Heavy Freezing Spray Warning 46, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKST WED JAN 18 2012

.MODEL DISCUSSION...MODELS GENERALLY INITIALIZED WELL ON SYNOPTIC
FEATURES. THE NAM AND ECMWF FORECAST TRENDS LOOK THE BEST IN THE
SHORT TERM AND WILL BE USED WITH SOME ADJUSTMENTS FOR THIS FORECAST
ISSUANCE.

.UPPER LEVELS....UPPER LEVELS...THE LARGE BLOCKING HIGH OVER THE
EASTERN BERING SEA ON TUE HAS MOVED TO OVER EASTERN RUSSIA. A BROAD
TROUGH EXTENDS FROM SE ALASKA TO SOUTH OF THE EASTERN ALEUTIANS. THE
HIGH OVER EASTERN RUSSIA WILL REMAIN STATIONARY WITH LITTLE CHANGE IN
INTENSITY THROUGH SAT AFTERNOON. A LOW MOVING SOUTH ACROSS THE
BEAUFORT SEA FRI MOVES TO OVER SOUTHCENTRAL ALASKA SAT.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...THE HIGH PRESSURE RIDGE OVER THE MAINLAND HAS
WEAKENED SOME OVER THE LAST 24 HRS. GAP FLOWS ACROSS THE NORTH GULF
AND THE MATANUSKA VALLEY HAVE DECREASED WITH WEAKENING PRESSURE
GRADIENTS AND LESS FAVORABLE FLOW ALOFT. PRESSURE GRADIENTS WILL
CONTINUE TO WEAKEN ACROSS THE AREA TONIGHT AND THU. PRESSURE
GRADIENTS AND SUPPORTING NE FLOW ALOFT WILL INCREASE LATE THU NIGHT
AND FRI AND CONTINUE INTO SAT...SO BRISK GAP FLOWS SHOULD REDEVELOP
ALONG THE NORTH GULF AND THE MATANUSKA VALLEY. PRESSURE GRADIENTS
ACROSS MUCH OF THE AREA WILL INCREASE ON SAT AS LOW PRESSURE MOVES
INTO THE NORTHERN GULF. EXPECT INCREASING CLOUDS AND CHANCES OF SNOW
THIS WEEKEND. INCREASING CLOUDS WILL HELP TEMPERATURES REBOUND A
LITTLE...ESPECIALLY ALONG THE COASTS...HOWEVER...850 MB TEMPS COOL
OVER THE REMAINDER OF THE AREA THROUGH SUN.

.SOUTHWEST MAINLAND...STRONG NORTHEAST FLOW WILL CONTINUE TO OCCUR
ACROSS MUCH OF THE SOUTHWEST MAINLAND OVER THE NEXT FEW DAYS. THE
UPPER LEVEL RIDGE THAT IS PROGRESSING SOUTHWESTWARD WILL INCREASE THE
INTERIOR PRESSURE...AND WILL SUPPORT GUSTY WINDS. MEANWHILE...COLD
AIR CONTINUES TO BUILD IN THE INTERIOR NORTH BENEATH THE HIGH. A
REINFORCING COLD FRONT WILL MOVE THROUGH THE REGION THURSDAY WHICH
WILL SUPPORT OFFSHORE WINDS AND CONTINUE TO SUPPORT BELOW NORMAL
TEMPERATURES. EXPECT WIND CHILL ADVISORY CONDITIONS TO CONTINUE
THROUGH THU MORNING.

.ALEUTIANS...HIGH PRESSURE CONTINUES TO BUILD INTO THE WESTERN
BERING. COLD AIR ADVECTION ACROSS THE REGION CONTINUES TO SUPPORT
INSTABILITY SHOWERS. A SHORT WAVE WILL MOVE THROUGH THE EASTERN
ALEUTIANS TODAY AND BRING GUSTY WINDS THROUGH THE EVENING HOURS.
ANOTHER SHOT OF COLD AIR WILL SURGE ACROSS THE BERING THURSDAY AS A
COLD FRONT MOVES FROM THE EAST TO WEST.

.LONG TERM FORECAST...MODELS INDICATE THAT THE UPPER LEVEL BLOCKING
HIGH WILL DOMINATE THE REGION FOR THE NEXT WEEK. MODELS ARE
INDICATING THAT AN UPPER LEVEL TROUGH WILL MOVE INTO THE MAINLAND
ALASKA BY THE MIDDLE OF THE WEEKEND...WHICH WOULD ALLOW FOR MORE
UNSETTLED WEATHER TO OCCUR.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...WIND CHILL ADVISORY ZONE 155.
MARINE...GALE 121,132,126,127,352,150,155,170,172,175,176,351,352,411
              413.
FIRE WEATHER...NONE

RMC JAN 12