Small Craft Advisory 371, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
130 PM ADT FRI APR 20 2007

.MODEL DISCUSSION...MODEL INITIALIZATIONS AND FORECAST TRENDS ARE IN GOOD
AGREEMENT AND REASONABLE THROUGH 84 HOURS. GFS HAS SLOW PROGRESSION OF
NEXT LOW MOVING SOUTH OF THE ALEUTIAN ISLANDS SUN AND MON. THIS LOOKS
REASONABLE AS NORTH PACIFIC JET HAS WEAKENED.

.ANALYSIS AND UPPER LEVELS...LOW COMPLEX SOUTH OF THE AK PEN SPLITS WITH
MAIN PORTION MOVING SE TO WEST COAST OF THE US. NORTHERN PORTION WEAKENS
AS IT MOVES TO THE SW COAST SAT/SUN. A SERIES OF WAVES DEVELOP OVER THE
NORTH PACIFIC SOUTH OF THE ALEUTIANS AS SHORT WAVES SPIN OFF OF LONG WAVE
OVER THE KAMCHATKA PEN. ON OF TWO SIGNIFICANT CENTERS DEVELOPS AS IT
MOVES TO SOUTH OF KODIAK SUN NIGHT. MODELS SHOWS VERY BROAD TROUGH OVER
THE GULF AT THAT TIME..SO WILL LIKELY SEE SHORT WAVES ROTATING AROUND
MAIN CENTER AND MAKING FOR A COMPLEX SURFACE PATTERN. SECOND MOST
SIGNIFICANT CENTER DEVELOPS NEAR THE WESTERN ALEUTIANS MON.

.SURFACE...

.EAST...RIDGE BUILDS ACROSS THE NORTH GULF TONIGHT. EXPECT SOME CLEARING
OVER SOUTH CENTRAL AND COPPER RIVER TONIGHT AND SAT. ALSO SHOULD SEE
PRESSURE GRADIENTS RELAX OVER SOUTH CENTRAL THIS EVENING. GENERAL
EASTERLY FLOW SHOULD WEAKEN OVER THE NORTHERN GULF TONIGHT AS LOW COMPLEX
SOUTH OF THE GULF MOVES SE. EASTERLY FLOW LIKELY TO INCREASE AGAIN SUN
OVER THE GULF AND WESTERN COASTAL LOCALS AS NEXT CENTER MOVES SOUTH OF
THE AK PEN AND FRONTAL TROUGH MOVES NORTH TO NEAR KODIAK. PRECIPITATION
PATTERN WILL LIVE AND DIE WITH WEAKENING AND STRENGTHENING OF EASTERLY
FLOW OVER THE GULF.

.WEST...E TO SE FLOW ACROSS THE ALEUTIAN/ALASKA RANGE WILL CONTINUE
DOWNSLOPE/RELATIVELY DRY CONDITIONS OVER INTERIOR SW AK THROUGH SAT.
EXPECT REMNANTS OF WEAKENING FRONTAL TROUGH STRETCHING ACROSS BRISTOL BAY
AND DELTA WILL WEAKEN THROUGH SUN NIGHT. HOWEVER...MAY KEEP SOME CHANCE
OF RAIN AND SNOW OVER AT LEAST COASTAL AREAS (MAINLY BRISTOL BAY) AND AK
PEN THRU SUN. PROB SEE SOME CLEARING OVER THE DELTA WITH ONSET OF
OFFSHORE FLOW SUN. LOW MOVING SOUTH OF THE EASTERN ALEUTIANS SAT WILL
BRING STRONG WINDS TO THE WEST AND CENTRAL ALEUTIANS SAT NIGHT SUN WITH
UPPER SMALL CRAFT TO EAST.

.LONG TERM FORECAST...MODELS TRENDING TOWARD LESS PROGRESSIVE PATTERN
WOULD LOOK FOR GREATER MOISTURE INTRUSION INTO SOUTH CENTRAL TUE AND WED.
FOR NOW WILL LEAN WITH GFS MODEL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 130 172 175
FIRE WEATHER...NONE.

RMC APR 07