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SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
458 AM AKDT SUN JUL 5 2015

.ANALYSIS AND UPPER LEVELS...
THERE IS A CLOSED LOW AT 300 MB NEAR 49N 168W AND IS VERTICALLY
STACKED THROUGH THE ATMOSPHERE. THIS IS REFLECT AT SURFACE WITH A
GALE FORCE LOW POSITIONED JUST SOUTH OF DUTCH HARBOR THIS MORNING.
AN ASSOCIATED WEATHER FRONT WITH THIS SYSTEM IS POSITIONED
THROUGH THE EASTERN ALEUTIANS AND CROSSING INTO THE EASTERN
BERING SEA BEFORE CURVING BACK TOWARD THE NORTH PACIFIC LOW. THIS
SYSTEM IS GETTING SUPPORT FROM A 110 KNOT SOUTHEASTERLY MERIDIONAL
JET STREAK OVER THE EASTERN ALEUTIANS AND A STRONG 130 KNOT
WESTERLY ZONAL JET STREAK RUNNING PARALLEL TO THE CHAIN AROUND
42N. THE SATELLITE IMAGERY IS SHOWING A LARGE PLUME OF MOISTURE
STREAMING INTO THE EASTERN ALEUTIANS AND SPILLING INTO THE BERING
SIDE. WHILE...THE SOUTHWEST ALASKA HAS THE REMNANTS OF THE
FRONTAL BOUNDARY DISSIPATING IN THE UPPER/LOWER KUSKOKWIM VALLEY
THIS MORNING. THE RADAR IMAGERY HAS NUMEROUS SHOWERS IN THE
KUSKOKWIM DELTA. WHILE...THE BRISTOL BAY INTERIOR AND THE LOWER
KUSKOKWIM VALLEY HAS SCATTERED SHOWERS THIS MORNING. THERE IS AN
UPPER LEVEL CLOSED HIGH PRESSURE NEAR 48N 140W WITH A RIDGE
EXTENDING NORTHWARD INTO THE GULF AND INTO THE COPPER RIVER BASIN.
THE SATELLITE IMAGERY IS SHOWING THE GULF WITH STRATUS/FOG UNDER
THE RIDGE OF HIGH PRESSURE. WHILE...THE SOUTHCENTRAL HAS THE
REMNANTS OF THE TROUGH AND FRONTAL BOUNDARY FALLING APART IN THE
REGION. THE RADAR IMAGERY HAS SHOWERY PRECIPITATION IN THE MATSU
VALLEYS AND SOME WEAK SHOWERS MOVING UP THE COOK INLET THIS
MORNING.

&&

.MODEL DISCUSSION...
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH THE NORTH PACIFIC
LOW THAT IS TRACKING THROUGH NEAR DUTCH HARBOR SUNDAY AFTERNOON
BEFORE MOVING INTO THE CENTRAL BERING SEA. WHILE...THE AMPLIFIED
HIGH PRESSURE RIDGE OVER THE EASTERN GULF AND THE SOUTHCENTRAL
ALASKA REGION REMAINS IN POSITION BEFORE TRACKING EASTWARD BY
MONDAY. THIS COINCIDES WITH THE NEXT WEATHER FRONT MOVING THROUGH
FROM THE SOUTHWEST ALASKA AREA INTO THE SOUTHCENTRAL REGION ON
MONDAY. THE GFS/ECMWF/GEM WERE THE PREFERRED MODELS OF CHOICE AND
THE FORECAST CONFIDENCE REMAINS ABOVE AVERAGE THROUGH THE SHORT
TERM.

&&

.FIRE WEATHER...
THE SOUTHWEST ALASKA REGION WILL CONTINUE TO HAVE MOISTURE MOVING
IN ASSOCIATED WITH THE ANOTHER NORTH PACIFIC LOW MOVING INTO THE
BERING SEA BY SUNDAY AFTERNOON. THIS WILL BRING MORE WETTING RAINS
ACCOMPANIED BY THE WEATHER FRONT THAT WILL SWING THROUGH THE
REGION AS WERE HEADING INTO MONDAY. THIS WILL BRING ONSHORE FLOW
AND COOLER TEMPERATURES FOR THE NEXT SEVERAL DAYS.

