Freezing Rain Advisory 3, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
548 AM AKST WED JAN 20 2016

.ANALYSIS AND UPPER LEVELS...

THE ANCHORING MEAN CENTER OF THE LARGE UPPER LEVEL LOW COMPLEX
HAS SHIFTED SLIGHTLY WEST TO AROUND 54N 155W...HOWEVER THAT
CIRCULATION IS RAPIDLY WEAKENING OUT AS THE NEW LARGE NORTH
PACIFIC LOW LIFTS NORTH TOWARDS THE SOUTHERN GULF TO REPLACE IT.
THE LATEST OF THE TROUGHS ROTATING AROUND THE NORTH SIDE OF THE
LOW IS CURRENTLY SOUTH OF PRINCE WILLIAM SOUND AND WILL SWING
INLAND OVER THE KENAI PENINSULA AND KODIAK ISLAND. WHILE THIS
FEATURE IS A BIT WEAKER AND MORE DIFFUSE THAN THE PREVIOUS TROUGH
LAST NIGHT...ASCAT SATELLITE DERIVED WINDS...MIDDLETON ISLAND AND
BUOYS 61 AND 76 HAVE ALL BEEN SHOWING NORTH TO EAST WINDS IN THE
35 KNOT RANGE TO THE NORTH AND EAST SIDE OF THE CIRCULATION
CENTER.

FURTHER WEST...A NEW STRONG LOW IS STARTING TO SPIN UP WELL TO
THE SOUTHWEST OF THE ALEUTIANS WITH FAIRLY QUIET WEATHER OVER MUCH
OF THE BERING...BRISTOL BAY AND MAINLAND SOUTHWEST ALASKA. SHOWERS
ARE CURRENTLY PUSHING ACROSS THE NORTHEASTERN ALASKA PENINSULA IN
ADVANCE OF THE TROUGH CROSSING THE GULF. OVER THE KUSKOKWIM DELTA
AND LOWER KUSKOKWIM VALLEY...COOL DRY NORTHEASTERLY FLOW CONTINUES
TO PREVAIL. NORTHERLY FLOW AND A COLD UPPER LEVEL TROUGH CONTINUES
TO SPILL COLD AIR AND STRATUS ACROSS THE WESTERN AND CENTRAL BERING.

&&

.MODEL DISCUSSION...

THE MODELS ALL LOOK TO BE WELL INITIALIZED ON THE MAIN SYNOPTIC
FEATURES AND IN GOOD AGREEMENT WITH THEIR PROGRESSION FOR THE
NEXT SEVERAL DAYS. THE GFS IS SLIGHTLY FASTER WITH THE TROUGH
ROTATING INTO SOUTH CENTRAL ALASKA THIS MORNING COMPARED WITH NAM
AND THE NAM A BIT STRONGER WITH THE DOWNSLOPING IMPACTS ON
PRECIPITATION...BUT OTHERWISE NET DIFFERENCES WERE VERY SMALL. IN
THE WESTERN DOMAIN THE GFS/EC SOLUTIONS WERE PREFERRED FOR BEING A
LITTLE FASTER WITH THE FRONT PUSHING INTO THE ALEUTIANS ON
THURSDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2...WED AND
THU)...
THE NEXT IN THE SERIES OF LOWS FROM THE GULF IS MAKING ITS
WAY THROUGH SOUTH CENTRAL THIS MORNING. RADAR AND SATELLITE LOOK
VERY SIMILAR TO MONDAY MORNING AS THE LAST LOW MOVED THROUGH THE
AREA. AREAS OVER WESTERN PRINCE WILLIAM SOUND AND THE EASTERN
KENAI WILL SEE THE BULK OF THE PRECIPITATION WHILE SOME OF IT
SNEAKS THROUGH INTO THE PORTAGE VALLEY. THIS SYSTEM IS BRINGING
ANOTHER POCKET OF WARMER TEMPERATURES...SO MOST OF THE
PRECIPITATION WILL FALL AS RAIN AT COASTAL SITES WITH SOME LIGHT
SNOW MAKING IT TO INLAND LOCATIONS. THIS LOW WILL ALSO STIR UP
ANOTHER ROUND OF GUSTY WINDS...BUT NOTHING OUT OF THE ORDINARY.

