Gale Warning 68, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
106 PM AKST SUN JAN 25 2009

.SHORT TERM...SURFACE HIGH ACROSS WESTERN CANADA CONTINUES TO SLOWLY
WEAKEN AND WILL DRIFT SE THROUGH MONDAY. THIS HAS ALLOWED NE
GRADIENTS TO WEAKEN WITH STRONGER OUTFLOW WINDS JUST ABOUT DONE
EXCEPT FOR FAR SE CORNER WHERE GALE FORCE NE WINDS CONTINUE OUT OF
PORTLAND CANAL. THIS IS FORECAST TO EASE LATER THIS AFTERNOON AND
PLAN ON DROPPING WIND ADVISORY FOR ZONE 29. WILL SEE NORTH WINDS
INCREASE A BIT ON MONDAY AHEAD OF AN APPROACHING FRONT.

UPPER RIDGE OVER THE GULF IS MOVING EAST AND TILTING OVER TO THE
SE AS A SHORT WAVE TOPS THE RIDGE IN NE GULF. THIS IS ALREADY
PRODUCING STEADY SNOW IN YAKUTAT WITH FLURRIES AS FAR SOUTH AS
ELFIN COVE. STILL NO RETURNS AT BIORKA ISLAND RADAR HOWEVER PLENTY
SHOWING ON MIDDLETON ISLAND RADAR THAT EXTENDS TO WESTERN PORTION
OF ZONE 17. EXPECT A BRIEF BREAK IN THE SNOW THIS EVENING WITH STEADY
SNOW RETURNING LATER TONIGHT AND WILL ISSUE A SNOW ADVISORY FOR
PAYA FOR TONIGHT.

A COMPLEX FRONTAL SYSTEM EXTENDS FROM THE NE GULF INTO THE NORTH
CENTRAL PACIFIC. THERE ARE SEVERAL SMALL WAVES/LOWS ALONG THIS
BOUNDARY WHICH IS CURRENTLY STATIONARY AS SURFACE HIGH ACROSS
EASTERN PACIFIC PUMPS WARM MOIST AIR NORTHWARD WHILE SHORTWAVE IS
DRAGGING COLD AIR ACROSS THE NORTHERN GULF. UPPER TROUGH OVER
WESTERN GULF WILL MOVE EAST THROUGH MONDAY AND EXPECTED TO SPIN UP
A 1004 MB LOW IN SW GULF THAT MOVES TO NE GULF AST 988 MB MONDAY
AFTERNOON. AS THIS DOES IT WILL SPREAD MODERATE PRECIP ACROSS THE
PANHANDLE STARTING LATE TONIGHT AND EARLY MONDAY FOR SOUTHEAST
ALASKA. FAIRLY STRONG OVERRUNNING/ISENTROPIC LIFT EXPECTED ACROSS
THE INNER CHANNELS WHERE COLD AIR IS IN PLACE. CURRENT GUIDANCE
SUGGESTING SNOWFALL THROUGH MONDAY NIGHT IN THE 8 TO 15 INCH RANGE
WITH HIGHER AMOUNTS NEAR FAVORED TERRAIN. ALONG THE COAST EXPECT
WARMER AIR TO ARRIVE MONDAY MORNING AND PUSH NE THROUGH THE
AFTERNOON FOR SNOW CHANGING TO RAIN. A MODERATE SE LOW LEVEL JET
ACCOMPANIES THE FRONT AS IT MOVES INLAND AND EXPECT GALES FORCE
WIND IN COASTAL WATERS AS WELL AS CLARENCE STRAIT WITH WINDY
CONDITIONS FOR COASTAL AND SOUTHERN ZONES MONDAY AFTERNOON.

CURRENT AK NAM SHOW FAIRLY STRONG FRONTOGENESIS ALONG A CSP-FFIA2
LINE THAT DEVELOPS MONDAY AFTERNOON AND WILL KEEP PRECIP ALL SNOW
NORTH OF THIS LINE. THIS WILL ALSO ENHANCE PRECIP RATES WITH
HIGHER SNOW AMOUNTS ALONG THIS LINE. WARMER AIR LIKELY TO REACH
SOUTH CENTRAL AREA THIS EVENING AND WILL EXPECT A MIX OF RAIN AND
SNOW WITH A CHANCE OF FREEZING RAIN NEAR THE STIKINE DELTA. COOLER
AIR BEGINS TO RETURN LATE TONIGHT.