THE SOUTHCENTRAL ALASKA WILL HAVE A RIDGE POSITIONED OVER THE
COPPER RIVER BASIN SOUTHWARD INTO THE EASTERN GULF. THIS WILL
RESULT IN WARMER TEMPERATURES AND THE PRESSURE GRADIENTS WILL BE 
STRENGTHENING AS THE WEATHER FRONT APPROACHES THE REGION FROM THE
WEST. THIS WEATHER FRONT WILL BRING WETTING RAINS TO THE MATSU
VALLEYS AND THE ANCHORAGE BOWL AS IT MOVES THROUGH THE AREA.
WHILE...THE WINDS IN THE COPPER RIVER BASIN WILL BE GUSTY AND
COMBINED WITH DRIER CONDITIONS THE RELATIVE HUMIDITIES WILL
POSSIBLY DROP INTO THE UPPER 20 PERCENT RANGE BY MONDAY FOR THE
AFTERNOON AND EVENING HOURS. THE KEY WILL BE THE TIMING OF THE
FRONT AS IT MOVES THROUGH THE REGION AND WHEN THE RIDGE MOVES
EASTWARD INTO THE YUKON TERRITORY. WHEN THE RIDGE MOVES
EASTWARD...THIS WILL ALLOW THE MOISTURE TO BE TRANSPORTED INTO THE
REGION AND AID IN THE RECOVERY OF HUMIDITIES AS WE HEAD INTO THE
EARLY PART OF THIS WEEK.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
CLOUD COVER AND LINGERING SHOWERS WILL CONTINUE TO CLEAR OUT TODAY
AS HIGH PRESSURE BUILDS IN OVER THE SOUTHCENTRAL FROM THE GULF.
THIS WILL HELP TO BRING IN SOME WARMER TEMPERATURES ON MONDAY.
HOWEVER...ANOTHER FRONT WILL MOVE IN OVER KODIAK THIS EVENING AND
THEN OVER THE SOUTHCENTRAL MONDAY NIGHT BRINGING IN MORE RAIN.
AHEAD OF THE FRONT STRONGER WINDS ARE EXPECTED THROUGH THE GAPS
AND ALONG THE COPPER RIVER ON MONDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE MAIN FORECAST FEATURE FOR THE NEXT 48 HOURS OVER THE SOUTHWEST
MAINLAND WILL BE THE PASSAGE OF THE COLD FRONT LOCATED SOUTH OF
THE ALASKA PENINSULA THIS MORNING THROUGH THE REGION. AS DISCUSSED
IN PREVIOUS FORECAST DISCUSSIONS...THIS SYSTEM WILL HAVE A VERY
DIRECT SOURCE OF MOISTURE COMING FROM THE SUB-TROPICS. SATELLITE
DERIVED PRECIPITABLE WATER VALUES THIS MORNING WITH THIS FRONT ARE
TOTALING ALMOST 2 INCHES...WHICH IS ROUGHLY 200% OF NORMAL.
SHOWERS WILL CONTINUE THROUGH THE DAY OVER MOST OF THE REGION IN
THE WAKE OF YESTERDAYS FRONT AND WILL SWITCH OVER TO MORE OF A
STEADY STRATIFORM RAIN BY LATE THIS AFTERNOON. RAINFALL WILL BE
THE HEAVIEST LATE THIS AFTERNOON THROUGH THE OVERNIGHT HOURS ALONG
UPSLOPE AREAS...ESPECIALLY THE AHKLUN MOUNTAINS NORTH AND WEST OF
DILLINGHAM WHERE RAINFALL MAY BE HEAVY AT TIMES. RAINFALL TOTALS
OF ALMOST 2 INCHES ARE POSSIBLE THROUGH MONDAY AFTERNOON IN THIS
AREA.

