Gale Warning 114, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
330 PM AKST SAT FEB 5 2011

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS THE PANHANDLE
UNDER CLOUDY SKIES AS CLOUDS FROM A DEVELOPING LOW IN THE
SOUTHERN GULF CONTINUE TO DRIFT OVER THE AREA. THERE IS A VERY
LONG FETCH OF MOISTURE THAT EXTENDS SOUTH NEAR HAWAII. THERE IS A
HIGH AMPLITUDE RIDGE OVER SE AK AND THE EASTERN PACIFIC WITH A
SHORT TROF LIFTING NORTH ALONG THE BACK SIDE OF THE RIDGE. THE
TROF WILL LIFTS NE THROUGH THE SHORT TERM PERIOD AND PUSH THE
RIDGE TO THE EAST OF THE AREA. THE ATMOSPHERIC RIVER ASSOCIATED
WITH THE LONG SW FETCH...SEEN ON WV IMAGERY...WILL MOVE OVER THE
SOUTHERN HALF OF THE PANHANDLE LATE TONIGHT AND PERSIST THROUGH
SUNDAY AS THE ASSOCIATED LOW PRESSURE SYSTEM LIFTS OUT OF THE
NORTH PACIFIC AND OVER DIXON ENTRANCE BY SUN AFTERNOON. THE LOW
PRESSURE SYSTEM WILL DEEPEN THROUGH TONIGHT AND BOTTOM OUT AROUND
1004MB AS IT DRIFTS NEAR THE NW SIDE OF THE QUEEN CHARLOTTES BY
SUN MORNING. THE LOW WILL THEN BEGIN TO WEAKEN THROUGH THE
AFTERNOON AS IT DRIFTS INLAND.

 SO WITH THAT SAID...PRECIPITATION WILL DEVELOP THROUGH THIS
EVENING OVER THE SOUTHERN COASTAL AREAS THIS EVENING WITH SOME
SNOW MIXED IN BUT IT WILL QUICKLY CHANGE OVER TO RAIN AS THE WAA
MIXES DOWN TO THE SURFACE. THE RAIN WILL BECOME HEAVY AT TIMES
THROUGH THE SUN AS THE STRONGEST LIFT ASSOCIATED WITH THE LOW AND
HIGH PRECIPITABLE WATER VALUES MOVE OVER THE FAR SOUTHERN AREAS.
THE BIGGEST FORECAST ISSUE TODAY WAS HOW MUCH SNOW THE SOUTH
CENTRAL AND MIST FJORD WILL GET AS WITH THE LOW UNDERCUTTING THE
AREA THE COLD AIR IN PLACE WILL REMAIN AND GET REINFORCED AS THE
SURFACE PRESSURE GRADIENT WILL INCREASE FROM THE EAST TO PULL IN
SOME COLDER AIR. SO WILL ISSUE A SNOW ADVY FOR ZONE 26 AND
29 FROM LATE TONIGHT THROUGH SUN AFTERNOON. AMOUNTS WILL RANGE
FROM 3 TO 6 INCHES OVER THE CENTRAL AREAS WITH 8 TO 10 INCHES
NEAR HYDER. THE A DEFORMATION BAND WILL SET UP OVER THE CENTRAL
AREAS THROUGH SUN AS THE LOW MOVES INTO DIXON ENTRANCE SO THERE
IS A CHANCE THAT SOME STATIONS MAY RECEIVE A BIT MORE SNOW. FOR
THE MOST PART THE PRECIP WILL REMAIN SOUTH OF FREDRICK SOUND BUT
THERE MAY BE A CHANCE THAT A FEW FLURRIES WILL MAKE IT NEAR THE
JUNEAU AREA BY THE AFTERNOON. THERE IS A LOT OF EASTERLY FLOW AT
THE SURFACE SO THE THINKING THIS AFTERNOON IS THAT THE ATMOSPHERE
WILL REMAIN TOO DRY.

