY LEVELS FOR ZONES 27 AND 28. WITH EACH
MODEL RUN TRENDING TOWARDS THIS SCENARIO FEEL A BIT MORE
CONFIDENT WITH THE INCREASED WINDS. WILL SEE RAIN SPREADING
NORTHWARD WITH THE MOVING FRONTAL BAND. WITH A STRONGER LOW
PRESSURE SOLUTION WOULD SEE WINDS FROM THE NORTH WITH COLDER
TEMPERATURES OVER THE NORTHERN PANHANDLE WHICH BRINGS SNOW TO
HIGHER ELEVATIONS AND POSSIBLE INTO PAGY AND PAHN TOWARDS THE END
OF THE SHORT TERM PERIOD.

.LONG TERM...GOOD AGREEMENT BETWEEN THE MODELS THROUGH FRIDAY
AFTERNOON. LATEST ECMWF LOOKS LIKE A COMPROMISE BETWEEN THE 12Z
GFS AND THE PREVIOUS EC MODEL RUN...WHICH GOES A LONG WAY TOWARD
REDUCING DIFFERENCES BETWEEN THEM FROM FRIDAY NIGHT ONWARD. USED
GFS FOR PRIMARY GUIDANCE THROUGH FRIDAY AND THEN ECMWF THEREAFTER.

LONG RANGE PERIOD BEGINS WITH A LOW ALONG THE CENTRAL OUTER COAST
THAT WILL TRACK NORTHEAST INTO CANADA BY WEDNESDAY MORNING. AFTER
THIS SYSTEM...A VERTICALLY STACKED UPPER LOW OVER THE BERING SEA
WILL DIG A 500H TROUGH DOWN TO NEAR 35 NORTH AND SPIN UP A WAVE
ALONG A FRONTAL BOUNDARY. AT THIS SAME TIME...A SHORT WAVE WITH
ASSOCIATED SURFACE LOW SOUTH OF THE ALEUTIANS WILL DIVE SOUTHEAST
AS THE SHORT WAVE AND LONG WAVE TROUGH COME INTO PHASE. ALL THREE
SURFACE LOWS THEN MERGE INTO A VERY LARGE...VERY DEEP BINARY SYSTEM
THAT TRACKS NORTHWEST TOWARDS THE NORTHWEST GULF. THIS COMPLEX LOW
IS CURRENTLY FORECAST TO REMAIN OFFSHORE. EVEN SO...IF THE TRACK
AND INTENSITY REMAINS CONSISTENT THROUGH THE WEEK WE WILL LIKELY
SEE ANOTHER PROTRACTED PERIOD OF STRONG WINDS BEGINNING THIS
FRIDAY NIGHT OVER THE SOUTHERN ZONES AND LAST UNTIL NEXT MONDAY
MORNING.

IN TERMS OF PRECIPITATION...LOOKS LIKE WE MAY SEE SOME DRY WEATHER
BEGINNING THURSDAY AFTERNOON WHICH WILL LAST UNTIL FRIDAY
AFTERNOON FOR THE SOUTHERN ZONES AND FRIDAY NIGHT FOR THE NORTHERN
ZONES. THEN...BACK INTO THE RAIN AND/OR SNOW TO GO ALONG WITH THE
STRONG WINDS ASSOCIATED WITH THE LOW TRACKING NORTHWEST ACROSS THE GULF.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ036-041>043-051-052.

&&

PRB/FRITSCH