THIS SYSTEM WILL TRACK QUICKLY OFF TO THE EAST THROUGH THE DAY AND
DISSIPATE OVER THE ALASKA RANGE. THIS WILL MAKE FOR CLEARING SKIES
AND A DECENT AMOUNT OF SUNSHINE WITH JUST SOME HIGH CLOUDS FOR
MOST OF THE DAYLIGHT HOURS THU. YET ANOTHER LOW IN THE SERIES
WILL CONTINUE TO TRACK NORTH IN THE GULF ON THU. WITH SOME COLDER
AIR INLAND...THIS SET UP WILL ONCE AGAIN HELP TO ENHANCE THE
OFFSHORE WINDS IN THE FAVORED MATANUSKA VALLEY AND THOMPSON PASS.
PRECIPITATION WITH THIS SYSTEM LOOKS TO REACH THE COAST LATE THU...BUT
WILL BE SLOW TO MAKE ANY PROGRESS INLAND.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE UPPER LEVELS HAVE SEVERAL WEAK SHORTWAVES MOVING THROUGH
THURSDAY MORNING. MAJORITY OF THE PRECIPITATION WILL BE SCATTERED
SNOW SHOWERS IN THE BRISTOL BAY REGION. THE REST OF SOUTHWEST
ALASKA REGION WILL CONTINUE WITH NORTHEASTERLY FLOW RESULTING IN
DRIER CONDITIONS HEADING INTO THURSDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE BERING SEA/ALEUTIANS WILL CONTINUE TO UNDER THE INFLUENCE OF
NORTHEASTERLY WINDS THROUGH WEDNESDAY. THIS WILL PRODUCE A SHOWERY
WEATHER REGIME. BY THURSDAY MORNING A WEATHER FRONT WILL APPROACH
THE WESTERN ALEUTIANS FROM THE PACIFIC SIDE. THIS WILL BRING GUSTY
GALE FORCE SOUTHEASTERLY WINDS TO THE WESTERN ALEUTIANS. BY THURSDAY
MIDDAY THERE WILL BE A SMALL WINDOW FOR THE POSSIBILITY OF
BLOWING SNOW FOR SHEMYA AS THE MOISTURE ARRIVES COMBINING WITH
THE SURFACE TEMPERATURE NEAR FREEZING ALONG THE WESTERN ALEUTIAN
CHAIN. BY THURSDAY AFTERNOON THE WARMER AIR WILL HAVE PUSHED
FARTHER NORTH WITH THE PRECIPITATION TRANSITIONING TO A RAIN/SNOW
MIXTURE BEFORE ALL RAIN BY THURSDAY EVENING. THE WESTERN/CENTRAL
BERING SEA WILL HAVE MOISTURE STREAMING INTO THE REGION AS THE
WEATHER FRONT CONTINUES TO MOVE INTO THE BERING SEA.

&&

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

ACROSS THE GULF THURSDAY NIGHT INTO FRIDAY...AN ORGANIZED LOW
PRESSURE SYSTEM WILL ANCHOR ITSELF IN THE REGION...BRINGING RAIN
AND SOME SNOW ALONG GULF COASTAL LOCATIONS...INCLUDING
KODIAK...WHILE A GALE-FORCE WINDS ALONG A DECAYING FRONT SLOWLY
DIMINISHES. MAINLY DRY CONDITIONS ARE EXPECTED INLAND WITH HIGH
PRESSURE RIDGING ALOFT THROUGH THE EXTENDED PERIOD. OUTFLOW WINDS
WILL ALSO CONTINUE THROUGH THE NORTH-SOUTH PASSES BETWEEN THE
COLDER INLAND AREAS AND WARMER AIR MASS OVER THE GULF...BUT DO NOT
LOOK TO BECOME PARTICULARLY STRONG AT THIS TIME.

TO THE WEST...A NORTH PACIFIC LOW CONTINUES TO MOVE A FRONT NORTH ACROSS
THE WESTERN AND CENTRAL ALEUTIANS INTO THE WESTERN AND CENTRAL
BERING THURSDAY NIGHT INTO FRIDAY...WHILE THE PRIMARY LOW MOVES
EAST TO THE SOUTH OF THE CHAIN. ACROSS THE NORTH AND EASTERN
BERING THURSDAY NIGHT THROUGH FRIDAY...MAINLY DRY CONDITIONS ARE
EXPECTED AS RIDGING SLOWLY SHIFTS NORTH AHEAD OF THE STORM SYSTEM.
WINDS WILL STAY GENERALLY FROM THE NORTH AND EAST AS THE FRONT
REMAINS SOUTH OF THIS REGION.

MODELS THEN SUGGEST ONE OR TWO STRENGTHENING TRIPLE POINT LOWS
MAY DEVELOP OVER THE NORTHEAST PACIFIC AND MOVE NORTH TOWARD
SOUTHERN ALASKA AND/OR THE SOUTHEAST BERING SUNDAY THROUGH
MONDAY...BUT CONFIDENCE IN THIS IS FAIRLY LOW AT THIS TIME.

THE MAIN IMPACTS WITH THIS PATTERN WILL BE A FAIRLY QUIET WEATHER
REGIME FOR MUCH OF THE REGION THE LATER PART OF THIS WEEK INTO THE
WEEKEND. THERE WILL BE LITTLE SIGNIFICANT CHANGE IN
TEMPERATURES...WITH NEAR NORMAL TO SLIGHTLY ABOVE NORMAL
TEMPERATURES OVER MUCH OF THE REGION...AND PRECIPITATION CHANCES
REMAINING NEAR NORMAL TO ABOVE NORMAL. STRONGER WINDS TO GALE-FORCE
WILL BE CONFINED TO STRONGER EMBEDDED LOWS WITHIN THE BROAD
CYCLONIC PATTERN.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 119 120 130 131 132 136 138 150 178
         HEAVY FREEZING SPRAY 180 181 185.

&&

SYNOPSIS AND MODEL DISCUSSION...JR
SOUTHCENTRAL ALASKA...MO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PD
LONG TERM...CC