Heavy Freezing Spray Warning 211, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
500 AM AKST FRI DEC 21 2012

.MODEL DISCUSSION...
IN THE SHORT TERM THE MODELS ARE ALL IN GOOD AGREEMENT WITH THE MAJOR
FEATURES BUT AS WE MOVE INTO THE MID TERM THE EC STARTS TO BECOME AN
OUTLIER KEEPING FEATURES FURTHER SOUTH THAN THE OTHER MODELS. IN THE
LONG TERM THINGS BEGIN TO FALL APART. THROUGHOUT THE LONG TERM
PLACEMENT AND INTENSITY OF MAJOR FEATURES IS INCONSISTENT FROM MODEL
TO MODEL AND RUN TO RUN CAUSING CONFIDENCE TO BE LOW LATE IN THE
FORECAST PERIOD.

.ANALYSIS AND UPPER LEVELS...
UPPER LEVEL RIDGING STRETCHES ACROSS WESTERN ALASKA FROM NORTH TO
SOUTH. THIS HIGH PRESSURE IS KEEPING MUCH OF THE STATE COLD AND CLEAR
OF MOST CLOUD COVER. TO THE WEST OF THE RIDGE A FRONT OVER THE
CENTRAL BERING IS SLOWLY MOVING TO THE EAST BRINGING IN WARMER AIR
FROM THE SOUTH. THE FRONT IS STALLING AS IT IS BEING HELD UP BY THE
RIDGING.

.SHORT TERM FORECAST...
SOUTHCENTRAL...THE RIDGING OVER THE WESTERN PART OF THE STATE IS
KEEPING CLEAR SKIES FOR MOST PLACES IN THE SOUTHCENTRAL. THIS IS ALSO
KEEPING COLDER TEMPERATURES IN MOST LOCATIONS. THIS HIGH PRESSURE
COMBINED WITH WEAK LOW PRESSURE IN THE GULF IS PROVIDING ENOUGH OF A
GRADIENT FOR STRONGER WINDS TO MOVE THROUGH THE MORE CHANNELED
TERRAIN...SPECIFICALLY AREAS THAT ARE ORIENTED NORTH TO SOUTH. SOME
OF THESE LOCATIONS WILL SEE WINDS AT OR NEAR WARNING LEVEL TODAY. AS
THE HIGH PRESSURE WEAKENS THROUGHOUT THE DAY THE WINDS WILL BEGIN TO
CALM DOWN. ON SATURDAY A LOW WILL FORM IN THE GULF THAT WILL BRING IN
MORE CLOUD COVER AND SOME PRECIP...ESPECIALLY ALONG THE GULF COAST.

SOUTHWEST ALASKA...HIGH PRESSURE IS KEEPING THE AREA CLEAR FROM MOST
CLOUD COVER AND PRECIP. LIGHT NORTHEAST FLOW COMBINED WITH THE CLEAR
SKIES ARE KEEPING TEMPERATURES COLD THROUGHOUT THE AREA. AS THE FRONT
OVER THE CENTRAL BERING MAKES ITS WAY CLOSER TO THE SOUTHWEST TODAY
IT WILL BRING IN WARMER AIR OUT AHEAD OF IT FROM THE SOUTH. THE FRONT
ITSELF WILL NOT MAKE IT AS THE RIDGING KEEPS IT OUT OVER THE BERING
WHERE IT WILL FALL APART EARLY SATURDAY.

BERING SEA AND ALEUTIAN ISLANDS...THE FRONT MOVING ACROSS THE
ALEUTIAN ISLANDS IS BRINGING PRECIP TO THE EASTERN ALEUTIANS AND IT
WILL MAKE ITS WAY TO THE ALASKA PENINSULA THIS AFTERNOON WHERE IT
WILL FALL APART EARLY SATURDAY. BEHIND THE FRONT HIGH PRESSURE IS
BUILDING INTO THE BERING AND WILL REMAIN THERE UNTIL SUNDAY EVENING
WHEN A NEW SYSTEM WILL MOVE INTO THE WESTERN ALEUTIANS.

.LONG TERM FORECAST...
THERE ARE DISCREPANCIES BETWEEN THE DIFFERENT MODELS IN THE LONG TERM
BUT OVERALL CONSENSUS IS FOR A MORE ACTIVE PATTERN NEXT WEEK. A LOW
MOVING INTO THE GULF EARLY NEXT WEEK SHOULD BRING PRECIP AND WARMER
TEMPERATURES TO MAINLAND ALASKA. ANOTHER LOW THAT IS DEEPER THAN THE
FIRST LOOKS TO MOVE ACROSS THE ALEUTIANS THROUGHOUT THE EARLY PART OF
THE WEEK BRINGING IN MORE WARM AIR AND PRECIP TO THE STATE AS IT
MOVES INTO THE EASTERN BERING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING...131 135
MARINE...GALES...127 128 130 180 170 176 185 179
         HEAVY FREEZING SPRAY...126 127 128 120 121 129 130 138 140
                                141 160
FIRE WEATHER...NONE

DWK DEC 12