Gale Warning 279, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
630 AM ADT MON OCT 22 2007

.SYNOPSIS...
.SHORT RANGE...THE STRONG LOW THAT TRACKED NE THROUGH THE NRN
PNHDL LAST NIGHT IS NOW 300 NM NE OF JUNEAU AND TRACKING AWAY.
COLD AIR ADVECTION BEGAN AFTER THE LANDFALL OF THE LOW BUT HAS
A LIMITED SPREAD SOUTHEAST ALONG THE PANHANDLE.  THE COLD
ADVECTION IS ENOUGH TO HAVE SNOW MIXED IN ESPECIALLY FOR
HAINES...SKAGWAY...AND YAKUTAT.  THE ASSOCIATED COLD FRONT
WILL MOVE S OF PRINCE RUPERT BY NOON AND BECOME STATIONARY
WHILE PERSISTING WITH A NE TO SW ORIENTATION WITH THE COLDER
AIR TO THE NW.

A STRONG FRONTAL WAVE ON THE FRONTAL BOUNDARY IN THE N PAC WILL
LIMIT THE DURATION OF THE COLD ADVECTION AND IS THE REASON FOR
THE FRONT GOING STATIONARY THIS AFTERNOON.  THE STATIONARY FRONT
WILL BECOME A WARMFRONT MOVE N MOVE ACROSS DIXON ENTRANCE THIS
EVENING.  THE FRONTAL WAVE THAT IS CAUSING THE CHANGE FROM COLD
FRONT TO WARM FRONT SHOULD DEEPENING TO ABOUT 994 MB AS IT TRACKS

NE ACROSS LANGARA B.C. IN THE QUEEN CHARLOTTES 12Z TONIGHT AND
THEN TRACK NE ACROSS THE SRN PNHDL.

SPREAD OF MODELS IS WIDER THAN USUAL FOR NEXT 24 HRS...DUE TO
SOLUTIONS FOR WAVE TRACKING TOWARD SRN SE AK.  GFS AGREEMENT WITH

THE UKMET IS ESPECIALLY USEFUL.  THE TIMING OF THE WAVE IS CLOSE
TO THE GFS ENSEMBLE MEAN AND UKMET.  THE ENSEMBLE MEAN FM THE
220000Z MODEL RUN MEAN SEA LEVEL PRESSURE IS USED AS THE PRIMARY
GUIDANCE FOR THE TRACK OF THE LOW.

.LONG RANGE...MODELS SUGGESTING A WIDE RANGE OF SOLUTIONS FOR THE
NEXT WAVE THAT MOVES ACROSS SOUTHEAST ALASKA TUESDAY AND HAVE
LITTLE CONFIDENCE IN ANY ONE SOLUTION AND LEFT GRIDS UNCHANGED.

AS MENTIONED IN SHORT TERM...WARM FRONT WILL BE MOVING NORTH
THROUGH SOUTHERN ZONES TUESDAY MORNING AND HOW FAR NORTH IT
REACHES IS MODEL DEPENDENT. GFS IS FASTEST AND FARTHEST SOUTH OF
ALL SOLUTIONS. UKEMT IS SLOWER AND HAS MORE ELONGATED LOW THAT
CROSS SOUTHERN ZONES TUESDAY AFTERNOON. ECMWF IS MOST AGGRESSIVE
KEEPING LOW FARTHER WEST AND DEEPENING IT TO 979 MB AS IT CROSSES
OVER THE CENTRAL PANHANDLE. THE GFS WOULD KEEP ALL STRONG
SOUTHERLY WINDS SOUTH OF OUR FORECAST AREA WHILE ECMWF SUGGEST
GALES FOR SOUTHERN INNER CHANNELS. CURRENT GRIDS HAVE A SOUTH
SMCR WHICH IS GOOD COMPROMISE FOR NOW.

DO EXPECT PLENTY OF RAIN THAT WILL BE HEAVY AT TIMES ACROSS
SOUTHERN ON TUESDAY. AS LOW MOVES OFF TO THE NE...WESTERLY
GRADIENTS INCREASE ACROSS SOUTHEAST ALASKA BRING SHOWERS TO THE
AREA TUESDAY NIGHT AND WEDNESDAY. AT SAME TIME COLD UPPER TROUGH
PASSES OVER SOUTHEAST ALASKA AND HAVE INCLUDED MIXED RAIN AND
SNOW SHOWERS FOR NORTHERN ZONES LATE TUESDAY NIGHT INTO EARLY
WEDNESDAY.

RIDGE OF HIGH PRESSURE BUILDS INTO EASTERN GULF WEDNESDAY AND
MOVES ACROSS SOUTHEAST ALASKA FRIDAY. INITIALLY RIDGE IS FAIRLY
FLAT ALLOWING ONSHORE FLOW INTO PANHANDLE BUT AS IT MOVES ACROSS
SOUTHEAST IS SHARPENS UP ENOUGH TO CAP SHOWER ACTIVITY THURSDAY
NIGHT INTO FRIDAY FOR PARTIAL CLEARING AND AREAS OF FOG AND
FROST. BY FRIDAY MORNING RIDGE HAS MOVED OFF INTO CANADA AS NEXT
OCCLUSION MOVES INTO EASTERN GULF WITH GALES AND OVER SOUTHEAST
ALASKA FRIDAY NIGHT WITH SMCR. WAVE ALONG THIS TRAILING FRONT
DEEPENS AS IT MOVES THROUGH CENTRAL GULF SATURDAY AND ONSHORE
NEAR YAKUTAT AS A 982 MB LOW SATURDAY NIGHT. THIS SOLUTION WOULD
BRING ANOTHER ROUND OF GALES TO EASTERN GULF AND PROBABLY INTO
THE INNER CHANNELS AS WELL. A PARADE OF TROUGH FOLLOWS ON SUNDAY
AND MONDAY.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE
MARINE...SCA...PKZ012-22-31-33-36-41>43-51>52.

JT/MM