Gale Warning 3, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
124 PM AKST TUE JAN 5 2010

.SHORT TERM...ARCTIC OUTFLOW CONTINUES TO PLAY A PART IN THE
WEATHER ACROSS THE PANHANDLE TODAY. DOWN SLOPE WINDS HAVE CLEARED
OUT THE SKIES ACROSS MUCH OF THE AREA AND CHANNELED TERRAIN IS
INCREASING THESE WINDS IN SOME AREAS. A WIND ADVISORY REMAINS UP
FOR HYDER AND SKAGWAY TODAY AS WINDS ARE STILL GUSTING UP TO
50 MPH AT SKAGWAY AIRPORT AND GRAY ISLAND HAS WIND GUSTS UP TO
50 MPH AS WELL. ELSEWHERE, THE WIND ADVISORY FOR JUNEAU WAS
CANCELED AT NOON TODAY AS THE WINDS HAVE NOT DEVELOPED NEAR
DOWNTOWN, WINDS AT SHEEP MOUNTAIN ARE DECREASING, AND DEVELOPMENT
OF A MOUNTAIN WAVE SCENARIO DOES NOT LOOK LIKELY.

 FOR TONIGHT AND TOMORROW, EXPECT CONTINUED HIGH WINDS IN SKAGWAY
AND IN CHANNELED TERRAIN IN ZONE 29. WINDS WILL BE STARTING TO
CALM DOWN LATE AS THE PRESSURE GRADIENT EASES UP AHEAD OF AN
APPROACHING FRONT. SKIES WILL BEGIN TO CLOUD OVER FROM SOUTH TO
NORTH THROUGH THE NIGHT AND PRECIP SHOULD BEGIN IN THE SOUTHERN
AREAS LATE TONIGHT. THE PRECIP WILL SPREAD OVER THE REST OF THE
PANHANDLE THROUGH THE DAY WED. PRECIP SHOULD REMAIN AS RAIN FOR
THE SOUTHERN ZONES AND COASTAL ZONES. THE NORTHERN AND CENTRAL
INNER CHANNELS MAY SEE THE PRECIP START OUT AS SNOW OR A
RAIN/SNOW MIX WED BEFORE CHANGING ALL TO RAIN. ANY SNOW
ACCUMULATIONS WILL BE LIGHT AS IT WILL BE FIGHTING THE LINGERING
DOWN SLOPE FLOW NEAR THE SURFACE AND A RATHER SIGNIFICANT DRY
LAYER. THE HAINES AND KLONDIKE HIGHWAYS AND HYDER WILL STILL TAKE
A BIT LONGER TO CHANCE OVER TO RAIN AS THERE WILL STILL BE PLENTY
OF ENTRENCHED COLD AIR TO SCOURER OUT.

 WINDS ASSOCIATED WITH THE FRONT ARE ANOTHER ISSUE TO DEAL WITH.
AT THIS TIME DO NOT THINK A WIND ADVISORY IS WARRANTED FOR
HYDABURG OR KETCHIKAN AS THE ORIENTATION OF THE WINDS AND LOW
LEVEL JET IS NOT QUITE RIGHT. THERE IS TOO MUCH OF AN EASTWARD
COMPONENT TO THE WINDS TO GET THE HIGH WINDS INTO THOSE AREAS AND
THERE WILL STILL BE ENOUGH COLD AIR AT THE SURFACE THAT THE
HIGHER WINDS ALOFT WILL NOT BE ABLE TO MIX DOWN TO THE SURFACE.

 MODELS TODAY WERE IN RATHER GOOD AGREEMENT TODAY, WITH JUST A
FEW MINOR TIMING ISSUES ASSOCIATED WITH THE APPROACHING FRONT.
UPDATED THE FORECAST WITH A BLEND TO NAM FOR TONIGHT AND THEN
NAM/GFS FOR TOMORROW. FORECAST CONFIDENCE IS A LITTLE ABOVE
AVERAGE.

&&

.LONG TERM...STRONG UPPER LEVEL RIDGE OVER THE WEST COAST WILL
SLOWLY DRIFT EAST THIS WEEK AND ALLOW UPPER TROUGH TO MOVE THROUGH
OVER THE WEEKEND. THIS RIDGE REBUILDS ALONG THE WEST COAST NEXT
WEEK .HE DETAILS OF THIS TRANSITION IS LESS CLEAR WITH LARGE
DISCREPANCIES IN INTENSITY BY THIS WEEKEND. OPTED TO LIMIT CHANGES
TO GRIDS THROUGH WED AND MADE NONE BEYOND. HAD A SLIGHT PREFERENCE
FOR GFS INTENSITY OF LATE WEEK LOW MOVING NORTH INTO GULF AND USED.

ONSHORE FLOW IN THE UPPER LEVELS WILL INCREASE THROUGH THE WEEK
WHILE LOW LEVEL EASTERLIES AND DOWN SLOPE INCREASE IN LOW LEVELS.
INITIALLY THE MAIN IMPACT OF THIS SCENARIO WILL BE WARMER
TEMPERATURES AND PIECE MEAL SCOURING OUT OF ARCTIC AIR AND
INVERSIONS IN PLACE OVER THE PANHANDLE. FIRST FRONT OVER CENTRAL
PANHANDLE WEDNESDAY NIGHT CONTINUES NORTH AND MOVES ALOFT OVER
NORTHERN PANHANDLE EARLY THURSDAY. EAST WINDS AND A SHOT OF +8C
TEMPS NEAR MTN TOPS WILL TURN PRECIP TO ALL LIGHT RAIN SOUTH OF
ERO BUT THINK WILL STILL HAVE ENOUGH COLD AIR INPLACE FOR FAR
NORTH TO PICK UP A FEW INCHES OF LIGHT SNOW. TEMPS FOR ALL BUT FAR
NORTH EXPECTED IN THE 40S WHILE FAR NORTH SLOWLY RISES ABOVE
FREEZING. THIS WILL ALSO OFFSET NORTHERLY GRADIENTS AND SHOULD
SEE A GENERAL WEAKENING OF WINDS.

A SECOND STRONGER FRONT LIFTS NORTH INTO THE GULF OVER THE
WEEKEND. LOW LEVEL FLOW BECOMES MORE ONSHORE AND EXPECTING LESS
DOWN SLOPE AND MDT TO LCLY HEAVY RAIN ALONG THE COAST. WILL
CONTINUE TO SEE GALE FORCE SE WINDS IN COASTAL WATERS AND MAY WORK
INTO OCEAN ENTRANCES FRIDAY. AGAIN TEMPS AND THICKNESS WELL TOO
WARM FOR SNOW AT NEAR SEE LEVEL LOCATIONS WITH FREEZING LEVEL
MAINLY ABOVE 3K FEET SO LITTLE TO NO SNOW EXPECTED.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 3 AM AKST WEDNESDAY FOR AKZ018-029.
MARINE...GALE WARNING FOR PKZ012-022-034>036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-013-021-031>033.

&&

EAL/MM