Small Craft Advisory 560, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT MON JUN 26 2006

.DISCUSSION...

12Z WATER VAPOR IMAGERY SHOWS AN UPPER LOW OVER THE NORTHERN GULF OF ALAKSA WITH A STRONG
VORTMAX OVER THE YUKON TERRITORY THAT IS IN THE PROCESS OF SPINNING UP INTO A SEPERATE
LOW WITH A DEFORMATION BAND THAT STRETCHES SW ALL THE WAY INTO THE SUBTROPICS. ANOTHER
COMPLEX UPPER LOW SYSTEM IS SITUATED OVER THE WESTERN BERING SEA WHILE AT THE SURFACE A
DECAYING FRONTAL BOUNDARY/BAROCLINIC IS STRETCHED ACROSS THE EASTERN BERING AND ACROSS
THE EASTERN ALEUTIANS. ABUNDANT MOISTURE IS DEPICTED ACROSS MUCH OF THE STATE IN THE WV
IMAGERY AND WIDESPREAD SHOWERS HAVE BEEN OCCURRING IN THE CYCLONIC FLOW THROUGH THE
OVERNIGHT HOURS ROUGHLY ALONG A NORTH-SOUTH ORIENTED LOW-LEVEL THETA-E RIDGE AXIS THAT
RUNS ACROSS THE EASTERN HALF OF THE STATE. MEANWHILE IN THE WEST...THE LOW LEVEL MOISTURE
AND CLEARING SKIES BROUGHT FOG TO LOCATIONS ALONG THE KUSKOKWIM VALLEY AND AROUND BRISTOL
BAY.

IN THE SHORT-TERM...EXPECT A BROAD AREA OF SHOWERS TO CONTINUE TO DROP SOUTH ACROSS
SOUTHCENTRAL AND THE COPPER RIVER BASIN THROUGH THE DAY AS THE AIRMASS ACROSS THE REGION
REMAINS MOIST AND RELATIVELY UNSTABLE WITH WEAK DIVERGENCE ALOFT AND A SHORTWAVE ROTATES
AROUND THE UPPER LOW OVER THE YUKON LATER IN THE DAY. THUNDERSTORM ACTIVITY SHOULD BE
MINIMAL THOUGH...AS THE ENHANCED CLOUD COVER SHOULD PRECLUDE DEEP CONVECTION. LOOK FOR
DRIER WEATHER ACROSS WESTERN ALASKA AS AN ADVANCING RIDGE SHOULD CAP MOST SHOWER ACTIVITY
WITH THE EXCEPTION OF THE EASTERN KUSKOKWIM VALLEY. THE WEAKENING FRONT MOVES ONSHORE
TONIGHT...HOWEVER IT PACKS LITTLE PUNCH AT THIS POINT AND THIS IS REFLECTED IN THE
CHANCE/SLIGHT CHANCE POPS FOR THE COASTAL ZONES.

MODELS ARE IN GOOD AGREEMENT SHOWING A MORE PROGRESSIVE PATTERN EVOLVING OVER THE NEXT
SEVERAL DAYS. AS MENTIONED IN THE PREVIOUS DISCUSSION...THE UPPER LOW THAT HAS BEEN
LINGERING OVER THE NORTHERN GULF OVER THE LAST SEVERAL DAYS AND HAS SERVED AS THE MAJOR
MOISTURE SOURCE FOR THE PREVIOUS DAYS CONVECTION WILL BE PUSHED OUT OF THE GULF AND INTO
THE PANHANDLE BY TUESDAY...ALLOWING FOR SOUTHCENTRAL TO BEGIN DRYING OUT. THE UPPER RIDGE
ALIGNS ITSELF FROM SW/NE ALONG THE AXIS OF THE AK PEN ON WEDNESDAY AND WESTERLY ZONAL
FLOW SETS UP TO THE NORTH. THIS SHOULD BRING ABOUT A DRIER PATTERN FOR MUCH OF THE
FORECAST AREA WITH THE EXCEPTION OF THE ALEUTIANS...WHERE ANOTHER LOW/FRONTAL COMPLEX
BRINGS RAIN AND GALES TO THE WESTERN AND CENTRAL PORTIONS OF THE CHAIN WEDNESDAY.

IN THE EXTENDED...A DRIER PATTERN THAN INDICATED YESTERDAY FOR MUCH OF THE MAINLAND AS
INDICATED BY THE GFS AS WELL AS THE ECMWF MODELS. RIDGING ACROSS SOUTHERN ALASKA KEEPS
THINGS DRY FOR THE MAINLAND AS THE UPPER/SURFACE LOW MOVES EAST ACROSS THE ALEUTIANS AND
DROPS INTO THE WESTERN GULF BY THE WEEKEND...LEAVING MUCH OF THE MAINLAND FORECAST AREA
IN THE CLEAR. A FEW SHOWERS MAY BE POSSIBLE THURSDAY NIGHT INTO FRIDAY ACROSS WESTERN
ALASKA AS A SHORTWAVE EMBEDDED IN THE ZONAL FLOW ALOFT IS PROGGED TO BRUSH THE AREA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 180 185
FIRE WEATHER...NONE

WOOD JUN 06