Small Craft Advisory 593, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM AKDT WED JUL 29 2009

.ANALYSIS AND UPPER LEVELS...THE LOW MOVING TROUGH BRISTOL BAY LAST
NIGHT INCREASED IN STRENGTH MORE THAN EXPECTED AND HAS BROUGHT STRONG
WINDS TO NUMEROUS AREAS IN SOUTHWEST ALASKA AND STEADY PRECIPITATION
OVER MUCH OF SOUTH CENTRAL ALASKA WHICH HAS BEEN IN THE FRONTAL
BOUNDARY ASSOCIATED WITH THIS LOW FOR THE PAST DAY. UPPER LEVEL FLOW
REMAINS STRONG FROM THE SOUTH OVER SOUTH CENTRAL ALASKA AND THEN
WEAKENS OVER SOUTHWEST ALASKA TOWARD THE UPPER LEVEL TROUGH AXIS
WHICH IS LOCATED NEAR THE 170W PARALLEL. NUMEROUS SHORT WAVES WILL
DEVELOP AROUND THIS UPPER LOW COMPLEX OVER THE NEXT FEW DAYS AND GIVE
CONTINUED CHANCES FOR PRECIPITATION.
THE SURFACE LOW CENTER IS APPROACHING THE HOOPER BAY AREA AND WILL
SLOWLY WEAKEN AS IT MOVES NEAR THE BERING STRAIT THURSDAY MORNING.

.SHORT TERM FORECAST...THE WHOLE STORM SYSTEM IS WEAKENING BUT STILL
HAS THE POTENTIAL TO PRODUCE GUSTY WINDS...ESPECIALLY NEAR CHANNELED
TERRAIN. THE KUSKOKWIM DELTA REGION WILL SEE A BIT OF PRECIPITATION
AS WELL AS GUSTY WINDS AS THE LOW MOVES OUT OF THE AREA TO THE
NORTHWEST.
A SIGNIFICANT SHORT WAVE IS SETTING UP SOUTH OF KODIAK ISLAND EARLY
THURSDAY WHICH WILL BE STRONG ENOUGH TO DEVELOP A LOW IN THE WESTERN
GULF TOMORROW AFTERNOON. THIS LOW WILL MOVE ON SHORE OVER THE KENAI
PENINSULA THURSDAY EVENING AND THEM MOVE INTO THE SUSITNA VALLEY BY
FRIDAY MORNING. EXPECT ANOTHER SHOT OF RAIN IN THOSE AREAS AS THIS
WAVE PASSES THROUGH THE AREA.
THE EASTERN SECTION OF THE COPPER RIVER BASIN LOOKS TO REMAIN DRY FOR
THE MOST PART WITH ONLY A SLIGHT CHANCE OF RAIN THURSDAY NIGHT OVER
THE CHAKINA FIRE NEAR MCCARTHY.

.MODEL DISCUSSION...MOST MODEL DIFFERENCES ARE MINOR THROUGH THE MID
TERM OF THE FORECAST. A NAM/GFS LOOKS GOOD IN THE SHORT
TERM...TRANSITIONING INTO A GFS/ECMWF BLEND IN THE MEDIUM RANGE.

.LONG TERM FORECAST...THE UPPER LEVEL PATTERN REMAINS NEARLY
UNCHANGED THROUGH THE WEEKEND. THIS WILL KEEP MOSTLY CLOUDY
CONDITIONS OVER THE AREA WITH PERIODS OF RAIN ASSOCIATED WITH SHORT
WAVES MOVING THROUGH THE AREA. THE EASTERN PART OF THE FORECAST AREA
MAY GET A SHORT BREAK IN THE CLOUDS EARLY IN THE WEEKEND AS A SURFACE
RIDGE LOOKS TO BUILD INTO SOUTH CENTRAL FRIDAY NIGHT BEFORE BREAKING
DOWN AGAIN SATURDAY NIGHT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FLOOD WARNING 125. FLOOD ADVISORY 121.
MARINE...NONE.
FIRE WEATHER...NONE.

JUL 09