Small Craft Advisory 38, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
230 PM AKST FRI JAN 9 2009

.MODEL DISCUSSION...MODEL INITIALIZATIONS ON SYNOPTIC SCALE FEATURES
ARE SOMEWHAT SIMILAR AND REASONABLE. FORECASTS SOLUTIONS VARY
CONSIDERABLY THROUGH MON...THEN CONVERGE TOWARD A COMMON SOLUTION BY
TUE NIGHT. DIFFERENCES ARISE AS PATTERN BECOMES MORE PROGRESSIVE.
SECONDARY LOW DEVELOPMENT ON SAT IMAGERY SUGGESTS THAT THE GFS MAY
HAVE A BETTER HANDLE INITIALLY ON LOW COMPLEX APPROACHING THE WESTERN
GULF. SO FOR NOW WILL BLEND CURRENT GRIDS TOWARD THE GFS SOLUTION
THROUGH 60 HOURS OR SO. LITTLE IF ANY ADJUSTMENTS TO CURRENT PACKAGE
LIKELY AFTER THAT DUE TO MODEL UNCERTAINTY.

.ANALYSIS
PATTERN SHIFT WILL INTRODUCE A MODERATE DEGREE IN UNCERTAINTY IN
FORECASTS OVER THE NEXT COUPLE OF DAYS. THOUGH...WE CAN SAY WITH SOME
DEGREE OF CONFIDENCE THAT INDICATORS POINT TOWARD A
WETTER..WARMER..AND WINDER WEATHER PATTERN NEXT WEEK.

.UPPER LEVELS...
SHORT WAVE OVER THE NE GULF MOVES RAPIDLY EAST AND WEAKENS. BROAD
UPPER TROUGH WITH SEVERAL LOW CENTERS STRETCHING FROM THE BERING SEA
TO OVER THE NORTH PACIFIC SOUTH OF THE ALEUTIANS LIFTS NORTH AND EAST
AS DEVELOPING WAVE MOVING ACROSS JAPAN BUILDS THE NORTH PACIFIC
RIDGE. THE ANCHOR LOW OVER THE BERING SEA MOVES TO OVER EASTERN
RUSSIA MON WHILE TWO FAIRLY SIGNIFICANT SHORT WAVES NEAR THE TROUGH
BASE PROGRESS RAPIDLY EAST ACROSS THE GULF SAT THROUGH EARLY MON
MORNING. DEVELOPING LOW CENTER MOVING ACROSS JAPAN TONIGHT
INTENSIFIES AS IT MOVES TO SOUTH OF THE ALEUTIANS MON EVENING. THIS
IN RESPONSE BUILDS THE RIDGE TO ITS EAST AND SETS UP A WARM AND MOIST
SOUTHERLY FLOW OVER THE MAINLAND/GULF WHICH PERSISTS THROUGH THE
MIDDLE OF NEXT WEEK.

.SHORT TERM FORECAST...
.EAST...UPPER 980S LOW CENTER OVER THE NE GULF MOVES INLAND TONIGHT
AND WEAKENS. TRAILING SNOW SHOWERS ON BACKSIDE ALONG THE NORTH GULF
COAST SHOULD END THIS EVENING. PRESSURE GRADIENTS WILL RELAX
OVERNIGHT AS LOW SHIFTS EAST....HOWEVER WILL SEE SOME LOCALLY BRISK
DRAINAGE FLOWS CONTINUING ACROSS THE NORTH GULF THROUGH TONIGHT. A
990S LOW MOVES TO SOUTH OF KODIAK ISLAND SAT THEN WEAKENS OVER THE NE
GULF SUN. THE ASSOCIATED FRONTAL TROUGH MOVES OVER KODIAK ISLAND AND
SOUTHERN GULF OF ALASKA SAT AFTERNOON AND THE NORTHERN AND EASTERN
GULF SAT NIGHT/SUN. SNOW DEVELOPING OVER KODIAK SAT WILL PROBABLY MIX
WITH RAIN WITH RISING THICKNESS VALUES SAT. SNOW SHOULD SPREAD TO THE
NORTH GULF COAST LATER SAT AND CONTINUE THROUGH SUN. SHOULD SEE
MOISTURE WORK INTO THE COPPER RIVER BASIN LATE SAT NIGHT/SUN MORNING.

.WEST...
.SW MAINLAND...WEAK STACKED LOW OVER THE SW MAINLAND HAS BROUGHT
CLOUD COVER TO THE AREA AND HAS MODERATED TEMPS OVER THE DELTA AND
BRISTOL BAY OVERNIGHT. MODELS ARE NOT DOING A GREAT JOB AT PICKING UP
CLOUD COVER...SO WELL HAVE TO MAKE ADJUSTMENTS TO OVERNIGHT TEMP
FORECASTS.  LOW CENTER APPROACHING THE AK PEN WILL BRING A SHOT AT
SNOW AND A LITTLE WIND SUN.

BERING SEA AND ALEUTIANS...FLOW OFF THE ICE PAC WILL CONTINUE
GENEARLLY MOSTLY CLOUDY CONDITIONS WITH AREAS OF SNOW AND SNOW
SHOWERS OVER THE NEXT DAY OR SO. AFTERNOON SAT IMAGE SHOWS WIDE
SPREADS SNOW SHOWERS WITH OPEN CELL CU OVER THE WESTERN BERING SEA
AND WEST ALEUTIANS. LOW CENTER SOUTH OF THE EASTERN ALEUTIANS WILL
DRIFT NORTH TONIGHT AND INCREASE TO EAST TO NE FLOW ACROSS THE AREA.
WINDS WILL SUBSIDE SOME IN THE EAST SUN THEN INCREASE OVER MUCH OF
THE CENTRAL AND WESTERN ALEUTIANS WITH APPROACH OF DEVELOPING STORM
SYSTEM SUN AFTERNOON.

.LONG TERM FORECAST...WET...WARM...AND WINDY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 132 150 170 172.
FIRE WEATHER...NON.E

RMC JAN 09