Freezing Rain Advisory 2, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST TUE FEB 19 2008

.ANALYSIS AND UPPER LEVELS...THE PARADE OF LOWS TRAVERSING THROUGH
THE GULF CONTINUES. A LOW CURRENTLY NEAR 55N 147W WILL TRACK QUICKLY
NW ACROSS KODIAK ISLAND THIS AFTERNOON. A DECAYING LOW NEAR ATKA
CONTINUES TO DRIFT EAST WITH WEAK RIDGING IN-BETWEEN THESE SYSTEMS.

.MODEL DISCUSSION...ALL MODELS INITIALIZED TOO DEEP AND A LITTLE TOO
FAR SOUTH WITH THE LOW IN THE GULF. A QUICK LOOK AT THE 06Z MODEL
RUNS SHOWS SLIGHT IMPROVEMENT BUT STILL A BIT BEHIND CURRENT TRENDS.
OVERALL...THE NAM HAS THE BEST HANDLE IN THE VERY SHORT TERM. THE
TRACK OF THE LOW HAS BEEN CONSISTENT FOR A COUPLE OF RUNS NOW WITH
THE NEXT SYSTEM IN THE NORTH PACIFIC HANDLED BEST BY THE GFS.
RELATIVELY QUIET FURTHER WEST WITH LITTLE FOR THE MODELS TO DISAGREE
ON.

.SHORT TERM FORECAST...AS THE LOW IN THE GULF CROSSES KODIAK ISLAND
LATER TODAY...THE GRADIENT CONTINUES TO TIGHTEN ALONG THE GULF COAST
WITH WINDS BEING THE BIGGEST FORECAST ISSUE. A BARRIER JET IS ALREADY
FORMING ALONG THE NORTH GULF COAST WITH STORM FORCE WINDS EXPECTED
JUST SOUTH OF PRINCE WILLIAM SOUND. A WIND WARNING WILL BE HOISTED
FOR THIS AFTERNOON AND TONIGHT ALONG TURNAGAIN ARM AND PORTAGE VALLEY
AS AN 80 KT LOW LEVEL JET PASSES BY ALIGNED WITH A FAVORABLE E-W
PRESSURE GRADIENT. THE TURNAGAIN ARM WIND SHOULD BEND NORTH INTO THE
ANCHORAGE BOWL THIS EVENING ONCE AGAIN INCREASING WINDS AND TEMPS
ACROSS TOWN. PRECIP WILL ONCE AGAIN FALL AS MAINLY RAIN. PLENTY OF
MOISTURE WILL SPILL OVER THE ALEUTIAN AND ALASKA RANGES THIS
AFTERNOON BRINGING A RAIN SNOW MIX TO BRISTOL BAY...SPREADING NORTH
OVERNIGHT.

A BRIEF REPRIEVE FROM THE INTENSE WIND AND RAIN WEDNESDAY MORNING
AHEAD OF THE NEXT GULF LOW. WITH HIGH PRESSURE BUILDING IN THE
INTERIOR...THIS NEXT LOW WILL BE A SLOWER MOVER THAN ITS
PREDECESSORS. MAIN EFFECTS WILL ONCE AGAIN BE FELT ALONG THE
IMMEDIATE COAST. WHERE THIS LOW PUSHES ONSHORE IS STILL IN
QUESTION...ANYWHERE FROM KODIAK TO COOK INLET...AND CERTAINLY HAS AN
IMPACT ON PRECIP FORECASTING ESPECIALLY THURSDAY NIGHT.

FURTHER WEST...AS HIGH PRESSURE BUILDS IN THE WESTERN BERING...COLD
ADVECTION RESULTING IN GUSTY NW WINDS WILL INTENSIFY IN THE EASTERN
BERING AND AKPENN BEGINNING THURSDAY.

.LONG TERM FORECAST...PATTERN CHANGE WILL BEGIN LATE WEEK AND BE IN
PLACE BY NEXT WEEKEND. A RIDGE WILL SET BACK UP OVER THE BERING WITH
A TROUGH OVER THE MAINLAND AND GULF. SO EXPECT AN END TO THE ACTIVE
STORM TRACK ACROSS MAINLAND ALASKA AND COLDER AIR TO MOVE BACK INTO
THE REGION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 101 125.
MARINE...STORM 120.
         HEAVY FREEZING SPRAY 179 185 411 412.
         GALE 125 130 132 138 172 351 352.
FIRE WEATHER...NONE.

JCA