Small Craft Advisory 302, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
255 PM ADT THU APR 3 2008

.MODEL DISCUSSION...
ALL MODELS ARE HANDLING PATTERN VERY REASONABLY AND ARE IN RELATIVE
AGREEMENT THROUGH 72 HOURS. ONE AREA OF CONCERN IS A DIFFERENCE
BETWEEN THE GFS MEAN ENSEMBLE AND THE OPERATIONAL GFS LATER THIS
WEEKEND IN THE EASTERN GULF. THE OPERATIONAL IS IN LINE WITH THE NAM
AND ECMWF SO HAVE MODERATE CONFIDENCE IN THIS SOLUTION.

.UPPER LEVELS...
COLD CORE UPPER LOW LOCATED NEAR THE CHUKOTSK PENINSULA WILL BEGIN
DIVING SOUTH TONIGHT WITH SOME ASSISTANCE FROM THE POLAR JET. THE
TROF AXIS WILL ROTATE EASTWARD ACROSS THE ALASKA PENINSULA AND INTO
THE NORTH GULF WHICH WILL ALLOW THE COLD AIR TO SPILL SOUTH AND EAST
ACROSS THE MAINLAND. A MORE CONCENTRIC UPPER LOW WILL EVENTUALLY
SETTLE BACK INTO A SIMILAR LOCATION SATURDAY AFTERNOON WITH
SHORTWAVES MOVING WEST TO EAST ALONG THE ALEUTIAN CHAIN.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...SHORTWAVE TROF MOVED ACROSS THE EASTERN DOMAIN THIS
MORNING BROUGHT SOME LIGHT RAIN SHOWERS TO INLAND AREAS...WITH MORE
STEADY RAIN AND SNOW ALONG THE MOUNTAINS. THE NORTHERN SUSITNA
CONTINUES TO SEE PRECIPITATION WITH GENTLE LOW LEVEL UPSLOPE WINDS
PROVIDING THE NECESSARY LIFT. SKWENTNA REPORTED 8 INCHES OF SNOW OVER
THE PAST 24 HOURS BUT TEMPERATURES AT OR ABOVE FREEZING HAVING A
LIMITING EFFECT ON ACCUMULATIONS.

A SHORTWAVE RIDGE WILL MOVE OVERHEAD TONIGHT AND THEN QUICKLY EAST
AHEAD OF THE NEXT SYSTEM. PRECIPITATION WILL BEGIN OVERNIGHT AGAIN ON
KODIAK ISLAND IN THE FORM OF RAIN...POSSIBLY MIXED WITH SNOW INLAND.
A TRIPLE POINT LOW WILL DEVELOP JUST SOUTH OF THE ISLAND AND MOVE
INTO THE NORTHERN GULF FRIDAY EVENING. BEHIND THE LOW WILL BE THE
MUCH ADVERTISED COLD AIR ADVECTION SCREAMING THROUGH THE ALEUTIAN
RANGE. MAX GALES ARE LIKELY WITH STORM FORCE GUSTS THROUGH THE USUAL
AREAS IN THE COASTAL WATER ZONES. RAIN AND SNOW ALONG THE COAST WILL
CHANGE TO ALL SNOW AS THE COLD AIR ARRIVES SATURDAY NIGHT...AND THIS
WILL LIKELY INCLUDE ANCHORAGE. THERE HAVE BEEN SOME INCONSISTENCIES
IN THE AMOUNT OF COLD AIR AND LOCATION OF TROF AXIS AS IT SHIFTS INTO
THE GULF BUT OVERALL FEELING MORE CONFIDENT THAT ANCHORAGE WILL SEE
SOME SNOW OVER THE WEEKEND...MOST LIKELY SATURDAY EVENING. WILL
CONTINUE THE CHANCE OF SNOW WORDING AT THIS POINT.

.WEST OF THE ALASKA RANGE...985 MB SURFACE LOW LOCATED NORTHWEST OF
HOOPER BAY NEAR ST LAWRENCE ISLAND. STRONG SOUTHWESTERLY FLOW AT 925
MB MIXING DOWN TO THE SURFACE FROM BRISTOL BAY ALL THE WAY UP TO
MCGRATH. AN UNCHARACTERISTICALLY BREEZY DAY IN MCGRATH TODAY WITH
SOUTH WINDS 15 TO 30 KTS AND SNOW. WINDS ACROSS THE REGION WILL STAY
UP THROUGH THE EVENING.

STRONG COLD AIR WILL MOVE ONSHORE ACROSS THE KUSKOKWIM DELTA EARLY
TOMORROW MORNING AND CONTINUE INLAND THROUGH THE DAY. BY LATE FRIDAY
NIGHT...THE FRONT WILL HAVE MADE IT TO THE ALASKA RANGE AND WILL
INCREASE THE GAP WINDS. ONCE AGAIN WILL HAVE TO CONSIDER FREEZING
SPRAY WITH SURFACE TEMPERATURES DROPPING INTO THE UPPER TEENS TO 20S
ACROSS THE ALASKA PENINSULA BY SATURDAY NIGHT AND SUNDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 130 132 150 155.
FIRE WEATHER...NONE.

AB APR 08