FXAK68 PAFC 050107
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST SAT FEB 4 2012

.ANALYSIS AND UPPER LEVELS...THE UPPER LEVEL PATTERN IS RATHER SIMPLE
TODAY BUT IT IS LEADING TO A BIT OF A COMPLEX SURFACE MAP. IN THE
UPPER LEVELS THERE IS A RIDGE WITH AN AXIS OVER SOUTHEAST ALASKA AND
INTO THE INTERIOR OF THE STATE. AN UPPER LOW CENTER IS OVER EASTERN
RUSSIA BRINGING SOUTHERLY FLOW ALOFT OVER MUCH OF THE FORECAST AREA.
THERE IS ALSO A WEAKENING UPPER LEVEL SHORT WAVE IN THE GULF OF
ALASKA.
THE SURFACE LOW ASSOCIATED WITH THE GULF SHORT WAVE IS STILL
IMPRESSIVE ON SATELLITE IMAGERY BUT IT WILL WEAKEN AS IT MOVES
NORTHWEST AS THE UPPER SUPPORT DIMINISHES.
THE BIGGEST WEATHER FEATURE IS THE STRONG FRONT THAT STRETCHES DUE
SOUTH TO NORTH OVER THE ALASKA PENINSULA TO THE SEWARD PENINSULA. THE
PARENT LOW FOR THE IS FRONT IS SOUTHWEST OF DUTCH HARBOR AND IS
DRIFTING NORTHWARD. THE MOST SIGNIFICANT WEATHER LIES ALONG THE FRONT
WHICH IS CAUSING BLIZZARD CONDITIONS IN THE KUSKOKWIM DELTA AND
WESTERN PORTIONS OF BRISTOL BAY.

.MODEL DISCUSSION...MODELS ARE A LITTLE BIT OF A MIXED BAG TODAY.
THEY ARE CONSISTENT WITH THE STORM TRACK AND TROUGH AXIS BUT THERE
ARE SOME SIGNIFICANT DIFFERENCES PAST SUNDAY AFTERNOON. THE THINKING
REMAINS THAT THE GFS HAS A MORE FAVORABLE SOLUTION AND IS BEING
LEANED ON FOR THE AFTERNOON FORECAST PACKAGES. THE NAM SOLUTIONS IS
ALSO VERY SIMILAR TO THE GFS.

.SHORT TERM FORECAST...BLIZZARD WARNINGS ARE IN EFFECT UNTIL MIDNIGHT
IN THE KUSKOKWIM DELTA AND THE BRISTOL BAY ZONE FOR AREAS NORTHWEST
OF KING SALMON. ENOUGH COLD AIR HAS REMAINED IN THESE AREAS TO KEEP
PRECIPITATION SNOW. THE BLOWING SNOW WITH WINDS GUSTING FROM 35 TO 55
MPH IS CAUSING WIDESPREAD WHITE OUT CONDITIONS IN THESE AREAS. TE
FRONT WILL WEAKEN OVERNIGHT AND DIMINISH THE WINDS TO CAUSE THE
BLIZZARD CONDITIONS TO END. WARM AIR MOVING INTO THESE AREAS FROM THE
SOUTH WILL ALSO HELP TO END THE BLIZZARD CONDITIONS.
RAIN WILL PERSIST IN THE WARM AIR OVER THE ALASKA PENINSULA WITH SNOW
SHOWERS IN THE CENTRAL TO WESTERN ALEUTIANS IN THE COLD AIR WRAPPING
AROUND THE WESTERN SIDE OF THE LOW.
THE WEAKENING SYSTEM IN THE SOUTHERN GULF WILL BRING PRECIPITATION
INTO KODIAK ISLAND TONIGHT INTO SUNDAY. IT WILL LIKELY BEGIN AS SNOW
BUT TURN TO RAIN AS THE WARMER AIR MOVES OVER THE ISLAND.

.LONG TERM FORECAST...A WARM CORE UPPER LEVEL RIDGE IS SETTING UP
OVER NORTHWESTERN CANADA AND WILL REMAIN THERE FOR SEVERAL DAYS WITH
A LONG WAVE TROUGH SETTING UP OVER THE WESTERN BERING SEA. THIS WILL
KEEP FLOW FOR MOST OF THE STATE FROM THE SOUTH BRINGING UP WARMER
MOIST AIR FROM THE NORTH PACIFIC AND BRING WARMER THAN NORMAL
TEMPERATURES TO SOUTHERN AND SOUTHWEST ALASKA THROUGH THE MIDDLE OF
THE WEEK NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 155 161.
MARINE...GALE 120 130 132 138 150 155 160 165 172 175 176 180 185.
FIRE WEATHER...NONE.

FEB 12
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