Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 030137
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
437 PM AKST TUE FEB 2 2016

.ANALYSIS AND UPPER LEVELS...
THE PERSISTENT UPPER LEVEL RIDGE OVER THE MAINLAND HAS WEAKENED
BUT IS STILL KEEPING THE STORM TRACK SOUTH OF MAINLAND ALASKA.
A SHORT WAVE MOVED ACROSS THE NORTH GULF COAST THIS MORNING AND
BROUGHT A BRIEF PERIOD OF SNOW SHOWERS TO THE SOUTHERN KENAI
PENINSULA BEFORE HEADING INTO THE LOWER KUSKOKWIM VALLEY. AT THE
SURFACE A STRONG LOW SOUTH OF KODIAK ISLAND CONTINUES TO MOVE
SLOWLY NORTHWARD. THE FRONT ASSOCIATED WITH THIS LOW IS MOVING
INTO THE GULF OF ALASKA THIS AFTERNOON AND WILL INCREASE WINDS
ACROSS THE GULF AND PRODUCE SOME OUTFLOW WINDS IN THE THOMPSON
PASS AREA BY EARLY WEDNESDAY. THE SECONDARY LOW THAT IS EXPECTED
TO MOVE INTO THE GULF WEDNESDAY NIGHT CAN BE SEEN DEVELOPING ON
SATELLITE NEAR 45N 175W.

&&

.MODEL DISCUSSION...

MODEL AGREEMENT WITH THE THE LARGE LOW MOVING TOWARD THE GULF OF
ALASKA REMAINS VERY GOOD TODAY. MODELS ARE MUCH IMPROVED ON THE
SECONDARY LOW THAT WILL MOVE INTO THE SOUTHERN GULF WEDNESDAY
NIGHT. WHERE THERE WAS A LARGE SPREAD ON POSSIBLE SOLUTIONS THEY
HAVE ALL LOCKED ONTO A COMMON SOLUTION WHICH WILL EVENTUALLY MERGE
THESE LOWS INTO A SINGLE LOW IN THE BRISTOL BAY REGION LATER THIS
WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THERE HAS BEEN LITTLE CHANGE IN THE EXPECTED FORECAST FOR THE NEXT
48 HOURS FOR SOUTHCENTRAL ALASKA AS THE MODELS REMAIN IN FAIRLY
GOOD AGREEMENT. THE OCCLUDED FRONT ASSOCIATED WITH THE VERTICALLY
STACKED 960MB LOW AROUND 50N 155W IS MOVING NORTHWARD THIS
AFTERNOON AND IS ALREADY STARTING TO BRING RAIN TO KODIAK ISLAND.
THE FRONT WILL CONTINUE ITS MARCH TO THE NORTHERN GULF COAST BY
WEDNESDAY AFTERNOON. PRECIPITATION WITH THIS FRONT SHOULD MAINLY
REMAIN ALONG THE COAST WITH INLAND AREAS SEEING SCATTERED SNOW
SHOWERS STARTING WEDNESDAY EVENING AS ENOUGH MOISTURE WILL MOVE
OVER THE TERRAIN. WITH COLD TEMPERATURES IN THE COPPER RIVER BASIN
AND THE ORIENTATION OF THE PRESSURE GRADIENT...WINDS WILL INCREASE
IN THOMPSON PASS BY EARLY WEDNESDAY MORNING. THIS SHOULD BE ENOUGH
WIND TO START BLOWING SNOW IN THE PASS. COMBINED WITH UP TO 6
INCHES OF NEW SNOW FROM THE FRONT...VISIBILITY MAY BE REDUCED AT
TIMES IN THE PASS TO ONE HALF MILE OR LESS DURING THE DAY
WEDNESDAY THROUGH EARLY THURSDAY MORNING.

