Small Craft Advisory 787, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT SAT OCT 1 2005

.DISCUSSION...
THE LOW PRESSURE SYSTEM THAT HAS BEEN BRINGING SHOWERS TO MOST OF THE STATE
CONTINUES TO SLOWLY FILL.  IN THE WESTERN PORTION OF THE STATE NORTHERLY FLOW
HAS PUSHED A WEAK ARCTIC FRONT INTO THE ANCHORAGE FORECAST REGION.  STATIONS
WEST OF THE ALASKA RANGE ARE EXPERIENCING THEIR FIRST SNOW IN THE OVERNIGHT
HOURS WITH THE COLD AIR ADVECTION.  THIS COLD AIR IS EXPECTED TO MOVE
SOUTHWARD AND EVENTUALLY UP THE COOK INLET...HOWEVER WITH MARINE MODIFICATION
AND CLEARING SKIES SNOW IS UNLIKELY EAST OF THE ALASKA RANGE. THE LOW
PRESSURE CENTER IS SLIDING WESTWARD SLIGHTLY TOWARD THE COLDER AIR. THIS HAS
BROUGHT THE HEAVIER SHOWERS SEEN YESTERDAY IN THE GULF TO THE KENAI PENINSULA
ANCHORAGE BOWL AND MAT SU VALLEY.  AS THE LOW LOSES ITS COLD AIR ADVECTION IT
WILL WEAKEN AND ALLOW THE UPPER LEVEL RIDGE TO MOVE IN BEHIND IT.  SKIES
SHOULD GRADUALLY CLEAR OVER THE STATE AS THE RIDGE MOVES IN...WITH THE
EXCEPTION OF SOME MARINE STRATUS ALONG THE WEST COAST.  FOR TODAY EXPECT
IMPROVING CONDITIONS WEST OF THE ALASKA RANGE WITH CONTINUED SHOWERS
DIMINISHING IN THE EAST.  BY SUNDAY THE RIDGE WILL MOVE ONTO THE MAINLAND AND
SKIES WILL CLEAR...BUT THE NEXT LOW PRESSURE SYSTEM WILL MOVE INTO THE
ALEUTIANS BRINGING MORE WIND AND RAIN FOR THAT REGION.

MODEL DISCUSSION...FOR THE FIRST 60 HOURS MODELS PROVIDE THE SAME SOLUTION.
HOWEVER AT 60 HOURS THEY DIVERGE DRASTICALLY.  GFS SEEMS TO MATCH UKMET AND
ECMWF FAIRLY WELL...HOWEVER THESE MODELS HAVE SHOWN POOR CONTINUITY OVER THE
PAST FEW RUNS.  ALTHOUGH ETA DIVERGES FROM THE OTHER THREE THE SOLUTION HAS
REMAINED THE SAME OVER THE PAST FEW RUNS. FOR THIS REASON ETA IS SLIGHTLY
PREFERABLE.  MODEL CONFIDENCE AT THIS POINT IS VERY LOW. THE CURRENT STRATEGY
IS TO KEEP CONTINUITY WITH THE PAST FORECAST...AND WAIT FOR THE NEW RUNS TO
SEE IF THE MODEL SOLUTIONS SETTLE OUT.

EXTENDED OUTLOOK...DEPENDS HIGHLY ON THE TRACK OF THE NEXT LOW PUSHING INTO
THE ALEUTIANS.  REGARDLESS THE ALEUTIAN CHAIN AND WEST COAST SHOULD SEE RAIN
AND GUSTY WINDS BEGINNING SUNDAY EVENING AND LASTING THROUGH NEXT WEEK.
CURRENT THINKING IS THAT THE MAINLAND WILL REMAIN FAIRLY CLEAR THROUGH MID
WEEK AS THE RIDGE CONTINUES TO HOLD.

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

LEW OCT 05