Blizzard in Alaska, April 16 to 17, 2007

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT MON APR 16 2007

.MODEL DISCUSSION...
THE MODELS HAVE SETTLED DOWN A BIT FROM THE PAST COUPLE OF DAYS WITH
REGARD TO THE LOW MOVING TO SOUTH OF KODIAK ISLAND WEDNESDAY. THERE
IS STILL A LEVEL OF UNCERTAINTY ON THE POSITION AND INTENSITY OF THIS
LOW WHICH WILL KEEP LOWER CONFIDENCE IN THE FORECASTS AROUND KODIAK
ISLAND.MODELS IN VERY GOOD AGREEMENT ON THE STORM MOVEMENT INTO THE
BERING SEA GENERALLY SETTLING ON THE MAIN STORM CENTER BEING IN THE
NUNIVAK ISLAND AREA BY TUE EVENING AND TO THE BERING STRAIT VICINITY
WED AFTERNOON WITH THE TROUGH SOUTH SOUTHEAST TO THE LOW SOUTH OF
KODIAK ISLAND.

.ANALYSIS AND UPPER LEVELS...
OUT WEST WE HAVE THE MODERATE 987 MB LOW SOUTH SOUTHWEST OF ADAK WITH
THE FRONT NOW ALONG THE ALEUTIANS THEN SOUTH SOUTHWEST TO THE TRIPLE
POINT LOW AROUND 35N 175E. A WEAK SURFACE LOW IS OVER THE LOWER YUKON
VALLEY WITH A TROUGH OF LOW PRESSURE TO THE WEAK 993 LOW NEAR
MIDDLETON ISLAND AND ANOTHER WEAK 992 LOW 400 NM SOUTH OF CAPE
YAKATAGA. THE ASSOCIATED FRONT FROM THE 993 LOW HAS DISSIPATED ALONG
THE GULF COAST FROM PRINCE WILLIAM SOUND SOUTHEAST ALONG THE
PANHANDLE. THE MAIN UPPER LEVEL CENTER IS ANCHORED OVER THE GULF OF
ANADYR WITH A TROUGH SOUTH TO OVER THE STORM SOUTH OF ADAK AND A
TROUGH SOUTHEAST TO ANOTHER UPPER CENTER OVER THE GULF OF ALASKA.

.SHORT TERM FORECAST...
THE LOW SOUTH OF ADAK WILL MOVE ACROSS THE PRIBILOF ISLANDS TONIGHT
TO NUNIVAK ISLAND THEN ON TO THE BERING STRAIT WEDNESDAY MORNING. THE
MAIN ISSUES WITH THE STORM PUSHING NORTHEAST ARE PRE FRONTAL WIND AND
JUST HOW MUCH WARM AIR WILL PUSH NORTH. WE EXPECT WIND TO REMAIN WELL
BELOW WARNING LEVELS FOR THE EASTERN ALEUTIANS TO ALASKA PENINSULA.
THE MAIN QUESTION REMAINING IS WHETHER THE SNOW AND BLOWING SNOW IN
THE PRIBILOFS WILL BE BAD ENOUGH FOR BLIZZARD CONDITIONS. EXPECT
VISIBILITIES TO REMAIN AROUND 1 TO 1/2 MILE INITIALLY. IT APPEARS AS
THOUGH WARM AIR SHOULD INTRUDE FROM THE SOUTH AS THE FRONT APPROACHES
RESULTING IN A WETTER SNOW AND THUS NOT AS MUCH RESUSPENSION AND
REDUCTION IN VISIBILITY.THE 850 MB -4 TEMP SHOULD BE OVER THE
PRIBILOFS BY TUESDAY MORNING THEN THE COLD AIR WILL WRAP BACK AROUND
FROM THE NORTH AS THE LOW PASSES BY. SNOW SQUALLS AND BLOWING SNOW
AROUND THE BACK SIDE OF THIS LOW WEDNESDAY MAY RESULT IN BRIEF
PERIODS OF BLIZZARD CONDITIONS.

IN THE GULF AND AN THE MAINLAND THE REMNANTS OF THE LOWS IN THE GULF
WILL BE PUSHED OUT OF THE PICTURE BY THE RIDGE IN ADVANCE OF THE
MASSIVE NORTH PACIFIC LOW THROUGH TUE MORNING. OVER THE WESTERN
MAINLAND, THE CLEAR CONDITIONS TODAY WILL BE REPLACED BY THE CLOUD
SHIELD OF THE NORTH PACIFIC STORM AND WE WILL MOST LIKELY SEE SNOW
AND RAIN ALONG THE BRISTOL BAY TO YUKON KUSKOKWIM DELTA COAST TONIGHT
AND BY MORNING. CLEAR SKIES EARLY TUES OVER SOUTH CENTRAL ALASKA WILL
YIELD TO THE INCOMING CLOUDS AND EXPECT KODIAK ISLAND TO BE IN THE
RAIN OR MIXED RAIN AND SNOW BY TUE AFTERNOON. THE CLOUDS WILL SPREAD
TO THE SOUND BY TUE NIGHT. THE RIDGING INTO THE SOUND TUE AS THE
STORM MOVES INTO THE BERING SEA WILL PRODUCE THE TYPICAL PORTAGE
VALLEY TURNAGAIN ARM AND UPPER HILLSIDE WINDS.

.LONG TERM FORECAST...
ANOTHER NORTH PACIFIC STORM IS ON TAP TO MOVE TO SOUTH OF THE ALASKA
PENINSULA THU NIGHT THEN BECOME STATIONARY AND DISSIPATE NEAR THE
SHUMAGIN ISLANDS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 155 161 165 170 171 172 175 179 180 185 410. HEAVY
FREEZING SPRAY 185.
FIRE WEATHER...NONE.

SAM APR 07