Heavy Freezing Spray Warning 40, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
428 AM AKST THU MAR 3 2016

.ANALYSIS AND UPPER LEVELS...

THE MAJORITY OF THE ACTIVITY IS TO THE SOUTH OF THE AREA WITH ONE
LOW SOUTH OF THE WESTERN ALEUTIANS AND ANOTHER SOUTH OF THE GULF.
THIS PROVIDES A GENERALLY EAST WIND OVER THE AREA AND IS KEEPING
FAIR CONDITIONS OVER THE SOUTHERN PART OF THE STATE. THE EASTERN
LOW HAS ALSO PULLED UP WARMER AIR OVER SOUTHERN ALASKA.

&&

.MODEL DISCUSSION...

THE MODELS ARE IN GOOD AGREEMENT WITH THE MAJOR FEATURES THROUGH
THE MID TERM. THIS RESULTS IN HIGH CONFIDENCE IN THE FORECAST.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE UPPER LEVEL HIGH OVER SOUTHERN ALASKA AND THE GULF WILL
CONTINUE TO SLIDE WEST INTO THE BERING SEA TODAY AND TOWARD
NORTHEAST RUSSIA TONIGHT. AN UPPER LEVEL LOW SOUTH OF THE GULF
WILL BEGIN TO PUSH WEATHER SYSTEMS TOWARD SOUTH CENTRAL ALASKA
TONIGHT. THE FIRST OF THESE SYSTEMS WILL REACH THE GULF COAST LATE
TONIGHT AND MOVE INTO THE KENAI PENINSULA AND KODIAK EARLY
FRIDAY. THERE WILL BE A CHANCE OF PRECIPITATION AS FAR NORTH AS
ANCHORAGE FRIDAY AFTERNOON...THEN IT WILL BE CONFINED TO THE
SOUTHERN KENAI AND KODIAK FRIDAY NIGHT. ANOTHER SYSTEM WILL BEGIN
TO MOVE INTO THE EASTERN PRINCE WILLIAM SOUND AREA BY LATE FRIDAY
NIGHT.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

A COOLER AND DRIER TREND IS SETTING UP FOR THE END OF THE WEEK AS
SURFACE RIDGING BECOMES THE DOMINANT INFLUENCE ACROSS THE SOUTHWEST
MAINLAND. NORTH TO EAST FLOW WILL BE GUSTY AT TIMES WITH SLIGHTLY
STRONGER WINDS ON FRIDAY AS A COLD FRONT PUSHES FROM THE KUSKOKWIM
DELTA IN THE MORNING TO THE ALASKA PENINSULA IN THE AFTERNOON.
ISOLATED TO SCATTERED SNOW SHOWERS WILL BE POSSIBLE ALONG THE WEST
COAST AREAS WITH INCREASED LOW LEVEL MOISTURE AND A STRONG SHORT
WAVE THAT HELPS PUSH THE FRONT SOUTH.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

RELATIVELY QUIET CONDITIONS ARE EXPECTED TO PERSIST INTO THE END
OF THE WEEK. THE MAIN CHANGE IN THE CURRENT PATTERN BEGINS TONIGHT
AS A COLD FRONT TRACKS INTO THE NORTHERN BERING. NORTHEASTERLY
FLOW INCREASES TONIGHT ACROSS THE NORTHERN WATERS...HOWEVER WINDS
ARE EXPECTED TO REMAIN IN THE SMALL CRAFT RANGE. THE COLDER
TEMPERATURES AND GUSTY WINDS WILL COMBINE TO CREATE HEAVY
FREEZING SPRAY ALONG THE ICE EDGE. THE SOUTHEASTERN AREAS OF THE
BERING AND EASTERN ALEUTIANS WILL SEE WINDS INCREASE BY FRIDAY
AFTERNOON. THE GREATEST CHANCES FOR PRECIPITATION WILL BE ALONG
THE FRONTAL PASSAGE AND ALSO ACROSS THE CENTRAL AND WESTERN
ALEUTIANS WHERE WEAK UPPER LEVEL DISTURBANCES MOVE AROUND A LOW IN
THE NORTH PACIFIC.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...

BEGINNING THE EXTENDED PERIOD SATURDAY...AN ARCTIC TROUGH WILL BE
CENTERED OVER SOUTHWEST ALASKA...WITH BROAD NORTHERLY FLOW ACROSS
THE BERING SEA. SOUTHCENTRAL WILL BE UNDER THE INFLUENCE OF BROAD
LOW PRESSURE SOUTH OF THE GULF OF ALASKA...WITH WEAK DISTURBANCES
WRAPPING AROUND THE PARENT LOW. COLD AIR OVER THE INTERIOR WILL
DRIVE AN OFFSHORE PRESSURE GRADIENT...WITH LOCAL GAP WINDS ALONG
THE COAST. IN THIS PATTERN...RAIN AND SNOW WILL BE RELEGATED TO
THE COASTAL AREAS WITH EXTENSIVE SHOWER ACTIVITY OVER THE BERING
SEA. THIS IS A DRY PATTERN FOR INTERIOR LOCATIONS WITH THE MAIN
JET STREAK WELL SOUTH OVER THE NORTH PACIFIC. THE MAIN PARENT LOW
WILL THEN WEAKEN AND LIFT INTO SOUTHERN ALASKA THROUGH
TUESDAY...BRINGING INCREASED CHANCES FOR INLAND
PRECIPITATION...BUT ONCE AGAIN WITH A LIMITED MOISTURE TAP AND
WEAK FORCING...THIS WILL GENERALLY BE ISOLATED TO SCATTERED WITH
MOST PRECIPITATION BEING FOCUSED ALONG THE COASTAL MOUNTAINS. THE
PACIFIC JET STREAM WILL CONTINUE TO SURGE EAST...WEAKENING THE
NORTH AMERICAN RIDGE...THUS KEEPING ALASKA OUT OF THE MAIN STORM
TRACK THROUGH NEXT WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...HEAVY FREEZING SPRAY 180 185

&&

SYNOPSIS AND MODEL DISCUSSION...DK
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KH
LONG TERM...JA