Small Craft Advisory 787, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
110 PM AKST WED DEC 19 2012

.SHORT TERM...A STRONG GALE FORCE LOW JUST S OF THE S-CENTRAL
GULF WILL MOVE SE THROUGH THU. THE ASSOCIATED WEAKENING OCCLUDED
FRONT WILL DISSIPATE OVER THE CENTRAL PANHANDLE THIS EVENING.
HIGH PRESSURE WILL BUILD OVER THE YUKON THROUGH THU. ENDED UP
MAKING NO CHANGE TO THE PRESSURE GRIDS AS THEY STILL LOOKED GOOD
COMPARED TO THE FAVORED 12Z EC/NAM BLEND.

 MAIN FORECAST CONCERNS WILL BE WIND AND TEMPS. RIGHT NOW WINDS
OVER THE FAR N ARE GUSTING OVER 60 MPH AND THIS WILL LIKELY
CONTINUE INTO THU AS THE PRESSURE GRADIENT WILL REMAIN TIGHT.
THIS WIND HAS CAUSED BLOWING SNOW AS WELL AROUND PAGY AND WHITE
PASS AREAS WHICH REDUCED VISIBILITY BELOW 1/4 MILE NEAR WHITE
PASS AND AS LOW AS 1/2 MILE NEAR PAGY. WILL KEEP BLIZZARD WARNING
GOING FOR THE PAGY ZONE THROUGH 4 PM THU TO HANDLE BOTH THE
BLOWING SNOW AND THE HIGH WINDS. THE STRONGER WINDS WILL ALSO
CONTINUE OUT OF INTERIOR PASSES AND OVER MUCH OF THE INNER
CHANNEL AREAS TONIGHT AND THU AS WELL. WILL KEEP STRONG WIND
HEADLINES FOR ZONES 17...19...AND 25 GOING THROUGH THE SHORT
RANGE PERIOD.

 TEMPS WILL BE GENERALLY BE COOLING THROUGH THU ESPECIALLY OVER
THE NRN AREAS AS COLD ADVECTION WILL CONTINUE THROUGH THE PERIOD.
TEMPS ARE LOW ENOUGH IN THE PAGY ZONE AND WINDS STRONG ENOUGH FOR
WIND CHILLS AS LOW AS 30 BELOW NEAR SEA LEVEL AND 50 BELOW NEAR
WHITE PASS. THESE WOULD NORMALLY NEED A WIND CHILL ADVY BUT WILL
INCORPORATE INTO THE BLIZZARD WARNING.

 OTHERWISE...EXPECT PRECIP TO DIMINISH OVER THE SRN AREA AS THE
FRONT WEAKENS OVER THEM AND FLOW BECOMES MORE OFFSHORE ESPECIALLY
THU. SHOULD REMAIN WARM ENOUGH OVER THE FAR S FOR SOME RAIN TO AT
LEAST MIX IN THROUGH LATE EVENING. NOT EXPECTING MUCH SNOW
ACCUMULATION TONIGHT AS MOST OF THE HEAVIER PRECIP WILL REMAIN
OFFSHORE.

&&

.LONG TERM...MODELS ARE IN GENERAL AGREEMENT THROUGH SATURDAY
WITH AN UPPER LEVEL CLOSED LOW OVER THE FAR SOUTHEASTERN GULF
CONTINUES FILLING AS IT DRIFTS FARTHER SOUTH AND A HIGHLY
AMPLITUDE UPPER RIDGE MOVES NORTH TO ARCTIC OCEAN. REFRESHED THE
INHERITED FORECAST PACKAGE WITH THE NAM AND ECMWF FOR THEIR GOOD
INITIALIZATION THROUGH SATURDAY. THE ASSOCIATED SURFACE LOW
WEAKENS AND SLIDES SOUTHEASTWARD AND NORTHERLY PRESSURE GRADIENT
WILL SLIGHTLY RELAX LATE THURSDAY NIGHT INTO FRIDAY MORNING. STORM
FORCE WINDS ACROSS THE NORTHERN MOST INNER CHANNELS WILL SLIGHTLY
EASE TO GALE FORCE. THE STRONG ARCTIC HIGH OVER THE YUKON WILL
CONTINUE TO RESPONSIBLE FOR STRONG OFFSHORE FLOW ACROSS THE
PANHANDLE. GENERALLY DRY...COLD...WINDY CONDITIONS WILL PREVAIL
THROUGH THE WEEKEND. WILL KEEP STRONG WIND HEADLINE FOR
YAKUTAT...SKAGWAY...HAINES AND JUNEAU ZONES.

 THE WEAKENING LOW WILL LIKELY MOVE BACK TO NEAR HAIDA GWAII
SATURDAY NIGHT THEN DISSIPATE AS A DEVELOPING LOW IN THE FAR
WESTERN GULF TRACKS NORTHEASTWARD OVER KODIAK SUNDAY NIGHT THEN
NEAR PRINCE WILLIAM SOUND BY MONDAY NIGHT. AT THIS TIME ANOTHER
DEVELOPING LOW IN THE NORTH PACIFIC MOVES NORTHEASTWARD INTO THE
FAR SOUTHEAST GULF THROUGH TUESDAY NIGHT. MODEL DIFFERENCES GROW
LARGER WITH THIS SCENARIO AND THE LEVEL OF UNCERTAINTY REMAINS
HIGH. LEANED OVER THE HPC ENSEMBLE APPROACH WHICH CONTAINS SOME
OPERATIONAL ECMWF AND GFS OUTPUTS. WITH RELATIVELY LOW
CONFIDENCE...AT THIS TIME...THE LOW MOVING INTO THE SOUTHEASTERN
GULF WILL LIKELY TO SLIDE SOUTHEASTWARD WITH NO DIRECT IMPACT OF
FRONTAL PASSAGE TO THE SOUTHERN PANHANDLE THROUGH THE MIDDLE OF
NEXT WEEK.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND THROUGH SATURDAY MORNING FOR AKZ019-025.
         STRONG WIND FROM THURSDAY EVENING THROUGH SATURDAY MORNING FOR
     AKZ018.
         BLIZZARD WARNING UNTIL 4 PM AKST THURSDAY FOR AKZ018.
         STRONG WIND THROUGH FRIDAY AFTERNOON FOR AKZ017.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ011-013.
         HEAVY FREEZING SPRAY WARNING FOR PKZ011-013.
         HEAVY FREEZING SPRAY WARNING FOR PKZ012.
         STORM WARNING FOR PKZ012-013.
         GALE WARNING FOR PKZ011-021-022-031>035-043-051-053.
         SMALL CRAFT ADVISORY FOR PKZ036-041-042-052.

&&

RWT/AHN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JUNEAU AK
1019 AM AKST WED DEC 19 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0939 AM     BLIZZARD         14 NE SKAGWAY           59.62N 135.05W
12/19/2012                   XXX                XX   UNKNOWN

            ALASKA DOT REPORTS BLIZZARD CONDITIONS FROM 10 MILE TO
            THE BORDER ON THE KLONDIKE HIGHWAY. NORTHEAST WIND 40 MPH
            IS CREATING MODERATE BLOWING AND DRIFTING SNOW.
            VISIBILITY IS REDUCED TO 500 FEET.

0939 AM     NON-TSTM WND GST SKAGWAY                 59.48N 135.33W
12/19/2012  M68.00 MPH                          AK   ASOS

            AT 511 AM A WIND GUST OF 68 MPH WAS MEASURED AT THE
            SKAGWAY AIRPORT. FREQUENT GUSTS OVER 60 MPH BEGAN
            OCCURRING AROUND 2 AM THIS MORNING.

&&

TPS