Gale Warning 584, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT SAT OCT 11 2008

.ANALYSIS AND UPPER LEVELS...A DEEP UPPER TROUGH IS SITUATED ALONG
ALASKAS WEST COAST WITH A SFC LOW OVER KODIAK ISLAND AND SEVERAL
FRONTS EXTENDING FROM THE LOW TO THE NORTH AND EAST. STRONG NORTHERLY
FLOW EXISTS ACROSS THE EASTERN BERING WITH HIGH PRESSURE IN THE
CENTRAL BERING AND A DEEPENING LOW WEST OF THE KAMCHATKA PENINSULA.

.MODEL DISCUSSION...NAM AND GFS ARE SIMILAR ON THE LARGE SCALE, BUT
THE NAM IS DEPECTING THE FRONTAL BOUNDARIES AND POSITION OF THE LOW A
BIT BETTER. THE NAM IS THE SLOWER OF THE OF THE TWO MODELS WHICH ALSO
FITS WITH CURRENT OBSERVATIONS.

.SHORT TERM FORECAST...THE LOW OVER KODIAK ISLAND HAS SEVERAL FRONTS
EXTENDING TO THE NORTH AND EAST. ONE SUCH FRONT STRETCHES NORTH
TOWARD MCGRATH. SNOW WILL CONTINUE ALONG THIS FRONT AS IT MOVES EVER
SO SLOWLY EAST. ANOTHER FRONT STRETCHING EAST JUST SOUTH OF THE
EASTERN KENAI WILL ALSO TAKE ITS TIME LIFTING NORTH. THESE FRONTS
WILL PRODUCE RAIN AND SNOW AND PLENTY OF WIND. COLD AIR IS BANKED UP
BEHIND THE WESTERN MOST FRONT AND WILL SLOWLY SEEP INTO SOUTHCENTRAL
ON SUNDAY.

THE LOW AND ASSOCIATED FRONT LIFTS NORTHEAST TOWARD WESTERN PRINCE
WILLIAM SOUND SUNDAY AFTERNOON. MUCH OF THE PRECIP IN SOUTHCENTRAL
WILL START AS RAIN THANKS TO A DOWNSLOPE COMPONENT TO THE WIND
KEEPING TEMPS IN THE 30S AND 40S. SPECIFICALLY FOR THE ANCHORAGE
BOWL...RAIN SHOULD BEGIN LATE TONIGHT...THEN MIX WITH OR CHANGE TO
SNOW SUNDAY AFTERNOON AS THE LOW MOVES INTO PRINCE WILLIAM SOUND AND
NORTHWEST WINDS COOL THE AIRMASS SUFFICIENTLY. THE UPPER TROUGH
SWINGS THROUGH MONDAY MORNING WITH THE SNOW COMING TO AN END. SNOW
AMOUNTS ARE TRICKY TO PREDICT AT THIS TIME AS AN EXACT CHANGEOVER
TIME IS YET TO BE DETERMINED.

THE LOW WEAKENS AS IT MOVES EAST...BUT RESIDUAL MOISTURE HANGING
AROUND AS THE COLD AIR TAKES OVER WILL CHANGE RAIN SHOWERS OVER TO
SNOW. AREAS ALONG AND WEST OF THE PARKS HIGHWAY IN THE SUSITNA VALLEY
MAY GET ANOTHER ROUND OF HEAVY SNOW WITH A PROLONGED PERIOD OF
UPSLOPE FLOW. WEAK HIGH PRESSURE BUILDS IN ALLOWING FOR SOME CLEARING
ON MONDAY AHEAD OF THE NEXT FRONT APPROACHING FROM THE BERING.

FURTHER WEST...SNOW WILL LINGER ALONG THE ALASKA/ALEUTIAN RANGES
OVERNIGHT WITH CLEARING SKIES ALONG THE COAST WITH SLOWLY DIMINISHING
WINDS. GALE FORCE WINDS WILL PERSIST FOR AT LEAST ONE MORE NIGHT
ALONG AND SOUTH OF THE AKPENN. WEAK RIDGING SLIDES EAST FROM THE
CENTRAL BERING AS A STRONG FRONT APPROACHES THE WESTERN ALEUTIANS
LATE TONIGHT. MAX GALE FORCE WINDS AND RAIN WILL ACCOMPANY THE FRONT
AS IT MAKES STEADY PROGRESS ACROSS THE BERING...REACHING THE SW COAST
BY MONDAY AFTERNOON.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 125 130 132 150 155 160 165 170 171 172 175 176 179
              180 185 411 412 413 414.
FIRE WEATHER...NONE.

JCA