Small Craft Advisory 802, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT SUN OCT 13 2013

.ANALYSIS AND UPPER LEVELS...
THE PROGRESSIVE LONGWAVE PATTERN CONTINUES ACROSS ALASKA...WITH ONE
LONGWAVE TROUGH/VERTICALLY STACKED LOW OVER THE FAR EASTERN BERING
SEA AND ANOTHER TROUGH/LOW OVER THE KAMCHATKA PENINSULA TODAY. THE
EASTERN BERING LOW WILL WEAKEN AS IT SWINGS NORTHWARD OVER THE
MAINLAND TONIGHT. BRIEF RIDGING WILL PUSH NORTHWARD BEFORE THE NEXT
LOW MOVES EASTWARD ACROSS THE ALEUTIANS/BERING SEA THROUGH THE EARLY
PART OF THE WEEK. THE SURFACE FRONT IS JUST NORTH OF KENAI THIS
AFTERNOON...THEREFORE GUSTY WINDS CONTINUE AHEAD OF THE FRONT THROUGH
TURNAGAIN ARM...KNIK RIVER VALLEY...AND ALONG THE NORTH GULF COAST AS
A BARRIER JET.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT TO START OUT...HOWEVER THERE ARE SOME
DIFFERENCES TOWARD THE END OF THE SHORT TERM. AS THE NEXT LOW MOVES
ACROSS THE BERING SEA EARLY IN THE WEEK...THE MODELS HAVE COME INTO
MUCH BETTER AGREEMENT THAN THEY WERE YESTERDAY WITH THE TRACK OF THAT
LOW. AT THIS POINT THE NAM IS THE MAIN OUTLIER...WITH THE ECMWF AND
GFS IN VERY GOOD AGREEMENT. DIFFERENCES INCREASE TOWARD WEDNESDAY AND
WEDNESDAY NIGHT HOWEVER. THE GFS IS THE PREFERRED MODEL OVERALL FOR
THE SHORT TERM.

.SHORT TERM FORECAST...
SOUTH CENTRAL AK...AS THE FRONT MOVES NORTHWARD TONIGHT...GAP WINDS
WILL DIMINISH AT MOST PLACES. HOWEVER...GUSTY WINDS WILL CONTINUE
THROUGH TURNAGAIN ARM TO SOME EXTENT WITH A WEAK LOW MOVING ACROSS
THE NORTHERN GULF ON MONDAY AND THEN THE APPROACH OF THE NEXT
LOWS/FRONTS ON TUESDAY AND THURSDAY. RAIN WILL BECOME SHOWERY TONIGHT
AFTER THE FRONT PASSES THROUGH...BUT OVERALL IT WILL BE A WET AND
WINDY WEATHER PATTERN THROUGH THE WEEK.

WESTERN ALASKA/BERING SEA/ALEUTIAN ISLANDS...AFTER THIS CURRENT LOW
EXITS THE AREA...WEAK RIDGING WILL BRIEFLY PUSH NORTHWARD INTO THE
CENTRAL AND EASTERN BERING. THE NEXT LOW TO AFFECT THE AREA IS
CURRENTLY WEST OF THE ALEUTIAN ISLANDS. IT WILL MOVE EASTWARD AND
GRADUALLY WEAKEN...SWINGING A FRONT ACROSS THE BERING ON MONDAY AND
TUESDAY. THIS WILL BRING ANOTHER ROUND OF RAIN AND WIND TO THESE
LOCATIONS. YET ANOTHER LOW WILL MOVE THROUGH THE WESTERN BERING ON
WEDNESDAY...AND THE PROGRESSIVE WEATHER PATTERN CONTINUES.

.LONG TERM FORECAST...
THE GENERAL PATTERN WILL CONSIST OF THE MEAN LOW POSITION OVER THE
BERING SEA AND THE MEAN RIDGE POSITION JUST TO THE EAST OF ALASKA.
THIS WILL USHER IN A PATTERN THAT FAVORS WARM...WET...AND POSSIBLY
WINDY CONDITIONS FOR SOUTHERN ALASKA.

.HYDROLOGY...
THERE WILL BE SEVERAL ROUNDS OF RAINFALL ACROSS SOUTH CENTRAL AK
DURING THIS TIME...EACH BRINGING THE SOIL MORE AND MORE TOWARD
SATURATION. THE MAIN AREA OF CONCERN FOR THIS COMING WEEK IS THE
KENAI PENINSULA...WHERE SIGNIFICANT RAINFALL IS EXPECTED AND THE SNOW
GLACIER DAMMED LAKE IS RELEASING...ALREADY CAUSING AT LEAST NEAR
BANKFULL CONDITIONS ALONG THE KENAI RIVER. ANOTHER AREA OF CONCERN IS
THE CREEKS/STREAMS OF THE ANCHORAGE BOWL WHICH RESPOND QUICKLY TO
SIGNIFICANT RAINFALL. WE WILL BE WATCHING THESE AREAS IN THE COMING
DAYS FOR POSSIBLE FLOODING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 130 131 132 150 155 170 171 172 173 174
                      175 176 177 178 179 185.
FIRE WEATHER...NONE.

SCHRECK