Small Craft Advisory 12, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AST FRI JAN 4 2008

.ANALYSIS AND UPPER LEVELS...
THE UPPER LEVEL PATTERN REMAINS RELATIVELY STEADY WITH A COLD CORE
LOW OVER NORTHWESTERN MAINLAND AND TROUGH STRETCHING DOWN THROUGH THE
GULF INTO THE NORTH PACIFIC. A SHORTWAVE IN THE TROUGH IS
STRENGTHENING INTO ANOTHER LOW JUST SOUTH OF KODIAK AND MOVING SLOWLY
EAST. A RIDGE CONTINUES TO STRENGTHEN OVER THE WESTERN ALEUTIANS AND
MOVE SLOWLY EAST AS WELL.
AT THE SURFACE...A LOW 160 MILES SOUTHWEST OF KODIAK IS DROPPING
LIGHT SNOW ON KODIAK ISLAND AS IT MOVES SLOWLY EAST. A TIGHTENED
PRESSURE GRADIENT BETWEEN THE LOW AND A RIDGE OVER THE CENTRAL
ALEUTIANS IS CAUSING GALE FORCE WINDS ON THE SOUTH AND WEST SIDE OF
THIS LOW AND STRONG WINDS TO BLOW THROUGH CHANNELED AREAS ON THE
ISLAND AND THE ALASKA PENINSULA. SNOW SHOWERS AND GUSTY WINDS ARE
SPREAD OVER THE BERING AHEAD OF THE RIDGE AS COLD AIR POURS DOWN THE
BACKSIDE OF THE UPPER LEVEL MAINLAND LOW.

.MODEL DISCUSSION...
MODELS DOING FINE OVER THE EAST DOMAIN IN THE RELATIVELY STEADY
PATTERN. ONLY DISCREPANCY LIES WITH THE MOVEMENT OF THE LOW IN A
TROUGH STRETCHED FROM THE NORTHWEST GULF TO THE SOUTHEAST GULF
THROUGH THE WEEKEND. HAVE LEANED TOWARD THE GFS SOLUTION KEEPING THE
LOW A LITTLE FARTHER SOUTHEAST THAN THE OTHER MODELS. MODELS ARE
DOING FINE OVER THE WEST DOMAIN WITH THE RIDGE DOMINATING MOST OF THE
AREA. HOWEVER A COUPLE SYSTEMS TRY TO PUSH EAST AGAINST THE RIDGE TO
BE NEAR THE WESTERN ALEUTIANS BY SATURDAY NIGHT...MODELS ARE NOT AS
WELL IN AGREEMENT. GFS WAS USED AS THE GUIDANCE IN THIS PACKAGE AS
CONSISTENCY IN RUNS HAVE BEEN IMPROVING.

.SHORT TERM FORECAST...
SOUTH AND EAST OF THE ALASKA RANGE...LIGHT SNOW WILL CONTINUE THIS
MORNING OVER THE KENAI PENINSULA AND UP THROUGH THE SUSITNA AS A WEAK
SHORTWAVE PASSES THROUGH. SNOW FROM THE LOW NEAR KODIAK ISLAND WILL
MAINLY AFFECT THE GULF COASTS AND ACROSS THE KENAI PENINSULA TODAY
BEFORE PULLING BACK INTO THE GULF TONIGHT. KODIAK WILL START TO CLEAR
OUT THIS AFTERNOON AS THE DRYING NORTHWESTERLY FLOW PUSHES THE LOW
EAST AWAY INTO THE GULF. THE NEXT UPPER SHORTWAVE LOOKS TO PUSH A
FRONTAL BAND ALONG THE NORTHERN GULF COASTS SUNDAY NIGHT AND REACH
INLAND ENOUGH TO EFFECT SOUTHERN COPPER RIVER BASIN AND SOUTHERN
SUSITNA VALLEY THROUGH TUESDAY. STEADY LOW PRESSURE IN THE GULF AND
HIGHER PRESSURE INLAND TO THE NORTH WILL KEEP NORTHERLY FLOW OVER
SOUTHCENTRAL THROUGH THE WEEKEND WITH GUSTY GAP WINDS. TEMPERATURES
WILL BE DROPPING THROUGH SATURDAY IN THE COLD AIR SWINGING DOWN ON
THE BACKSIDE OF THE UPPER LOW.

WESTERN ALASKA AND THE PENINSULA...THE MAINLAND WILL REMAIN MAINLY
DRY...COLD...AND BREEZY IN THE NORTHERLY FLOW. COASTAL AREAS AND THE
PENINSULA WILL SEE SNOW SHOWERS THROUGH SUNDAY BEFORE THE ADVANCING
RIDGE DRIES THINGS OUT. GUSTY NORTHWESTERLY FLOW WILL CONTINUE OVER
THE PENINSULA IN THE TIGHTENED PRESSURE GRADIENT.

ALEUTIANS AND BERING...SNOW SHOWERS WILL BE AFFECTING MAINLY THE
EASTERN ALEUTIANS...EASTERN BERING AND THE PRIBILOFS THROUGH SATURDAY
BEFORE THE RIDGE DRIES THESE AREAS OUT AND ESTABLISHES ITSELF OVER
THE EASTERN ALEUTIANS BY SATURDAY NIGHT. AT THE SAME TIME...THE
WESTERN AND CENTRAL ALEUTIANS WILL BE SEEING A RAIN AND SNOW MIX
ALONG WITH GALE FORCE WINDS WITH TWO LOWS APPROACHING FROM SOUTH AND
WEST. THE RIDGE OVER THE EASTERN ALEUTIANS WILL HOLD THE SYSTEMS FROM
ADVANCING ANY FARTHER EAST.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...HEAVY FREEZING SPRAY 130 132 138 141 150 155 160 165 179 180
                              185
      ...GALE 130 132 138 150 155 176
FIRE WEATHER...NONE

LR JAN 08