Small Craft Advisory 395, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
300 PM AKDT SUN JUN 5 2011

.MODEL DISCUSSION...

MODELS IN REASONABLY GOOD AGREEMENT. GFS HAS HAD GOOD RUN TO RUN
CONSISTENCY LAST SEVERAL RUNS AND IS OUR MODEL OF CHOICE THROUGH THE
SHORT TERM. SAW NO NEED TO MAKE CHANGES TO MID OR LONG TERM FORECAST
PACKAGE AT THIS TIME.

.ANALYSIS AND SHORT TERM FORECAST...

A 994 MB LOW CENTERED NEAR SAINT MATTHEW ISLAND REMAINS NEARLY
STATIONARY AND WEAKEN TO 1014 MB BY TUESDAY MORNING. MOIST WEST TO
SOUTHWESTERLY ONSHORE FLOW WILL PERSIST ACROSS THE ALEUTIANS AND
SOUTHWEST MAINLAND THROUGH TOMORROW AFTERNOON.

A 1004 MB NORTH PACIFIC LOW WILL MOVE TO JUST SOUTH OF COLD BAY LATE
MONDAY NIGHT. THE ASSOCIATED OCCLUDED FRONT WILL PASS OVER THE ALASKA
PENINSULA AND SOUTHERN BRISTOL BAY MONDAY EVENING THEN GRADUAL BREAK
DOWN AS IT PRESSES FURTHER NORTHWARD AND FURTHER INLAND.
NORTHWESTERLY FLOW ALONG THE REAR FLANK OF THIS SYSTEM WILL KEEP THE
CENTRAL BERING SEA AND CENTRAL ALEUTIANS COVERED IN SCATTERED RAIN
SHOWERS...AND POSSIBLY EVEN SNOW SHOWERS...THROUGH MIDWEEK.

A SHALLOW SURFACE RIDGE HAS BUILT IN OVER SOUTHCENTRAL TODAY BUT THE
TRANSVERSE LONG WAVE TROUGH ALOFT HAS BEEN STRENGTHENING THROUGH THE
DAY AS WELL. FEW SUNNY BREAKS DEVELOPING OVER SOUTHCENTRAL THIS
AFTERNOON AND EVENING BUT MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS
WILL PREDOMINATE OVER THE AREA THROUGH TOMORROW. TROUGH ALOFT BEGINS
TO BREAK DOWN MONDAY EVENING...LEADING TO A BRIEF DRYING TREND. HIGH
PRESSURE WILL PREVAIL ACROSS THE REGION MONDAY NIGHT THROUGH TUESDAY
BUT WILL BE SHOVED OFF THE THE EAST WHEN THE NEW NORTH PACIFIC
LOW...DISCUSSED ABOVE...MOVES IN EARLY TUESDAY.

GRADIENT BEGINS TO TIGHTEN AHEAD OF THE APPROACHING SYSTEM LATE
MONDAY NIGHT...PRODUCING GUSTY SOUTHEAST WINDS THROUGH THE USUAL
CHANNELED AREAS OF BOTH SOUTH CENTRAL AND SOUTHWESTERN ALASKA THROUGH
TUESDAY NIGHT.

ASSOCIATED WARM FRONT RAPIDLY OCCLUDES AS IT PASSES OVER KODIAK
ISLAND MON NIGHT...REACHING THE GULF COAST TUESDAY AFTERNOON. SYSTEM
IS BOTH WARM AND SLOW MOVING...WHICH WILL BE CONDUCIVE TO MODERATE TO
HEAVY RAINFALL...ESPECIALLY OVER KODIAK ISLAND...PRINCE WILLIAM
SOUND...THE SOUTHERN KENAI PENINSULA...AND SOUTHERNMOST EXTENSION OF
THE ALASKA RANGE. THE MATANUSKA VALLEY AND ANCHORAGE MUNICIPALITY
WILL BE SHIELDED FROM MOST OF THE RAIN BY THE CHUGACH AND TALKEETNA
MOUNTAINS. PRECIPITATION IN THE NORTHERN SUSITNA VALLEY AND COPPER
RIVER BASIN WILL BE LIMITED TO SCATTERED SHOWERS.

.LONG TERM FORECAST...

THE 1004 MB LOW SOUTH OF COLD BAY MONDAY NIGHT WILL GRADUALLY WEAKEN
AS IT PASSES OVER KODIAK ISLAND TUESDAY NIGHT THEN DISSIPATE IN THE
NORTHERN GULF OF ALASKA WEDNESDAY NIGHT. THE GUSTY SOUTHEAST WINDS
WILL DROP OFF EARLY WEDNESDAY BUT LIGHT RAIN AND SCATTERED SHOWERS
WILL LINGER OVER SOUTH CENTRAL AND SOUTHWESTERN ALASKA INTO THURSDAY.

A 984 MB LOW WILL MOVE OUT OF THE NORTHWEST PACIFIC ON TUESDAY AND
TRACK JUST SOUTH OF THE ALEUTIAN CHAIN TUESDAY NIGHT THROUGH
THURSDAY. GALE FORCE WINDS AND PLENTY OF RAIN ALONG AND AHEAD OF THIS
SYSTEM.

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

ASB JUN 11