Small Craft Advisory 512, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTH CENTRAL AND SOUTHWEST ALASKA
200 PM AKDT THU JUN 26 2008

.MODEL DISCUSSION...
MODELS ARE IN GENERAL AGREEMENT WITH SYNOPTIC SCALE FEATURES THROUGH
72 HOURS. THERE ARE SOME DIFFERENCES IN STRENGTHS AND GRADIENTS.  THE
UKMET AND NAM MAINTAIN A STRONGER MORE DISTINCT CIRCULATION FOR THE
WEAKENING LOW CROSSING THE GULF AND MOVING ONSHORE OVER THE PANHANDLE
BY SAT MORNING. ALL MODELS BUILD A RIDGE OVER THE EASTERN BERING AND
EASTERN ALEUTIANS FRI AND SAT.  THE STRENGTH AND POSITION OF THE
INTERIOR THERMAL TROUGH IS SIMILAR FOR ALL MODELS THROUGH SAT.
THE LAST TWO NAM RUNS PICK UP AN EASTERLY WAVE OVER THE COPPER RIVER
BASIN TONIGHT AND MOVE IT OVER THE SUSITNA VALLEY FRI AND THE
KUSKOKWIM FRI NIGHT.  THE GFS FORECASTS PRECIPITATION WITH THIS
FEATURE INITIALLY BUT DOES NOT MOVE IT OUT OF THE BASIN.

.ANALYSIS AND UPPER LEVELS...
A CUTOFF UPPER LOW SOUTH OF KODIAK ISLAND WILL WEAKEN AND SLOWLY MOVE
NORTHEAST TO THE CENTRAL ALASKA CANADA BORDER BY SAT NIGHT.  THE
POLAR JET WILL REMAIN SOUTH OF THE ALEUTIANS AND TURN NORTH OVER THE
SOUTHEASTERN GULF FRI AND SAT. A WEAK TROUGH WILL CONSOLIDATE OVER
THE WESTERN ALEUTIANS SAT AND SUN THEN MOVE TO THE CENTRAL ALEUTIANS
MON.

.SHORT TERM FORECAST...
SOUTH CENTRAL...WIND AND RAIN WILL CONTINUE TO DIMINISH TONIGHT AS
THE FRONT DISSIPATES ALONG THE NORTH GULF COAST. RAIN WILL MOSTLY BE
CONFINED TO NEAR THE COAST AND IN SOUTHEAST UPSLOPE AREAS IN SOUTH
CENTRAL.  THE THERMAL LOW OVER THE INTERIOR IS STRENGTHENING AND
MOVING NORTH KEEPING THUNDERSTORM POTENTIAL LOW EXCEPT FOR A SLIGHT
CHANCE ALONG OR JUST NORTH OF THE EASTERN ALASKA RANGE. EXPECT AN
INCREASE IN PRECIPITATION OVER THE NORTHERN COPPER BASIN TONIGHT TO
MOVE TO THE SUSITNA VALLEY FRI. THE COMBINATION OF THE INTERIOR
TROUGH AND WEAK RIDGING IN THE GULF WILL BRING COOL ONSHORE WINDS
OVER SOUTH CENTRAL FRI THROUGH SUN.

SOUTHWEST...IMPROVING WEATHER WITH A SLIGHT CHANCE OF THUNDERSTORMS
OVER THE KILBUCK MOUNTAINS AND THE KUSKOKWIM VALLEY. OTHERWISE A FEW
SHOWERS AND LIGHTER WINDS INTO THE WEEKEND

ALEUTIANS/BERING...HIGH PRESSURE BUILDING IN WILL KEEP LOW CLOUDS AND
FOG AROUND. A LOW WILL APPROACH THE WESTERN ALEUTIANS FRIDAY NIGHT
AND BRING SMALL CRAFT OR MINIMUM GALE WINDS AND RAIN

.LONG TERM FORECAST...
EXPECT CLOUDY AND COOL WEATHER OVER SOUTH CENTRAL AS ONSHORE FLOW
SETS UP BETWEEN THE INTERIOR LOW...GULF COAST RIDGING AND HIGH
PRESSURE OVER THE BERING. EXPECT SHOWERS OVER INLAND AREAS
THROUGH THE WEEKEND AS THE UPPER LOW MOVES OVERHEAD. THERE IS A
POSSIBILITY FOR SOME WARMER AND DRYER WEATHER NEXT WEEK AS RIDGING
CONTINUES TO BUILD FROM THE SOUTHEAST.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...NONE.
FIRE WEATHER...NONE

RHH JUN 08