Area Forecast Discussion
Issued by NWS Anchorage, AK

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FXAK68 PAFC 181401
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
601 AM AKDT SAT OCT 18 2014

.ANALYSIS AND UPPER LEVELS...
AN AMPLIFIED LONGWAVE PATTERN OVER THE MAINLAND HAS A CLOSED
STACKED LOW APPROXIMATELY 450 MILES SOUTHEAST OF KODIAK ISLAND.
INFRARED SATELLITE IMAGERY SHOWS A DEVELOPING PRECIPITATION BAND
NORTH OF THE LOW CENTER WHICH STRETCHES TO NEAR THE DIXON
ENTRANCE. TO THE WEST...WEAK RIDGING IS OVER THE CENTRAL BERING
WITH ANOTHER LOW MOVING TOWARD THE WESTERN ALEUTIANS. AT THE
SURFACE...A REMNANT LOW IN THE NORTHERN GULF IS MOVING ISOLATED TO
SCATTERED RAIN SHOWERS INTO THE SOUTHERN PRINCE WILLIAM SOUND AND
KENAI PENINSULA. MAINLY DRY CONDITIONS ACROSS INLAND LOCATIONS OF
SOUTHCENTRAL WITH FOG DEVELOPING ACROSS THE COPPER RIVER VALLEY.
LIGHT SNOW IS FALLING ACROSS THE SOUTHWESTERN COASTAL AREAS AND
EASTERN BERING MIXED WITH LIGHT RAIN ALONG BRISTOL BAY AND THE
SOUTHEASTERN BERING. RIDGING BUILDING INTO THE CENTRAL BERING IS
TIGHTENING THE PRESSURE GRADIENT OVER THE EASTERN BERING/ALEUTIANS
AND ALASKA PENINSULA WITH GUSTY NORTHERLY WINDS.


&&

.MODEL DISCUSSION...
MODELS WERE IN GOOD AGREEMENT THROUGH THE BEGINNING OF NEXT
WEEK...HOWEVER THE DEVELOPING FRONT ALONG THE LOW NEAR THE GULF OF
ALASKA WILL NEED TO BE MONITORED. MODELS ARE STARTING TO SHOW A
STRONGER SHORTWAVE DEVELOPING ALONG A TROUGH AXIS THAT BEGINS TO
PINWHEEL FROM THE EASTERN BERING/ALASKA PENINSULA SATURDAY NIGHT.
THIS WAVE KICKS THE STACKED LOW TOWARD THE NORTHEASTERN GULF
SUNDAY. THE LOW BECOMES AN OPEN WAVE AS THE SHORTWAVE SWINGS INTO
THE SOUTHERN GULF BY MONDAY MORNING. BY THIS TIME...A NEW LOW
CENTER DEVELOPS IN THE EASTERN BERING AND BEGINS TO SLOWLY DIG
TOWARD KODIAK ISLANDS WITH ANOTHER STRONG WAVE ALONG THE BACKSIDE
OF THIS SYSTEM IN THE BERING. FOR THE WESTERN BERING...AN UPPER
LOW AND ASSOCIATED FRONT MOVES INTO THE WESTERN BERING/ALEUTIANS
LATER TODAY FROM KAMCHATKA. THE SYSTEM SLIDES SOUTHEAST THROUGH
THE CENTRAL ALEUTIANS BY SUNDAY WITH WEAK RIDGING BUILDING
BUILDING IN BEHIND THIS SYSTEM.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
SCATTERED RAIN SHOWERS ACROSS THE WESTERN GULF AND KENAI WILL
TAPER OFF THIS EVENING AS LOW PRESSURE WEAKENS. MAINLY DRY
CONDITIONS ACROSS THE MAINLAND FOR THE WEEKEND WITH INCREASED
RAIN CHANCES AND GUSTY WINDS ENTERING THE NORTHEASTERN GULF ON
SUNDAY. THE CHANCES FOR RAIN AND SNOW INCREASE ACROSS THE MAINLAND
EARLY NEXT WEEK WITH CONTINUED LIGHT NORTHERLY FLOW.

SOUTHWEST ALASKA...
A COLDER AIR MASS IS FILTERING IN ACROSS THE SOUTHWEST WITH LIGHT
SNOW DEVELOPING ALONG LOW PRESSURE NEAR THE KUSKOKWIM DELTA. SNOW
WILL MIX WITH RAIN LATER TODAY ACROSS BRISTOL BAY AS TEMPERATURES
IN THIS REGIONS ARE STILL NEAR FREEZING THIS MORNING.
PRECIPITATION WILL CHANGE OVER TO SNOW AS THE COOLER AIR MASS
SETTLES FURTHER SOUTH. STRONGER WINDS ALONG THE COAST CONTINUE
THROUGH THE BEGINNING OF NEXT WEEK AS A TIGHT PRESSURE GRADIENT
REMAINS ALONG THE BERING.

BERING SEA/ALEUTIANS...
A FRONT WILL MOVE ACROSS THE WESTERN AND CENTRAL ALEUTIANS/BERING
TODAY AND TODAY TONIGHT...BRIEFLY CHANGING WIND DIRECTION OUT OF
THE SOUTH AND EAST. GUSTY GALES WINDS AND RAIN ARE EXPECTED ALONG
THE FRONT. NORTHERLY FLOW RETURNS BEHIND THE PASSING FRONT WITH
RIDGING BUILDING THROUGH MONDAY NIGHT.

&&

.LONG TERM FORECAST...
WHILE THERE REMAINS MODEL DISAGREEMENT WITH LOW LOCATION NEAR THE
GULF INTO THE MIDDLE OF NEXT WEEK...THE GENERAL LONG TERM FORECAST
PATTERN REMAINS UNCHANGED SINCE YESTERDAY. AFTER THE NEXT GULF LOW
DISSIPATES OVER THE GULF COAST ON MONDAY...THE LONGWAVE TROUGH
CURRENTLY OVER THE EASTERN BERING WILL SLOWLY MIGRATE INTO THE
SOUTHERN GULF BY MID WEEK. THIS SETUP WILL KEEP A SERIES OF GULF
LOWS CONFINED TO THE SOUTHERN GULF OR NORTH PACIFIC...AND THE
MODELS ARE TRENDING FURTHER TO THE SOUTH. AS LONG AS THIS TREND
CONTINUES...THE CHANCES OF PRECIPITATION AND GAP WINDS WILL ALSO
DIMINISH...INCLUDING FOR THE GULF COAST. OUT WEST...RIDGING OVER
THE WESTERN BERING WILL MOVE TO THE WEST COAST BY MID WEEK...THEN
SPREAD OVER THE MAINLAND LATE NEXT WEEK. THIS WILL CAUSE GUSTY
NORTHERLY FLOW AND SHOWERS TO DEVELOP OVER THE EASTERN BERING AND
ALEUTIANS UNTIL WEDNESDAY...WHEN RIDGING WILL APPROACH THE AREA.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 155 165 170 172 178.
FIRE WEATHER...NONE.

&&

$$

KH/DEK OCT 14



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