Heavy Snow in Alaska, December 24, 2002

SOUTHEAST ALASKA FORECAST DISCUSSION
945 PM AST MON DEC 23 2002

.SYNOPSIS...
.SHORT RANGE...A FRONTAL BOUNDARY REMAINS STALLED ACROSS THE
CENTRAL PANHANDLE INTO THE NORTHEAST PACIFIC WITH AWAVE FORMING
ON THE BOUNDARY OVER THE NORTHEAST GULF. THE ETA SEEMS TO BE
INITIALIZING BEST WITH THIS SYSTEM AND TRACKS THE WAVE NORTHEAST
ALONG THE COAST OF SOUTHEAST ALASKA INTO TOMORROW MORNING. A
STRONG VORT MAX SUPPORTING THIS WAVE WILL HELP GENERATE DECENT
LIFT WITH HEAVIER PRECIPITATION SPREADING FROM SOUTH TO NORTH
ACROSS THE PANHANDLE INTO TOMORROW MORNING.

A MUCH WARMER AIRMASS WITH TEMPERATURES IN THE LOW TO MID 40S
COVERS THE SOUTHERN HALF OF THE PANHANDLE FROM PAPG AND CDE
SOUTHWARD WHERE PRECIPITATION WILL CONTINUE TO BE IN THE FORM OF
RAIN. TO THE NORTH, THE AIRMASS IS MUCH COLDER WITH SNOW
DOMINATING MUCH OF THE INTERIOR AREAS, RAIN ALONG THE COAST, AND
A MIX OVER THE FAR NORTHEAST ZONES. AS THE LOW TRACKS NORTHEAST,
EXPECT WARMER AIR TO GRADUALLY WORK NORTHWARD WITH FREEZING
LEVELS RISING ENOUGH TO SUPPORT MIXED RAIN AND SNOW CHANGING TO
ALL RAIN IN SOME AREAS. THE EXCEPTION TO THIS WILL BE THE
NORTHERN LYNN CANAL AREA WHERE NORTHERLY FLOW DEVELOPS WITH THE
APPROACH OF THIS SYSTEM ALLOWING THE AIRMASS TO COOL ENOUGH FOR
PRECIPITATION TO CHANGE TO ALL SNOW BY MORNING. THE NORTHWEST
PANHANDLE WILL REMAIN IN A MORE UNSTABLE ENVIRONMENT WITH SHOWERS
MIXED WITH SNOW AND SLEET CONTINUING OVERNIGHT.

WINDS HAVE DROPPED DOWN TO ADVISORY CRITERIA IN ZONE 28 BUT WINDS
ALOFT INCREASE TO 50 TO 60 KTS AGAIN OVER THE NEXT COUPLE OF
HOURS SO WILL KEEP THE WIND WARNING OUT. WINDS WILL FINALLY TAPER
OFF AFTER 12Z.

.LONG RANGE...992 MB LOW MOVG N ALG OUTER CST OF SE AK MOVG ONSHR
ERN GLF CST MIDDAY TUE. ASSOCD WM FNT LIFTG OVR CNTRL PNHDL MOVG
NNE INTO BC BY LATE MRNG. CDFNT WILL SWING EWD S OF LOW AND ACRS
SE AK BY TUE AFTN. WK RDG SFC-85H BLDG ACRS NRN PNHDL TUE EVE. A
STG LOW BGNG TI LIFT NWD ALG OUTER CST CHRISTMAS DAY AND FCST TO
CUT INLAND THRU FREDERICK SOUND CHRISTMAS NIGHT. AS THIS LOW MOVS
EWD INTO BC IT DRAGS ARCTIC FNT SWD INTO NRN PNHDL THU MRNG.
RESIDUAL LOW IN NE GLF ACTS AS RUNNER THU NGT AND MOVS THRU CNTL
PNNHDL FRI MRNG. MFR STILL HINTING AT COLDER AMS SETTLING ACRS
NRN THIRD FRI-SUN MRNG WITH NEXT BIG SYS FM SW MOVING ONSHR SUN
WITH WRM AMS.

XPC RA SRN TWO THIRDS ON TUE WITH HVYST PCP ALG CST MTNS. ALTHO
SLY REACH NRN LYNN CANAL...ITLL BE BRIEF WITH CAA BGNG FM NW
LATE AFTN. STG VORT OVERHEAD WILL SUPPORT MDT PCP AND HAVE ISSUE
WWA FOR HAINES AND KLONDIKE HYS FOR TUE. RMNDR OF PNHDL SHUD BE
RA AND WILL PROBABLY STILL HAVE WND ADVSRY 25-29 UNTIL MIDDAY.
WNDS TURN OFFSHR TUE NGT AND DRY AND COOL OFF NRN HLF. GAP FLOW
INCRS TUE NGT AND PRBLY GUSTING AT LEAST 35 OUT OF INTERIOR
PASSES. AS STG SYS LIFTS N RA AND ADVSRY LVL WNDS REDVLPS ACRS
SRN LATE TUE NGT. COULD SEE PCP MXD WITH SNW ACRS S CNTL
CHRISTMAS MRNG BUT WILL GO BACK TO RA AND WNDS WED AFTN. NRN
THIRD XPCD TO SEE SNW AFT-NGT AS LOW CUT INLAND THRU FREDERICK
SOUND IN NW DEFORMATION ZONE. ONCE THIS LOW PULLS INLAND LATE WED
COLD AMS SPRDS THRU NRN HLF WITH MXD SHWRS FOR SRN INTO FRI.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...WIND WARNING ZONE 28
         WIND ADVISORY ZONES 27 29
MARINE...SCA CROSS SOUND, NORTHERN 1A3, NORTHERN 1B,
         SCA DUE TO SEAS 2A
         GALES SOUTHERN 1A3
         STORMS SOUTHERN 1B