.LONG TERM...FOCUS DURING THIS SHIFT HAS BEEN ON SNOW TOTALS
FROM THE END OF THE SHORT TERM PERIOD AND INTO THE BEGINNING OF THE
LONG RANGE. ACCORDINGLY...NO CHANGES MADE PAST TUESDAY NIGHT
EXCEPT FOR WAVE HEIGHT AND SWELL. FAIRLY GOOD AGREEMENT AMONGST
THE MODELS THROUGH TUESDAY NIGHT WITH THE LOW NOW EXPECTED TO
ARRIVE ALONG THE OUTER COAST SOMEWHERE BETWEEN CROSS SOUND AND
CAPE EDGECUMBE AT AROUND 990 MB. INCREASED SNOW TOTALS A BIT
THROUGH TUESDAY NIGHT SO NOW HAVE STORM TOTALS OF 8 TO 15 INCHES
WITH THE BULK OF THIS FALLING BY NOON ON TUESDAY. BELIEVE ALL
ZONES WILL SEE SOME SNOW BUT THE OUTER COAST DOES NOT LOOK LIKE IT
IS GOING TO GET REALLY HAMMERED AND THEIR SNOW EVENT MAY LIKELY BE
OVER BY MONDAY MIDNIGHT IN THE LOWER ELEVATIONS AS WARM AIR
ADVECTION CHANGES THE SNOW TO RAIN DOWN LOW.

THERE WILL BE A BRIEF BREAK IN THE SNOW TUESDAY AFTERNOON THROUGH
TUESDAY NIGHT...BUT IT LOOKS LIKE ANOTHER ROUND OF HEAVY SNOW
ACROSS THE PANHANDLE IS POSSIBLE WEDNESDAY AFTERNOON THROUGH
THURSDAY AFTERNOON.

BLENDED SREF AND NAM TO EXISTING POP GRID AND UPDATED QPF WITH NAM
TO REVISE SNOW TOTALS. MINOR CHANGES TO TEMPERATURES WITH TUESDAY
NIGHT LOWS RANGING FROM THE LOW 20S TO THE LOW 30S IN MOST
LOCATIONS EXCEPT MID TO UPPER 30S FROM CAPE EDGECUMBE SOUTH TO
PRINCE OF WALES ISLAND AND EAST TO CLARENCE STRAIT.
CONSEQUENTLY...AM EXPECTING A FAIRLY HIGH SNOW WATER EQUIVALENT IN
THOSE PLACES THAT DO NOT CHANGE OVER TO RAIN.

FORECAST CONFIDENCE ABOVE AVERAGE THROUGH MONDAY NIGHT AND AVERAGE
THROUGH WEDNESDAY.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER STORM WARNING FROM 6 AM TO 9 PM AKST MONDAY FOR AKZ026.
         WINTER WEATHER ADVISORY FROM 6 AM TO 12 PM AKST MONDAY FOR
     	 AKZ023-027-028.
         WINTER STORM WARNING FROM 6 AM TO 3 PM AKST MONDAY FOR AKZ024.
         WINTER STORM WARNING FROM 6 AM MONDAY TO 6 AM AKST TUESDAY FOR
     	 AKZ019>021-025.
         WINTER STORM WARNING FROM 3 AM TO 3 PM AKST MONDAY FOR AKZ022.
         WIND ADVISORY UNTIL 3 PM AKST THIS AFTERNOON FOR AKZ029.
         WINTER STORM WARNING FROM 12 PM MONDAY TO 6 AM AKST TUESDAY FOR
     	 AKZ029.
         WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO 6 AM AKST TUESDAY
     	 FOR AKZ018.
         WINTER WEATHER ADVISORY UNTIL 12 PM AKST MONDAY FOR AKZ017.
MARINE...GALE WARNING FOR PKZ036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
&&

MM/FRITSCH