Small Craft Advisory 1055, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
315 PM AKST SAT DEC 28 2013

.MODEL DISCUSSION...
GFS SUSPECT IN THE SHORT TERM AS IT DOES NOT APPEAR WELL INITIALIZED
WITH SMALLER SCALE FEATURES AS EVIDENCED IN THE WV IMAGERY SO PREFER
THE NAM.

ALL MODELS PICKING UP WITH SYSTEM EJECTING EASTWARD FROM KAMCHATKA
AND GENERALLY HANDLING THE DEVELOPING FRONTAL SYSTEM. HOWEVER THERE
IS DIVERGENCE IN THE UPPER LOW LATE IN THE WEEK AS IT APPROACHES
BRISTOL BAY. APPEARS THE EC MAY BE CARRYING TOO MUCH ENERGY IN THE
NORTHERLY BRANCH IN THE SPLIT FLOW ACROSS THE KUSKOKWIM DELTA. THOUGH
GFS DOES NOT HAVE A GREAT TRACK RECORD PREFER THE GFS SOLUTION MOVING
MOST ENERGY IN SOUTHERLY BRANCH INTO THE NORTHERN GULF.

.ANALYSIS AND UPPER LEVELS...
WELL DEFINED DIPOLE IN THE 500MB 5 WAVE ANCHORED 140E AND 60W REMAINS
INTACT. PSEUDO REX BLOCK ACROSS NORTHWEST ALASKA INTO THE ARCTIC
CONTINUES TO WEAKEN AS UPPER LOW DRIFTS SLOWLY WEST. STORM TRACK
GENERALLY DEPRESSED SOUTH OF THE FORECAST AREA. WV IMAGERY SHOWS
COMPLEX STRUCTURE SEVERAL EMBEDDED WAVES IN BROAD UPPER LOW IN THE
NORTH PACIFIC NEAR 160W.

VERY DEEP UPPER LOW IN SEA OF OKHOTSK EJECTED SIGNIFICANT CHUNK OF
ENERGY EASTWARD ALONG 50N...ALREADY DE-AMPLIFYING THE MID LEVEL FLOW
OVER THE WESTERN ALEUTIANS.

GENERAL SURFACE PATTERN ACROSS STATE IS DOMINATED BY A 1044MB HIGH
CENTERED IN THE ARCTIC. SURFACE WINDS DIMINISHING THROUGH THE PASSES
AS THE PRESSURE GRADIENT RELAXING ALONG COASTAL RANGE. WEAK SURFACE
LOW DRIFTING INTO THE NORTHEAST GULF COAST.

.SHORT TERM FORECAST...
LIGHT SNOW ACROSS KUSKOKWIM OVERNIGHT WITH RAIN ALONG THE ALEUTIANS
INTO SOUTHERN BRISTOL BAY. MIXED PRECIPITATION OVER NORTHERN BRISTOL
BAY. PRECIPITATION CONTINUING INTO SUNDAY.

SNOW ENDING ACROSS THE NORTHERN SUSITNA VALLEY AND COPPER BASIN THIS
EVENING. EXTENSIVE MID LEVEL CLOUDS REMAIN IN WEAK SOUTHERLY FLOW
WITH SOME PATCHY MORNING LOW CLOUDS AND FOG. MODERATING TEMPERATURES.

.LONG TERM FORECAST...
TEMPERATURE MODERATION WILL CONTINUE AS STORM TRACK DRIFTS NORTH WITH
A SERIES OF EMBEDDED LOW PRESSURE SYSTEMS UNTIL LATER IN THE WEEK.
RAIN SNOW LINE SHOULD MOVE INLAND UNDER WARM ADVECTION WITH LIQUID
PRECIPITATION MOVING NORTH INTO MID KUSKOKWIM AND INTO SOUTHCENTRAL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING...155 174 176 177 178.
         HEAVY FREEZING SPRAY WARNING...139 185.
FIRE WEATHER...NONE.

CAS DEC 13