Small Craft Advisory 50, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
410 AM AKST MON JAN 12 2009

.MODEL DISCUSSION...
MODELS WERE IN VERY GOOD AGREEMENT OVERALL THROUGH 84 HRS. THERE
WERE SOME MINOR DIFFERENCES ON THE HANDLING OF THE LOW IN THE GULF.
WENT WITH A POSITION SOMEWHERE NEAR CORDOVA BEFORE IT WEAKENS AND
MOVES INLAND LATE THIS AFTERNOON INTO THIS EVENING. LEANED TOWARD
GFS/EC FOR MOST OF THE PACKAGE. LONG TERM FORECAST STILL HAS A FEW
KINKS. MODELS ARE BEGINNING TO RESOLVE NEW WAVE PATTERN IN THE
BERING. WENT WITH THE 00Z EC AND BLENDED WITH HPC 12Z GRIDS.

.ANALYSIS AND UPPER LEVELS...
A MAJOR LOW IS CURRENTLY IN THE CENTRAL GULF JUST SOUTHWEST OF
MIDDLETON ISLAND. ITS ASSOCIATED OCCLUDED FRONT IS BRINGING SNOW FROM
BRISTOL BAY TO THE Y-K DELTA..KUSKOKWIM VALLEY AND ACROSS COASTAL
SOUTHCENTRAL. WITHIN THE NEXT FEW HOURS EXPECT SNOW TO MOVE INTO THE
ANCHORAGE BOWL AND SUSITNA VALLEY AS WELL AS NE PRINCE WILLIAM SOUND.
THE FRONT HAS BROUGHT VERY LOW CEILINGS AND VIS FOR EXTENDED PERIODS.
THE FORECAST CHALLENGE THIS MORNING IS TIMING THE INTIAL DROP AND THE
EVENTUAL RISE ESPECIALLY IN THE TAFS. SNOW INTENSITY HAS BEEN FAIRLY
LIGHT..HOWEVER STILL EXPECT MORE SIGNIFICANT AMOUNTS OF 4 TO 8 INCHES
IN BRISTOL BAY AND NEAR KACHEMAK BAY ESPECIALLY IN SELDOVIA AND THE
HOMER BLUFF.

A SECOND 960S LOW IS IMPACTING THE WESTERN AND CENTRAL ALEUTIANS.
ALTHOUGH OBS ARE NOT PLENTIFUL IN THAT AREA..WE DO EXPECT BLIZZARD
CONDITIONS TO DEVELOP THIS MORNING FROM AMCHITKA EAST. WINDS ARE
CURRENTLY BETWEEN 35 AND 50 MPH ACROSS THE REGION AS THE FRONTAL BAND
MAKES ITS WAY EAST. THIS IS A SLOW MOVING SYSTEM SO DO NOT EXPECT
MUCH CHANGE THROUGH TUE NIGHT EXCEPT FOR WIND SHIFTS. WHILE THERE MAY
BE A BRIEF WARM UP TODAY..EXPECT COLD NORTHERLIES BEHIND THE LOW.

.SHORT TERM FORECAST...

IN THE WEST...THE LOW MOVING SOUTH OF THE ISLANDS BRINGS SNOW AND
WIND THROUGH TUESDAY AT IT MAKES ITS WAY EAST WITH BLIZZARD
CONDITIONS FROM AMCHITKA TO ATKA. IT LOOKS LIKE THE LOW WILL REMAIN
FAR ENOUGH SOUTH TO NOT ADVECT MUCH WARMER AIR TO THE AREA AND THEN
COLD AIR WILL FOLLOW BEHIND THE LOW WITH NORTH WINDS AND SNOW
SHOWERS.

FOR SW AK...THE LOW CURRENTLY IN THE GULF WILL BRING MORE
SNOW..SNOW SHOWERS AND WIND TO ALL OF MAINLAND SW AK TODAY.
BY THIS AFTERNOON THE LOW RESPONSIBLE FOR THESE EVENTS WEAKENS IN THE
GULF AND PRECIPITATION DIMINISHES. HOWEVER THE LOW CURRENTLY SOUTH OF
THE CENTRAL ALEUTIANS WILL BEGIN TO IMPACT THE AREA ON WED WITH MORE
WIND AND PRECIP AS A BROAD LOW PRESSURE COMPLEX DEVELOPS FROM NW AK
TO THE AK PENN AND EASTERN ALEUTIANS.

SOUTH AND EAST OF THE AK RANGE...THE LOW IN THE GULF WILL BRING SOME
SNOW TO MOST OF SOUTHCENTRAL TODAY. A BARRIER JET WILL PRODUCE SOME
GALES ALONG THE NORTH GULF COAST TODAY. MUCH OF THE PRECIP WILL LEAVE
THE WESTERN PART OF SOUTHCENTRAL BY LATE THIS MORNING. THE COPPER
RIVER VALLEY AND NE GULF COAST WILL SEE MORE SNOW THROUGH THIS
EVENING.

.LONG TERM FORECAST...EXPECT WARMER CONDITIONS ACROSS SOUTHCENTRAL
MIDWEEK. IT WILL BE WETTER AND WINDIER OUT WEST. THEN BY THURSDAY
COLD AIR WILL MOVE BACK IN TO SOUTHCENTRAL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 187 191
MARINE...STORMS 175
         GALES 120 130 138 140 170 172 176 179
         HEAVY FREEZING SPRAY 140 165 179 185
FIRE WEATHER...NONE

RNW JAN 09