Gale Warning 28, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST SUN JAN 7 2007

.SYNOPSIS...
.SHORT RANGE...THE STRONG LOW THAT MOVED RAPIDLY ONSHORE
LAST NIGHT HAS NOW REDEVELOPED IN B.C. ABOUT 200 MI EAST OF
KETCHIKAN.  RAPID PRESSURE RISES ARE TAKING PLACE IN ALL
OF PANHANDLE AT THIS TIME EXCEPT NEAR HAINES AND SKAGWAY.

OLD PARENT OF ABOUT 998 MB NEAR MIDDLETON ISLAND IS
CLOSE TO VERITICALLY STACKED AND UNTIL MONDAY IS
QUASISTATIONARY DUE TO TERRAIN LOCK AS WELL AS ARCTIC
OUTFLOW OVER RELATIVELY WARM WATER OF THE GLFALSK.

NEXT IMPORTANT CHANGES ASSOCIATED WITH LARGE SCALE ARCTIC
OUTBREAK BEGINNING MONDAY NIGHT.  WHAT HAS BEEN THE PERSISTENT
LOW ALOFT OVER THE NORTH CENTRAL GULF WILL BE MOVED EAST
BY A STRONG AND LARGE SCALE RIDGE ALOFT.  12Z TUE THE
RIDGE WILL BE EXTENDING N FROM THE NPAC TO OVER BRISTOL
BAY AND THE YUKON KUSKOKWIM DELTA.  THE ARCTIC AMS IN THE
AK INTERIOR WILL BECOME DEEPER AND STRONGER FURTHER TO
THE EAST AND SHOULD GEN GALE FORCE NORTH WINDS AS FAR EAST
AS LYNN CANAL MON NIGHT.

MODELS...NAM GFS CONSENSUS GOOD AND WILL BE USED.  ONE PREFERENCE

FOR THE NAM IS THE SURFACE PRESSURE GRADIENT DEVELOPING FROM
THE NORTHERN INTERIOR DUE TO THE ARCTIC OUTBREAK.  THE NAM
TYPICALLY GIVES A MORE INTENSE AND REALISTIC GRADIENT.  THE
THE NEW HIGH RES GFS MAY HELP BUT TECHNICAL DIFFICULTIES ARE
PRESENTLY PREVENTING THEIR USE.

.LONG RANGE...COLD...DRY...AND WINDY CONDITIONS ARE EXPECTED TO
BE ON TAP THROUGH MUCH OF THE LONG RANGE.  WELL AMPLIFIED RIDGE
WILL CONTINUE TO BUILD OVER THE CENTRAL GULF OF ALASKA BY TUESDAY
MORNING.  THIS RIDGE WILL NUDGE THE PERSISTENT UPPER LEVEL TROF
(FORMERLY OVER THE NORTHERN GULF) TO THE SOUTHEAST INTO CANADA.
ANY REMAINING SHOWERS ASSOCIATED WITH THIS TROF WILL DISSIPATE
EARLY TUESDAY AS CONDITIONS CLEAR OUT FROM NORTH TO SOUTH.

A STRONG ARCTIC SURFACE HIGH SUPPORTED BY THE GULF RIDGE WILL
BUILD TO AROUND 1045 MB OVER SOUTHERN YUKON AND REALLY TIGHTEN UP
THE PRESSURE GRADIENT OVER THE NORTHERN FORECAST AREA.
NORTHERLY/NORTHEASTERLY WINDS WILL SETTLE IN OVER THE PANHANDLE
BEGINNING TUESDAY AND LIKELY LASTING THROUGH THE END OF THE WEEK.
850 MB TEMPERATURES OF -20 AND COLDER WILL SINK SOUTH FROM THE
INTERIOR MIDWEEK...WHICH ALONG WITH CLEAR SKIES OVERNIGHT...WILL
SUPPORT LOWS IN THE SINGLE DIGITS AND TEENS FOR MUCH OF THE
FORECAST AREA. ALSO OF CONCERN WITH THIS SYSTEM WILL BE THE
POTENTIAL FOR ADVISORY LEVEL WINDS OUT OF OUTFLOW AREAS IN THE
NORTH.  IN PARTICULAR A TAKU WIND EVENT IS ENTIRELY POSSIBLE MID
WEEK.

HEADING TOWARDS THE END OF THE WEEK...OPERATIONAL GFS AND ECMWF
TRY TO PUSH THE RIDGE OFF TO THE EAST IN FAVOR OF A LARGE WAVE
TROF OVER THE BERING SEA.  MODELS BRING AN ASSOCIATED FRONT INTO
THE CENTRAL GULF STARTING THURSDAY.  GRADUALLY THIS FRONT MOVES
INTO THE EASTERN GULF FRIDAY THEN ACROSS THE PANHANDLE FRIDAY
NIGHT.  WHILE THIS TIMING IS SLOWER THAN PREVIOUS MODEL
RUNS...STILL THINK THAT THESE MODELS ARE TOO AGGRESSIVE GIVEN THE
RELATIVE STRENGTH OF THE RIDGE. THE GFS ENSEMBLE MEAN ON THE
OTHER HAND HOLDS THIS RIDGE IN PLACE THROUGH AT LEAST NEXT
SUNDAY.  THIS SOLUTION SEEMS FAR MORE REASONABLE AND THEREFORE
WILL LEAVE ONLY CHANCE POPS IN THE FORECAST FOR THE WEEKEND/START
OF NEXT WEEK.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...THIS IS THE LIST AS THIS DISCUSSION IS BEING PREPARED.
         PLEASE NOTE SEVERAL EXPIRATIONS WILL OCCUR AT NOON
         INCLUDING ALL THE HIGH WIND WARNINGS.
      ...HEAVY SNOW WARNING...ZONE 29 INLAND VALLEYS.
      ...HIGH WIND WARNING...ZONES 22...27...28
      ...WIND ADVY...ZONES 23...26...29 SW COAST AREA.
      ...SNOW ADVY...ZONES 20>22-024>026

MARINE...STORM...PKZ310...WILL BE DOWNGRADED TO GALE BY NOON.
      ...GALE...PKZ022-033>036-041>043
      ...SCA...ALL REMAINING WATERS

JT/KJH