Small Craft Advisory 532, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
100 PM AKDT SAT JUL 5 2008

.MODEL DISCUSSION...
MODELS IN GOOD AGREEMENT IN THE SHORT TERM. MAIN ISSUE IS THE MID
RANGE. GFS HAS BEEN VERY CONSISTENT BUT IS THE OUTLIER. SINCE THIS IS
TYPICALLY ITS GLITCH PERIOD WILL LEAN MORE TOWARD THE EC FOR NOW FOR
THE UPCOMING SIBERIAN LOW THAT DROPS INTO THE BERING.

.ANALYSIS AND UPPER LEVELS...
A LOW SOUTH OF SAND POINT CONTINUES TO BRING MORE RAIN TO KODIAK AND
INTO THE AK PENN. A BROAD AREA OF LOW PRESSURE ACROSS THE GULF OF
ALASKA WILL PERSIST THROUGH THE WEEKEND. FOR NOW ITS BIGGEST IMPACT
IS THE SHORTWAVES CIRCULATING AROUND IT. ONE IS CURRENTLY OVER THE
SUSITNA VALLEY AND MOVING WEST BRINGING SHOWERS AND INSTABILITY IN
ITS WAKE AS IT CLEARS OUT THIS AFTERNOON. ANOTHER WAVE WILL MOVE IN
FROM THE YUKON THIS AFTERNOON AND RIDE ALONG THE THERMAL TROUGH THAT
IS SETTING UP ALONG THE ALASKA RANGE. ISOLATED THUNDERSTORMS HAVE
ALREADY BEGUN TO POP ALONG THE ALASKA RANGE NORTH OF THE COPPER RIVER
VALLEY AND INTO THE Y-K DELTA NEAR THE KUSKOKWIM BAY.

.SHORT TERM FORECAST...
SOUTHCENTRAL AND SOUTHWEST ALASKA...
NUMEROUS THUNDERSTORMS ARE EXPECTED FROM THE COPPER RIVER
BASIN...STRETCHING ALONG THE ALASKA RANGE TO THE KUSKOKWIM DELTA AND
AS FAR SOUTH AS THE ANCHORAGE BOWL. STABILITY INDICES ARE CERTAINLY
SUFFICIENT FOR STRONG THUNDERSTORMS...WITH A LACK OF STRONG SHEAR THE
ONLY DETERRING FACTOR TO A FEW POTENTIALLY SEVERE STORMS. CAPES ARE
FORECAST UP TO 1500 J/KG IN THE KUSKOKWIM AND SUSITNA VALLEYS WITH LI
NEAR -7 C. YET ANOTHER WAVE TAKES A SIMILAR PATH ON SUNDAY...BUT
WITH PLENTY OF CONVECTIVE DEBRIS HANGING AROUND...A MORE STABLE,
STRATIFORM RAIN EVENT MAY TAKE SHAPE FOR MUCH OF SOUTHCENTRAL. FEWER
THUNDERSTORMS ON SUNDAY WILL BE DUE TO THE FACT THAT THE THERMAL
TROUGH WILL BE PUSHED FURTHER NORTH. THE EXCEPTION WILL BE FOUND IN
SOUTHWEST AK FROM THE KUSKOKWIM VALLEY TO THE Y-K DELTA AND BRISTOL
BAY WHERE THE FRONT WILL REMAIN FIRMLY ENTRENCHED FOR ONE MORE DAY.

BERING SEA...NORTHERLY FLOW WILL DOMINATE THE BERING BEHIND THE
DEPARTING LOW. SHOWERS WILL CONTINUE ALONG THE BERING SIDE OF THE
AKPENN AND EASTERN ALEUTIANS WITH THE EVER PRESENT FOG MAINTAINING
ITS GRASP ON THE AREA. HIGH PRESSURE IN THE WESTERN BERING BUILDS
INTO THE CENTRAL BERING AHEAD OF A STRONG FRONT POISED TO DROP SOUTH
ON TUESDAY.

EXTENDED...THE LOW IN THE SOUTHERN GULF BECOMES VERTICALLY
STACKED BY MONDAY AND THUS WILL BE A SLOW MOVER. THIS MEANS PERIODIC
WAVES APPROACHING SOUTHCENTRAL FROM THE EAST PROMPTING SCATTERED TO
NUMEROUS SHOWER ACTIVITY. BY MID-WEEK...THE MAINLAND SEES RIDGING
IN-BETWEEN THE DEPARTING LOW IN THE YUKON AND A STRONG LOW DROPPING
INTO THE CENTRAL BERING. MODELS HAVE BEEN MORE CONSISTENT OVER THE
PAST COUPLE OF RUNS DROPPING THE LOW INTO THE CENTRAL BERING BRINGING
PLENTY OF RAIN...WIND AND COOLER TEMPS. QUESTIONS ARISE BY WEEKS END
AS TO IF THE LOW DROPS SOUTH OF THE ALEUTIAN CHAIN OR DRIFT EAST.

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

RW JUN 08