Heavy Freezing Spray Warning 227, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST FRI DEC 14 2012

.MODEL DISCUSSION...MODEL SYNOPTIC INITIALIZATIONS REASONABLE.
FORECAST TRENDS IN THE EAST ARE IN GOOD AGREEMENT THROUGH THE
WEEKEND. OUT WEST...MODEL CONSENSUS IS POOR WITH THE NEXT WAVE WHICH
IS FORECAST TO IMPACT THE ALEUTIANS/BERING SEA SUN AND MON. THE
NAM/GFS ARE FASTER AND STRONGER WITH THIS LOW...WHERE AS THE GEM AND
ECMWF AND SLOWER AND INITIALLY A LITTLE WEAKER. CURRENT THINKING IS
TO LEAN TOWARD A BLEND OF THE CURRENT GRIDS WITH THE THE FASTER AND
STRONGER GFS/NAM SOLUTIONS.

.ANALYSIS...
STRONG INVERSIONS AND ABUNDANT LOW LEVEL MOISTURE PRODUCED WIDESPREAD
STRATUS AND FOG OVER COOK INLET...ANCHORAGE BOWL...AND THE MATANUSKA
VALLEY. LOW PRESSURE OVER THE GULF PUSHED SNOW SHOWERS UP ALONG THE
NORTH GULF COAST AND PRODUCED GUSTY OUTFLOW WINDS OVER THE EASTERN
KENAI AND WESTERN GULF OF ALASKA.

FURTHER WEST...A WEAK LOW PRESSURE CENTER ALONG THE SW COAST PRODUCED
SNOW AND SNOW SHOWERS OVER MUCH OF SW ALASKA. BRISK NORTHERLY WINDS
ASSOCIATED WITH THIS FEATURE ALSO PRODUCED BLOWING SNOW OVER THE
DELTA. SNOW SHOWERS WERE EVIDENT OVER MUCH OF THE BERING SEA AND
ALEUTIANS.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
THE INVERSIONS SHOULD WEAKEN SOME OVER COOK INLET...ANCHORAGE
BOWL...MAT VALLEY TONIGHT WITH THE ONSET OF COLD ADVECTION. THUS WE
SHOULD SEE A REDUCTION IN EXTENT OF STATUS AND FOG. LOW PRESSURE
STRENGTHENS OVER THE GULF TONIGHT AND SAT AS HIGH PRESSURE BUILDS
ACROSS THE MAINLAND. BUILDING PRESSURE GRADIENTS ALONG WITH COLD
ADVECTION FROM THE INTERIOR WILL PRODUCE STRONG OUTFLOW WINDS ACROSS
THE THE REGION...THE STRONGEST ALONG THE NORTH GULF COAST AND EASTERN
KENAI.

.SW ALASKA...THE LOW OVER KUSKOKWIM BAY WILL MOVES SE AND WEAKEN
TONIGHT. SNOW SHOULD DIMINISH RAPIDLY FROM THE WEST ACROSS THE REGION
OVERNIGHT. NORTHERLY WINDS WILL DIMINISH ACROSS THE DELTA THIS
EVENING...BUT INCREASE ACROSS BRISTOL BAY. EXPECT SOME PATCHY FOG
ACROSS THE DELTA LATE TONIGHT AS HIGH PRESSURE BUILDS ALONG THE SW
COAST. A WEAK WAVE OVER THE NORTHERN BERING SEA APPROACHES SW AK ON
SAT NIGHT AND BRINGS A CHANCE OF SNOW TO THE DELTA...THEN A CHANCE TO
BRISTOL BAY SUN.

.ALEUTIANS/BERING SEA...UNSETTLED WEATHER WITH SNOW/MIXED RAIN
SHOWERS WILL CONTINUE THROUGH MUCH OF WEEKEND. A DEVELOPING STORM
OVER THE NORTH PACIFIC BRINGS STRONG WINDS AND SOME RAIN AND SNOW TO
THE WESTERN ALEUTIANS LATE SUN. MODEL CONSENSUS WITH THIS CENTER IS
POOR...SO TIMING AND INTENSITY AT THIS TIME IS PROBLEMATIC.

LONG TERM...LOW CONFIDENCE IN THE LONG TERM FORECAST AS MODELS DIFFER
IN THE AMPLIFICATION OF A RIDGE OVER THE BERING TUESDAY THROUGH
THURSDAY. THE TREND WITH FOR THE WEATHER NEXT WEEK LOOKS DRIER AND
COLD AS THE RIDGE STRENGTHENS THROUGH MID WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM 130 132. GALES 121 127 129 138 150 155 165.
FIRE WEATHER...NONE.

RMC DEC 12