Small Craft Advisory 1000, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
452 AM AKST MON DEC 15 2014

.ANALYSIS AND UPPER LEVELS...
A BROAD AREA OF LOW PRESSURE STRETCHES OUT ACROSS THE BERING SEA.
THE MAIN LOW CENTER IS NEAR THE ALASKA PENINSULA AND THIS LOW IS
BRINGING A SOUTHERLY PUSH OF WARM AIR OVER MAINLAND ALASKA. ON
THE OTHER SIDE OF THE LOW WESTERLY FLOW IS BRINGING COLDER AIR TO
THE BERING AND ALEUTIANS.

&&

.MODEL DISCUSSION...
THERE IS DECENT MODEL AGREEMENT WITH THE SYNOPTIC FEATURES BUT THE
MODELS ARE STRUGGLING WITH THE SMALLER LOW CENTERS IN THIS COMPLEX
PATTERN. AS A FRONT APPROACHES THE GULF FROM THE SOUTH TODAY ALL
MODELS ARE TRYING TO SPIN UP A LOW ON IT BUT THE POSITIONS VARY
ALL ACROSS NORTHERN GULF ON TUESDAY. ANOTHER PROBLEM IS WITH A
LOW APPROACHING THE GULF WEDNESDAY NIGHT WHERE THE GFS AND GEM
TAKE IT WEST WHILE THE NAM AND EC TAKE IT EAST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
WARM AIR MOVING IN FROM THE SOUTH WILL KEEP MOST AREAS AROUND THE
SOUTHCENTRAL IN RAIN. THE THREAT OF FREEZING RAIN WILL BE MINIMAL
AS OVERALL PRECIPITATION IN AREAS THAT ARE BELOW ZERO IS TAPERING
OFF AND THOSE AREAS SHOULD STAY DRY. EVEN THOUGH THERE IS MODEL
INCONSISTENCY WITH THE FRONT APPROACHING THE SOUTHERN GULF ALL
MODELS AGREE THAT A LOW WILL FORM AND MOVE INTO THE COOK INLET
AREA LATER ON TUESDAY. THIS WILL BRING IN SOME COLDER AIR AND
SOUTHWEST FLOW TO THE SOUTHCENTRAL WHICH WILL BRING BACK SNOW TO
THE AREA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (TODAY AND TOMORROW)...

RAIN SHOWERS...OCCASIONALLY MIXED WITH SNOW NORTH AND WEST OF KING
SALMON...HAVE STEADILY BEEN ON THE RISE OVERNIGHT AS AN AREA OF
LOW PRESSURE HAS MOVED OVER THE EASTERN BERING SEA AND BRISTOL
BAY. AN ASSOCIATED STATIONARY FRONT IS DRAPED ACROSS THE ALASKA
PENINSULA AND EXTENDED NEAR KODIAK AND THEN INTO THE NORTH PACIFIC.
THIS FRONT HAS ACTED AS A LIFTING MECHANISM...ALLOWING FOR RAIN
AND SNOW SHOWERS TO DEVELOP ALONG THIS BOUNDARY. HOWEVER...THE
12Z KING SALMON (PAKN) RAOB SHOW DECENT CROSS BARRIER FLOW WHICH
HAS BEEN KEEPING DOWNWIND LOCATIONS OF THE ALASKA RANGE (LIKE KING
SALMON) RELATIVELY DRY OVERNIGHT. THIS DOWNSLOPING COMPONENT WILL
WEAKEN THIS AFTERNOON AND FORCING WILL BECOME GREATER AS THE AREA
OF LOW PRESSURE OVER THE EASTERN BERING SEA PUSHES CLOSE TO
BRISTOL BAY. THE KUSKOKWIM DELTA WILL CONTINUE TO SEE SNOW
SHOWERS...WITH THE HIGHEST PROBABILITIES OF THESE SHOWERS ALONG
THE COAST. SNOW ACCUMULATIONS FOR THE DELTA WILL RANGE FROM 1 TO
3 INCHES WHILE THE BRISTOL BAY AREA COULD SEE 1 TO 4 INCHES...WITH
THE HIGHEST AMOUNTS NEAR THE AHKLUN MOUNTAINS.

A CHANCE FOR LIGHT FREEZING RAIN AGAIN CONTINUES THIS MORNING...
MAINLY FROM A LINE EXTENDING FROM NEAR DILLINGHAM NORTHWARD INTO
THE LOWER KUSKOKWIM VALLEY. THE FORECAST FOR THE LOWER KUSKOKWIM
VALLEY IS A BIT INTERESTING BECAUSE EVEN THOUGH A WARM LAYER
EXISTS...A THICK ENOUGH COLD LAYER BENEATH THE WARM LAYER EXISTS
TO WHERE THE FORMATION OF SLEET IS POSSIBLE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (TODAY AND TOMORROW)...

