Small Craft Advisory 954, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AST MON NOV 12 2007

.MODEL DISCUSSION...THE GFS MODEL OVERALL IS PREFERRED. SHORT TERM
MODEL SOLUTIONS ARE FAIRLY SIMILAR...BIGGEST DIFFERENCES IN NAM/GFS
COME INTO PLAY ON HOW THEY HANDLE NEXT STORM MOVING TO THE NE PAC
THU. THE NAM SOLUTION CARRIES THE CENTER MUCH FURTHER NORTH THAN THE
GFS/EC MODELS. THE GFS HAS BEEN FAIRLY CONSISTENT IN THE LAST COUPLE
OF RUNS AND LINES UP BETTER WELL WITH EC. CONCERNS WITH THE GFS ARE
THAT THE OPERATIONAL RUNS APPEARS TO BE THE OUTLIER OF THE ENSEMBLE
SOLUTIONS...SO NOT SURE HOW REALISTIC CURRENT MODEL RUN IS. FOR NOW
WILL CONTINUE ALONG WITH FORECASTS BEYOND 72 HOURS AND MAKE SOME
MINOR CHANGES.

.ANALYSIS AND UPPER LEVELS...
THREE LOW CENTERS ARE EASILY IDENTIFIED THIS AFTERNOON SAT PICTURE. A
970S CENTER WEST OF SAINT MATTHEW ISLAND...980S CENTER SW OF THE
PRIBILOFS...AND A 980S CENTER NEAR SW OF KUSKOKWIM BAY. MODEL
FORECAST WEAKENS CENTER NEAR KUSKOKWIM BAY AND MAKES THE CENTER SW OF
THE PRIBILOFS THE DOMINANT FEATURE. CENTER MOVES INTO EASTERN BRISTOL
BAY IN THE 970S TUE MORNING. THIS SCENARIO APPEARS REASONABLE AS SAT
PIC SHOWS DEEP CONVECTION AND FAVORABLE JET POSITION. CENTER
EVENTUALLY MOVES INTO THE SW MAINLAND WED AND WEAKENS. ASSOCIATED
FRONTAL TROUGH OVER SW AK WEAKENS...AS A SECONDARY BOUNDARY...
ASSOCIATED WITH THE DEVELOPING CENTER SW OF THE PRIBILOFS...
STRENGTHENS AS MOVES INTO SOUTHCENTRAL/GULF OF ALASKA TUE THEN INTO
THE INTERIOR AND EASTERN GULF WED. HIGH PRESSURE BUILDS OVER THE
WESTERN ALEUTIANS TUE AND SPREADS TO THE CENTRAL BERING SEA/ALEUTIANS
THU MORNING. LONGER RANGE OUT TO FRI AFTERNOON SHOWS A DEEP LOW OVER
THE GULF OF ALASKA...HIGH PRESSURE RIDGE OVER THE CENTRAL BERING
SEA...AND A WEAK FRONTAL TROUGH OVER THE WESTERN ALEUTIANS/BERING
SEA.

.SHORT TERM FORECAST...
.EAST...FAIRLY STRONG INVERSION OVER VALLEY SECTIONS OF SOUTHCENTRAL
LIKELY TO HOLD STRATUS IN THROUGH TONIGHT. EXPECT OVERRUNNING SNOW TO
SPREAD TO SOUTHCENTRAL TONIGHT WITH APPROACH OF FRONTAL TROUGH TO
WEST. PRECIPITATION LIKELY TO START AS SNOW OVER COASTAL AREAS AND
KENAI PEN...BUT SHOULD CHANGE OVER TO RAIN/MIX DURING THE DAY
TUE...THEN COOLS AGAIN TUE NIGHT. TEMPS SHOULD REMAIN COLD ENOUGH
OVER INTERIOR AND PORTIONS OF ZONE 131 TO KEEP PRECIPITATION AS SNOW
THROUGH WED. MAY SEE SIGNIFICANT SNOW AMOUNTS OVER HIGHER
ELEVATIONS/COLD POCKETS OF ZONE 125 AND PORTIONS OF ZONE 131 TUE
THROUGH WED MORNING. EXPECT STRONG GAP WINDS OVER PORTIONS OF
SOUTHCENTRAL...ESPECIALLY ZONE 101...TUE AS INTENSIFYING LOW CENTER
MOVES INTO BRISTOL BAY. WINDS SHOULD DIMINISH TUE/NIGHT/WED AS CENTER
WEAKENS AND DRIFTS NORTH.

.WEST...SNOW LIKELY TO CONTINUE OVER ZONES 155 AND 161 THROUGH TUE.
MOST SNOW SHOULD BE THE MOST PRONOUNCED OVER BRISTOL BAY WITH
APPROACH OF LOW CENTER. SNOW WILL BE FAIRLY CONVECTIVE AS SEEN ON
CURRENT SAT IMAGERY. SO...MAY SEE LOCALLY SIGNIFICANT SNOW AMOUNTS
AND LOCALLY GUSTY WINDS TUE. COASTAL AREAS OF BRISTOL BAY WILL SEE A
MIX TONIGHT AND TUE. GENERALLY LIGHT SNOW WILL BE THE CENTRAL RULE
OVER BRISTOL BAY. STRONG W TO NW WINDS LIKELY ON THE BACKSIDE OF LOW
MOVING INTO BRISTOL BAY. EXPECT WINDS TO SPREAD FROM THE ALEUTIANS TO
THE EASTERN BERING SEA/AK PEN TONIGHT/TUE. WINDS WILL BE SLOW TO
DIMINISH OVER THE EASTERN BERING SEA A LOW ANCHORS OVER SW AK THRU
WED.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 120 130 132 138 150 155 160 165 AND 170.
FIRE WEATHER...NONE.

RMC NOV 07