Gale Warning 675, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
545 AM ADT TUE SEP 19 2006

.DISCUSSION...
MODELS INITIALIZE WELL AND IN GOOD AGREEMENT DURING THE FIRST 54
HOURS. AT 60 HOURS GFS INTRODUCES A 991 MB LOW IN THE NORTH PACIFIC
AND DEEPENS IT QUICKLY TO 975 MB 18 HOURS LATER. ALTHOUGH ALL MODELS
DEPICT THIS LOW...THE GFS IS THE LONE MODEL TO DEVELOP IT SO RAPIDLY
AND INTENSELY. THIS SYSTEM INTRODUCED SOME DIFFICULT DECISIONS FOR
THE MEDIUM RANGE FORECAST AS WHOLE SALE CHANGES COULD PROVE TO BE AN
OVERREACTION IF THE GFS FLIPS DURING THIS MORNINGS RUN. ON THE OTHER
HAND GIVEN THAT ALL THE MODELS INTRODUCE SOME SORT OF LOW DURING THE
SAME TIME FRAME AND OUR RELATIVE PROXIMITY TO THE EVENT...IT WOULD
ALMOST BE IRRESPONSIBLE TO NOT AT LEAST TREND THE FORECAST PACKAGE
TOWARD THIS NEW SOLUTION. SO...AFTER MUCH DELIBERATION AND
COORDINATION WITH JUNEAU DECIDED TO DO JUST THAT. THIS MORNINGS
FORECAST PACKAGE IS A BLEND OF THE GFS AND NAM IN THE SHORT
TERM...THEN BLENDS IN THE NEW GFS SOLUTION WITH THE OLD DURING THE
MEDIUM AND LONG RANGE. AT THIS POINT CONFIDENCE IS LOW IN THE MEDIUM
TO LONG RANGE FORECAST AS THE MODELS TRY TO COME TO SOME CONSENSUS ON
THE DEVELOPING LOW.

SOUTHCENTRAL SURFACE...WILL FOCUS ON THE SHORT TERM GIVEN THE
AFOREMENTIONED UNCERTAINTIES. 990 MB LOW WEAKENING AS IT MOVES OVER
SHELIKOF STRAIT THIS MORNING AND INTO THE NORTHERN GULF TONIGHT. THIS
IS A CHANGE FROM YESTERDAYS MODEL RUNS AS THE CONSENSUS WAS TO TAKE
THE LOW NORTH ACROSS THE ALASKA PENINSULA AND INTO BRISTOL BAY. THIS
DIFFERENCE WILL PROVE TO BE BENEFICIAL FOR THE ANCHORAGE BOWL AS IT
KEEPS RAIN OUT OF THE FORECAST MID WEEK. UNTIL THEN...THE UPSLOPED
RANGES AND COASTAL AREAS WILL SEE THE MAJORITY OF THE PRECIPITATION
DURING THE NEXT 24 HOURS. THE WESTERN KENAI...ANCHORAGE
BOWL...SUSITNA VALLEY EAST OF THE PARKS HIGHWAY...AND COPPER RIVER
BASIN WILL SEE VERY LITTLE RAIN DURING THIS PERIOD. CLOUDS WILL BE IN
ABUNDANCE BUT DOWNSLOPED WINDS WILL KEEP THE MAJORITY OF THE PRECIP
FROM FALLING. WEAK HIGH PRESSURE BUILDS IN WEDNESDAY AFTERNOON AND
THEN UNCERTAINTY THURSDAY AS THE AFFECTS OF THE NEW SYSTEM COULD BE
APPROACHING THEN.

WEST OF THE ALASKA RANGE SURFACE...A WET AND BREEZY DAY IN STORE FOR
MOST EVERYWHERE WEST OF THE ALASKA RANGE WITH THE NORTHERN KUSKOKWIM
THE LONE EXCEPTION. SHOWERS WILL DIMINISH IN COVERAGE OVERNIGHT BUT
THE UPPER LOW WILL REMAIN OVER CENTRAL ALASKA KEEPING THE ATMOSPHERE
UNSTABLE ENOUGH TO SQUEEZE OUT A FEW SHOWERS WEDNESDAY. LIGHT
WESTERLY FLOW IS ESTABLISHED ALONG THE COAST TONIGHT AND WILL LAST
THROUGH MID WEEK. THIS SCENARIO TYPICALLY LENDS ITSELF TO LOW CLOUDS
AND MORNING FOG.

FURTHER WEST...CONDITIONS IMPROVING OVER THE EASTERN ALEUTIANS AS THE
MAIN LOW MOVES EAST OF THE ALASKA PENINSULA. GUSTY NORTHWESTERLY
WINDS WILL DIMINISH DURING THE DAY. OVERNIGHT A MUCH WEAKER LOW WILL
MOVE ALONG THE CENTRAL ALEUTIANS AND DISRUPT THE NORTHWESTERLY FETCH.

THANK YOU JUNEAU FOR THE COORDINATION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 155 165 170
FIRE WEATHER...NONE

AB SEP 06