GUSTY WINDS HAVE BEEN OBSERVED THIS MORNING ALONG THE SOUTHERN TIP
OF THE ALASKA PENINSULA AS A JET STREAK ON THE BACK SIDE OF THE
LOW IN THE EASTERN BERING SEA HAS TIGHTENED UP THE PRESSURE
GRADIENT. WIND GUSTS APPROACHING 75 MPH HAVE BEEN OBSERVED NEAR
FALSE PASS (PAKF) AND GUSTS IN THE 50 TO 65 MPH RANGE HAVE BEEN
OBSERVED NEAR COLD BAY. THESE WINDS SHOULD WEAKEN AS THE LOW
SHIFTS EASTWARD AND THE JET STREAK PUSHES ACROSS THE AREA THIS
MORNING. BECAUSE OF THESE STRONGER WINDS...WENT AHEAD AND BUMPED
UP THE COASTAL FORECAST FOR THE PACIFIC SIDE OF THE ALASKA
PENINSULA (MARINE ZONE 155) TO STORMS FOR THIS MORNING. RAIN AND
SNOW SHOWERS WILL CONTINUE ACROSS THE BERING SEA AND ALEUTIAN
ISLANDS AS THE LOW IN THE EASTERN BERING SEA BEGINS TO DRIFT
NORTHWESTWARD INTO THE CENTRAL BERING SEA LATE TODAY AND INTO
TUESDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A VERTICALLY STACKED LOW WILL TRACK INTO THE NORTHERN BERING BY
WEDNESDAY AFTERNOON...KEEPING A SHOWERY REGIME OVER MUCH OF THE
REGION THROUGH THURSDAY. THE WET PATTERN WILL THEN CONTINUE INTO
THE WEEKEND AS A PAIR OF LOWS OVER THE NORTH PACIFIC BEGIN TO
TRACK CLOSER TO THE REGION...WITH ONE LOW APPROACHING THE GULF
LATER IN THE WEEK AND ANOTHER SKIRTING THE ALEUTIAN CHAIN IN THE
SAME TIME FRAME. THE ECMWF BRINGS IN A MUCH WEAKER LOW INTO THE
GULF MID WEEK AND DISSIPATES BY THURSDAY...WHERE THE LOW SOUTH OF
THE ALEUTIAN CHAIN IS SLOWER TO APPROACH THE WESTERN ALEUTIANS AND
DRAGS BEHIND THE OTHER SOLUTIONS INTO THE WEEKEND. THE GFS AND
CANADIAN MODEL SHOW A STRONGER LOW ENTERING THE SOUTHWESTERN GULF
THURSDAY AFTERNOON THEN TRACKS INTO THE EASTERN BERING BY FRIDAY
MORNING. THE GFS ALSO DEPICTS A FASTER MOVING SOLUTION REGARDING
THE LOW TRACKING SOUTH OF THE CHAIN INTO THE WEEKEND. THE MODELS
AGREE ON A STRONG ZONAL JET SOUTH OF THE CHAIN INITIALLY ON
THURSDAY...WHICH BEGINS TO BUCKLE LATER ON FRIDAY. ONE CAN EXPECT
A SLIGHTLY FASTER PROGRESSION OF THIS SYSTEM GIVEN THE STRONGER
ZONAL FLOW INITIALLY. CONFIDENCE REMAINS LOW REGARDING THE
SPECIFIC DETAILS OF THESE FEATURES GIVEN A RELATIVELY LARGE AMOUNT
OF MODEL SPREAD. THE MODELS CONTINUE TO DIVERGE INTO THE
WEEKEND...THEN BEGIN TO COME INTO AGREEMENT SYNOPTICALLY AGAIN BY
NEXT MONDAY WITH A BROAD AREA OF LOW PRESSURE OVER THE
SOUTHCENTRAL MAINLAND. IN THE SAME TIME FRAME...THE MODELS ALSO
COME INTO BETTER AGREEMENT ON A RIDGE BUILDING OVER THE CENTRAL
AND EASTERN BERING AND A FRONTAL SYSTEM MOVING THROUGH THE
WESTERN BERING/ALEUTIANS BY MONDAY.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORMS 155
         GALES 119 125 150 165 170 172 179 181 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MC
LONG TERM...TP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1105 AM AKST MON DEC 15 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0100 AM     FREEZING RAIN    11 S TALKEETNA          62.18N 150.03W
12/15/2014  U0.00 INCH                          AK   DEPT OF HIGHWAYS

            SPOTTY LIGHT FREEZING RAIN FROM MILEPOST 7 AND SOUTH ON
            TALKEETNA SPUR ROAD. THIN LAYER OF ICE ACCUMULATION ON
            ROADS.

&&

RSD