Gale Warning 373, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT FRI APR 23 2010

.ANALYSIS AND UPPER LEVELS...
THE LONG WAVE UPPER PATTERN IS A STABLE ONE...CONSISTING OF A BROAD
TROUGH CENTERED OVER THE SEWARD PENINSULA AND MULTIPLE SHORTWAVES
MOVING WEST TO EAST NEAR THE BASE OF THE TROUGH. HIGH PRESSURE AT THE
SURFACE IS BUILDING OVER SOUTHCENTRAL ALASKA AND THE BERING SEA WHILE
A 987 MB LOW AND ASSOCIATED FRONTAL BOUNDARY SKIMS THE CENTRAL
ALEUTIANS TODAY.

.MODEL DISCUSSION...MODELS CONTINUE TO DO A GREAT JOB UNTIL THE LOW
SOUTH OF THE CHAIN ENTERS THE GULF LATER IN THE WEEKEND. WE CONTINUE
TO LEAN TOWARD THE ECMWF THAT IS THE SLOWEST AND MOST WESTWARD TRACK
OF THE LOW. THE GFS HAS BEEN TRENDING SLOWLY TOWARD THIS SOLUTION. IN
THE SHORT TERM...THE NAM IS THE PREFERRED MODEL BECAUSE OF ITS
SUPERIOR RESOLUTION AND DEPICTION OF THE SMALL SCALE FEATURES.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...HIGH PRESSURE CENTERED OVER THE COPPER RIVER BASIN
WHILE A WEAK UPPER TROUGH MOVES NORTH ALONG THE ALASKA RANGE. THE
UPPER LEVELS ARE RELATIVELY MOIST ALTHOUGH DRY AIR AT THE SURFACE IS
RESULTING IN FAIR SKIES AROUND MOST OF THE REGION. THE LOWER LEVELS
ARE WARMING UP QUICKLY EARLY THIS AFTERNOON WHILE THE UPPER LEVELS
ARE STILL PRETTY COOL...GIVING US AN UNSTABLE PROFILE. SHOWERS ARE
DEVELOPING FROM THE WESTERN KENAI UP TO THE SUSITNA VALLEY ALTHOUGH
THE DRY AIR NEAR THE SURFACE IS EVAPORATING MOST OF THE MOISTURE
BEFORE IT REACHES THE GROUND. SHOWER ACTIVITY WILL DIMINISH SATURDAY
AS MOSTLY CLEAR SKIES PREVAIL UNTIL THE FRONT IN THE GULF APPROACHES
SUNDAY AFTERNOON. THIS FRONT WILL BRING PLENTY OF MOISTURE TO THE
COAST BUT RAIN WILL HAVE A DIFFICULT TIME MAKING IT INLAND.
INLAND...EXPECT MOSTLY CLOUDY SKIES TO PREVAIL MONDAY THROUGH
WEDNESDAY NEXT WEEK.

.SOUTHWEST...
CLOUDY AND COOL WEATHER CONTINUES OUT WEST UNDER THE UPPER LEVEL
TROUGH CENTERED OVER THE KUSKOKWIM VALLEY. ONSHORE FLOW IS USHERING
THE MOISTURE INLAND RESULTING IN WIDESPREAD LOW CEILINGS AND PERIODS
OF LIGHT SNOW. FLOW WILL REVERSE OVER THE NEXT 24 HOURS AS HIGH
PRESSURE BUILDS TO THE NORTH. THE CALM WINDS AND BUILDING HIGH
PRESSURE COULD LEAD TO WIDESPREAD FOG SATURDAY MORNING. THE
ATMOSPHERE BECOMES A LITTLE BIT MORE UNSTABLE EARLY NEXT WEEK SO LOW
TOP AFTERNOON AND EVENING CONVECTIVE ACTIVITY ARE POSSIBLE THROUGH
MID WEEK AS TEMPERATURES WARM UP TO ABOVE CLIMATOLOGICAL AVERAGES.

.BERING SEA/ALEUTIANS...HIGH PRESSURE BUILDING WILL PROVIDE FAIR
WEATHER FOR MUCH OF THE BERING SEA. THE LOW MOVING JUST SOUTH OF THE
CHAIN WILL BRING GALE FORCE EASTERLY WINDS TO THE CENTRAL ALEUTIANS
TONIGHT BEFORE DROPPING SOUTH AWAY FROM OUR AREA OF RESPONSIBILITY.
HIGH PRESSURE STAYS IN CONTROL WITH BROAD EAST TO NORTHEASTERLY FLOW
THROUGH EARLY NEXT WEEK.

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

AB APR 10