Brisk Wind Advisory 62, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AKDT SUN APR 26 2009

.MODEL DISCUSSION...

MODELS ARE GENERALLY IN GOOD AGREEMENT AND CONSISTENCY THROUGH THE
SHORT TERM.  THE GFS WAS USED MAINLY OVER MARINE AREAS IN THE SHORT
TERM WITH A LEAN TOWARDS THE NAM FOR THE LAND AREAS DUE TO ITS
ENHANCED SPATIAL RESOLUTION IN THE IMMEDIATE SHORT TERM.  FOR THE
EXTENDED PERIODS...THE EXISTING FORECASTS WERE PREFERRED SO FEW
CHANGES WERE MADE BEYOND TUESDAY.

.ANALYSIS AND UPPER LEVELS...

MOST OF OUR VAST FORECAST AREA OF RESPONSIBILITY IS EXPERIENCING
UNSETTLED WEATHER WITH STRONG SOUTHERLY FLOW BETWEEN HIGH PRESSURE AT
THE SURFACE AND RIDGING ALOFT LOCATED OVER THE CENTRAL AND EASTERN
GULF OF ALASKA AND A 981 MB LOW PRESSURE CENTER WITH A CO-LOCATED
MID-LEVEL TROUGH JUST NORTH OF THE CENTRAL ALEUTIANS IN THE SOUTHERN
BERING SEA.  THE SOUTHERLY FLOW IS SERVING TO TRANSPORT PLENTY OF
MOISTURE INTO THE STATE...WITH TEMPERATURES WARM ENOUGH IN MOST
PLACES FOR THE PRECIPITATION TO FALL AS RAIN.  A FEW LOCATIONS IN THE
HIGHER ELEVATIONS OF THE ALASKA RANGE ARE EXPERIENCING LIGHT SNOW
THIS MORNING.  PRECIPITATION APPEARS TO BE MOST WIDESPREAD OVER THE
MAINLAND WEST OF THE ALASKA RANGE...WHERE A NORTH-SOUTH ORIENTED
FRONT IS JUXTAPOSED WITH A NORTH-SOUTH JET STREAK
ALOFT...CONTRIBUTING TO ENHANCED LIFT.

.SHORT TERM FORECAST...

SOUTH AND EAST OF THE ALASKA RANGE...HIGH PRESSURE BUILDS SLIGHTLY
NORTH AND WESTWARD ACROSS PRINCE WILLIAM SOUND AND INTO THE COPPER
RIVER BASIN TODAY FROM THE GULF OF ALASKA.  THIS WILL LIKELY RESULT
IN DIMINISHING PRECIPITATION FROM EAST TO WEST ACROSS THE REGION
TODAY.  ALSO...WITH CONTINUED LOW PRESSURE WEST OF THE ALASKA RANGE
AND HIGH PRESSURE TO THE EAST...EXPECT TO CONTINUE TO SEE STRONGER
WINDS OF 30 TO 45 MPH BLOWING THROUGH TURNAGAIN ARM INTO THE
OVERNIGHT HOURS SUNDAY NIGHT BEFORE GRADUALLY WEAKENING.  HIGHER
ELEVATIONS ALONG THE ALASKA RANGE SHOULD CONTINUE TO EXPECT TO SEE
PRECIPITATION WITH SOUTHEASTERLY FLOW PROVIDING FOR GOOD UPSLOPE
CONDITIONS.  BY MONDAY NIGHT INTO TUESDAY...EVEN UPSLOPE
PRECIPITATION WILL DIMINISH AS HIGH PRESSURE BUILDS ALL THE WAY INTO
SOUTHCENTRAL FROM THE SOUTH AND EAST.  THEREFORE...WARMER
TEMPERATURES IN THE 50S WITH POSSIBLY A FEW READINGS IN THE LOWER 60S
FOR PARTS OF SOUTHCENTRAL LOOK POSSIBLE FOR TUESDAY.

WEST OF THE ALASKA/ALEUTIAN RANGE...HIGH PRESSURE BUILDS GRADUALLY
BUILDS OVER THE EAST AND A STRONG TROUGH DIGS TO THE SOUTH TOWARDS
THE GULF.  THUS...THE FLOW WILL BECOME INCREASINGLY BACKED THROUGH
THE PERIOD WITH UNSETTLED WEATHER THROUGHOUT THE ENTIRE AREA...DUE TO
SYNOPTIC SCALE LIFT AND MOISTURE TRANSPORT WITH SOUTHERLY FLOW.  THE
GREATEST AMOUNTS OF PRECIPITATION WILL LIKELY BE LOCATED ALONG THE
ALASKA PENINSULA AND THE KUSKOKWIM DELTA REGIONS.

ALEUTIANS AND BERING SEA...THE LOW PRESSURE SYSTEM OVER THE SOUTHERN
BERING WILL LIFT NORTHWARD AND WEAKEN TODAY...WITH ONLY SHOWERS
REMAINING OVER THE CENTRAL ALEUTIANS THROUGH TONIGHT.  THE NEXT LOW
PRESSURE SYSTEM FROM THE NORTHWEST PACIFIC BEGINS TO BRING
PRECIPITATION TO THE WESTERN ALEUTIANS ON MONDAY AFTERNOON AND THEN
POSSIBLY REACHES THE CENTRAL ALEUTIANS ON TUESDAY.

.LONG TERM FORECAST...

HIGH PRESSURE ALOFT CONTINUES TO STRENGTHEN OVER THE STATE FROM
TUESDAY NIGHT THROUGH FRIDAY...AND THEN BEGINS TO WEAKEN A BIT NEXT
WEEKEND AS LOW PRESSURE STRENGTHENS IN THE NORTH PACIFIC JUST SOUTH
OF THE GULF OF ALASKA.  THIS WILL MEAN BROAD EASTERLY OR
SOUTHEASTERLY FLOW ACROSS THE AREA...WITH DRY CONDITIONS AND FAIR
WEATHER OVER THE MAINLAND AND GENERALLY UNSETTLED WEATHER CONDITIONS
OVER THE ALEUTIANS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE...150 155 176
FIRE WEATHER...NONE.

CC APR 09