Gale Warning 518, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
519 AM AKDT SUN SEP 7 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER-LVL LOW NEAR CAPE SUCKLING IS MOVING SE AND OPENING INTO
A TROUGH AS IT FILLS. WEAK TO MODEST NORTH TO WEST OFF-SHORE WINDS
PERSIST BEHIND IT THROUGH THE TYPICAL GAPS/PASSES OF SOUTHCENTRAL
AK. THE LOW STILL SUPPORTS SOME RAIN SHOWERS OVER SE REACHES OF
THE COPPER RIVER BASIN. IN IT'S WAKE AN UPPER- LVL RIDGE IS
ADVANCING FROM THE EASTERN BERING SEA. THE RIDGE IS DAMPENING A
BIT DUE TO A LARGE BERING SEA LOW MOVING UP AGAINST IT FROM THE
WEST. THIS LOW CENTERED 90 MI NW OF ADAK IS DRIFTING NORTH AND
FILLING. THE ASSOCIATED OCCLUDED FRONT IS DYING THOUGH SOME LIGHT
RAINS STILL FALL ACROSS THE CHAIN AND NOSE TOWARDS THE SW
MAINLAND. OTHER UPSTREAM FEATURES OF NOTE ARE A STRONG SHORTWAVE
TROUGH DIGGING SOUTHWARD FROM NE SIBERIA AND TROPICAL STORM
FENSHENG RECURVING OFF S JAPAN.

&&

.MODEL DISCUSSION...
THE CHIEF DISCREPANCY OF NOTE HAS BEEN THE FASTER PROGRESSION OF
THE MOISTURE/PRECIPITATION IN SW AK WITH THE DYING FRONT.
OTHERWISE...THE MAIN WEATHER FEATURES ARE HANDLED SATISFACTORILY
AND WITH REASONABLY CLOSE AGREEMENT AMONG THE MODELS. THE LOW
NEAR ADAK WILL SLOWLY DRIFT NORTH TO AROUND 250 MI W OF SAINT PAUL
BY TUE. MODELS THEN SHOW THE SHORTWAVE DIGGING DOWN FROM SIBERIA
FORMING A LOW OVER THE N KAMCHATKA PENINSULA WHICH THEN TRACKS
INTO THE FAR W BERING SEA ON TUE AND ABSORBS THE ENERGY OF THE
FIRST LOW. THIS REINVIGORATED LOW THEN MOVES TO JUST NORTH OF
SHEMYA ON WED AROUND 990 MB. MEANWHILE A STRENGTHENING JET STREAM
PUSHING OFF E ASIA IS DEPICTED UNDERCUTTING THE BERING SYSTEM
WITH MORE ENERGY...MANIFESTED IN A SFC LOW WRAPPING UP TO THE
EAST- CENTRAL CHAIN BY WED AS WELL. REMNANTS OF TROPICAL STORM
FENSHENG ARE SHOWN APPROACHING 40N 160E MID WEEK. OVERALL...THE
ECMWF APPEARS STRONGEST WITH THE 300 MB JET AND APPEARS TO MIGRATE
THE ASSOCIATED ENERGY CLOSEST TO THE BERING SYSTEM...BUT THE
GENERAL SPIRIT AND IDEA IS CAPTURED BY ALL THE MODELS THROUGH MID-
WEEK.

