Brisk Wind Advisory 37, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT SAT MAR 21 2009

.ANALYSIS AND UPPER LEVELS...
IN THE UPPER LEVELS...THE BLOCKING RIDGE OVER NORTHEAST SIBERIA IS
BEGINNING TO RETROGRADE WEST...AS AN UPPER LOW UNDERCUTS THE RIDGE.
ANOTHER UPPER LOW CENTERED OVER THE INTERIOR IS SLIDING
SOUTHWEST...WITH THE TROUGH AXIS EXTENDING THROUGH THE GULF OF
ALASKA.

AT THE SURFACE...A 997 MB LOW OVER THE GULF OF ALASKA IS MOVING
NORTHWEST TOWARD THE KENAI PENINSULA. A DEVELOPING 991 MB TRIPLE
POINT LOW IS EVIDENT ON SATELLITE IMAGERY SOUTH OF DUTCH
HARBOR...WITH DEEP MOISTURE TRANSPORT FROM THE SUBTROPICS AHEAD OF
THE LOW.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT THROUGH 72 HOURS...OR 12Z TUESDAY. WHILE
MINOR DIFFERENCES ARISE CONCERNING EXACT POSITIONING AND STRENGTH OF
LOWS IN THE GULF OF ALASKA THROUGH THE BEGINNING OF THE WEEK...THE
GENERAL SOLUTION IS THE SAME AMONGST THE OPERATIONAL MODELS.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
CLOUDS AND SNOW WILL BE MOVING BACK INTO SOUTHCENTRAL OVERNIGHT AS
THE AFOREMENTIONED LOW IN THE GULF MOVES TOWARDS MONTAGUE ISLAND.
EXPECT ACCUMULATIONS TO BE RELATIVELY LIGHT...ESPECIALLY FOR CORDOVA
AND VALDEZ WHERE DOWNSLOPING WILL DRY THINGS OUT. THE NEXT LOW
CURRENTLY SOUTH OF DUTCH HARBOR WILL MOVE INTO THE GULF
SUNDAY...SPREADING MOISTURE ACROSS SOUTHCENTRAL AGAIN. WARMER AIR
WILL ACCOMPANY THIS LOW...WITH RAIN MIXING IN ALONG COASTAL
LOCATIONS. AT THIS TIME EXPECT THE LOW TO MOVE TO NEAR THE BARREN
ISLANDS. CONSEQUENTLY...THE POTENTIAL FOR HIGH WINDS IN PORTAGE WILL
HAVE TO BE MONITORED...AS WILL POTENTIAL BLIZZARD CONDITIONS ALONG
KODIAK ISLAND DUE TO STRONG COLD AIR ADVECTION. TYPICAL DOWNSLOPING
WITH THIS LOW WILL MINIMIZE PRECIPITATION AMOUNTS ACROSS THE
ANCHORAGE BOWL.

.SOUTHWEST...
TEMPERATURES WILL BEGIN MODERATING OVER SOUTHWEST ALASKA...AS CLOUDS
AND MOISTURE MOVE BACK INTO THE AREA IN ASSOCIATION WITH THE TRIPLE
POINT LOW MOVING INTO THE GULF. GUSTY WINDS THROUGH CHANNELED TERRAIN
WILL LEAD TO BLOWING SNOW ALONG THE AKPEN THROUGH TOMORROW...WITH
NORTHERLY WINDS CONTINUING ACROSS SOUTHWEST AS WE HEAD INTO THE FIRST
PART OF THE WEEK. A SHORTWAVE WILL PUSH NORTHWARD INTO THE AREA
MONDAY...BRINGING AN ADDITIONAL SHOT OF LIGHT SNOW ACROSS SOUTHWEST.
SNOW SHOWERS WILL BE MOST WIDESPREAD OVER THE AKPEN AND BRISTOL BAY
ZONES...WITH GENERALLY ISOLATED SHOWERS ELSEWHERE.

.BERING SEA AND ALEUTIANS...
CONDITIONS WILL BE IMPROVING ACROSS THE CENTRAL AND EASTERN ALEUTIANS
TONIGHT AS THE DEVELOPING TRIPLE POINT LOW MOVES INTO THE GULF OF
ALASKA. BLIZZARD CONDITIONS OVER THE CENTRAL AND EASTERN ISLANDS
SHOULD BE COMING TO AN END THIS AFTERNOON INTO TONIGHT...ALTHOUGH
BLOWING SNOW WILL REMAIN A CONCERN OVER THE EASTERN ISLANDS THROUGH
TOMORROW. ON THE BACKSIDE OF THE LOW...COLD ADVECTION WILL RESULT IN
CONTINUED GUSTY NORTHERLY FLOW WITH WIDESPREAD SNOW SHOWERS THROUGH
THE BEGINNING OF THE WEEK.

.LONG TERM FORECAST...
AS MENTIONED IN THE PREVIOUS DISCUSSION...THE SIBERIAN BLOCK WILL
CONTINUE TO SLOWLY RETROGRADE WEST THROUGH NEXT WEEK. THE MEAN TROUGH
WILL BECOME WELL ESTABLISHED OVER THE EASTERN AND CENTRAL BERING SEA.
WHILE IN AGREEMENT ON THE OVERALL PATTERN...THE NUMERICAL MODELS
DIFFER ON IMPORTANT DETAILS SUCH AS HOW MUCH MOISTURE AND WARM AIR
WILL AFFECT THE STATE. IT DOES APPEAR LIKELY THAT TEMPERATURES WILL
BE MODERATING TO MORE SEASONABLE VALUES BY LATE WEEK...WITH SHOWERY
WEATHER PERSISTING OVER SOUTHERN ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING 185
MARINE...GALE WARNING 120 125 130  132 138 140 155 165 170
                      172 175 176 351 352 411 412
         HEAVY FREEZING SPRAY 165 411 412 414
FIRE WEATHER...NONE

NRH MAR 09