Small Craft Advisory 883, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AKST WED NOV 12 2008

.MODEL DISCUSSION...THE MODELS ARE DOING WELL OVERALL. THERE IS ONE
DIFFERENCE THAT MAKES THE NAM THE PREFERRED MODEL FOR THE FIRST 36 TO
42 HOURS. THERE IS A WEAK CIRCULATION SOUTH OF COLD BAY THAT IS ONLY
DETECTED ADEQUATELY BY THE NAM AND ITS HIGHER RESOLUTION. WHILE THE
GFS DOES SEE A WAVE IN THE SAME LOCATION IT DOES NOT HAVE IT RESOLVED
AS WELL. THEREFORE THE NAM SOLUTION BRINGING THIS VORTEX INTO PRINCE
WILLIAM SOUND TOMORROW LOOKS LIKELY.
FROM 48 HOURS AND BEYOND THE GFS HAS THE PREFERRED SOLUTION. THE GFS
UKMET AND ECMWF ALL BRING A DEVELOPING LOW INTO THE FAR EASTERN GULF
FRIDAY. NAM IS THE OUTLIER MOVING IT INTO THE CENTRAL GULF. THE UPPER
LEVEL PATTERN ALSO LOOKS BETTER FOR BRINGING THIS LOW INTO THE
EASTERN GULF SO THE GFS SOLUTION SHOULD WORK FINE FOR THE ANCHORAGE
FORECAST AREA.

.ANALYSIS AND UPPER LEVELS...THE DOMINANT UPPER LEVEL FEATURE
CONTINUES TO BE A LARGE LOW OVER THE SOUTHWEST ALASKA COAST. THIS LOW
WILL REMAIN IN PLACE AND THEN LIFT NORTHWARD FRIDAY AS A SECONDARY
UPPER LEVEL LOW DEVELOPS IN THE WESTERN BERING SEA AND A MODERATE LOW
MOVES INTO THE GULF OF ALASKA. AT THE SURFACE THERE IS THE REMNANTS
OF A LOW IN THE SUSITNA VALLEY THIS AFTERNOON.L THIS LOW WILL MOVE
SLOWLY NORTH AND DISSIPATE OVERNIGHT. A SURFACE LOW IN THE EASTERN
BERING SEA WILL WILL MOVE INTO THE BRISTOL BAY AREA OVERNIGHT. THIS
LOW IS A LITTLE DIFFICULT TO SEE ON THE IR SATELLITE BUT IS PROMINENT
ON THE VISIBLE SATELLITE.

.SHORT TERM FORECAST...SNOW CONTINUES TO FALL IN THE SUSITNA VALLEY
AS THE LOW REMNANTS MOVE THROUGH THAT AREA. THIS SNOW SHOULD TAPER
OFF THROUGH THE EVENING.
THE KUSKOKWIM VALLEY IS ALSO BEING AFFECTED BY THIS SYSTEM WITH SNOW
FALLING IN MCGRATH. THIS SNOW SHOULD TAPER OFF OVERNIGHT AS WELL.
FOG IS PLAGUING THE PARTS OF THE KUSKOKWIM DELTA AND BRISTOL BAY
COAST. THIS FOG WILL LIKELY PERSIST INTO THE EVENING AND THEN
DIMINISH BEFORE THE NEXT WEAK DISTURBANCE MOVES INTO THAT AREA AFTER
MIDNIGHT.
NUMEROUS SNOW SHOWERS HAVE BEEN OCCURRING FOR DAYS OVER MOST OF THE
MARINE AREAS AND THIS WILL LIKELY CONTINUE.

WHILE IT WAS MENTIONED EARLIER THAT THE WEAK LOW SOUTH OF COLD BAY
WILL MOVE INTO PRINCE WILLIAM SOUND TOMORROW THAT DOES NOT
AUTOMATICALLY MEAN SNOWFALL FOR ANCHORAGE. THIS SYSTEM WILL MOST
LIKELY BRING SOME SNOW TO THE EASTERN PART OF THE SOUND WITH SOME
SNOW SHOWERS ON THE WESTERN SIDE. THE 850 MB ISOTHERMS AND OTHER
IMPORTANT VARIABLES ALL INDICATE NO SNOW WILL MAKE IT PAST THE KENAI
OR CHUGACH MOUNTAINS INTO THE ANCHORAGE OR MAT-SU AREAS.

.LONG TERM FORECAST...THE UPPER LEVEL PATTERN FIVE DAYS FROM NOW IS
VERY SIMILAR TO TODAY. THIS WILL HELP KEEP THE MAJOR STORM SYSTEMS
SOUTH OF THE AREA THROUGH THE WEEK. WHILE A LOW DOES MOVE INTO THE
BERING SEA ON FRIDAY IT WILL WEAKEN AS IT MOVES EAST AND WILL BE
UNDERCUT BY A LOW DEVELOPING TO ITS SOUTH. WEAK RIDGING WILL DEVELOP
OVER SOUTHWEST ALASKA FRIDAY AFTERNOON AND MOVE OVER SOUTH CENTRAL
SATURDAY. THIS WILL BRING SOME BRIEF CLEARING TO THOSE AREAS AT THAT
TIME.

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

NOV 08