Small Craft Advisory 727, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM ADT WED SEP 5 2007

.MODEL DISCUSSION...MODEL INITIALIZATION AND PERFORMANCE IS MUCH MUCH
BETTER THAN YESTERDAY. THE LOW IN THE GULF IS RECOGNIZED BY THE GFS
AND NAM AND THEY BOTH HAVE A REASONABLE PLACEMENT AND CENTRAL
PRESSURE FOR IT.
IN THE WEST THE GFS AND ECMWF MODELS ARE QUITE SIMILAR AND LOOK TO
HAVE A SUPERIOR SOLUTION WHEN COMPARED TO THE NAM. THE PRESSURE
GRADIENTS AROUND THE FRONT IN THE SHORT TERM ARE BETTER AND THE NAM
IS THE OUTLIER IN THE POSITIONING OF THE MAIN LOW IN THE LONGER TERM.
THE OTHER BIG MODEL QUESTION THE LAST FEW DAYS HAS BEEN HOW A LOW IN
THE NORTH PACIFIC THAT HAS BEEN EXPECTED TO DEVELOP WILL DO SO. THE
GFS AND ECMWF HAVE BEEN CONSISTENT AS TO THERE BEING A MAIN LOW IN
THE BERING SEA WITH THIS SECONDARY WAVE MOVING TOWARD THE GULF.
HOWEVER THEY HAVE BOTH BEEN POOR IN THE LOCATION AND STRENGTH OF IT
WITH WILD VARIATIONS FROM MODEL RUN TO RUN. BOTH MODELS HAVE NOW
SETTLED INTO A VERY SIMILAR SOLUTION WITH THE WAVE BEING VERY WEAK
AND THE FRONT SLOW MOVING. THIS IS THE SOLUTION WE WILL BE USING
SINCE THERE NOW SEEMS TO BE SOME STABILITY IN THE MODELS. HOWEVER IT
STILL BEARS WATCHING TO MAKE SURE A STRONG WAVE DOES NOT DEVELOP
ALONG THE FRONT.

.ANALYSIS AND UPPER LEVELS...THE STRONG LOW NEAR MIDDLETON ISLAND
YESTERDAY REMAINED NEARLY STATIONARY AS IT WEAKENED OVERNIGHT. IT IS
NOW HEADING EAST SOUTHEAST TOWARD THE JUNEAU FORECAST AREA.
THERE IS A LOW THAT WILL BE MOVING INTO THE WESTERN ALEUTIANS TONIGHT
AND THEN SLOWLY TO THE CENTRAL ALEUTIANS BY FRIDAY. THE FRONT
ASSOCIATED WITH THIS LOW IS ALREADY IN THE WESTERN ALEUTIANS AND WILL
PUSH TO THE ALASKA PENINSULA BY THURSDAY AFTERNOON.

.SHORT TERM FORECAST...A RESULT OF THE LOW PERSISTING NEAR MIDDLETON
ISLAND AND NOW PULLING OUT IS THAT IT IS BRINGING SOME OF THE
CLOUDINESS OVER SOUTH CENTRAL ALASKA WITH IT. AFTERNOON AND EVENING
SHOWERS ARE POSSIBLE ALONG THE ALASKA RANGE WITH A MODERATELY
UNSTABLE ATMOSPHERE UP THERE COMBINED WITH PLENTY OF SUN THERE TODAY.
SOME SHOWERS ARE PERSISTING IN THE BRISTOL BAY AND KUSKOKWIM AREAS
DUE TO THE MODERATELY UNSTABLE AIRMASS. THE LIFTED INDEX WAS BELOW
ZERO THIS MORNING AT ANCHORAGE KING SALMON AND BETHEL.
EXPECT RAIN AND GALE FORCE WINDS IN THE CENTRAL AND WESTERN ALEUTIANS
THROUGH THURSDAY WITH THE FRONT MOVING THROUGH THAT AREA.

.LONG TERM FORECAST...THE WEEKEND LOOKS WET FOR MOST OF THE AREA. THE
AREA OF BIGGEST CONCERN BEGINS ALONG THE ALASKA PENINSULA FRIDAY AND
MOVES INTO SOUTH CENTRAL ALASKA BY SATURDAY. STRONG SOUTHWEST FLOW
WILL BRING WARM TEMPERATURES AND DEEP MOISTURE WITH PLENTY OF UPPER
LEVEL SUPPORT TO BRING CONSIDERABLE RAINFALL TO THE AREA THIS
WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 170 171 175 176.
FIRE WEATHER...NONE.

SEP 07