Small Craft Advisory 8, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AST WED JAN 2 2008

.ANALYSIS...
AN UPPER LOW CURRENTLY SITS IN THE EASTERN GULF WITH ANOTHER OVER THE
WESTERN BERING AND YET ANOTHER OVER WESTERN ALASKA. A 970 MB SURFACE
LOW 200 NM WEST OF SITKA IS DRIFTING NORTH AND WEAKENING THIS
AFTERNOON ALONG WITH ITS UPPER LEVEL LOW. THE UPPER LEVEL AND
UNDERLYING SURFACE LOWS IN THE BERING ARE WEAKENING AS WELL. THE ONLY
STRENGTHENING LOW IS THE COLD CORE LOW OVER THE MAINLAND. A FRONT TO
REMAIN OVER THE WESTERN AND CENTRAL BERING WITH HIGH PRESSURE OVER
THE NORTHERN BERING AND OVER THE WEST COAST OF ALASKA. A WEAK VORT
MAX ROTATING AROUND THE MAINLAND LOW CREATING ENOUGH LIFT FOR SNOW
SHOWERS IN THE NORTHERN SUSITNA VALLEY THIS AFTERNOON. THIS ACTIVITY
IS ANTICIPATED TO SWING INTO THE COPPER RIVER BASIN AND NORTH OF THE
ALASKA RANGE THIS EVENING AS THE WAVE LIFTS NORTH AND EAST. A
SECONDARY WAVE ROTATING AROUND THE UPPER LOW OVER THE MAINLAND TO
HEAD SOUTH THROUGH THE EASTERN BERING. THIS WILL KICK UP WINDS FROM
THE NORTH TONIGHT.

.MODEL DISCUSSION AND UPPER LEVELS...
CLOSED LOW IN THE GULF TO DISSIPATE INLAND NEAR YAKUTAT TOMORROW WITH
A COLD CORE LOW REMAINING OVER THE MAINLAND. THIS COLD LOW TO MOVE
LITTLE THROUGH THE WEEK WITH A TROUGH EXTENDING INTO THE GULF. A
SECONDARY LOW WEST OF KAMCHATKA TO ROTATE NORTH THEN WEST AS THE LOW
NEAR THE POLE IS EXPECTED TO BACK INTO WESTERN SIBERIA AND THEN MOVE
NEAR KAMCHATKA BY MID WEEK. IN GENERAL...NCEP AND EURO MODELS AGREE
ON THIS PROGRESSION. AT THE SURFACE...THIS GENERALITY BREAKS DOWN
SOMEWHAT BY EARLY NEXT WEEK. THIS IS MAINLY DUE TO THE STRENGTH AND
POSITION OF THE JET UNDERNEATH THE COLD KAMCHATKA LOW NEXT WEEK. THE
POSITION OF A LOW IN THE GULF IS ALSO AN AREA OF DISCREPENCY BY
TUESDAY WITH THE EC HAVING A LOW FARTHER SOUTH WITH A TROUGH
EXTENDING INTO THE NORTHERN GULF. THE GFS HAS A MUCH STRONGER LOW
PUSHED TO THE NORTHERN GULF. EVENTUALLY THE LOW ENDS IN THE SAME
PLACE AND STRENGTH BY WEDNESDAY OF NEXT WEEK.

