Gale Warning 38, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST SAT JAN 13 2007

.SHORT RANGE...LATEST SATELLITE AND LIMITED OBSERVATIONS INDICATE
THAT THE MODELS ARE NOT INITIALIZING WELL THE POSITION AND DEPTH
OF THE LOW MOVING INTO THE SOUTH-CENTRAL GULF. THE GFS WILL BE
THE MODEL OF CHOICE BUT WILL BE ADJUSTED TO ACCOUNT FOR THE
ERRORS IN POSITION AND DEPTH. THIS LOW WILL DEEPEN INTO THE 980S
AS IT MOVES NORTH-NORTHWEST INTO THE NORTHWEST GULF THROUGH
SUNDAY...THEN WEAKEN  INTO THE 990S THROUGH SUN NIGHT. THE FRONT
ASSOCIATED WITH THIS LOW WILL MOVE ACROSS THE EASTERN GULF AND
PANHANDLE THROUGH SUNDAY AFTERNOON. A LOW DEVELOPS ON THE FRONT
OVER THE NORTHEAST PACIFIC AND MOVES NORTH INTO THE SOUTHEAST
GULF SUNDAY NIGHT. CONFIDENCE IS LOW WITH THIS FEATURE AS TRACK
AND INTENSITY STILL DIFFER AMONG THE MODELS AND ENSEMBLE DATA.

THE FRONT WILL BRING A BAND OF PRECIPITATION ACROSS THE PANHANDLE
LATE TONIGHT AND EARLY SUNDAY MORNING. PRECIPITATION TYPE IS
GOING TO BE DIFFICULT OVER THE NORTHERN AND NORTH-CENTRAL
PANHANDLE AS COLD AIR IN PLACE WILL ALLOW THE PRECIP TO START OUT
AS SNOW. SOUTHWEST FLOW ALOFT WILL BRING A SURGE OF WARMER AIR
INTO THE PANHANDLE WITH THE LOW LEVEL FLOW SWITCHING TO THE
SOUTH-SOUTHEAST LATE TONIGHT AND EARLY SUNDAY MORNING. A CHANGE
TO RAIN WILL THEREFORE OCCUR OVER THESE AREAS DURING THAT TIME
MAKING SNOW AMOUNTS FORECASTS TRICKY. SNOW ADVISORY SNOWFALL
LOOKS HIGHLY LIKELY OVER ZONE 19 AND POSSIBLY ZONE 18 OVER THE
NORTHEAST PANHANDLE BEFORE CHANGING TO RAIN. CONFIDENCE IS NOT AS
HIGH FOR ADVISORY AMOUNTS OVER THE NORTH-CENTRAL PANHANDLE AND
ZONE 17 (YAKUTAT) DUE TO UNCERTAINITY IN THE TIMING OF THE CHANGE
OVER. WILL CONTINUE MINIMUM SNOW ADVISORIES OVER THESE AREAS FOR
LATE TONIGHT AND EARLY SUNDAY MORNING.

THE OTHER AREA OF CONCERN IS HYDER IN ZONE 29 WHERE PRECIP TYPE
WILL BE ALL SNOW THROUGH SUNDAY AND POSSIBLY INTO EARLY SUNDAY
NIGHT AS THE NEXT LOW MOVES UP. WILL CONSIDER A SNOW ADVISORY
THERE LATE TONIGHT THROUGH EARLY SUNDAY NIGHT THEN CHANGE TO
RAIN. THIS LOW WILL SPREAD MORE RAIN INTO THE SOUTHERN TWO-THIRDS
BUT LIGHT NORTHERLY FLOW OVER THE NORTHERN THIRD COULD ALLOW
PRECIP TO MIX WITH OR CHANGE TO SNOW.

PUBLIC WIND...GUSTY WINDS AHEAD OF THE FRONT TONIGHT MAY BRING
MINIMAL WIND ADVISORY GUSTS TO THE COASTAL AREAS WITH WINDY TO
BREEZY CONDITIONS ELSEWHERE. WIND ADVISORY GUSTS WILL BE POSSIBLE
OVER THE SOUTHERN THIRD LATE SUNDAY NIGHT AS THE LOW MOVES INTO
THE SOUTHEAST GULF.

AVIATION...AREAS OF FREEZING DRIZZLE THIS MORNING OVER THE
NORTH-CENTRAL PANHANDLE WILL TAPER OFF INTO EARLY THIS AFTERNOON.

.LONG RANGE...
ALL MODELS START OUT WITH SFC LOW NEAR 52N 147W WAY NOT DEEP ENUF
AT 18Z. DISCUSSED THIS IN THIS OFFICE AND WITH PAFC AND THEY
CONCUR. THE GFS-190 STILL IS THE PREFERRED NCEP MODEL IN SPITE OF
POOR INITIALIZATION. GFS FORECASTS SECONDARY LOW 998 MB OFF DIXON
ENTRANCE 12Z MON WHICH IS CONFIRMED BY UKMET (DEEPER) AND GFS
ENSEMBLES. THIS IS A DIFFERENT PATTERN THAN LAST NIGHTS RUNS. THE
PARENT SURFACE LOW LINGERS NEAR CAPE SUCKLING MON TRACKING SLOWLY
ESE WHICH IS ACCEPTED AND VERY SIMILAR TO THE PAST BEHAVIOR IN A
PROGRESSIVE PATTERN. LOOK FOR ANOTHER UPPER RIDGE TO BUILD OVER
THE WESTERN GULF TUE MOVING OVER THE PANHANDLE WED WITH
SHORTWAVES TRYING TO BUST THROUGH THE RIDGE. LEARNED A LESSON
FROM THE LAST UPPER RIDGE FOR LESS DRYING IN AND THROUGH THE
UPPER RIDGE. LITTLE CHANGE TO LONG TERM EXCEPT MARINE WITH
MODERATE CONFIDENCE.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...FREEZING DZ ADV 20 21 25 TODAY
         SNOW ADV 17 19 20 21 25 LATE TONIGHT-SUN MORNING

MARINE...NONE

TAR/JC