Gale Warning 577, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
150 PM AKDT TUE AUG 31 2010

.ANALYSIS AND UPPER LEVELS...
A BROAD UPPER LEVEL TROUGH IS IN PLACE OVER MAINLAND ALASKA AND THE
YUKON TERRITORY. THE TROUGH IS POSITIVELY TILTED WITH AXIS FROM THE
CENTRAL INTERIOR TO BRISTOL BAY. THE SUBTROPICAL JET IS FLOWING
AROUND THE BASE NEAR 50N AT ABOUT 140 KTS. SEVERAL SHORT WAVES ARE
EMBEDDED IN THE CYCLONIC CIRCULATION...THE MOST POTENT ARE LOCATED
JUST SOUTH OF THE KENAI PENINSULA AND A SECOND IS NEAR THE CENTRAL TO
EASTERN ALEUTIANS.

VERY FEW FEATURES TO DISCUSS AT THE SURFACE...A BROAD AND WEAK AREA
OF LOW PRESSURE PERSISTS OVER THE NORTHERN GULF OF ALASKA THAT
EXTENDS OVER SOUTHCENTRAL INTERIOR. HIGH PRESSURE IS BUILDING AT THE
SURFACE ON THE BACKSIDE OF THE UPPER TROUGH OVER THE WESTERN BERING
SEA.

.MODEL DISCUSSION...
MODELS ARE IN EXCELLENT AGREEMENT AND CONSISTENT FROM RUN TO RUN.
FORECAST CONFIDENCE IS HIGHER THAN AVERAGE.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...SIMILAR TO YESTERDAY...SHORTWAVE MOVING OFF
THE ALASKA PENINSULA AND OVER THE NORTHWESTERN GULF. STEADY RAIN
ASSOCIATED WITH THIS FEATURE IS LIMITED TO THE COASTAL WATERS WHILE
SHOWERS PREVAIL OVER MOST OF SOUTHCENTRAL AND THE INTERIOR. MORNING
SOUNDING INDICATING A MORE STABLE AIRMASS OVER ANCHORAGE THAN
YESTERDAY. STILL EXPECTING SOME SHOWER ACTIVITY TO DEVELOP AGAIN THIS
AFTERNOON DESPITE THE UNFAVORABLE PROFILE. ABUNDANT LOW LEVEL
MOISTURE AND BROAD CYCLONIC CIRCULATION SHOULD BE ENOUGH TO INITIATE
AT LEAST SCATTERED ACTIVITY.

WORTH WATCHING IS THE VERY WEAK STORM MOTION. ANY SHOWERS THAT
DEVELOP HAVE THE POTENTIAL TO DROP A QUARTER INCH OR MORE OF RAIN DUE
TO THE WEAK FLOW AND HIGH PRECIPITABLE WATER.

AFTER THIS LAST SHORTWAVE DEPARTS THE AREA...HIGH PRESSURE BUILDS
ACROSS SOUTHCENTRAL. SOME CLOUDS MAY LINGER NEAR THE MOUNTAINS IN THE
MORNING BUT ANTICIPATING A PLEASANT DAY OTHERWISE WEDNESDAY. THE HIGH
PRESSURE QUICKLY BREAKS DOWN AS SOUTHWESTERLY FLOW SPREAD MOISTURE
BACK OVER THE REGION THURSDAY NIGHT AND FRIDAY WITH WIDESPREAD RAIN
BECOMING LIKELY BY THE WEEKEND.

.SOUTHWEST ALASKA...MOIST WEST TO NORTHWESTERLY FLOW CONTINUES TO
SPREAD MARGINAL CEILINGS AND AREAS OF FOG ACROSS MOST OF SOUTHWEST
ALASKA. HIGH PRESSURE BUILDS EARLY WEDNESDAY MORNING BUT IS SQUEEZED
TO THE EAST BY THURSDAY WHEN A FRONTAL BOUNDARY APPROACHES FROM THE
NORTHERN BERING SEA. RAIN SPREADS ACROSS THE KUSKOKWIM DELTA EARLY
THURSDAY MORNING. THE MAIN WARM FRONT WHICH WILL TAP INTO SOME DEEPER
SUBTROPICAL MOISTURE APPROACHES THE COAST FRIDAY.

.BERING SEA AND ALEUTIANS...THE TROUGH AXIS WILL EVENTUALLY SET UP
BACK OVER THE BERING SEA OVER THE NEXT COUPLE OF DAYS. SURFACE HIGH
PRESSURE WILL GIVE WAY TO A SERIES OF FRONTS. THE WINDS ASSOCIATED
WITH THESE FRONTAL BOUNDARIES WILL BE MOSTLY SMALL CRAFT WITH GALES
POSSIBLE RIGHT ALONG AND AHEAD OF THE FRONT.

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

AB AUG 10