Small Craft Advisory 985, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT WED OCT 25 2006

.DISCUSSION...
A VERTICALLY STACKED LOW IS SEEN CLEARLY ON IR SATELLITE THIS MORNING
JUST SOUTH OF PRINCE WILLIAM SOUND. RAIN AND SNOW SHOWERS CONTINUE TO
WRAP AROUND ACROSS SOUTHCENTRAL AS ITS FRONT MOVED INLAND OVER THE
NORTHEASTERN GULF COAST THIS MORNING. ON WATER VAPOR SATELLITE THE
VERY BROAD UPPER LEVEL TROUGH OVER THE BERING AND EMBEDDED UPPER LOW
ASSOCIATED WITH THE PWS LOW IS CLEARLY SEEN AS WELL. THE JET STREAM
IS SEEN STRETCHING BELOW THE ALEUTIAN CHAIN ALONG 40N THEN TURNING
NORTHEAST AT 170W AND INTO THE SOUTHERN PANHANDLE. COLD AIR WRAPPING
AROUND THE PWS LOW INTO THE BERING AND A RIDGE BUILDING FROM THE WEST
IS BRINGING RAIN AND SNOW SHOWERS OVER MOST OF THE BERING AND
ALEUTIANS.

MODEL AGREEMENT WAS MUCH BETTER THAN PREVIOUS RUNS. HOWEVER GFS HAD
THE PWS LOW 4 MB TOO WEAK AND THE NAM HAD IT 4 MB TOO STRONG. UKMET
SEEMED TO HAVE THE BEST HANDLE ON THE SYSTEM. USED A BLEND OF GFS/NAM
FOR THE FORECAST PACKAGE.

EAST...THE PWS LOW WILL REMAIN NEARLY STATIONARY THROUGH THURSDAY
NIGHT KEEPING RAIN AND SNOW SHOWERS AROUND...MAINLY EAST OF THE KENAI
PENINSULA AND UP INTO THE COPPER RIVER BASIN. AS AN UPPER LEVEL RIDGE
PRESSES EAST AND NUDGES THE TROUGH TOWARD CANADA...A SURFACE RIDGE
WILL BUILD INTO THE MAINLAND AND CLEAR CONDITIONS FROM THE WEST
BEGINNING TOMORROW THROUGH SATURDAY. THIS RIDGE WILL HELP KEEP MOST
PRECIP OUT OF THE AREA. WITH THE BACK SIDE OF THE TROUGH MOVING EAST
OVER THE AREA AND HIGH PRESSURE TO MOVE IN AND REMAIN OVER
SOUTHCENTRAL THROUGH THE WEEKEND EXPECT TEMPERATURES...ESPECIALLY LOW
TEMPERATURES AT NIGHT...TO BE ON A DOWNWARD TREND THROUGH THE END OF
THE WEEK.

WEST...SHOWERS OVER THE SOUTHWESTERN MAINLAND WILL DECREASE THROUGH
TONIGHT AS THE PWS LOW WEAKENS AND THE UPPER TROUGH IS PUSHED EAST.
SHOWERS OVER THE WESTERN AND CENTRAL ALEUTIANS WILL DIMINISH TODAY
THROUGH TOMORROW AS THE SURFACE RIDGE BUILDS EAST. THREE LOWS
STRETCHING FROM NORTH OF EASTERN RUSSIA TO JUST SOUTHWEST OF THE
WESTERN ALEUTIANS BEGINNING TOMORROW NIGHT WILL PUSH SHOWERS AND
STRONG SOUTHERLY WINDS ACROSS THE WESTERN AND CENTRAL CHAIN AND THE
BERING THROUGH THE END OF THE WEEK. THE KUSKOKWIM DELTA WILL SEE
SHOWERS FROM THESE SYSTEMS STARTING TOMORROW NIGHT AS THE MOISTURE
RIDES OVER THE TOP OF THE RIDGE. SHOWERS WILL CONTINUE THROUGH
SATURDAY AS THE LOWS PUSH THE RIDGE EAST AND SPREAD MOISTURE INLAND
OVER THE SOUTHWESTERN MAINLAND.

EARLY NEXT WEEK COULD SEE MUCH COLDER TEMPERATURES AS AN UPPER LOW
NORTH OF CANADA BUILDS DOWN OVER EASTERN ALASKA BRINGING POLAR AIR
ALONG THE BACKSIDE OF IT. WILL HAVE TO WATCH SUBSEQUENT MODEL RUNS TO
SEE IF THIS SCENARIO HOLDS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 121 125 130 132 138
FIRE WEATHER...NONE

LR OCT 06