Small Craft Advisory 696, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
315 PM AKST MON NOV 19 2012

.SHORT TERM...SATELLITE AND BIORKA RADAR IMAGERY SHOWS A COMPLEX
LOW ROTATING OFFSHORE MOVING TO THE WEST THIS AFTERNOON. THIS LOW
HAS BROUGHT SOME SNOW SHOWERS TO THE CENTRAL INTERIOR
PANHANDLE...SOME RAIN SHOWERS ALONG THE COAST AND IN THE SOUTHERN
PANHANDLE AS WELL AS SOME PERSISTENT WINDS TO 30 MPH IN SPOTS
OVER THE COAST AND THE SOUTH. YUKON HIGH PRESSURE IS STILL FIRMLY
IN PLACE WITH SOME COLD TEMPERATURES...LIKE 3 DEGREES IN WATSON
LAKE AND 1 DEGREE IN WHITEHORSE. PRESSURE GRADIENT...ALTHOUGH
RELAXING SOMEWHAT OVERNIGHT WILL STILL YIELD STORM FORCE WINDS IN
LYNN CANAL INTO TUESDAY. STRONG GALE WILL CONTINUE FOR CROSS
SOUND...MUCH OF THE NORTHERN OUTSIDE WATERS...AS WELL SEVERAL
ZONES IN THE NORTHERN INSIDE. IN ADDITION...FREEZING SPRAY WILL
CONTINUE OVERNIGHT IN LYNN CANAL AND GLACIER BAY.

 AS COMPLEX LOW MOVES TO THE WEST OVERNIGHT AND EVENTUALLY
SOUTHWEST INTO THE SOUTHWEST GULF...ANOTHER LOW ROTATING AROUND
THE UPPER LEVEL TROUGH SITTING OVER THE GULF WILL APPROACH THE
SOUTHEAST GULF TUESDAY. THIS WILL ENSURE GRADIENT TIGHTENS AGAIN
OVER THE PANHANDLE...PARTICULARLY TUESDAY AFTERNOON. IN ADDITION
THE EXITING LOW TONIGHT WILL USHER IN SOME DRIER FLOW FROM THE
INTERIOR THAT WILL EVENTUALLY ERODE SOME OF THE CLOUDY SKIES
TUESDAY AFTERNOON FOR MUCH OF THE INTERIOR PANHANDLE. POPS WILL
RETREAT FROM ALL BUT THE FAR SOUTHEASTERN COAST ZONES BY TUESDAY
AFTERNOON.

 USED THE ECMWF TO REFRESH GRIDS. MODELS STILL NOT RESOLVING
SMALL SHORTWAVES ROTATING AROUND THE MAIN UPPER LEVEL TROUGH IN
THE GULF OF ALASKA....BUT ECMWF SEEMS TO SIMPLIFY THINGS IN AN
ACCEPTABLE WAY. MADE LITTLE CHANGES TO INNER CHANNEL WINDS. DID
MAKE SOME MINOR TWEAKS TO TEMPERATURE GRIDS TONIGHT AND TUESDAY
TO GIVE SOME NECESSARY HIGH AND LOW DIFFERENCES, ALTHOUGH MINIMAL
TO WINDY AREAS OF LYNN CANAL. CONFIDENCE IN FORECAST IS AVERAGE.

&&

.LONG TERM...MEDIUM RANGE MODELS ARE IN FAIR AGREEMENT THROUGH
EARLY THURSDAY WITH A DEVELOPING LOW MOVES INTO THE SOUTHEAST
GULF. SOME MINOR DIFFERENCES STILL EXIST AMONG THE MODEL
OUTPUTS...BUT THE OVERALL GENERAL CONSENSUS SHOWS HIGHLY
ACCEPTABLE PERFORMANCE. REFRESHED THE INHERITED FORECAST PACKAGE
WITH THE MOST PERSISTENT ECMWF THROUGH THANKSGIVING DAY. POTENTIAL
WINDY CONDITIONS ARE NOW MORE PRONOUNCED FROM THANKSGIVING DAY
THROUGH SATURDAY. A SPECIAL WEATHER STATEMENT HAS BEEN POSTED. AT
THIS TIME...THE STORM IS EXPECTED TO INTENSIFY AS IT MOVES INTO
THE SOUTHEAST GULF AND DRIFTS SLOWLY NORTH ACROSS THE EASTERN
GULF. WITH PERSISTING ARCTIC HIGH OVER THE YUKON...NORTHERLY
PRESSURE GRADIENT WILL BECOME EVEN TIGHTER. MODELS BEGIN DIVERTING
LATE THURSDAY NIGHT AND OPTED TO LEAN OVER THE NEW HPC ENSEMBLE
APPROACH WITH THEIR PREVIOUS FORECAST.

