Heavy Freezing Spray Warning 5, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
502 PM AKST SUN JAN 24 2016

.ANALYSIS AND UPPER LEVELS...

THE RIDGE OF HIGH PRESSURE OVER WESTERN NORTH AMERICA HAS RESURGED...AND
AS A RESULT HAS BEGUN TO STEER MORE ACTIVE WEATHER TOWARD THE SOUTHERN
MAINLAND. A WEAK WARM FRONT IS PUSHING THROUGH COOK INLET AND SOUTHWEST
ALASKA TODAY...WITH SOUTHEAST WINDS KEEPING THE USUAL DOWNSLOPE AREAS
DRY...AND PRECIPITATION FALLING ALONG THE GULF COAST GENERALLY IN
THE FORM OF RAIN. AREAS OF PRECIPITATION ARE ALSO SPREAD ACROSS THE
SOUTHWEST MAINLAND...FALLING AS SNOW ACROSS THE DELTA AND LOWER KUSKOKWIM
VALLEY...WITH WARMER TEMPERATURES AND A RAIN/SNOW MIX ACROSS THE BRISTOL
BAY ZONE. WINDS ARE NOT OVERLY STRONG IN ANY LOCATIONS AS THIS OVERALL
FEATURE IS QUITE WEAK...BUT IT IS ALLOWING A WARMER AIRMASS TO GRADUALLY
SURGE INTO THE MAINLAND.

A MUCH LARGER AND MORE IMPRESSIVE STORM IS APPARENT ON SATELLITE
IMAGERY ABOUT 500 MILES SOUTH OF THE ALASKA PENINSULA. THIS LOW IS
APPROACHING ITS PEAK INTENSITY AROUND 959 MB...AND WILL BEGIN TO
WEAKEN THIS EVENING. A SOUTHERLY JET STREAM CLIMBING THE
AFOREMENTIONED UPPER LEVEL RIDGE OVER THE PANHANDLE WILL CAUSE
THIS STORM TO MOVE INTO SOUTHERN ALASKA OVERNIGHT TONIGHT WITH
STRONGER WINDS AND MODERATE TO HEAVY PRECIPITATION.

&&

.MODEL DISCUSSION...

THE MODELS ARE IN GOOD AGREEMENT ON A RETURN TO A STORM TRACK
WHERE INDIVIDUAL STORMS MOVE NORTHWARD ACROSS THE ALASKA PENINSULA
AND INTO THE VICINITY OF BRISTOL BAY BEFORE RECURVING WESTWARD
INTO THE LONGWAVE TROUGH. FORTUNATELY...THE JET STREAM IS EXPECTED
TO REMAIN FAR ENOUGH EAST THAT MOST OF THESE STORMS AND ASSOCIATED
WEATHER FRONTS SHOULD BEGIN TO WEAKEN FROM THEIR MAX STRENGTH BEFORE
THEY IMPACT THE SOUTHERN MAINLAND. AS A RESULT...MULTIPLE ROUNDS
OF WARM AND WINDY (AND OCCASIONALLY WET) WEATHER ARE EXPECTED OVER
THE NEXT SEVERAL DAYS...THOUGH NO WINDS ARE EXPECTED TO REACH
WARNING LEVELS AND THE USUALLY DRY DOWNSLOPE AREAS SHOULD
GENERALLY REMAIN ON THE DRY SIDE OF THESE STORMS. THE GFS HAD BEEN
AN OUTLIER WITH A STRONGER TRAILING SHORTWAVE/SURFACE LOW MOVING
THROUGH THE CENTRAL GULF TOMORROW TOWARD PRINCE WILLIAM SOUND.
THIS WOULD AFFECT PRECIPITATION DISTRIBUTION AND GAP WINDS.
WITH THE 12Z RUNS...ALL MODELS NOW SEEM TO BE IN BETTER AGREEMENT
THAT THIS FEATURE WILL REMAIN WEAK AND EAST OF THE ANCHORAGE
FORECAST AREA...WITH NO SIGNIFICANT IMPACTS EXPECTED. THE ECMWF IS
THE PREFERRED MODEL TODAY...THOUGH THE CANADIAN REGIONAL MODEL WAS
USED AS A HIGH-RESOLUTION REFERENCE FOR SOME OF THE SMALLER LOCAL
AREAS OF COMPLEX TERRAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THERE IS LITTLE CHANGE IN THE FORECAST REASONING WITH THIS
AFTERNOONS PACKAGE. THE FRONT ASSOCIATED WITH THE LOW MOVING
TOWARDS KODIAK ISLAND WILL IS CURRENTLY ENTERING INTO THE SOUTHERN
GULF OF ALASKA. THIS FRONT WILL BRING MOSTLY RAIN TO THE NORTHERN
GULF COAST WITH SNOW AT THE HIGHER ELEVATIONS OF PRINCE WILLIAM
SOUND...THE KENAI PENINSULA...AND THE ALASKA RANGE. UPPER COOK
INLET IS LIKELY TO REMAIN MOSTLY DOWNSLOPED WITH THIS FRONT...BUT
WHAT SPILLOVER THERE IS LIKELY WILL BE MIXED PRECIPITATION THROUGH
MONDAY AFTERNOON. THE FRONT IS EXPECTED TO STALL OVER THE GULF
COAST MONDAY EVENING BEFORE DISSIPATING BY TUESDAY. THIS WILL KEEP
COASTAL AREAS IN A GENERALLY WET PATTERN.

