High Wind in Alaska, November 17, 2014

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
450 AM AKST MON NOV 17 2014

.ANALYSIS AND UPPER LEVELS...
THE UPPER LEVEL NEGATIVELY TILTED RIDGE REMAINS OVER SOUTHEAST
ALASKA EXTENDING THROUGH BARROW INTO THE ARCTIC OCEAN. AN UPPER
LEVEL TROUGH IS POSITIONED OVER THE ANCHORAGE BOWL EXTENDING
EASTWARD INTO THE LOWER COPPER RIVER BASIN. A WEAK LOW PRESSURE
SYSTEM IS LOCATED OVER THE BARREN ISLANDS WITH AN INVERTED TROUGH
ALONG THE NORTHERN GULF COAST. A SWATH OF MOISTURE OVER
SOUTHCENTRAL ALASKA EXISTS ON SATELLITE IMAGERY. STEADY
PRECIPITATION IS MOVING THROUGH THE COOK INLET NORTHWARD INTO THE
MATSU VALLEY...WITH THE HEAVIEST SHOWERS IN THE LOWER SUSITNA
VALLEY. ANCHORAGE OBSERVATIONS OVER NIGHT HAVE REPORTED A MIXTURE
OF LIGHT PRECIPITATION RANGING FROM LIGHT FREEZING RAIN TO SNOW
GRAINS. THE FREEZING RAIN WILL DIMINISH FOR THE ANCHORAGE BOWL IN
THE EARLY MORNING HOURS. THERE IS AN UPPER LEVEL CLOSED LOW JUST
SOUTH OF DUTCH HARBOR THIS MORNING...WITH ASCAT SCATTEROMETER
WINDS INDICATING UPPER END GALE FORCE WINDS. THIS COINCIDES WITH
THE SOUTHEAST TO NORTHWEST 100 KNOT MERIDIONAL JET STREAK OVER THE
EASTERN ALEUTIANS INTO THE EASTERN BERING SEA. SATELLITE IMAGERY
IS ALSO SHOWING A COMMA CLOUD WITH A LARGE SWATH OF MOISTURE FROM
THIS LOW BEING TRANSPORTED INTO THE CENTRAL BERING SEA. SOUTHWEST
ALASKA HAS A WEAK SHORTWAVE TROUGH MOVING THROUGH THE REGION WITH
RAIN SHOWERS MOVING SOUTH TO NORTH THROUGH THE AREA THIS MORNING.

&&

.MODEL DISCUSSION...
THE MODELS ARE IN GOOD AGREEMENT WITH THE LOW NORTH OF KODIAK THIS
MORNING AS IT MOVES NORTHWEST BEFORE DISSIPATING THIS AFTERNOON.
BY TUESDAY...ANOTHER NORTH PACIFIC LOW WILL TRACK ON ALMOST
IDENTICAL PATH AS THE PREVIOUS LOW. THE NAM/GFS/ECMWF KEEP THE
LOW SOUTHEAST OF KODIAK...WHILE THE GEM-REG SEEM TO BE THE
OUTLIERS BY PUSHING THE LOW FARTHER NORTH OVER KODIAK ISLAND.
OUT WEST...THE MODELS ARE IN GOOD AGREEMENT WITH THE NORTH
PACIFIC LOW TRACKING NEAR UNALASKA THIS MORNING BEFORE CROSSING
OVER UNALASKA BY MONDAY EVENING INTO THE CENTRAL BERING SEA. THE
NAM/ECMWF WERE THE PREFERRED MODELS OF CHOICE WITH FORECAST
CONFIDENCE ABOVE AVERAGE WITH SOME UNCERTAINTY IN PRECIPITATION
TIMING...AND WITH THE POSSIBILITY OF FREEZING RAIN FOR TUESDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (TODAY AND TUESDAY)...
A WEAK UPPER WAVE WILL PUSH THROUGH SOUTH CENTRAL ALASKA FROM
SOUTH TO NORTH TODAY. THE ATMOSPHERE IS GENERALLY QUITE
WARM...EXCEPT AT THE LOWER LEVELS WHERE THERE IS SOME COLD AND DRY
AIR. AS A RESULT THERE ARE SOME POCKETS OF FREEZING RAIN THIS
MORNING IN ANCHORAGE AND IN THE LOWER (SOUTHERN) SUSITNA VALLEY.
TEMPERATURES WILL WARM TO ABOVE FREEZING THIS AFTERNOON AND BY
LATE AFTERNOON THE UPPER WAVE WILL PUSH NORTH OF THE AREA. BRIEF
RIDGING IS EXPECTED TONIGHT AHEAD OF THE NEXT SYSTEM RACING UP
FROM THE SOUTH. THIS NEXT LOW WILL ENTER THE OFFSHORE WATERS EARLY
TUESDAY THEN RAPIDLY PUSH TO THE NORTHWEST ACROSS KODIAK ISLAND ON
TUESDAY. THIS IS ANOTHER WARM SYSTEM AND MOST OF THE PRECIPITATION
WILL BE IN THE FORM OF RAIN. SOUTHEAST FLOW ALOFT WILL KEEP THINGS
FAIRLY DRY INLAND...UNTIL THE TRAILING UPPER TROUGH PUSHES INTO
SOUTH CENTRAL ALASKA LATE TUESDAY NIGHT.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 THROUGH 3)...

