Small Craft Advisory 314, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
140 PM ADT MON APR 2 2007

.DISCUSSION...

ANALYSIS...IR SATELLITE IMAGERY DEPICTS A STRONG UPPER JET RIDING
EASTWARD ALONG 40N...AMPLIFYING THE EAST-WEST ORIENTED TROUGH.
MULTIPLE SURFACE LOWS ARE EMBEDDED IN THE TROUGH. THE STRONGEST
ONE AT 48N 168W IS DEEPENING IN THE LEFT EXIT REGION OF THE UPPER
JET. HOWEVER...THE JET WILL MOVE ON BY THIS EVENING AND A NEW LOW
WILL FORM DOWNSTREAM. ANOTHER WEAK LOW IS CURRENTLY NEAR ATKA
TRACKING WESTWARD ON THE DOWNSTREAM SIDE OF THE EAST-WEST TROUGH.
SIGNIFICANT PRECIP AND WINDS LIE ALONG THE FRONT EXTENDING FROM THIS
LOW SOUTHEASTWARD ACROSS THE EASTERN ALEUTIANS TO THE NORTH PACIFIC.
DUTCH HARBOR IS REPORTING ALL SNOW. SINCE THE FRONT IS OCCLUDING
LOW LEVEL TEMPS ARE NOT GOING TO GET ANY WARMER. SO IT DOES NOT
LOOK LIKE PRECIP WILL CHANGE TO RAIN AS ORIGINALLY THOUGHT. SNOW
MAY MIX WITH RAIN THIS AFTERNOON OR JUST REMAIN ALL SNOW. QUIKSCAT
SHOWS A BAND OF GALE FORCE WINDS CENTERED ON THE EASTERN ALEUTIANS.
ALTHOUGH WE HAVE NO OBS TO CONFIRM THIS...BUT STORM FORCE GUSTS SEEM
POSSIBLE THROUGH BAYS AND PASSES.

WATER VAPOR IMAGERY SHOWS A SHORT-WAVE TROUGH EXTENDING FROM THE
EASTERN BERING SOUTHEAST ACROSS THE AKPENN TO SOUTH OF KODIAK ISLAND
AND MOVING NORTHWARD. STRATUS HAS OVERSPREAD MUCH OF THE WESTERN
GULF WITH HIGHER CLOUDS SPREADING OVER BRISTOL BAY AND TOWARD
SOUTHCENTRAL. SO FAR THERE ARE NO SIGNS OF PRECIP...BUT WE DO EXPECT
SOME SHOWERS AS THIS SHORT-WAVE CONTINUES TO MOVE OFF TO THE NORTH
AND WEST. YET ANOTHER SHORT-WAVE EXTENDS ACROSS NORTHWEST ALASKA
DOWN INTO THE NORTHERN BERING. THE KUSKOKWIM DELTA...ON THE PERIPHERY
OF THIS...HAS SEEN SOME PATCHY AREAS OF LIGHT PRECIP.

MODEL DISCUSSION...FAIR MODEL AGREEMENT AND RUN-TO-RUN CONSISTENCY.
MODELS DEPICT SHORT-WAVE SOUTH OF KODIAK ISLAND MAKING IT A LITTLE
FARTHER NORTH BEFORE ROTATING WESTWARD OVER SOUTHWEST ALASKA...SO
FORECAST WILL BE ADJUSTED TO BRING CHANCE OF SHOWERS A LITTLE
FARTHER NORTH AND WEST. MODEL SOLUTIONS DIVERGE IN THE MID TO LONG
TERM. HOWEVER...THE STORM TRACK IS WELL TO THE SOUTH OF THE ANCHORAGE
AOR AND DIFFERENCES AWAY FROM THE ACTUAL STORMS ARE MINIMAL...SO
CURRENT FORECAST TRENDS LOOK SOLID.

FORECAST...AS UPPER JET CONTINUES TO DRIVE EASTWARD ACROSS THE NORTH
PACIFIC ONE VERY LARGE LOW WILL SET UP OVER THE NORTHEAST PACIFIC.
THE UPPER TROUGH AXIS WILL REMAIN ALONG OR JUST SOUTH OF THE
ALEUTIANS SO PRECIP WILL REMAIN IN THE FORECAST...BUT WINDS WILL
DIMINISH TO SMALL CRAFT OR LESS. MEANWHILE...THE SHORT-WAVE SOUTH OF
KODIAK WILL MERGE WITH THE ONE DROPPING DOWN OVER NORTHWEST ALASKA
TUESDAY NIGHT AND MOVE INTO THE NORTHERN BERING AS A CLOSED LOW
THURSDAY. SOUTHWEST ALASKA MAY SEE A FEW SHOWERS WITH THESE
FEATURES...BUT NOTHING SIGNIFICANT...BECAUSE MOST OF THE SYNOPTIC
LIFT WILL BE OVER THE BERING. AS WE HEAD TO LATE IN THE WEEK
SHORT-WAVES ROTATING AROUND THE NORTHEAST PACIFIC ANCHOR
LOW WILL MOVE ACROSS THE GULF BRINGING WIND AND PRECIP TO COASTAL
REGIONS. RIGHT NOW IT LOOKS LIKE THEY WILL REMAIN FAR ENOUGH SOUTH
THAT INLAND AREAS WILL REMAIN MOSTLY DRY...BUT A CHANCE OF SHOWERS
IS A DEFINITE POSSIBILITY. BY THE WEEKEND MODELS INDICATE THE MAIN
LOW CENTER MOVING NORTHWARD INTO THE GULF...WHICH WOULD RESULT IN
LOTS OF CLOUDS AND A BETTER SHOT OF PRECIP ACROSS INLAND AREAS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 132 170 171 172 176.
FIRE WEATHER...NONE.

SEB APR 07