AS THE ASSOCIATED LOW MOVES INTO BRISTOL BAY AND THE FRONT BEGINS
TO DISSIPATE OVER THE GULF COAST...A SECOND DEEP LOW AGAIN WILL
APPROACH THE REGION ON TUESDAY. THE ASSOCIATED FRONT WILL BEGIN TO
IMPACT THE SOUTHERN GULF AND THE COASTAL WATERS NEAR KODIAK ISLAND
LATE TUESDAY...ONCE AGAIN BRINGING GALE FORCE WINDS INTO THE
REGION.

&&

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

THE ACTIVE PATTERN CONTINUES AS A SERIES OF NORTH PACIFIC
LOWS TRACK THROUGH SOUTHWEST ALASKA...WITH THE NEXT IN LINE
MOVING INTO THE REGION TONIGHT THROUGH TUESDAY. WARMER PACIFIC AIR
ALOFT WILL KEEP A RAIN MIX ACROSS THE BRISTOL BAY REGION...AND AND
MAY ALLOW FOR A BIT OF FREEZING SPRINKLES ACROSS THE KUSKOKWIM
DELTA. STRONG SOUTHEAST WINDS WILL ACCOMPANY THE LOW ACROSS
BRISTOL BAY AND NEAR THE ALASKA/ALEUTIAN RANGES BEFORE THE LOW
DEPARTS TUESDAY.

&&

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

QUIET WEATHER FOR THE BERING WILL REMAIN DOMINANT AS NORTHEASTERLY
FLOW AND SHOWERS WILL REMAIN OVER THE BERING SEA AS THE MAIN
STORM TRACK STAYS OVER THE NORTH PACIFIC. ANOTHER GALE FORCE FRONT
WILL MOVE INTO THE EASTERN ALEUTIANS TONIGHT AND MONDAY...SPREADING
RAIN AND SHOWERS OVER THE REGION.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A BROAD LONGWAVE TROUGH STRETCHING FROM NORTHEASTERN RUSSIA THROUGH
THE BERING SEA/ALEUTIANS AND INTO THE NORTH PACIFIC TUESDAY WILL
BEGIN TO TILT NEGATIVELY OVER THE AREA THROUGH THURSDAY...WITH A
VERTICALLY STACKED LOW OVER THE NORTH PACIFIC APPROACHING THE
ALASKA PENINSULA BY WEDNESDAY MORNING. AT THE SURFACE...THE FRONT
ASSOCIATED WITH THE ABOVE MENTIONED LOW WILL PUSH INTO THE
NORTHERN GULF COAST AND AKPEN WEDNESDAY MORNING. HOWEVER...MUCH
LIKE MANY SYSTEMS OVER THE RECENT TIMES IT IS WEAKENING AS IT
APPROACHES THE SOUTHERN MAINLAND...WITH THE BRUNT OF THE
PRECIPITATION STAYING CONFINED TO THE COAST AND THE LEE SIDE OF
THE MOUNTAIN RANGES EXPERIENCING A DRIER DOWNSLOPING EFFECT. THE
AIR MASS IT BRINGS UP FROM THE SOUTH IS SLIGHTLY WARMER THAN WHAT
IS CURRENTLY IN PLACE...BUT IT IS NOT GOING TO BRING A HUGE WARM
UP FROM CURRENT TEMPERATURES. LOOKING OUT TOWARD THE END OF THE
WEEK AND INTO THE WEEKEND...THE PATTERN LOOKS MOSTLY THE SAME WITH
A TROUGH ANCHORED OVER MUCH OF THE BERING SEA AND ALEUTIANS...WITH
A LITTLE MORE RIDGING BUILDING OVER THE NORTHEASTERN PACIFIC. AS
FAR AS SENSIBLE WEATHER GOES...EXPECT TEMPERATURES SLIGHTLY ABOVE
NORMAL IN MOST LOCATIONS AND THE ONSET OF A MORE SHOWERY REGIME.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 119 120 125 130 131 132 136 137 138 150 155 351 352.

&&

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