Small Craft Advisory 1098, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST THU DEC 29 2005

.DISCUSSION...

THE LOW THAT WAS EAST OF KODIAK ISLAND ON WEDNESDAY DISSIPATED AS IT
MOVED ACROSS KODIAK ISLAND TO THE AKPENN OVERNIGHT. WE ARE NOW LEFT
WITH A LARGE AREA OF LOW PRESSURE CENTERED OVER THE NORTHERN AKPENN
WITH A SURFACE TROUGH EXTENDING NORTHEASTWARD FROM SHELIKOF STRAIT
ACROSS THE KENAI PENINSULA INTO NORTHERN PRINCE WILLIAM SOUND.
PRESSURE GRADIENT IS AT ITS TIGHTEST RIGHT NOW ALONG THE COOK INLET
CORRIDOR(45 KT NOTED AT AUGUSTINE). AS TROUGH MOVES OFF TO THE WEST
NEXT FEW HOURS GRADIENT AND WINDS WILL BEGIN TO DIMINISH. MIDDLETON
RADAR SHOWS BACK EDGE OF STEADY PRECIP CURRENTLY MOVING ACROSS PRINCE
WILLIAM SOUND WITH SCATTERED SHOWERS TO FOLLOW. AS TROUGH MOVES
ACROSS SOUTHWEST ALASKA THIS MORNING EXPECT SCATTERED SHOWERS.

SEVERAL MORE LOWS ARE ALREADY MOVING ON THE SCENE AND AS PER THE
NORM OF LATE ARE NOT HANDLED WELL BY THE MODELS. THE FIRST IS NEAR
53N 151W WITH AN OLDER LOW TO THE SOUTHWEST AT 49N 154W. NONE OF THE
MODELS HAVE BOTH LOWS IN THE RIGHT LOCATION. HOWEVER...THEY ALL SHOW
TREND OF OCCLUDED FRONT MOVING TOWARD THE GULF THIS MORNING SPREADING
GALE FORCE WINDS ACROSS THE GULF. WITH A FASTER LOW AND FRONT WINDS
WILL INCREASE A BIT EARLIER THAN INDICATED BY MODELS. SO AFTER A
BRIEF BREAK THIS MORNING RAIN AND WINDS WILL ONCE AGAIN OVERSPREAD
THE GULF COASTAL REGIONS THIS AFTERNOON AND EVENING.

LOOKING TO THE SOUTHEAST OF THESE TWO LOWS IS THE NEWEST DEVELOPING
TRIPLE POINT LOW. IT IS CURRENTLY NEAR 47N 143W AND WILL CONTINUE
TO DEVELOP IN THE LEFT EXIT REGION OF THE UPPER JET. ALTHOUGH EXACT
SURFACE PRESSURE IS UNKNOWN UKMET (WHICH SHOWS A 975 MB LOW) SEEMS
TO BE VERIFYING BEST. GFS/UKMET DEEPEN THIS LOW INTO THE LOW 950S
AND TRACK IT TO JUST EAST OF KODIAK ISLAND BY FRIDAY MORNING. IT
MAKES SENSE THAT THE LOW WOULD MOVE BACK WESTWARD TOWARD UPPER LEVEL
CENTER OF CIRCULATION. THE NAM IS THE OUTLIER IN KEEPING THE LOW IN
THE EASTERN GULF AND IS WAY TOO WEAK. SO THIS EASTERN MOST LOW WILL
BECOME THE DOMINANT LOW TONIGHT AND THE OTHER WEAKER LOWS TO THE WEST
WILL BE ABSORBED. STORM FORCE WINDS AND ANOTHER BATCH OF RAIN WILL
OVERSPREAD THE GULF WATERS TONIGHT. INLAND AREAS OVER SOUTHCENTRAL
WILL ONCE AGAIN REMAIN DRY WITH GUSTY OFFSHORE WINDS IN THE USUAL
PLACES AS THIS LOW MOVES INTO THE GULF. THE LOW WILL THEN GRADUALLY
WEAKEN FRIDAY THROUGH SATURDAY AND REMAIN NEARLY STATIONARY EAST OF
KODIAK ISLAND.

LOOKING OUT WEST WE FIND THREE MORE LOWS SOUTH OF THE ALEUTIANS.
MODELS ONLY HANDLE ONE OF THESE WELL BUT THERE WILL BE LITTLE TO NO
IMPACT ON THE ALEUTIANS FORECAST. THESE LOWS WILL CONTINUE TO ROTATE
AROUND IN ONE LARGE CYCLONIC CIRCULATION AND GRADUALLY SINK SOUTHWARD
TODAY AND THURSDAY. SO AFTER A BIT OF RAIN AND SNOW ALONG THE CENTRAL
AND WESTERN ALEUTIANS TODAY FLOW WILL BECOME NORTHERLY ACROSS MOST OF
THE CENTRAL BERING ALEUTIANS AND COLD AIR WILL BE ADVECTED FROM THE
RUSSIAN FAR EAST DOWN ACROSS THE BERING RESULTING IN COLD ADVECTION
SHOWERS. THE EASTERN BERING/SOUTHERN AKPENN IS CURRENTLY CAUGHT
BETWEEN SYSTEMS. VERY WEAK FLOW ACCOMPANIED BY LOW CLOUDS AND A FEW
SHOWERS WILL PERSISTS FOR THE NEXT COUPLE DAYS BEFORE GETTING INTO
THE COLD ADVECTION OVER THE WEEKEND.

EXTENDED FORECAST - GFS IS STILL INDICATING A GRADUAL PATTERN CHANGE
AS WE HEAD THROUGH DAYS 4 THROUGH 7. WEAK RIDGING OVER THE NORTHWEST
PACIFIC WILL ALLOW COLDER AIR TO WORK IT WAYS DOWN ACROSS THE BERING
SEA AND EVENTUALLY BACK UP INTO SOUTHCENTRAL. SURFACE LOWS WILL
HOLD OVER THE GULF AS RIDGING CONTINUES INLAND. SO FOR THE EXTENDED
FORECAST EXPECT A COOLING TREND...GREATEST OVER THE BERING
SEA/ALEUTIANS AND A CONTINUATION OF MAINLY DRY INLAND WITH
PRECIPITATION ALONG THE GULF COAST.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 120 130 132 140.
         HEAVY FREEZING SPRAY WARNING 185.

SEB DEC 05