Gale Warning 448, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
545 AM AKDT WED JUN 16 2010

.UPPER LEVEL ANALYSIS...
A BROAD REGION OF LOW PRESSURE LINGERS OVER THE NORTH CENTRAL
BERING SEA THIS MORNING...WITH SEVERAL SHORTWAVES WRAPPING AROUND THE
SOUTHERN AND EASTERN FLANKS OF THE SYSTEM. THE LATTER SHORTWAVE ARCS
EAST ACROSS WESTERN ALASKA AND CURVES SOUTHWARD OVER SOUTHCENTRAL.
THIS SYSTEM IS EMBEDDED IN A RELATIVELY SMALL LONGWAVE TROUGH THAT
ENCOMPASSES THE BERING SEA AND MAINLAND ALASKA. UPPER LEVEL RIDGING
PROTRUDES NORTHWARD ACROSS THE PANHANDLE AND THE YUKON TERRITORY.

.SURFACE ANALYSIS...
A 992 MB BARBELL LOW IS STACKED UNDER ITS UPPER LEVEL COUNTERPART IN
THE NORTH BERING SEA. WINDS ON THE SOUTHERN PERIPHERY OF THIS SYSTEM
ARE PRODUCING GALE FORCE WINDS OVER THE ALEUTIANS ISLANDS AND THE
AKPEN. A WEAK SHORTWAVE IS WRAPPING NORTHEASTWARD OVER THE WESTERN
GULF AND KODIAK ISLAND. ANOTHER SHORTWAVE IS DISSIPATING OVER THE
NORTH GULF COAST. THE THERMAL TROUGH RESIDES IN THE NORTHEAST CORNER
OF THE STATE.

.MODEL DISCUSSION...
MODELS ARE IN AGREEMENT ON THE GENERAL POSITION AND STRUCTURE OF THE
MAIN WEATHER SYSTEMS...THOUGH NUMEROUS SUB-SYNOPTIC INCONSISTENCIES
ARISE RATHER QUICKLY BETWEEN THE MODELS. THE BIGGEST PROBLEM FOR THE
MODELS IN THE NEAR SHORT-TERM IS THE EVOLUTION OF THE BERING SEA LOW
AS IT CONSOLIDATES INTO A SINGLE CORE AND MEANDERS AROUND THE
NORTHERN AND EASTERN BERING DURING THE REMAINDER OF THE WEEK.
SUBSEQUENT TIMING ISSUES DEVELOP WITH THE NUMEROUS WEAK SHORTWAVES
THAT TRAIN ALONG THE SOUTHERN SIDE OF THE LOW AND ACROSS SOUTHERN
ALASKA.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...BROAD SOUTHWESTERLY FLOW WITH EMBEDDED
SHORTWAVES WILL CONTINUE TO BE THE PRIMARY WEATHER MAKER FOR THE
REGION FOR THE NEXT FEW DAYS. THE REMNANTS OF A FRONT THAT IMPACTED
SOUTHCENTRAL YESTERDAY IS NOW LIMITED TO THE IMMEDIATE COAST NEAR
CORDOVA AND EASTERN PRINCE WILLIAM SOUND. THE ANCHORAGE BOWL AREA IS
BETWEEN WAVES OF PRECIP THIS MORNING...BUT WILL REMAIN CLOUDY WITH
GUSTY SOUTHERLY WINDS EVEN WHEN RAIN IS NOT FALLING. A WEAK WAVE IN
CENTRAL COOK INLET WILL LIKELY BRING A BRIEF PERIOD OF RAIN LATE THIS
MORNING BEFORE A MORE SUBSTANTIAL WAVE IMPACTS SOUTHCENTRAL TONIGHT.
WITH THIS STRONGER WAVE THE ANCHORAGE AREA SHOULD BE DOWNSLOPED
INITIALLY...BUT WILL SEE RAIN DEVELOP BY MIDNIGHT TONIGHT.

.SOUTHWEST ALASKA...THE VIGOROUS SHORTWAVE THAT WILL IMPACT
SOUTHCENTRAL TONIGHT IS CURRENTLY MOVING ONSHORE THE SOUTHWEST COAST.
EXPECT RAIN TO DEVELOP EARLY THIS MORNING NEAR BETHEL AND KING
SALMON...SPREADING INLAND THROUGHOUT THE DAY. STEADY RAIN WILL GIVE
WAY TO SHOWERS THIS EVENING AT MOST LOCATIONS...WHICH WILL PERSIST
FOR SEVERAL DAYS ALONG WITH GUSTY WINDS. ONSHORE FLOW WILL ALSO BRING
THE STRONG POSSIBILITY OF FOG SPREADING TO COASTAL SITES AND POSSIBLY
FURTHER INLAND TONIGHT.

.BERING SEA AND ALEUTIANS...LOW PRESSURE CURRENTLY WEST OF THE
PRIBILOF ISLANDS WILL MOVE SLOWLY NORTHWARD OVER THE NEXT FEW DAYS.
ISOLATED TO SCATTERED SHOWERS WILL PERSIST ACROSS THE REGION WHILE
THE LONGWAVE TROUGH REMAINS ENTRENCHED OVER THE BERING. STRONG
SOUTHWEST WINDS WITH GUSTS TO NEAR 40 MPH WILL CONTINUE OVER THE
EASTERN BERING THROUGH TONIGHT BEFORE SLOWLY DIMINISHING ON THURSDAY.

.LONG TERM FORECAST...THE ACTIVE PATTERN FOR MAINLAND ALASKA WILL
GIVE WAY TO A DRYING TREND BY THE END OF THE WEEK AS THE PRIMARY
STORM TRACK SHIFTS TO THE WESTERN BERING FOR THE START OF THE
WEEKEND. EXPECT TEMPERATURES TO REBOUND TO NEAR NORMAL BY THE END OF
THE WEEK...WITH A POSSIBLE RETURN TO AN AFTERNOON/EVENING CONVECTION
PATTERN FOR THE WEEKEND OVER MAINLAND ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 155 160 170 172
FIRE WEATHER...NONE.

KS/AMD JUN 10