Small Craft Advisory 179, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST MON FEB 19 2007

.DISCUSSION...
A SURFACE LOW IN THE SOUTHERN GULF OF ALASKA CONTINUES TO WEAKEN AS
IT MOVES TOWARDS SOUTHEASTERN ALASKA. ANOTHER WEAKENING SURFACE LOW
IN THE BERING IS HEADED SOUTHEAST TO DISSIPATE AS IT CROSSES THE
AKPENN. RADAR SHOWS AREAS OF LIGHT PRECIPITATION FROM BOTH LOWS ALONG
THE WESTERN ALASKA COAST AND THE NORTHERN GULF COAST...HOWEVER
DISSIPATING RAPIDLY. COLD ADVECTION BEHIND THE BERING LOW IS BRINGING
SNOW SHOWERS AND GALE FORCE WINDS TO THE CENTRAL AND EASTERN
ALEUTIANS. A SURFACE HIGH OVER THE NORTHERN YUKON TERRITORY ALONG
WITH A DEEPENING UPPER LOW OVER THE ARCTIC OCEAN...BOTH MOVING
SOUTHEAST TOWARD ALASKA...IS HELPING CLEAR THE STATE FROM THE NORTH
AND ARE THE MAIN PLAYERS IN THIS WEEKS WEATHER OVER THE MAINLAND.

GFS WAS THE MODEL OF CHOICE FOR GUIDANCE DUE TO ITS CONSISTENCY IN
BOTH THE SHORT TERM AND LONG TERM.

MAINLAND ALASKA...LOOK FOR CLEARING CONDITIONS...COLDER TEMPERATURES
AND GUSTY GAP WINDS THIS WEEK DUE TO THE UPPER LOW MOVING OVER THE
ALCAN BORDER. SEVERAL IMPULSES ON THE BACKSIDE OF THE LOW WILL CAUSE
COLD ARCTIC AIR TO SPREAD SOUTH. MODELS STILL SHOW AN ALMOST 20
DEGREE DROP IN 850 MB TEMPERATURES OVER THE AREA. THE COMBINATION OF
AN INCREASING PRESSURE GRADIENT ALONG THE NORTHERN GULF
COAST...BETWEEN THE SURFACE GULF LOW AND THE STRENGTHENING SURFACE
HIGH OVER THE INTERIOR...AND THE STRONG COLD ADVECTION WILL INCREASE
WIND SPEEDS...ESPECIALLY THROUGH NORTH TO SOUTH CHANNELED TERRAIN AND
BAYS. WITH MODELS STILL HOLDING ON TO THE PATTERN...HAVE PUSHED THE
HIGH WIND WARNINGS FOR THOMPSON PASS AND COPPER RIVER DELTA. WIND
CHILL ADVISORIES WILL REMAIN IN EFFECT DUE TO THE WIND AND
TEMPERATURE CONDITIONS THROUGH THOMPSON PASS...COPPER RIVER VALLEY
AND NORTH OF TALKEETNA.

BERING SEA AND ALEUTIANS...CENTRAL AND EASTERN ALEUTIANS WILL HAVE
WINDY CONDITIONS THROUGH TODAY AS THE STRONGER BACKSIDE WINDS OF THE
BERING SURFACE LOW PUSH THROUGH TOWARD THE PACIFIC. AFTER A RIDGE
BUILDS INTO THE CENTRAL BERING...A STRONG FRONT WILL MOVE ACROSS THE
WESTERN BERING MONDAY NIGHT THEN DISSIPATE OVER THE CENTRAL BERING
AND EASTERN ALEUTIANS WEDNESDAY NIGHT AS IT TRIES TO PUSH INTO THE
RIDGE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 131 135
MARINE...STORM 121 176
      ...GALE 120 125 129 130 132 150 155 165 170 171 172 175 179
      ...HEAVY FREEZING SPRAY 120 121 125 129 130 138 140 141 150
                               180 185
FIRE WEATHER...NONE

LR FEB 07