A WEAKENING FRONT WILL SPREAD SHOWERS ACROSS THE NORTHERN BRISTOL
BAY ZONE INTO THE SOUTHERN PORTIONS OF THE LOWER KUSKOKWIM VALLEY
TODAY BEFORE DIMINISHING THIS EVENING. A MUCH STRONGER WARM FRONT
WILL MOVE INTO SOUTHWEST TONIGHT THROUGH TUESDAY...SPREADING
WIDESPREAD RAIN ACROSS THE REGION. THE POSSIBILITY EXISTS OF SOME
ISOLATED POCKETS OF FREEZING RAIN ACROSS THE LOWER KUSKOKWIM
VALLEY AND KUSKOKWIM DELTA TUESDAY MORNING BEFORE TURNING TO ALL
RAIN. COLDER AIR ALOFT WILL SWEEP INTO THE REGION TUESDAY
NIGHT...WITH LINGERING ISOLATED TO SCATTERED RAIN AND SNOW
SHOWERS LINGERING THROUGH WEDNESDAY. LOCALLY STRONG EAST TO
NORTHEAST WINDS WILL DEVELOP ACROSS THE BRISTOL BAY ZONE AS THE
FRONT TRACKS INLAND THIS EVENING INTO TUESDAY MORNING.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 THROUGH 3)...

A LARGE GALE FORCE LOW WILL MOVE INTO THE BERING SEA
TODAY...SPREADING RAIN AND RAIN SHOWERS ACROSS THE REGION
WEDNESDAY. STRONG EAST TO SOUTHEAST WINDS WILL IMPACT THE EASTERN
ALEUTIANS AND THE PRIBILOF ISLANDS TODAY AND TONIGHT...WITH STRONG
NORTHWEST WINDS IMPACTING THE CENTRAL ALEUTIANS WEST OF DUTCH
HARBOR. THE LOW WILL GRADUALLY WEAKEN TUESDAY NIGHT AND WEDNESDAY.

&&

.LONG TERM FORECAST (WEDNESDAY THROUGH SUNDAY)...
THE BLOCKING PATTERN LOOKS TO CONTINUE THROUGH MUCH OF THIS WEEK
WITH A PERSISTENT RIDGE OVER WESTERN CANADA AND A BROAD UPPER
LEVEL TROUGH OVER THE ALEUTIANS AND BERING SEA. THIS WILL RESULT
IN A CONTINUATION OF SOUTHERLY FLOW OVER THE GULF OF ALASKA AND
HELP TO KEEP THE BULK OF THE PRECIPITATION FOCUSED ALONG THE NORTH
GULF COAST INTO NEXT WEEKEND...WITH OCCASIONAL CHANCES FOR
PRECIPITATION FURTHER INLAND AS DISTURBANCES ROTATE THROUGH THE
GULF. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL AND ALLOW
MOST OF THE PRECIP TO FALL AS RAIN...WITH SNOW MIXING IN AT TIMES.
MEANWHILE...THE BERING SEA WILL REMAIN IN A SHOWERY REGIME WITH AN
ELONGATED UPPER LOW CENTERED OVER THE ALEUTIAN CHAIN AND VARIOUS
WAVES ROTATING THROUGH THE EASTERN BERING. THE STRONGEST OF THESE
FEATURES LOOKS TO APPROACH THE AKPEN LATE IN THE WEEK AS A NORTH
PACIFIC SHORT WAVE ROUNDS THE BASE OF THE TROUGH AND AN ASSOCIATED
SURFACE LOW RAPIDLY DEEPENS BENEATH THE LEFT EXIT REGION OF A 160
KT JET STREAK. THE DETAILS OF THIS SYSTEM WILL COME INTO BETTER
FOCUS LATER IN THE WEEK...BUT THERE IS INCREASING AGREEMENT THAT
THE BLOCKING RIDGE WILL SLIDE (AT LEAST MOMENTARILY) TO THE EAST
BY LATE THIS WEEK/EARLY THIS WEEKEND...ALLOWING FOR ACTIVE WEATHER
TO REACH THE SOUTHERN MAINLAND.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...FREEZING RAIN ADVISORY 101 145.
MARINE...GALE 119 120 125 130 131 138 139 155 165 170 171 172 174
              176 177 178 179 180 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...PD
SOUTHCENTRAL ALASKA...BL
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...JA
LONG TERM...CB/DEK