Heavy Freezing Spray Warning 52, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
420 AM AKST WED MAR 2 2016

.ANALYSIS AND UPPER LEVELS...
TRANQUIL CONDITIONS PREVAIL ACROSS THE SOUTHERN MAINLAND THIS
MORNING BENEATH A RATHER DIFFUSE UPPER LEVEL RIDGE WHICH EXTENDS
FROM A CLOSED HIGH OVER THE ARCTIC THROUGH THE INTERIOR AND INTO
THE EASTERN GULF. A WEAK TROUGH IS LIFTING THROUGH THE WESTERN
GULF ON THE PERIPHERY OF THE RIDGE...BUT THE IMPACTS FROM THIS
FEATURE ARE MAINLY LIMITED TO INCREASED MID AND UPPER LEVEL CLOUD
COVER AS RADAR IMAGERY SHOWS SHOWER ACTIVITY RAPIDLY DIMINISHING
ACROSS THE NORTHERN GULF. SHOWERS ARE ALSO BEGINNING TO DECREASE
IN COVERAGE ACROSS THE EASTERN BERING AS A BROAD VERTICALLY
STACKED LOW SHIFTS WESTWARD ALONG THE ALEUTIANS CHAIN...BRINGING
INCREASED SHOWER ACTIVITY TO THE CENTRAL AND WESTERN ALEUTIANS.

&&

.MODEL DISCUSSION...
MODELS ARE IN GENERALLY GOOD AGREEMENT IN THE SHORT TERM AS HIGH
PRESSURE DOMINATES MUCH OF THE REGION THROUGH THE END OF THE WORK
WEEK. UTILIZED THE REGIONAL GEM IN THE EARLY PART OF THE FORECAST
FOR ITS ENHANCED DETAIL GIVEN THE GOOD OVERALL AGREEMENT.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A FEW SHOWERS ARE POSSIBLE ON THE SOUTHERN KENAI AND KODIAK
ISLAND TODAY...OTHERWISE DRY CONDITIONS ARE EXPECTED FOR SOUTH
CENTRAL ALASKA FOR THE NEXT COUPLE OF DAYS. THIS IS DUE TO AN
UPPER LEVEL RIDGE THAT WILL BUILD OVER SOUTHERN ALASKA AND THE
GULF THROUGH TONIGHT. THIS RIDGE WILL THEN PUSH WESTWARD ON
THURSDAY AND THURSDAY NIGHT. THIS WILL LEAVE SOUTH CENTRAL IN A
"COL" BETWEEN LOWS OVER CENTRAL ALASKA/NORTHEAST PACIFIC AND THE
AFOREMENTIONED HIGH OVER THE BERING AND ANOTHER OVER NORTHEAST
CANADA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
SOUTHWEST ALASKA WILL BE UNDERGOING A PATTERN CHANGE FOR THE NEXT
48 HOURS AS THE LOW OVER THE CENTRAL ALEUTIANS CONTINUES TO MOVE
WESTWARD AND HIGH PRESSURE MOVES INTO THE REGION. EAST TO
NORTHEAST FLOW WILL USHER IN COLDER AIR THROUGH THURSDAY...BRINGING
TEMPERATURES OVER THE AREA BACK TO MORE SEASONAL VALUES. DRY
CONDITIONS AND FAIR SKIES WILL LARGELY PREVAIL FOR MOST OF THE
REGION UNTIL FRIDAY EVENING WHEN A WEAK SHORTWAVE WILL MOVE
SOUTHWARD INTO THE KUSKOKWIM RIVER VALLEY. THE WAVE WILL HAVE
LITTLE MOISTURE AVAILABLE AS IT MOVES SOUTH...THUS PRECIPITATION
WILL LIKELY BE IN THE FORM OF FLURRIES.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
CONDITIONS OVER THE BERING SEA WILL GENERALLY STAY SHOWERY AND
WINDY THROUGH FRIDAY NIGHT AS THE LOW NEAR ADAK THIS MORNING
CONTINUES TO MOVE EASTWARD AND WEAKEN. EAST TO NORTHEAST FLOW WILL
DEVELOP OVER THE REGION AS HIGH PRESSURE MOVES INTO THE BERING
STRAIGHT AND Y-K DELTA REGION. SHORTWAVES ROTATING AROUND THE
UPPER LOW WILL KEEP THE WESTERN TWO-THIRDS OF THE BERING SEA AND
ALEUTIAN CHAIN SHOWERY THOUGH TOMORROW NIGHT...WITH PRECIPITATION
OVER THE ALASKA PENINSULA TAPERING OFF THIS AFTERNOON AS THE LOW
MOVES WESTWARD.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE PERIOD WILL START WITH HIGH PRESSURE OVER THE SOUTHERN
MAINLAND RECEDING TO THE NORTH AND WEST AS LOW PRESSURE GRADUALLY
MOVES IN FROM THE SOUTH STARTING FRIDAY. CLEAR SKIES AND DRY
CONDITIONS ASSOCIATED WITH THE HIGH PRESSURE WILL PERSIST OVER
THESE AREAS THROUGH FRI...BEFORE PRECIPITATION AND WINDS BEGIN TO
PICK UP ALONG THE NORTHERN GULF COAST FRI NIGHT AS THE LOW TRACKS
INTO THE GULF. TEMPERATURES WILL ALSO RETURN TO MUCH MORE
SEASONABLE WITH THE SLIGHT REPRIEVE FROM THE WARM SOUTHERLY FLOW.
OVER THE WEST...A BROAD WEAKENING LOW WILL CONTINUE TO TRACK NORTH
OF THE ALEUTIAN CHAIN TOWARD THE WESTERN ALEUTIANS. EAST TO
NORTHEAST FLOW BEHIND IT WILL BRING DRYING CONDITIONS TO THE
EASTERN BERING. IT WILL LEAVE THE ONLY REAL POTENTIAL FOR
PRECIPITATION CONFINED TO AREAS WEST OF THE PRIBILOF ISLANDS. AND
EVEN THIS PRECIPITATION WILL BE LIGHT AT BEST.

HEADING TOWARD THE WEEKEND...THE BROAD AREA OF LOW PRESSURE
SOMEWHERE NEAR 50N 145W WILL SLOWLY DRIFT NORTH TOWARD THE GULF OF
ALASKA. THIS WILL ONCE AGAIN OPEN UP COASTAL AREAS TO INCREASING
EASTERLY WINDS AND BETTER CHANCES FOR PRECIPITATION. THE LONG-
RANGE MODELS AND THEIR ENSEMBLE MEANS DID TREND SLIGHTLY FARTHER
NORTH AND EAST WITH THE PRIMARY LOW CENTER. THIS MIGHT OPEN UP
THE POSSIBILITY OF SOME PRECIPITATION MAKING IT INTO SOUTH CENTRAL
SAT INTO SUN. HOWEVER...THE TRACK OF THE SYSTEMS FROM THE
SOUTHEAST DOES NOT FAVOR MUCH MOISTURE MAKING IT OVER THE CHUGACH
AND KENAI MOUNTAINS. OUT WEST...FLOW REORIENTS TO A MORE NORTHERLY
DIRECTION. THIS COULD MAKE FOR A SHORT PERIOD OF GALES OVER THE
NORTHERN BERING AND SHOULD LEAD TO AN INCREASE IN COLD AIR
ADVECTION SHOWERS...ESPECIALLY ON THE BERING SIDE OF THE CHAIN.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...CB
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...RF
LONG TERM...TP