&&

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
INITIAL DRYING WITH THE UPPER RIDGING WILL ALLOW FOR SOME DECENT
WARMING/SUNSHINE TODAY ACROSS MUCH OF SOUTHCENTRAL AK. CLOUDS MAY
TAKE A BIT LONGER TO SCOUR OUT ACROSS THE COPPER RIVER BASIN BUT
THERE TOO SHOULD BE SOME IMPROVEMENT THROUGH THE DAY. WHAT'S LEFT
OF THE UPSTREAM FRONT POKES INTO THE GULF OF AK WHERE IT WILL
STALL BRIEFLY. ASSOCIATED MID AND HIGH CLOUDS WILL BE FILTERING IN
TONIGHT WITH LESS SUNSHINE IN STORE FOR MON. THERE SHOULD ALSO BE
A PERIOD OF RAIN FOR KODIAK ISLAND AS THE FRONT SLIDES EAST
TONIGHT INTO MON. SHORTWAVE AND JET STREAM ENERGY ADVANCING
TOWARDS THE RESIDUAL FRONTAL BOUNDARY FROM THE SOUTHWEST WILL HELP
FORM SUBTLE SURFACE WAVES ALONG IT WHICH WILL THEN BE STEERED
NORTHWARD TO THE SOUTHERN MAINLAND. NORTH TO WEST GAP WINDS
DIMINISH AND BECOME MORE SOUTH TO EAST ORIENTED AS THE PRESSURE
GRADIENT ORIENTATION REVERSES IN THE ONSHORE FLOW...BUT THESE
WINDS SHOULD REMAIN GARDEN VARIETY. WINDS ACROSS MARINE AREAS ALSO
SHOULD BE 25 KT OR LESS AS THESE FEATURES TRAVERSE THE REGION.

SOUTHWEST ALASKA...
EXPECT LIGHT RAINS TO SPREAD INLAND TODAY AS FRONTAL AND POST
FRONTAL SHORTWAVES SWING THROUGH THE AREA. THE DYING NATURE OF THE
FRONT AND DISORGANIZED SHORTWAVE ENERGY SHOULD KEEP PRECIPITATION
GENERALLY LIGHT. THE BERING SEA SYSTEM WILL NOT MOVE APPRECIABLY
ENOUGH TO CHANGE THE CLOUDY PATTERN WITH CHANCES OF PRECIP IN THE
COMING DAYS.

BERING SEA/ALEUTIANS...
ANY RESIDUAL GALES ACROSS THE MARINE ZONES SHOULD TREND TO SMALL
CRAFT LEVELS OVERNIGHT TONIGHT TO MON AS THE BERING LOW CONTINUES
TO FILL AND THE PRESSURE GRADIENT RELAXES SOME. THERE WILL STILL
BE PERIODS OF RAIN AS LOBES OF ENERGY ROTATE AROUND THE PARENT
UPPER-LOW IN THE BERING SEA.

&&

.LONG TERM FORECAST...
THE LARGE UPPER-LVL LOW NEAR ATTU ON WED WILL DRIFT EAST TOWARDS THE
MAINLAND BY NEXT WEEKEND. THERE ARE  DIFFERENCES WITH REGARDS TO
WHERE AND HOW THOUGH. THE GFS IS SHOWING THIS FEATURE HUGGING THE
ALEUTIAN CHAIN/AKPEN TO A POSITION ON SAT NEAR BRISTOL BAY. THE
ECMWF IS CLOSE IN SPIRIT THROUGH THU NIGHT BUT THEN DEPICTS A
SIGNIFICANT SOUTHERN LOBE OF ENERGY (REMNANTS OF TROPICAL STORM
FENGSHEN) WRAPPING UP FROM THE N PACIFIC ON FRI...WITH THE PARENT
UPPER-LOW CENTER PIVOTING NORTHWARD TO AROUND NUNIVAK/SAINT
MATTHEW ISLAND AT A COMMENSURATE TIME ON SAT. WHILE LOW CONFIDENCE
EXISTS WITH TIMING AND PLACEMENT DETAILS THIS FAR OUT IN
TIME...THE FORECAST DOES LEAN MORE TOWARDS THE ECMWF AS IT TENDS
TO HANDLE SOME OF THOSE TROPICAL FEATURES BETTER. CONSIDERING THE
DEGREE OF THE AMPLIFIED FLOW ALOFT...THE CLOUDY AND WET PATTERN
FOR THE AOR IS UNLIKELY TO CHANGE MUCH THROUGH THE LATTER PART OF
THE WEEK. IF ANYTHING...THERE MAY BE AN ENHANCED THREAT OF HEAVY
RAINFALL FOR SOUTHCENTRAL AK/PRINCE WILLIAM SOUND AND PENDING
SURFACE LOW TRACK...PERHAPS AN INCREASED RISK OF A STRONG WIND
EVENT FOR THE POPULATION CENTERS OF SOUTCHENTRAL AK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE...173 174 176 411 412 413
FIRE WEATHER...NONE.

&&

JAM