Small Craft Advisory 825, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
1150 AM ADT THU OCT 13 2005

.DISCUSSION...
ANALYSIS - A WEAKENING MAJOR UPPER LOW IS OVER THE SEWARD PENINSULA
THIS MORNING AND IS CONNECTED TO THE DEEP COLD ANCHOR LOW ON THE
RUSSIAN SIDE OF THE POLE. TWO UPPER TROUGHS EXTEND FROM THIS LOW: THE
FIRST THROUGH SW ALASKA THEN ALONG 155W AT 12Z AND THE SECOND OVER
THE WESTERN BERING SEA. 500 MB TEMPERATURES ARE LOOKING MORE LIKE
WINTER WITH -35C IN THE UPPER LOW CENTER AND INTO THE -30S IN THE
TROUGHS. A 987 MB SURFACE LOW REMAINS NEAR MIDDLETON ISLAND THIS
MORNING AND A LOW COMPLEX OVER THE BERING STRAIT AND WESTERN BERING
IS DRIVING SOME MODERATE WESTERLIES OVER THE MARINE AREAS. SATELLITE
IMAGERY SHOWS A DEVELOPING LOW AROUND 40/175E WHICH THE CANADIANS
SHOWED AT 991 MB 12Z. THE JET IS REALLY SET UP FOR THIS ONE WITH AND
EXIT / ENTRANCE COUPLET OVER THE DEVELOPING LOW. THIS 250 MB JET GOES
ALL THE WAY FROM THE TROPICS WELL SOUTH OF THE WESTERN ALEUTIANS ALL
THE WAY TO MONTANA.

AER FORECASTS - FIRST, WITH SW FLOW ALOFT OVER THE AREA AND A
RESIDUAL SURFACE LOW REMAINING IN THE NORTHERN GULF WE HAVE TO KEEP
MENTIONING SHOWERS. WITH THE COLD AIR ALOFT ANY PRECIP THAT REACHES
THE GROUND WILL HAVE FLAKES IN THE VERY SHORT TERM. NEXT THERE IS A
GOOD DEAL OF CLEARING ON THE WAY BEHIND THE UPPER TROUGH. THIS TROUGH
WILL PASS THEN DISSIPATE INTO THE NORTH THIS EVENING. LOOK FOR GOOD
RADIATION COOLING TONIGHT WHICH WILL CAUSE EITHER FOG OR HEAVY FROST.
FINALLY IT WILL TAKE SOMETIME BEFORE THE MAINLAND SOUTH CENTRAL FEELS
THE AFFECTS OF THE STORM DEVELOPING TO THE SW. WE FIGURE THAT THE
ONSHORE FLOW HITS KODIAK PRETTY HARD FRI NIGHT WITH VERY STRONG
OUTFLOW WINDS FOR ALMOST ALL MARINE AREAS BY SATURDAY INCLUDING SOME
STORM WARNINGS FRI NIGHT. THERE IS MODERATE TO STRONG WARM AIR
ADVECTION AHEAD OF THIS SYSTEM SO DONT PUT ON YOUR SKIS JUST YET
UNLESS YOU LIVE IN THE MOUNTAINS. THE MODELS ARE IN GOOD AGREEMENT
AND TRACK THE LOW INTO THE EASTERN GULF. THAT PATTERN FOR A MEDIUM
RANGE PROJECTION DOES NOT INDICATE SIGNIFICANT SNOW ANYWHERE EXCEPT
HIGHER ELEVATIONS.

ALU FORECASTS - THE SERIES OF SURFACE LOWS FROM THE BERING INTO THE
CENTRAL INTERIOR IS CAUSING SOME SNOW TODAY BUT NOTICE THAT CLEARING
HAS BEGUN FROM THE EASTERN BERING SEA ASSOCIATED WITH THE UPPER RIDGE
IN BETWEEN THE TROUGHS. AS THE SECOND UPPER TROUGH PROGRESSES A
SURFACE LOW CONSOLIDATES IN THE CENTRAL BERING BUT THEN IS
IMMEDIATELY ABSORBED INTO THE DEVELOPING STORM TO THE SOUTH. ALL
MODELS FORECAST THIS. LOOK FOR THE STORM TO BOMB INTO THE 960S BY 12Z
SAT MORNING BUT THE WIND WILL ONLY BE MODERATE IN THE EASTERN
ALEUTIANS AND AKPENN UNTIL FRI AFTERNOON. AS THE STORM CENTER CROSSES

50N SOUTH OF UNIMAK ISLAND AT 00Z SAT THE WIND WILL RAPIDLY BACK AND
INCREASE FRI EVENING. IT LOOKS LIKE THE OCCLUDED FRONT WILL BE TOO
FAR FROM UNALASKA TO GET TO 100 MPH THERE AT THIS TIME BUT WE WILL BE
ISSUING A WATCH WITH THE AFTERNOON PACKAGE FOR THE GARDEN VARIETY
HURRICANE FORCE WINDS THERE. FOR COLD BAY THE DIRECTION IS OFF FOR
THE SUPER STRONG WIND. THE HIGH TO THE SOUTH WILL BUILD RAPIDLY
BEHIND THIS STORM SAT NIGHT BUT THE GFS-190 BRINGS ANOTHER STORM
FORCE LOW INTO THE NORTHERN BERING SUN NIGHT FROM OFF SIBERIA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM 170. GALES 155 171 172 175.
FIRE WEATHER...NONE.

JC OCT 05