Small Craft Advisory 558, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT SAT JUL 18 2009

.ANALYSIS AND UPPER LEVELS...
ALOFT...LARGE LOW NEAR SAINT MATTHEW ISLAND...WITH A BROAD TROUGH
ENCOMPASSING THE AK MAINLAND AND BERING SEA. THE TROUGH AXIS EXTENDS
DOWN THROUGH THE EASTERN ALEUTIANS.

AT THE SURFACE...A VERTICALLY STACKED SURFACE LOW NEAR SAINT MATTHEW
ISLAND...WITH AN ASSOCIATED FRONT STRETCHING ACROSS SOUTHWEST AK AND
INTO THE NORTHERN GULF OF ALASKA. THIS LOW WILL WEAKEN WHILE THE
ASSOCIATED FRONT MOVES NORTHWARD INTO SOUTHCENTRAL AK THROUGH THE END
OF THE WEEKEND.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT THROUGH THE WEEKEND. BY MONDAY
DIFFERENCES IN DETAILS BEGIN TO ARISE. PARTICULARLY WITH REGARDS TO
THE LOW FORMING NEAR THE BARREN ISLANDS...AS WELL AS THE EVOLUTION OF
THE NEXT LOW AFFECTING THE BERING AND ALEUTIANS. NAM STILL PREFERRED
OVER THE BARRENS DUE TO BETTER RESOLUTION. MODELS STAY IN GOOD
AGREEMENT THROUGH MIDWEEK STALLING THE BERING LOW IN OR AROUND
BRISTOL BAY.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
VARIOUS SYSTEMS WILL BE MOVING INTO SOUTHCENTRAL OVER THE NEXT
SEVERAL DAYS...BRINGING PROGRESSIVELY INCREASING CHANCES OF RAIN
INLAND. RAIN THIS AFTERNOON AND TONIGHT WILL REMAIN CONFINED MAINLY
TO COASTAL LOCATIONS...WITH GOOD DOWNSLOPING INHIBITING PRECIP FOR
THE MATSU VALLEY...ANCHORAGE BOWL...AND WESTERN KENAI. BY TOMORROW
AFTERNOON AND MONDAY DOWNSLOPING SHOULD BE NEGATED...WITH SHOWERS
BECOMING POSSIBLE ACROSS SOUTHCENTRAL. WINDS ALONG COASTAL LOCATIONS
AND AREAS OF ENHANCED AND CHANNELED TERRAIN WILL BE INCREASING
TOMORROW INTO MONDAY AS ANOTHER FRONT AND LOW NEAR KODIAK IMPACT THE
AREA. EXPECTING COOLER AND WETTER WEATHER TO CONTINUE WELL INTO THE
COMING WEEK.

.SOUTHWEST...
COOL AND WET WEATHER WILL CONTINUE THROUGH EARLY MONDAY AS THE FRONT
AFFECTS THE AREA. MOST OF MONDAY SHOULD BE FAIRLY QUIET BEFORE THE
NEXT SYSTEM BEGINS TO IMPACT THE REGION ON TUESDAY.

.BERING SEA AND ALEUTIANS...
SHOWERS WILL PERSIST ACROSS THE ISLANDS TODAY AND EARLY TOMORROW
BEFORE THE NEXT DEVELOPING LOW BEGINS IMPACTING THE REGION. RAIN AND
WIND WILL BE ON THE INCREASE ONCE AGAIN LATE SUNDAY THROUGH
TUESDAY...ALTHOUGH AT THIS TIME IT APPEARS THE STRONGEST WINDS WITH
THIS LOW WILL REMAIN SOUTH OF THE ALEUTIANS.

.LONG TERM FORECAST...
AS MENTIONED IN THE PREVIOUS DISCUSSION...LITTLE CHANGE TO THE
EVOLVING PATTERN EXPECTED THROUGH THE COMING WEEK. THE PATTERN WILL
BE CHARACTERIZED BY A LOW COMPLEX OVER THE EASTERN BERING...WITH
UNSETTLED WEATHER IMPACTING THE SOUTHERN AK MAINLAND AS WELL. EXPECT
TEMPERATURES ACROSS THE AREA TO REMAIN NEAR NORMAL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...NONE
FIRE WEATHER...NONE

NRH JUL 09