Gale Warning 41, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST TUE JAN 22 2008

.SYNOPSIS...
.SHORT RANGE...UPPER LEVEL PATTERN INDICATES A DEEP TROUGH
EXTENDING SOUTH ACROSS THE BERING WITH A RIDGE AXIS STRETCHING
ACROSS THE PANHANDLE. THE RIDGE IS SLOWLY TILTING SOUTHWARD AS A
SHORTWAVE SLIDES EASTWARD INTO THE WESTERN GULF.  WITH THE FLOW
TURNING MORE ONSHORE OVER THE NORTHERN PANHANDLE...A LAYER OF LOW
LEVEL STRATUS WITH PATCHY FOG AND A FEW FLURRIES IS SPREADING
SOUTHWARD TO A LINE NORTH OF WRANGELL.  THE MAIN FRONTAL BAND
ASSOCIATED WITH THE WAVE IN THE NORTHWESTERN GULF EXTENDS FROM
NORTH TO SOUTH THROUGH THE CENTRAL GULF.  WINDS REMAIN LIGHT
ACROSS THE FORECAST AREA.

THE AFOREMENTIONED NORTHWESTERN GULF WAVE SLIDES OVER THE RIDGE
AND FLATTENS IT...HOWEVER MUCH THE DYNAMICS ASSOCIATED WITH THE
SYSTEM WILL DIMINISH.  HIGH CLOUDS WITH A LOWER MARINE LAYER WILL
BE THE STORY TONIGHT AND WEDNESDAY.  LIGHT RAIN AND SNOW WILL
ARRIVE WITH THE WEAKENED WAVE BUT ACCUMULATION WILL BE
INSIGNIFICANT.  TEMPERATURES WILL WARM FROM THE PREVIOUS FEW
NIGHTS WITH WARMER MARINE AIR ARRIVING.

FOR WEDNESDAY...A SECOND WAVE MOVES INTO THE NORTHWESTERN GULF
THEN PUSHES SOUTH OF ZONE 17 AND INTO THE NORTHEASTERN GULF LATE
IN THE AFTERNOON.  PRECIPITATION WILL SPREAD EAST INTO YAKUTAT
EARLY WEDNESDAY THEN THE REST OF THE PANHANDLE BY AFTERNOON.  A
RAIN AND SNOW MIXTURE IN THE MORNING FOLLOWED BY MAINLY RAINFALL
IN THE AFTERNOON.  WINDS WILL INCREASE OVER THE GULF BEHIND THE
LOW WITH GALE FORCE WINDS DEVELOPING IN THE OUTSIDE WATERS.

.LONG RANGE...MODELS ARE IN GOOD AGREEMENT WITH STRENGTHENING THE
UPPER LEVEL RIDGE IN THE GULF OF ALASKA AND INTERIOR ALASKA WED
NIGHT AND THURSDAY. DIFFERENCES BEGIN TO GROW WITH THE NEXT
TROUGH THAT IS PROJECTED TO CROSS THE ALASKAN INTERIOR ON FRI AND
THEN DIG SOUTHEASTWARD INTO THE EASTERN GULF OF AK...EVENTUALLY
DEVELOPING INTO AN UPPER LOW JUST OFFSHORE OF VANCOUVER ISLAND BY
THU NIGHT.  THE UPPER RIDGE REBUILDS BEHIND THE TROUGH A LITTLE
FURTHER TO THE NORTH AND WEST...WHICH IS CLOSE ENOUGH AND STRONG
ENOUGH TO DIRECT AN INTENSE ARCTIC AIR MASS FROM NEAR THE POLE
DOWN ACROSS THE CANADIAN YUKON OVER THE WEEKEND.

ENSEMBLE VARIATIONS IN THE STRENGTH OF THE DIGGING UPPER TROUGH
LEAVE SOME UNCERTAINTY IN THE DISTRIBUTION OF PRECIPITATION WED
NIGHT AND EARLY THU BUT COASTAL AND SOUTHERN SECTIONS HAVE THE
HIGHEST PROBABILITIES FOR SNOW. MOST OF SOUTHEAST ALASKA WILL BE
DRY BY LATE FRI.

TEMPERATURES SHOULD DROP SIGNIFICANTLY OVER THE WEEKEND WITH
NORTHERN INTERIOR SECTIONS DIPPING BELOW ZERO. BUILDING SURFACE
HIGH PRESSURE IN THE YUKON WILL CAUSE NORTHERLY WINDS TO
INTENSIFY TO STORM LEVEL IN NORTH-NORTHEASTELY EXPOSED GAPS AND
CHANNELS.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE
MARINE...SMCR (SEAS)...ZONES 41-42-43-51-52