Small Craft Advisory 1008, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
404 PM AKST TUE DEC 16 2014

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW CENTERED OVER THE EASTERN BERING SEA.
THERE ARE SEVERAL TROUGHS ASSOCIATED WITH THIS LOW. ONE OF THESE
IS JUST ALONG THE NORTH GULF COAST...WITH ANOTHER OVER THE
NORTHERN GULF PARALLEL TO THE FIRST...AND ANOTHER IN THE SOUTHERN
GULF. THERE IS A DEVELOPING LOW SOUTH OF THE CENTRAL ALEUTIANS AND
ANOTHER ONE CENTERED OVER HOKKAIDO (ISLAND OF JAPAN).

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.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH ABOUT HOUR 60
OF THE FORECAST (3PM AKST THURSDAY)...THEN BEGIN TO SHOW
INCREASING GREATER SPREAD THROUGH 84 HOURS. THE MAIN DIFFERENCES
ARE HOW THEY HANDLE THE SPEED/DEPTH OF A LOW SOUTH OF THE
ALEUTIANS THURSDAY NIGHT/FRIDAY AND THE VARIOUS CENTERS OF A
COMPLEX LOW IN THE GULF.

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.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE TROUGH ALONG THE GULF COAST WILL RAPIDLY MOVE INLAND AND
DISSIPATE EARLY THIS EVENING. THE SECOND TROUGH WILL OVERTAKE THE
PREVIOUS ONE DURING THE EVENING AND SHOULD PROVIDE ENOUGH DYNAMICS
TO PRODUCE PRECIPITATION FOR INLAND AREAS. PRECIPITATION WILL
CONTINUE OVERNIGHT AND INTO WEDNESDAY...PROLONGED A LITTLE BY THE
THIRD TROUGH THAT MOVES ONSHORE EARLY WEDNESDAY AFTERNOON.
PRECIPITATION TYPE WILL PROBABLY START AS RAIN OR A RAIN/SNOW
COMBINATION THEN SWITCH TO ALL SNOW OVERNIGHT. NOT A LOT OF
ACCUMULATION IS EXPECTED AS THE WINDS ALOFT NEVER BECOME VERY
FAVORABLE...BUT SOME IS POSSIBLE. ON WEDNESDAY NIGHT AND THURSDAY
THE LOW THAT IS CURRENTLY SOUTH OF THE CENTRAL ALEUTIANS WILL PUSH
NORTHWESTWARD INTO THE GULF. THIS WILL PUT US IN A PATTERN WHERE
WE HAVE PRECIPITATION IN COASTAL AREAS AND LITTLE OR NONE INLAND.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
CONDITIONS LOOK TO BE IMPROVING ACROSS THE MAINLAND THIS
EVENING INTO TOMORROW. THE SYSTEM RESPONSIBLE FOR THE PREVIOUS
FRONT WILL SLOWLY DRIFT NORTH IN THE BERING AND
DISSIPATE...HOWEVER...DEEP COLD AIR ALOFT WILL BRING A SHOWERY
REGIME THROUGH TOMORROW MORNING FOR MOST LOCATIONS. EXPECT
WIDESPREAD LOW AND MID-LEVEL CLOUDS TO DISSIPATE AND MOVE OUT OF
THE AREA WHILE INTERMITTENT CLOUDS AND SNOW SHOWERS TO AFFECT MOST
AREAS. WEDNESDAY INTO THURSDAY A SYSTEM PROGRESSING SOUTH OF THE
ALASKA PENINSULA WILL SPREAD SOME HIGHER CLOUDS OVER INTERIOR
BRISTOL BAY...BUT THE AREA SHOULD STAY DRY UNTIL THURSDAY WHEN THE
CHANCE FOR SNOW RETURNS...MAINLY ALONG THE ALASKA PENINSULA. ABOVE
AVERAGE TEMPERATURES AND LIGHT WINDS WILL PREVAIL FOR THE NEXT
COUPLE DAYS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE ALEUTIANS CURRENTLY SIT BETWEEN THE UNSTABLE SHOWERY REGIME OF
THE PREVIOUS SYSTEM IN THE BERING AND A NEW SYSTEM DEVELOPING TO
THE SOUTH. THE CENTRAL AND EASTERN ALEUTIANS WILL REMAIN IN
SCATTERED SNOW SHOWERS WHILE THE TIP OF THE ALASKA PENINSULA WILL
SEE SOME RAIN AND SNOW AS THE FRONTAL BOUNDARY FROM THE SOUTHERN
SYSTEM MOVE OVERHEAD. GENERAL TROUGHINESS CONTINUES OVER THE
BERING SEA THROUGH THURSDAY AS ANOTHER FRONT WASHES OUT OVER THE
WESTERN/CENTRAL ALEUTIANS.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE GENERAL PATTERN FROM THE SHORT TERM WILL CONTINUE THROUGH
FRIDAY AND SATURDAY. THE GULF LOW WILL PUSH WESTWARD ACROSS
KODIAK ISLAND WHILE LOWS IN THE BERING AND ALEUTIANS WILL SPIN
SOUTH/SOUTHEAST. THE PATTERN WILL BEGIN TO SHIFT ON SUNDAY...WITH
STRONG ZONAL (STRONG WESTERLY) FLOW BEGINNING TO PUSH INTO THE
WESTERN BERING SEA. THIS ZONAL FLOW WILL PUSH EASTWARD FOR THE
NEXT FEW DAYS AND ENCOMPASS THE ENTIRE AREA BY TUESDAY AFTERNOON.
WPC IS AGAIN GOING WITH ALL ENSEMBLE MEANS...A BASICALLY EVEN
SPLIT OF GFS...EC...AND NAF (WHICH IS A COMBINATION OF THE
CANADIAN MODELS AND THE GFS).

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES...119 120 131 132 150 178 179 185
FIRE WEATHER...NONE.

&&