AS THE FRONT MOVES INLAND LATE TONIGHT INTO EARLY MONDAY
MORNING...PRECIPITATION WILL GRADUALLY DECREASE ALONG COASTAL
AREAS AND BECOME MORE SHOWERY IN NATURE...BUT COVERAGE INLAND WILL
REMAIN WIDESPREAD.

WINDS WILL CONTINUE TO INCREASE TODAY WITH THE STRONGEST WINDS
ALONG THE COAST AND THROUGH THE KAMISHAK GAP INTO THE HIGHER
TERRAIN OF THE AHKLUN/KILBUCK MOUNTAINS. WINDS WILL BEGIN TO
DECREASE ON MONDAY AS THE LOW ASSOCIATED WITH THE WEATHER FRONT
MOVES FURTHER OFF TO THE WEST AND WEAKENS.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
WINDS TO GALE FORCE AND WIDESPREAD RAINFALL ARE THE HIGHLIGHTS OF
THE FORECAST FOR THE REGION THROUGH MONDAY AFTERNOON AS THE LOW
AND ITS ASSOCIATED FRONT PUSH NORTHWARD INTO THE EASTERN BERING
SEA TODAY BEFORE MOVING INTO THE WESTERN BERING BY LATE MONDAY
AFTERNOON. WINDS WILL CONTINUE TO INCREASE OVER THE EASTERN THIRD
OF THE REGION THIS MORNING WITH GALES DEVELOPING THIS AFTERNOON
ALONG THE COASTAL WATERS FROM UNALASKA EASTWARD OVER THE EASTERN
BERING/SOUTHWESTERN ALASKA COASTAL WATERS. WIDESPREAD RAINFALL IS
EXPECTED ALONG THIS FRONT AS IT MOVES NORTH THROUGH THE ALASKA
PENINSULA TO THE PRIBILOF ISLANDS AND THEN INTO THE NORTHWEST
BERING SEA BY LATE TONIGHT. AS DISCUSSED ABOVE...THIS SYSTEM HAS
AN AMPLE TAP OF SUB-TROPICAL MOISTURE...THEREFORE THERE WILL BE
PERIODS OF HEAVY RAINFALL MAINLY ALONG THE ALASKA PENINSULA
THROUGH LATE TONIGHT.

AS THE LOW MOVES WESTWARD...WINDS WILL DECREASE TO AROUND 30 KNOTS
OVER THE NORTHERN AND EASTERN BERING SEA WHILE WINDS WILL
INCREASE TO NEAR GALE FORCE MONDAY NIGHT OVER THE SOUTHWEST BERING
ON THE SOUTH SIDE OF THE LOW.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
A LARGE AREA OF LOW PRESSURE WILL REMAIN CENTERED OVER THE BERING
THROUGH AT LEAST NEXT WEEKEND WHILE THE UPPER LEVEL RIDGE OVER MAINLAND
ALASKA SHIFTS EAST INTO CANADA AND FLATTENS. THE NET RESULT WILL
PUT THE AREA INTO A COOLER AND MOISTER FAIRLY STEADY STATE
PATTERN WITH A SURFACE RIDGE IN THE GULF SUPPORTING LOW LEVEL
ONSHORE FLOW. SHORTWAVE TROUGHS WILL PERIODICALLY ROTATE UP FROM
THE WESTERN GULF AND EASTERN BERING KEEPING SKIES MOSTLY CLOUDY
AND BRINGING SCATTERED SHOWERS...PERIODS OF RAIN AND MILD
TEMPERATURES TO MUCH OF SOUTHWEST AND SOUTH CENTRAL ALASKA.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING...138 155 160 165 170 172 180.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...PLD
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...RF
LONG TERM...JR

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