Gale Warning 805, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT TUE OCT 24 2006

.DISCUSSION...
LOW ROLLING UP THE WESTERN PORTION OF THE GULF A BIT DEEPER THAN 12Z
MODEL RUNS INDICATED. THEREFORE...WINDS AND PRECIPITATION A BIT MORE
THAN EXPECTED EARLIER. HAVE INCREASED WINDS AND PRECIPITATION CHANCES
OVER SOUTH CENTRAL ALASKA AS A RESULT.

THE DIFFERENCE IN MODELS TONIGHT INTO TOMORROW IS IF A LOW DEVELOPS
ALONG THE JET STREAM IN THE CENTRAL GULF THIS EVENING. THE NAM DOES
DEVELOP A LOW IN THE GULF WHICH WRAPS UP INTO THE NORTHERN GULF COAST
LATE TONIGHT. THIS IS THE PREFERRED SOLUTION SINCE THE THERMAL
STURCTURE ALONG THE FRONT SHOULD SUPPORT FURTHER DEVELOPMENT ALONG
THE JET STREAM. A STRONG FRONT WILL BE FORCE TO THE PANHANDLE ALONG
THE GULF COAST TO THE SOUND.

UPPER LEVELS...BROAD TROUGH OVER WESTERN ALASKA WITH A LOW AMPLITUDE
RIDGE IN THE EASTERN GULF OF ALASKA. THE TROUGH AXIS IS OVER WESTERN
ALASKA WITH A STRONG JET AT THE BASE OF THE TROUGH POINTED DIRECTLY
TO THE PANHANDLE. A STRONG SHORT WAVE/VORT MAX ROTATING THROUGH THE
BASE OF THE TROUGH TO SWING THE TROUGH AXIS INTO THE CENTRAL PORTION
OF THE STATE. THIS ALLOWS A RIDGE TO BUILD IN THE WESTERN BERING
TONIGHT. RIDGE SETS UP OVER THE BERING WEDNESDAY AND THURSDAY AS
TROUGH DEEPENS OVER THE GULF. A LOW THEN MOVES OFF THE KAMCHATKA
PENINSULA THURSDAY NIGHT AND KNOCKS DOWN AND PUSHES THE RIDGE EAST
FRIDAY. THE RIDGE AXIS WILL BE OVER THE MAINLAND FRIDAY AS THE
KAMCHATKA LOW MOVES ACROSS THE BERING. THIS LOW TO TRACK ACROSS THE
MAINLAND SATURDAY WITH A RIDGE AMPLIFYING OVER THE BERING ONCE AGAIN
BEHIND IT. IN THE MEANTIME...A LOW MOVES TO THE WESTERN ALEUTIAN
CHAIN SATURDAY AND MOVES INTO THE WESTERN BERING SUNDAY. THE RIDGE
GETS PUSHED TO THE WEST COAST OF ALASKA WHILE A TROUGH REMAINS OVER
SOUTH CENTRAL AND THE PANHANDLE.

SURFACE EAST OF THE ALASKA RANGE...THE LOW OVER SHELIKOFF STRAIT TO
MOVE TO COOK INLET THIS EVENING WHILE THE PARENT LOW DISSIPATES LOW
OVER THE ALASKA PENINSULA. A SECONDARY LOW TO DEVELOP ALONG THE FRONT
IN THE GULF AND MOVE TO NEAR THE PRINCE WILLIAM SOUND LATER TONIGHT.
PLENTY OF MOISTURE WRAPPED AROUND THIS LOW TO BRING PRECIPITATION TO
SOUTHWEST AND SOUTH CENTRAL ALASKA TONIGHT. THE LOW IS DEEPER THAN
PREVIOUSLY INDICATED...SO WINDS AND PRECIPITATION A BIT STRONGER. AS
THE FRONTAL LOW MOVES INLAND BY TOMORROW MORNING IT WILL DISSIPATE
AND JOIN THE PARENT LOW JUST SOUTH OF THE KENAI PENINSULA EARLY
WEDNESDAY. A GOOD PRESSURE GRADIENT SETS UP OVER THE WESTERN GULF FOR
STRONG WESTERLY WINDS BEHIND THIS LOW WITH A HIGH IN THE WESTERN
BERING BUILDING OVER THE ENTIRE BERING BY THURSDAY. IN ADDITION...THE
LOW CONSOLIDATING OVER THE NORTHWEST GULF WILL SHUT OFF TURNAGAIN ARM
WINDS AND ALLOW THE ANCHORAGE BOWL TO BE MORE ACCEPTABLE TO
PRECIPITATION. WITH THE LIGHT FLOW AROUND THE LOW IN THE NORTHERN
GULF WEDNESDAY AND THE UPPER LEVEL TROUGH AXIS STILL TO THE
WEST...EXPECT SOME LIGHT SNOWFALL TO WORK INTO THE ANCHORAGE AREA
LATER TONIGHT AND TOMORROW. THE LOW REMAINS IN THE NORTHERN GULF
THROUGH THURSDAY...SO EXPECT SNOW SHOWERS TO REMAIN OVER SOUTH
CENTRAL THROUGH THEN. HIGH PRESSURE THEN FILTERS INTO THE AREA
THURSDAY AFTERNOON AND REMAINS THROUGH FRIDAY. A LOW MOVING THROUGH
THE HIGH PRESSURE WILL WEAKEN AS IT MOVES INLAND SATURDAY AND CROSSES
THE ALASKA RANGE. THIS STILL MAY BRING SNOW EVEN THROUGH IT GETS
SEVERELY WEAKENED. HIGH PRESSURE THEN DOMINATES ONCE AGAIN LATE
SATURDAY AND INTO SUNDAY.

SURFACE WEST OF THE ALASKA RANGE...A LOW IN SHELIKOFF STRAIT
PROVIDING SOME WRAP AROUND PRECIPITATION TO SOUTHWEST ALASKA THROUGH
TONIGHT. HIGH PRESSURE OVER THE WESTERN BERING COMBINED WITH THE LOW
IN THE GULF CREATING A GOOD PRESSURE GRADIENT OVER THE EASTERN BERING
AND SOUTHWEST ALASKA. SHOWERS TO REMAIN OVER THESE AREAS AS WELL.
THIS SCENARIO TO REMAIN THROUGH THURSDAY UNTIL A LOW WORKS OUT OF
EASTERN SIBERIA FRIDAY AND KNOCKS DOWN THE HIGH PRESSURE FOR SNOW AND
STRONG WINDS TO REACH THE KUSKOKWIM DELTA FRIDAY AFTERNOON. THIS
ACTIVITY WILL SPREAD OVER MUCH OF SOUTHWEST ALASKA FRIDAY EVENING
THEN WEAKEN SATURDAY WITH HIGH PRESSURE RETURNING TO SOUTHWEST ALASKA
SATURDAY AND REMAIN SUNDAY. IN THE MEANTIME...A STRONG LOW TO MOVE
OUT OF THE NORTHERN PACIFIC TO THE WESTERN ALEUTIAN CHAIN FRIDAY.
HAVE GONE WITH THE CURRENT GFS SOLUTION WITH THIS LOW AS IT HAS BEEN
QUITE CONSISTENT. THIS LOW WILL BRING STRONG WINDS AND QUITE A BIT OF
PRECIPITATION TO THE WESTERN ALEUTIANS FRIDAY NIGHT AND SATURDAY
BEFORE MOVING INTO THE WESTERN BERING SUNDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 130 132 138 150 155 165 170 171 172
FIRE WEATHER...NONE

JN OCT 06