Storm Warning 162, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT FRI OCT 15 2010

.MODEL DISCUSSION...MODELS ARE DOING WELL WITH THE STORM IN THE
BERING SEA WITH THE ONLY ITEM OF INTEREST BEING THE NAM HANDLING OF
THE LOW. THE LOW WILL ESSENTIALLY HIT A WALL IN THE EASTERN BERING
SEA BUT THE NAM IS DANCING THE LOW A LITTLE FARTHER EAST OF THE OTHER
MODELS BEFORE SENDING OVER THE ALASKA PENINSULA ON SUNDAY. THE NAM
HAS HAD LESS RUN TO RUN CONSISTENCY THAN OTHER MODELS SO THAT
SOLUTION IS A BIT SUSPECT.
THE MODELS ARE HAVING MORE DIFFICULTY DEALING WITH A TRIPLE POINT LOW
THAT WILL DEVELOP SOUTH OF THE GULF OF ALASKA SUNDAY AND MOVING TO
THE NORTH GULF COAST MONDAY. THERE IS A LARGE DIFFERENCE WITH THE
STORM TRACK AND STRENGTH BETWEEN MODELS. THE UKMET AND NAM BRING THE
LOW IN THE THE 960S WHILE THE GFS AND ECMWF ARE ABOUT 10 MB WEAKER.
WHOLE STRONGER THE NAM AND UKMET ARE HUNDREDS OF MILES APART ON THEIR
TRACK BUT THE UKMET AND GFS TRACKS ARE SIMILAR. THIS ONE WILL HAVE TO
BE WATCHED CLOSELY OVER THE WEEKEND TO SEE HOW IT DEVELOPS.

.ANALYSIS AND UPPER LEVELS...THE IS WEAK UPPER LEVEL RIDGING OVER
SOUTH CENTRAL ALASKA WHILE A SIGNIFICANT UPPER LEVEL TROUGH IS
DIGGING INTO THE CENTRAL BERING SEA. THE 250 MB JET STREAM COMES OFF
JAPAN AND HEADS EASTWARD ACROSS THE ALEUTIAN ISLANDS BEFORE
WEAKENING. THIS PUTS THE SURFACE LOW IN THE BERING SEA IN THE UPPER
LEFT EXIT REGION OF THE JET STREAM AND THUS THE LOW IS RAPIDLY
STRENGTHENING AS IT MOVES SLOWLY EASTWARD ACROSS THE BERING SEA.

.SHORT TERM FORECAST...THE BIG WEATHER MAKER TODAY AND THROUGH THE
WEEKEND IS THE LARGE LOW IN THE BERING SEA. LOOK FOR RAIN WITH THIS
SYSTEM AS WARM ADVECTION WILL KEEP TEMPERATURES ABOVE FREEZING WHERE
THERE IS PRECIPITATION. AN ASPECT OF THIS STORM THAT IS A LITTLE
UNUSUAL IS THAT IT WILL BECOME NEARLY STATIONARY FOR ALMOST A DAY
FROM TONIGHT THROUGH SATURDAY NIGHT WHILE MAINTAINING A CENTRAL
PRESSURE IN THE MID 960S MB. THE IMPACT IS THAT THE PRIBILOF
ISLANDS...ALEUTIANS...AND ALASKA PENINSULA WILL REMAIN IN STRONG
WINDS THAT ENTIRE TIME. BRISTOL BAY AND THE KUSKOKWIM DELTA WILL SEE
THE STRONGEST WINDS LATE TONIGHT THROUGH TOMORROW AFTERNOON AS THE
FRONT PUSHES THROUGH BUT WILL SEE WINDS COME DOWN AFTER FRONTAL
PASSAGE.
IN THE GULF OF ALASKA AND SOUTH CENTRAL REGIONS THINGS ARE A BIT MORE
SETTLED. HOWEVER THERE IS STILL A LOW IN THE GULF THAT IS CAUSING
SOME GUSTY WINDS AND BRINGING SOME RAIN AND SNOW SHOWERS ALONG THE
GULF COAST AND AS FAR INLAND AS ANCHORAGE. THESE SHOWERS SHOULD PULL
OFFSHORE LATER IN THE EVENING AS THE LOW MOVES FARTHER EAST.

.LONG TERM FORECAST...A LARGE COMPLEX LOW WILL MOVE INTO THE BERING
SEA BY THE MIDDLE OF NEXT WEEK WHICH WILL LIKELY GIVE COMPUTER MODELS
FITS AS THEY TRY TO RESOLVE THE DETAILS OF THE SYSTEM.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 130 132 138 140 141 150 155 160 165 171 172 175 176
180 185.
        STORM 170 179.
FIRE WEATHER...NONE.

OCT 10