 AS FOR THE WINDS...AS THE LOW LIFTS NORTH THROUGH TONIGHT IT
WILL TIGHTEN UP THE PRESSURE GRADIENT WITH THE INTERIOR HIGH
PRESSURE. THIS WILL INCREASE THE NORTHERLY WINDS IN THE INNER
CHANNELS TO GALES BY LATE TONIGHT AND THEN AS THE LOW WEAKENS AND
LIFTS INTO THE CANADA THEY WINDS WILL SLOWLY DIMINISH THROUGH THE
AFTERNOON TO SMALL CRAFT. ALONG WITH THE NORTHERLY WINDS
INCREASING THE OUTFLOW WINDS FROM THE EAST WILL ALSO INCREASE
WITH GUSTS FROM 40 TO 50 KT. MOST LAND AREAS ALONG THE COAST
RANGE WILL SEE LOCALLY BREEZY/WINDY CONDITIONS NEAR INTERIOR
PASSES FROM LATE TONIGHT THROUGH EARLY SUN AFTERNOON. THE FAR
NORTHERN AREAS WILL SEE THE WINDS FROM THE NORTH INCREASE TO BE
ON THE WINDY SIDE AND THERE IS A POSSIBILITY THAT GUSTS TO 40 MPH
WILL DEVELOP IN THE MORNING BUT ATTM THERE IS NOT MUCH OF AN
INDICATION THAT THERE WILL SIGNIFICANT CROSS BARRIER FLOW THAT
CAN INDUCE WIND ADVY LEVEL GUSTS NEAR PAGY.

&&

.LONG TERM...LOW COMPLEX ACROSS DIXON ENTRANCE MOVES OFF TO THE
EAST SUNDAY EVENING. AN UPPER LEVEL RIDGE BUILDS THROUGH THE
EASTERN GULF MONDAY AND MOVES ACROSS SOUTHEAST ALASKA THROUGH
TUESDAY NIGHT AND IS EAST OF AREA ON WEDNESDAY. A GALE FORCE LOW
MOVES INTO THE GULF THURSDAY AND WARPS A SERIES OF FRONTS THROUGH
SOUTHEAST ALASKA THU AND FRI.

EXPECT TO SEE COLDER TEMPS ACROSS THE PANHANDLE STARTING SUNDAY
NIGHT AS ATMO DRIES OUT AND OFFSHORE WINDS DEVELOP AND CONTINUES
THROUGH TUESDAY. NEXT SYSTEM SPREADS GALES AND SNOW TO COAST
TUESDAY EVENING WHICH MIXES WITH RAIN BY MORNING. WAA SPREADS
THROUGH INNER CHANNELS TUESDAY NIGHT AND TURNS SNOW TO RAIN ON
WEDNESDAY. OCCLUDED FRONT WITH RAIN...POSSIBLY HEAVY AT TIMES...
ALONG THE COAST THURSDAY. A SECONDARY TROUGH BRINGS ANOTHER ROUND
OF PRECIP...MAINLY RAIN...ON FRIDAY. WITH POSITION OF LOW SOUTH OF
PAYA AND TROUGH ACROSS NORTHERN LYNN CANAL COULD SEE SOME SNOW
PAYA-PAHN ON FRIDAY.

MODELS IN FAIRLY GOOD AGREEMENT ACROSS OUR AREA WITH HANDLING OF
MAIN FEATURES. AS USUAL THERE ARE SOME DIFFERENCES IN TIMING AND
POSITION OF INDIVIDUAL FEATURES THAT WILL AFFECT HOW FAR SNOW
MAKES INTO SOUTH CENTRAL SUNDAY NIGHT. USED GFS THROUGH DAY 4 AND
TRANSITIONED TO HPC WHICH HAD A BIGGER EC COMPONENT FOR DAYS 5-8.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY FROM 3 AM TO 4 PM AKST SUNDAY FOR AKZ026-
     029.
MARINE...GALE WARNING FOR PKZ011>013-021-022-031>036-041.
         SMALL CRAFT ADVISORY FOR PKZ042-043-051-052.

&&

ABJ/MM