.SHORT TERM FORECAST...
SOUTH CENTRAL...
THE CURRENT LOW IN THE EASTERN GULF TO LIFT NEAR YAKUTAT AND
DISSIPATE TONIGHT AS ANOTHER LOW DEVELOPS SOUTH OF KODIAK WITH A
SHORT WAVE MOVING AROUND THE WESTERN ALASKA UPPER LOW. THIS WILL
BRING MODERATE TO STRONG COLD AIR ADVECTION AROUND KODIAK ISLAND
WEDNESDAY NIGHT. IN ADDITION...WINDS WILL DEVELOP ON THE BACKSIDE OF
THIS LOW THURSDAY THROUGH THE ALEUTIAN RANGE. ANOTHER CONSEQUENCE OF
THIS LOW DEVELOPING SOUTH OF KODIAK...SOUTHERLY FLOW TO OPEN UP OVER
THE GULF AND BRING MOISTURE INLAND. IN COMBINATION WITH A SHORT WAVE
ROTATING NORTH ACROSS SOUTH CENTRAL THURSDAY NIGHT INTO FRIDAY...SNOW
WILL LIKELY SPREAD OVER THE AREA DURING THIS TIME FRAME. THE LOW THEN
WRAPS UP IN THE WESTERN GULF FRIDAY INTO SATURDAY WITH STRONG GAP
WINDS DEVELOPING AROUND THE LOW FROM KODIAK TO THE KENAI PENINSULA TO
THE COPPER RIVER DELTA. SO...EXPECT GALE FORCE WINDS THROUGH THESE
GAPS. PRECIP TO BE CONFINED TO CLOSE TO THE LOW CENTER DURING THIS
SPIN UP.

WESTERN ALASKA AND ALASKA PENINSULA...
COLD AIR TO KEEP FILTERING INTO THE AREA AS THE COLD UPPER LOW
SETTLES OVER WESTERN ALASKA. THERE SHOULD BE SOME STRONG GAP WINDS
DEVELOPING ALONG THE ALEUTIAN RANGE TO THE ALASKA PENINSULA THURSDAY
AS THE VORT MAX ROTATES SOUTH OF THE PENINSULA. BERING COASTAL AREAS
ALONG THE ALASKA PENINSULA TO EXPERIENCE SOME INTENSE SNOW SHOWERS AT
TIMES IN THIS MODERATE TO STRONG NORTHWEST FLOW DEVELOPING BY
THURSDAY AFTERNOON.

ALEUTIANS...
FRONTAL BAND ACROSS THE AREA THIS AFTERNOON TO WEAKEN THROUGH TONIGHT
AND TOMORROW. WINDS WILL BE NEAR GALE FORCE WITH A MODERATE LOW
MOVING ACROSS THE WESTERN ALEUTIANS. COMBINED WITH PRESSURE IN THE
NORTHERN BERING...STRONG EASTERLIES WILL BE PRESENT NORTH OF THIS
FRONT/LOW. HIGH PRESSURE TO MOVE IN OVER THE CENTRAL BERING WITH
ANOTHER FRONT MOVING TO THE WESTERN ALEUTIANS FRIDAY AFTERNOON AND
WEAKEN AS IT MOVES INTO THE HIGH PRESSURE SATURDAY. MODERATE
NORTHERLY WINDS TO REMAIN OVER THE EASTERN BERING BEHIND THE LOW IN
THE WESTERN GULF. A STRONGER LOW WORKS TO THE WESTERN ALEUTIANS
SATURDAY EVENING.

.LONG TERM FORECAST...
AFTER SATURDAY...HIGH PRESSURE TO REMAIN OVER THE CENTRAL AND EASTERN
BERING INTO WEDNESDAY. A LOW WILL ROTATE NORTH THROUGH THE WESTERN
BERING WITH A FRONT INTO THE CENTRAL ALEUTIANS. THE GFS KEEPS A
TROUGH OVER THIS AREA THROUGH WEDNESDAY AS A PACIFIC LOW ROTATES TO
THE CENTRAL ALEUTIANS. HOWEVER...THE EC DEVELOPS A STRONGER LOW
FARTHER SOUTH AND KEEPS A STRONGER RIDGE OVER THE BERING. IN THE
EAST...A LOW IN THE GULF SATURDAY REMAINS BEFORE BEING REPLACE BY
ANOTHER BY WEDNESDAY. COLD AIR TO REMAIN OVER THE BERING AND WESTERN
ALASKA WITH SOME FRONTS MOVING THROUGH THE WESTERN AND CENTRAL
ALEUTIANS. IN ADDITION...STRONG WINDS AND MODERATE PRECIPITATION TO
RING THE GULF LOCATIONS AND POSSIBLY INLAND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 150 176.
         HEAVY FREEZING SPRAY...150 160 165 180 185.
FIRE WEATHER...NONE

JN JAN 08