Heavy Freezing Spray Warning 75, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST TUE JAN 31 2012

.MODEL DISCUSSION...MODELS INITIALIZATIONS WERE REASONABLE. THE ECMWF
WITH THE FURTHER WEST TRACK OF THE MODELS APPEARS TO BE THE BEST
SOLUTION AT THIS POINT.

.UPPER LEVELS...MINOR SHORT WAVES OVER SOUTHCENTRAL TRACK EAST
TONIGHT. A SHORT WAVE SOUTH THE EASTERN ALEUTIANS INTENSIFIES AS IT
COMES IN PHASE OF WITH TROUGH OVER THE BERING SEA AND COLD AIR
FLOWING OUT OF BERING SEA. A LOW FORMS WITHIN THE SHORT WAVE TROUGH
AND INTENSIFIES AS IT MOVES TO SOUTH OF KODIAK ISLAND WED. THE LOW
DRIFTS NORTH AND WEAKENS THU. A STRONG SOUTHERLY JET FORMS ON THE
EAST FLANK OF THE LOW AND MOVES SLOWLY EASTWARD WED. MINOR SHORT
WAVES MOVE EAST ACROSS THE BERING SEA THROUGH THU.

.SURFACE...
THE MAIN FEATURE IS A DEVELOPING LOW WITHIN THE COMPLEX SOUTH OF THE
EASTERN ALEUTIANS. THE CENTER WHICH IS PROBABLY IN THE 970S THIS
AFTERNOON INTENSIFIES UNDER A DIGGING UPPER TROUGH AND A STRONG JET.
THE LOW SHOULD DEEPEN INTO THE 940S AS IT APPROACHES KODIAK ISLAND
WED AND THEN SLOWLY WEAKEN AS IT HEADS TOWARD COOK INLET THU. THIS
TRACK IS A LITTLE FURTHER WEST THEN YESTERDAYS RUNS...BUT LOOKS
REASONABLE AS THE LOW SHOULD MOVE TOWARD THE COLD AIR TO THE WEST AS
IT OCCLUDES. THE ASSOCIATED FRONT MOVES TO KODIAK TONIGHT AND TO THE
NORTH GULF COAST AND COOK INLET WED NIGHT. A VIGOROUS 970S MB LOW
NEAR ATKA IS PRODUCING BLIZZARD CONDITIONS OVER THE CENTRAL
ALEUTIANS. CONDITIONS SHOULD IMPROVE TONIGHT AS THE LOW DROPS
SOUTHEAST AND WEAKENS.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...
GALE TO STORM FORCE WINDS ARE EXPECTED IN ADVANCE OF THE FRONT AS IT
TRACKS NORTH IN THE GULF. HIGH WIND CONDITIONS ARE EXPECTED OVER
KODIAK ISLAND AND IN ZONE 135. WINDS WILL DIMINISH OVER KODIAK WED
AFTERNOON AND ZONE 135 WED NIGHT. WARM AIR WILL SPREAD NORTH WITH THE
FRONTAL BOUNDARY. PRECIPITATION DEVELOPING ALONG THE COASTS WILL
START AS SNOW BUT SHOULD RAPIDLY SHIFT TO RAIN OR A MIX. THAT
SAID...KODIAK AND ZONE 135 MAY SEE A BRIEF PERIOD OF LOW VISIBILITIES
IN BLOWING SNOW WITH THE ONSET OF PRECIPITATION. TEMPS WILL REMAIN
COLD ENOUGH IN 125(INTERIOR LOCATIONS) AND 131 (THOMPSON PASS)...SO
BLIZZARD CONDITIONS ARE LIKELY WITH THE ONSET OF SNOW WED. TEMPS WARM
ENOUGH IN ZONE 125 WED NIGHT...SO BLIZZARD CONDITIONS SHOULD END.
STRENGTHENING SOUTHEAST FLOW ACROSS THE TALKEETNA AND CHUGACH
MOUNTAINS SHOULD PRODUCE RELATIVELY DRY DOWNSLOPE CONDITIONS TO THE
LEE. HOWEVER...UPSLOPE CONDITIONS SHOULD DEVELOP OVER THE WESTERN
SUSITNA VALLEY WED AFTERNOON AND BRING SIGNIFICANT SNOW POTENTIAL.

.SOUTHWEST ALASKA AND AK PEN...
INCREASING NORTHERLY FLOW WILL CONTINUE WIND CHILLS OVER THE DELTA
THROUGH THU. STRONG NORTHERLY WINDS COMBINED WITH SNOW ALONG THE
LEADING EDGE OF OCCLUDED FRONT WILL BRING BLIZZARD CONDITIONS TO THE
AK PEN STARTING WED MORNING AND CONTINUE INTO THU MORNING.

.ALEUTIANS AND BERING SEA...BLIZZARD CONDITIONS OVER THE CENTRAL
ALEUTIANS SHOULD END OVERNIGHT AS LOW TRACKS SOUTH AND WEAKENS.
ANOTHER LOW...A LITTLE WEAKER THAN THE LAST ONE WILL BRING UNSETTLED
WEATHER WITH SHOWERS AND GENERALLY SUB-GALE WINDS WED AND THU.

.LONG TERM FORECAST...
COLD ADVECTION SNOW WILL DEVELOP FRIDAY OVER THE UPPER COOK INLET
REGION INCLUDING ANCHORAGE AS LOW PRESSURE WINDS DOWN AND SLIDES
NORTH AND EAST TOWARDS THE ALCAN BORDER. AS THIS HAPPENS...ANOTHER
POWERFUL LOW WILL TAKE SHAPE NEAR THE CENTRAL AND WESTERN ALEUTIANS
AND THEN BECOME STATIONARY OVER THE CENTRAL AND/OR WESTERN BERING
SEA. THIS WILL SET UP DEEP SOUTHEASTERLY UPPER LEVEL FLOW OVER MUCH
OF SOUTHWEST AND SOUTHCENTRAL ALASKA BY THIS WEEKEND INTO EARLY NEXT
WEEK. EXPECT CONTINUED INCREASED STORMINESS WITH TEMPERATURES NEAR
NORMAL TO ABOVE NORMAL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING...187
         BLIZZARD WATCH...125 131 161 181 (UPGRADES LIKELY)
         HIGH WIND WATCH...135 171 (UPGRADES LIKELY)
MARINE...GALES...125 140 141 160 165 170 171 172 175 179 180
         STORMS...120 130 132 138 150 155
FIRE WEATHER...NONE.

RMC JAN 12