Small Craft Advisory 382, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM ADT WED APR 25 2007

.MODEL DISCUSSION...MODELS IN GOOD AGREEMENT FROM THE OVERNIGHT RUNS.
BIGGEST DIFFERENCE IS IN THE GULF OF ALASKA WITH THE APPROACHING LOW.
THE NAM MOVES THE LOW FURTHER NORTHEAST TOMORROW THAN DOES THE GFS
BEFORE BRINGING IT BACK TO THE GFS POSITION THURSDAY NIGHT. THE UKMET
MODEL MAY HAVE THE BEST POSITIONING WITH THE LOW BETWEEN THE NAM AND
GFS SOLUTIONS. HOWEVER THE UKMET PRESSURE APPEARS A LITTLE WEAK.
WHILE THERE ARE SOME DIFFERENCES IT WILL NOT MAKE MUCH DIFFERENCE IN
THE FORECAST AS THIS IS ALL OCCURRING WELL OFFSHORE IN THE GULF OF
ALASKA. THERE IS ALSO A DIFFERENCE IN THE LOW MOVING INTO THE WESTERN
ALEUTIAN AREA THURSDAY NIGHT AND FRIDAY. WHILE THE FOUR MODELS ALL
HAVE THE LOW WEST OF ATTU THEY HAVE FOUR DIFFERENT POSITIONS FOR
THURSDAY NIGHT. PREFER THE GFS OUT WEST AT THIS TIME FOR THIS LOW.

.ANALYSIS AND UPPER LEVELS...UPPER LEVEL FLOW IS RELATIVELY WEAK OVER
MUCH OF THE AREA. NOT UNTIL ONE GETS TO THE WESTERN ALEUTIANS DOES IT
INCREASE SIGNIFICANTLY FROM THE NORTHWEST. THIS IS IN CONJUNCTION
WITH A RIDGE BUILDING INTO THE WESTERN BERING SEA BEHIND THE LOW
MOVING INTO THE GULF. HOWEVER THE STRONG UPPER LEVEL FLOW WILL BE
CONSTRAINED TO THE BERING SEA AREA WHILE THE MAINLAND ALASKA REMAINS
UNDER VERY WEAK UPPER LEVEL FLOW INTO THE WEEKEND.
IR SATELLITE SHOWS THE LOW APPROACHING THE GULF CURRENTLY NEAR 51N
150W. THE STRONG FRONTAL STRUCTURE IS CLEAR IN THE SATELLITE PICTURE
AS IS THE JET STREAM WHICH IS BEGINNING TO SHOOT EAST OF THE LOW AND
HENCE WILL CAUSE THE LOW TO STOP IN THE CENTRAL GULF AND THEN SLOWLY
WEAKEN.

.SHORT TERM FORECAST...SOUTHEAST FLOW IS BRINGING SHOWERS ALONG THE
GULF COAST AND INTO TURNAGAIN ARM. SHOWERS ALSO ARE IN THE NORMAL
UPSLOPE REGION OF WESTERN COOK INLET AND HAVE SPILLED OVER INTO THE
BRISTOL BAY AREA. RAIN IS THE PRECIPITATION TYPE EVERYWHERE EXCEPT
FOR THE PRIBILOF ISLANDS WHICH WERE EXPERIENCING SNOW SHOWERS EARLIER
TODAY. SHOWERS WILL PERSIST INTO THE EVENING AND THEN BEGIN TO
DIMINISH AS RIDGING PUSHES IN FROM THE NORTHEAST IN CONJUNCTION WITH
THE LOW MOVING INTO THE GULF.

.LONG TERM FORECAST...NOT A LOT OF CHANGE IN THE LONG RANGE FORECAST.
THE LONG WAVE TROUGH REMAINS OVER US THROUGH THE WEEKEND AND WILL
KEEP THE JET STREAM SOUTH OF MAINLAND ALASKA AND UPPER LEVEL FLOW
RELATIVELY WEAK. SCATTERED SHOWERS WILL POP UP IN INTERIOR REGIONS
WITH RAIN ALONG COASTAL AREAS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 132 172 175 176.
FIRE WEATHER...NONE.

EZ APR 07