Gale Warning 180, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
530 AM AKST WED FEB 11 2009

.ANALYSIS AND UPPER LEVELS....
A COLD UPPER LEVEL LOW REMAINS OVER NORTHERN ALASKA AND WILL SLOWLY
DRIFT NORTH. TWO TROUGHS EXTEND OUT FROM THE LOW...THE FIRST..EXTENDS
SOUTHEAST OVER NORTHEASTERN ALASKA AND INTO CANADA...THE
SECOND...EXTENDS SOUTHWEST OVER RUSSIAN CHUKOTKA / KAMCHATKA MOVING
EASTWARD ACROSS THE BERING. LOCATED BETWEEN THE TWO TROUGHS IS A
RIDGE THAT CAN BE FOUND OVER MUCH OF SOUTHCENTRAL.

AT THE SURFACE...HIGH PRESSURE OVER THE YUKON FLATS CONTINUES TO MOVE
EAST. A 978 MB LOW NORTH OF SHEMYA CONTINUES TO WEAKEN AS IT MOVES
NORTH AND EAST. AN OCCLUDED FRONT STRETCHES FROM THE BERING LOW
EASTWARD ACROSS THE WESTERN COASTAL AREAS...FROM BETHEL THROUGH PILOT
POINT THIS MORNING. A WEAK SURFACE LOW HAS DEVELOPED WEST OF AKHIOK
AND WILL MOVE EAST OVER KODIAK ISLAND TODAY AND INTO THE GULF. THE
NEXT MAJOR SYSTEM CAN ALREADY BE SEEN ON SATELLITE OVER THE NORTH
PACIFIC AS IT CONTINUES TO INTENSIFY AND MOVE TOWARDS THE WESTERN
ALEUTIANS.

.MODEL DISCUSSION...MODELS ARE GENERALLY IN GOOD AGREEMENT THROUGH
THE 48 TO 60 HOUR TIME FRAME...AND ARE IN LINE WITH THE DEVELOPING
NORTH PACIFIC STORM SYSTEM THAT WILL AFFECT THE WESTERN ALEUTIANS IN
THE COMING DAYS AS WELL. THE MODELS ARE STILL HAVE SOME POSITION
DIFFERENCES WITH THE WEAK KODIAK LOW THIS MORNING...WITH THE LATEST
RUNS HAVING MORE OF A NORTHERLY TRACK INTO THE GULF. TOWARDS THE
WEEKEND...THE ECMWF CONTINUES TO BE AN OUTLIER AMONGST THE MODELS.
THE CURRENT FORECAST PACKAGE WAS TRENDED TOWARDS THE RECENT GFS RUNS
THROUGH THE LONG RANGE.

.SHORT TERM FORECAST...

.SOUTHCENTRAL...SNOW WILL CONTINUE TO SPREAD UP AND ALONG THE KENAI
PENINSULA THIS MORNING AS A LOW MOVES ACROSS KODIAK. THE 06Z MODEL
RUNS WERE BACKING OFF SLIGHTLY ON THE AMOUNT OF MOISTURE OVER THE
ANCHORAGE AREA TODAY BEFORE THE LOW IS SHEARED APART IN GULF LATE
WEDNESDAY NIGHT. HEAVIEST SNOW THIS MORNING HAS BEEN IN KODIAK CITY
WHERE ADVISORY LEVEL SNOWS HAVE FALLEN. SNOW WILL TAPER OFF AS THE
LOW PULLS OUT...BUT THE QUESTION REGARDING BLOWING SNOW TONIGHT FOR
KODIAK STILL LOOMS...AS THE CONFIDENCE ON BLIZZARD LEVEL VISIBILITY
IS STILL LOW...AND THE OTHER KEY CHALLENGE TO THE FORECAST WILL BE ON
THE TRACK OF THE LOW...MORE OF A NORTHERLY TRACK WILL POTENTIALLY
BRING RAIN TO KODIAK AND NIX THE NEED FOR A WWA. NORTHWEST WINDS WILL
PICKUP THIS AFTERNOON BEHIND THE LOW AND WILL BRING THE POTENTIAL FOR
BLOWING SNOW ACROSS WESTERN KODIAK ISLAND. SNOW SHOWERS WILL MAKE
THEIR WAY TOWARDS THE GULF AND EASTERN COASTAL AREAS LATER THIS
AFTERNOON AS A FRONT WILL PUSH NORTH IN WITH THE WEAK KODIAK LOW.

