Small Craft Advisory 291, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT MON MAR 31 2008

.MODEL DISCUSSION...MODEL INITIALIZATIONS LOOK REASONABLE. GFS/NAM
SOLUTIONS ARE GENERALLY THE CLOSEST POSITIONALLY THROUGH 84 HOURS.
GFS HAS SPED UP THE LOW CENTER MOVING ACROSS THE BERING SEA WED.
THIS SEEMS REASONABLE WITH SUCH A PROGRESSIVE PATTERN. UNDER CURRENT
PATTERN...TIMING ISSUES WILL CREATE CHALLENGES. FOR NOW WILL BLEND
TOWARD THE FASTER 12Z GFS POSITION.

.UPPER LEVELS...
5/6 WAVE PATTERN WILL CONTINUE UNSETTLED WEATHER OVER ALASKA FOR THE
NEXT SEVERAL DAYS. RIDGE SETTING UP OVER THE GULF TODAY MOVES INTO
WESTERN CANADA EARLY TUE. THE FIRST IN A SERIES OF SIGNIFICANT WAVES
MOVES TO THE EASTERN BERING SEA EARLY TUE. THIS TROUGH SPLITS N/S
WITH A LOW AMPLITUDE SHORT WAVE MOVING OVER THE MAINLAND AND A
STRONGER LOW CENTER MOVING OVER THE SOUTHERN GULF WED. SW FLOW WHICH
SETS UP OVER THE MAINLAND WED INTENSIFIES THU AS THE TROUGH DIGS OVER
THE BERING SEA. THE MAIN BODY OF THE LONG WAVE TROUGH DIGS OVER THE
MAINLAND ALONG 150W SAT. AT THIS TIME ANOTHER SIGNIFICANT WAVE MOVES
TO THE WESTERN ALEUTIANS JUST BEHIND A LOW AMPLITUDE RIDGE OVER THE
EASTERN BERING SEA.

.SHORT TERM FORECAST...
.EAST...MAIN CONCERNS ARE GAP WINDS OVER SOUTHCENTRAL AND SNOW
POTENTIAL FOR ZONES 145 OVER THE NEXT 36 HOURS. RIDGE ALONG THE NORTH
GULF COAST WILL CONTINUE IN PLACE THROUGH TUE. PRESSURE GRADIENTS
WILL INCREASE ACROSS SOUTHCENTRAL THROUGH TONIGHT AS FRONTAL SYSTEM
AND ASSOCIATED BERING SEA CENTER MOVE EAST. EXPECT STRONG GAP WINDS
OVER SOUTHCENTRAL THROUGH TUE. WINDS SHOULD SUBSIDE TUE EVENING AS
THE RIDGE WEAKENS ALONG THE NORTH GULF AND A WEAK TRIPLE POINT
DEVELOPS OVER THE GULF. SOUTHERLY FLOW IN THE LOW AND MID LEVEL AND
ABUNDANT MOISTURE WITH THE APPROACHING FRONTAL TROUGH WILL BRING SNOW
ADVISORY POTENTIAL TO ZONE 145(MAINLY WESTERN AND NORTHERN VALLEY)
TONIGHT AND TUE. POTENTIAL FOR SIGNIFICANT SNOW AMOUNTS MAY CONTINUE
INTO TUE NIGHT. MILD TEMPS LIKELY TO CONTINUE THROUGH WED.

.WEST...980S LOW CENTER OVER THE NORTH/CENTRAL BERING SEA TODAY
MOVES INTO THE CHUKCHI SEA AND WEAKENS TUE AFTERNOON. FRONTAL TROUGH
OVER THE EASTERN BERING SEA...EASTERN ALEUTIANS MOVES TO THE AK PEN
SW ALASKA COAST THIS EVENING...THEN INTO THE WESTERN
GULF/SOUTHCENTRAL TUE. EXPECT PRECIPITATION IN ADVANCE OF FRONT TO BE
MIXED...SNOW SHOWERS ON THE BACKSIDE WITH COLD ADVECTION AND
SHARPENING TROUGH OVER THE BERING SEA. FAIRLY BRISK GAP WINDS ARE
EXPECTED WITH APPROACH OVER THE FRONTAL TROUGH OVER THE AK PEN AND
ALEUTIAN/ALASKA RANGE THROUGH TONIGHT. WINDS SHOULD DIMINISH ON TUE
WITH PASSAGE OF FRONTAL TROUGH. NEXT DEVELOPING CENTER IMPACTS THE
WESTERN ALEUTIANS TUE NIGHT. THIS CENTER MOVES TO THE PRIBILOF
ISLANDS WED NIGHT. EXPECT THIS CENTER WILL BRING ANOTHER BATCH OF
WARM AIR AND WINDS.

..LONG TERM FORECAST...UNSETTLED WEATHER CONTINUES WITH PROGRESSIVE
PATTERN. EXPECT COOLER TEMPERATURES FOR THE WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...SNOW ADVISORY UPCOMING ZONE 145.
MARINE...GALES 170..172..AND 175
FIRE WEATHER...NONE.

RMC MAR 08