Small Craft Advisory 475, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM ADT WED JUN 4 2008

.ANALYSIS AND UPPER LEVELS...A WEAKENING LOW IN THE NORTHWEST GULF OF
ALASKA IS CONTINUING TO BRING RAIN TO THE NORTH GULF COAST AND
SCATTERED SHOWERS INLAND IN SOUTH CENTRAL ALASKA. THIS LOW WILL
DISSIPATE OVERNIGHT AND JUST LEAVE SOME RESIDUAL MOISTURE IN THE AREA
THURSDAY.

THE BIGGER WEATHER MAKER IS DEVELOPING IN THE NORTH CENTRAL BERING
SEA. THERE IS A COLD UPPER LEVEL TROUGH EXTENDING INTO THE NORTHERN
BERING SEA THAT IS BREAKING OFF AN UPPER LEVEL LOW THAT WILL MOVE
OVER SOUTHWEST ALASKA TONIGHT AND THEN OVER KODIAK ISLAND THURSDAY
NIGHT BEFORE ENDING UP IN THE GULF OF ALASKA FRIDAY. THIS IS
UNUSUALLY COLD AIR FOR THIS TIME OF YEAR AND MAY BRING A MIX OF RAIN
AND SNOW INTO THE KUSKOKWIM DELTA TONIGHT AND OVER KODIAK THURSDAY
NIGHT. 850 MB TEMPERATURES WILL BE FROM -6 TO -8 C OVER KODIAK
THURSDAY NIGHT WHICH IS COLD ENOUGH FOR SNOW. THE BIG QUESTION WILL
BE WHETHER THERE WILL BE PRECIPITATION SINCE THIS WILL HAVE TO OCCUR
IN THE POST FRONTAL SECTION OF THIS SYSTEM AND WOULD BE SHOWERS.
SINCE THIS AREA OF VERY COLD AIR IS NOT VERY LARGE IN SIZE OTHER
AREAS OF SOUTH CENTRAL ALASKA SHOULD NOT SEE TEMPERATURES THIS COLD.
THIS AIR MASS WILL PASS ALONG THE COASTAL SECTION OF BRISTOL BAY
DURING THE DAY ON THURSDAY SO ALL PRECIPITATION SHOULD BE RAIN THERE.

.MODEL DISCUSSION...DISAGREEMENT BETWEEN THE GFS AND NAM WITH THE
MOVEMENT OF THE LOW THAT WILL BE MOVING FROM THE BERING SEA INTO THE
GULF OF ALASKA. GFS SOLUTION LOOKS TO BE BETTER WITH A MORE
CONSISTENT MOVEMENT OF THE LOW AS WELL AS A BETTER RECOGNITION OF THE
COLD AIR ASSOCIATED WITH THE SYSTEM. ECMWF ALSO IS SIMILAR TO THE
GFS.

.SHORT TERM FORECAST...THERE IS A POSSIBILITY OF THUNDERSTORMS IN THE
SUSITNA VALLEY AND KUSKOKWIM VALLEY LATE THIS AFTERNOON AND THIS
EVENING.

.LONG TERM FORECAST...GREAT UNCERTAINTY IN THE LONG RANGE FORECAST
DUE TO A LOW DEVELOPING WELL SOUTH OF THE ALEUTIAN ISLANDS EARLY THIS
COMING WEEKEND. THIS LOW WILL MOVE INTO THE FORECAST AREA AROUND
SUNDAY NIGHT TO MONDAY. THE FORECAST LOCATIONS FROM THE LAST FEW
MODEL RUNS RANGE FROM DUTCH HARBOR TO VANCOUVER ISLAND. RUN TO RUN
CONSISTENCY HAS NOT BEEN VERY GOOD BUT THE SOLUTIONS THAT BRING IT
INTO THE DUTCH HARBOR AREA ARE PROBABLY MORE CORRECT THAN SOLUTIONS
THAT BRING IT INTO THE GULF OF ALASKA OR AREAS EAST OF THERE. THE
DYNAMICS OF THIS TYPE OF DEVELOPING SYSTEM ARE DIFFICULT FOR THE
MODELS TO LOCK ON UNTIL IT BEGINS TO DEVELOP SO THE FORECAST FOR
EARLY THROUGH THE MIDDLE OF NEXT WEEK WILL PROBABLY BE A BIT
UNCERTAIN UNTIL THIS LOW BEGINS ITS DEVELOPMENT EARLY THIS WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 179 180 185.
FIRE WEATHER...RED FLAG WARNING 141.

JUN 08