.SOUTHWEST...AS THE AFOREMENTIONED WESTERN KODIAK LOW CONTINUES TO
MOVE TO THE EAST...NORTHERLY WINDS WILL PRODUCE MODEST SNOWFALL ALONG
THE MOUNTAINS. KING SALMON RADAR IS SHOWING THE HIGHEST RETURNS ALONG
A LINE FROM IGIUGIG SOUTH...WHILE MODERATE SNOWS ARE BEING REPORTED
FROM MCGRATH SOUTH. THE HEAVIEST SNOWS WILL CONTINUE THROUGH THE
AFTERNOON EAST OF KING SALMON...ESPECIALLY ALONG THE
MOUNTAINS...WHILE SCATTERED SNOWSHOWERS WILL REMAIN ACROSS THE OTHER
AREAS. A RIDGE WILL BUILD ON THURSDAY BRINGING IN A BREAK FROM THE
ACTIVE WEATHER UNTIL FRIDAY MORNING WHEN A STRONG FRONT MOVES THROUGH
THE AREA.

.BERING SEA AND ALEUTIANS...THE RELATIVE CALM BEFORE THE STORM WILL
BE FELT THIS AFTERNOON AS WINDS WILL BACK OFF SLIGHTLY UNTIL THE
EVENING. THE RAPIDLY DEVELOPING NORTH PACIFIC LOW WILL MOVE NORTH
ACROSS THE FAR WESTERN CHAIN LATE TONIGHT INTO TOMORROW MORNING AS A
963 MB LOW. THIS SYSTEM WILL WRAP ARCTIC AIR DOWN THE BACKSIDE AND
SOME OF THE STRONGEST WINDS WILL BE PRESENT JUST SOUTH OF THE CHAIN
IN MARINE ZONE 175 WHERE HURRICANE FORCE WINDS ARE EXPECTED. AT THIS
POINT A HIGH WIND WATCH HAS BEEN ISSUED FOR THE CENTRAL AND WESTERN
ALEUTIANS STARTING LATE TONIGHT AND LASTING THROUGH THURSDAY
NIGHT/FRIDAY MORNING...BUT THE OVERALL FEELING AS THAT THIS WILL
LIKELY BE UPGRADED TO A WARNING. FOR AREAS EAST AND ALONG THE
CHAIN...A WATCH WILL LIKELY BE ISSUED FOR FRIDAY AS THE LOW TRACKS
ACROSS THE SOUTHERN BERING AND STRONG WINDS ALONG THE BACKSIDE OF THE
LOW MOVE EAST BEFORE DISSIPATING FRIDAY NIGHT OVER BRISTOL BAY.

.LONG TERM FORECAST...MODELS CONTINUE TO HAVE A LACK OF STRONG RUN TO
RUN CONSISTENCY...BUT THE OVERALL LONG-WAVE PATTERN WILL CONTINUE TO
BE THAT OF LOW AMPLITUDE THROUGH THE WEEKEND. THE RESULTANT STORM
TRACKS WILL CONTINUE TO MOVE QUICKLY FROM WEST TO EAST. BY THE
WEEKEND A STRONG FRONT IS EXPECTED TO MOVE ACROSS THE CHAIN...ALONG
THE AKPEN AND INTO BRISTOL BAY BEFORE SLOWING AND WEAKENING NEAR THE
ALEUTIAN RANGE. IN GENERAL...THE OVERALL PATTERN WILL CONTINUE TO BE
QUITE ACTIVE ACROSS THE DOMAIN THROUGH THE WEEKEND AND BEYOND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...SNOW ADVISORY...171
         HIGH WIND WATCH...187 191
MARINE...HURRICANE FORCE WIND WARNING...175
         STORM WARNING...172 176 185 411
         GALE WARNING...120 130 132 150 155 160 165 170 171 179 180
                        351 352 412 413 414
         HEAVY FREEZING SPRAY WARNING...141
FIRE WEATHER...NONE

SSS FEB 09