A SECOND LOW IS EXPECTED TO ENTER THE SOUTHERN GULF THURSDAY
MORNING AS A SHORTWAVE ROTATES AROUND THE UPPER LOW CENTERED OVER
THE ALASKA PENINSULA. THE FRONT ASSOCIATED WITH THIS LOW WILL
BRING A SECOND SHOT OF PRECIPITATION TO COASTAL AREAS BY THURSDAY
AFTERNOON.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
INCREASING OFFSHORE FLOW AHEAD OF THE LOW APPROACHING THE ALASKA
PENINSULA COUPLED WITH STRONG DOWNSLOPE FLOW ACROSS THE ALEUTIAN
AND ALASKA RANGES WILL HELP TO KEEP THE SOUTHWEST MAINLAND MOSTLY
DRY THROUGH THURSDAY AS THE LOW AND AN ASSOCIATED FRONT MOVE INTO
THE SOUTHEAST BERING. THE MAIN IMPACTS FROM THIS SYSTEM WILL
THEREFORE BE INCREASING MID AND UPPER LEVEL CLOUD COVER AS THE
FRONT APPROACHES FROM THE SOUTH...WITH ANY CHANCES FOR
PRECIPITATION LARGELY LIMITED TO THE IMMEDIATE COAST OF THE
KUSKOKWIM DELTA AND FAVORABLE UPSLOPE AREAS ALONG THE AHKLUN
MOUNTAINS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE ADVANCING SYSTEM WILL KEEP A RATHER PROLONGED PERIOD OF GUSTY
EAST TO NORTHEAST WINDS AND PRECIPITATION OVER THE SOUTHEAST
BERING THROUGH THURSDAY AS THE LOW CENTER LINGERS NEAR THE ALASKA
PENINSULA...WITH THE INITIAL RAIN/SNOW MIX OVER THE AKPEN AND
EASTERN ALEUTIANS CHANGING TO ALL RAIN BY WEDNESDAY AS WARMER
NORTH PACIFIC AIR MOVES INTO THE REGION. PRECIPITATION WILL REMAIN
ALL SNOW AT THE ONSET AS IT SPREADS TO THE PRIBILOFS ON WEDNESDAY
MORNING...BUT TEMPERATURES HOVERING NEAR FREEZING SHOULD HELP TO
MITIGATE ANY BLOWING SNOW CONCERNS BEFORE RAIN BEGINS TO MIX IN
WEDNESDAY NIGHT AND THURSDAY. PRECIPITATION WILL CONTINUE TO
SPREAD WESTWARD THROUGH LATE WEDNESDAY AS A DEFORMATION BAND
FORMING OVER THE CENTRAL BERING PUSHES INTO THE CENTRAL ALEUTIANS
ACCOMPANIED BY LIGHT SNOW. INCREASING NORTHWEST FLOW WILL ALSO
CONTINUE TO PRODUCE SNOW SHOWERS OVER THE WESTERN ALEUTIANS
THROUGH THURSDAY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE WEATHER FROM FRIDAY ONWARDS INTO EARLY NEXT WEEK WILL BE
DOMINATED BY A SERIES OF WARM SYSTEMS MAKING A NORTHERLY TRACK
FROM THE NORTH PACIFIC INTO THE GULF AND SOUTHWEST MAINLAND. THIS
WILL KEEP TEMPERATURES THROUGHOUT SOUTHERN MAINLAND WELL ABOVE
NORMAL WITH DEEP AND MOIST SOUTHERLY FLOW. THE FIRST OF THESE
SYSTEMS WILL BE BEGINNING ITS DISSIPATION PHASE OVER THE EASTERN
BERING/SOUTHWEST COAST ON FRIDAY...BRINGING GALE FORCE WINDS TO
THE WESTERN GULF AND WIDESPREAD RAIN/WET SNOW TO THE GULF COAST.
ANOTHER SYSTEM WILL THEN QUICKLY FOLLOW ON ITS HEELS ON
SUNDAY...BRINGING PERSISTENT RAIN/SNOW TO THE GULF COAST INTO
EARLY NEXT WEEK. STRONG CROSS BARRIER FLOW OVER THE CHUGACH
MOUNTAINS WILL LIKELY KEEP SOUTHCENTRAL DRY AND CLOUDY THROUGH
THIS WEEKEND...WITH GUSTY GAP WINDS ALONG THE GULF COAST. THE
BERING SEA REGION WILL REMAIN UNDER A BROAD UPPER LEVEL TROUGH
THROUGH THIS WEEKEND...KEEPING ANY SIGNIFICANT SYSTEMS AT BAY WITH
WINDS GENERALLY BELOW GALE FORCE.

BY THE MIDDLE OF NEXT WEEK THE MODELS ARE BEGINNING TO HINT THAT
THE PERSISTENT AND BROAD UPPER LEVEL TROUGH OVER THE BERING WILL
BEGIN TO LIFT NORTHWARD AND FALL APART...ALLOWING FOR RIDGING OVER
THE YUKON TO MOVE INTO THE MAINLAND. THERE IS SIGNIFICANT
UNCERTAINTY IN THE MODELS BY THAT POINT...BUT IT DOES APPEAR THAT
QUIETER AND COOLER WEATHER WILL RETURN (AT LEAST TO THE MAINLAND)
BY THE MIDDLE OF NEXT WEEK.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...BLOWING SNOW ADVISORY...131.
MARINE...GALE 119 120 130 131 132 136 137 138 139
              150 155 160 165 174 176 180 351 352
         HEAVY FREEZING SPRAY...180 181 185.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...RF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CB
LONG TERM...DEK



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