 WITH GROWING UNCERTAINTIES...THE STORM MAY TRACK A LITTLE MORE
TO THE WEST. IF THAT HAPPENS...THE STRONG WINDS MAY NOT REACH AS
FAR TO THE NORTHEASTERN GULF COAST. WITH THE SAME
TOKEN...SIGNIFICANT SNOWFALL FROM THE STORM MOVEMENT MAY SHIFT
MORE WESTWARD. HOWEVER...RELATIVELY WARM AIR MASS WILL ACCOMPANY
THE STORM AND THE AIR MASS WILL BE MODIFIED AS IT MOVES ONSHORE
OVER THE PANHANDLE. WITH PERSISTING ARCTIC AIR TO THE
NORTH...POTENTIAL SIGNIFICANT SNOWFALL CANNOT BE RULED OUT
COMPLETELY AND/OR POSSIBLE FREEZING RAIN...ESPECIALLY ACROSS THE
CENTRAL PANHANDLE. THE ENSEMBLE APPROACH DEPICTS THE STORM
CONTINUES TO WEAKEN ACROSS THE EASTERN GULF OVER THE WEEKEND AND
TRACK BACK SOUTHEASTWARD INTO EARLY NEXT WEEK.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 9 PM AKST THIS EVENING FOR AKZ018-019-025.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ012.
         STORM WARNING FOR PKZ012-013.
         GALE WARNING FOR PKZ011-021-022-031-032-035-043-051-053.
         SMALL CRAFT ADVISORY FOR PKZ033-034-036-041-042-052.

&&

JWA/AHN

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JUNEAU AK
214 PM AKST MON NOV 19 2012

AKZ017>020-022-023-025-027-029-200115-
CAPE FAIRWEATHER TO CAPE SUCKLING COASTAL AREA-
TAIYA INLET AND KLONDIKE HIGHWAY-HAINES BOROUGH AND LYNN CANAL-
GLACIER BAY-SALISBURY SOUND TO CAPE FAIRWEATHER COASTAL AREA-
CAPE DECISION TO SALISBURY SOUND COASTAL AREA-
JUNEAU BOROUGH AND NORTHERN ADMIRALTY ISLAND-
DIXON ENTRANCE TO CAPE DECISION COASTAL AREA-MISTY FJORDS-
INCLUDING THE CITIES OF...YAKUTAT...SKAGWAY...HAINES...GUSTAVUS...
ELFIN COVE...PELICAN...SITKA...PORT ALEXANDER...JUNEAU...CRAIG...
KLAWOCK...HYDER
214 PM AKST MON NOV 19 2012

...WINDY CONDITIONS EXPECTED THANKSGIVING THROUGH SATURDAY...

A DEVELOPING LOW PRESSURE IN THE NORTHEAST PACIFIC WILL INTENSIFY
AS IT MOVES INTO THE SOUTHEAST GULF EARLY ON THANKSGIVING DAY.
THIS INCOMING LOW WILL PRODUCE STRONG WINDS IN THE ALASKAN
PANHANDLE FROM LATE WEDNESDAY NIGHT THROUGH SATURDAY.

AT THIS TIME...THE STORM IS EXPECTED TO MOVE NORTH ACROSS THE
EASTERN GULF AND SLOWLY WEAKEN THERE THROUGH LATE SATURDAY NIGHT.
PERSISTING ARCTIC HIGH OVER THE YUKON WILL ENHANCE NORTHERLY
STRONG WINDS ACROSS THE NORTHERN PANHANDLE...WHILE THE INCOMING
STORM WILL BRING STRONG SOUTHERLY WINDS OVER THE CENTRAL AND
SOUTHERN PANHANDLE. THE ADJACENT COASTAL MARINE AREAS WILL BE
AFFECTED WITH POSSIBLE STORM FORCE WINDS.

THE EXACT TRACK OF THE SYSTEM IS STILL UNCERTAIN AT THIS MOMENT BUT
CONFIDENCE IS INCREASING WITH EVERY MODEL RUN TO DETERMINE EXACTLY
WHICH AREAS SEE THE STRONGEST WINDS IN LATER FORECASTS. IF THE SYSTEM
TRACKS A LITTLE FARTHER WEST THAN CURRENT FORECASTS...THE STRONG
WINDS MAY NOT REACH AS FAR TO THE NORTHEASTERN GULF COAST.