Small Craft Advisory 503, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
512 AM AKDT SUN JUN 14 2015

.ANALYSIS AND UPPER LEVELS...UPPER LEVEL RIDGING AND HIGH PRESSURE
AT THE SURFACE IS FIRMLY IN CONTROL OVER MUCH OF THE STATE. THERE
IS STILL A FAIRLY COHERENT PIECE OF A 60-75 KT JET COMING OVER THE
RIDGE AND DIVING SOUTHWESTWARD INTO THE GULF OF AK. INFRARED
SATELLITE SHOWS SOME COLDER CIRRUS THROUGH THIS AREA. A FEW
RECORDS WERE BROKEN SATURDAY AS SOME RATHER IMPRESSIVE OFFSHORE
WINDS LIMITED SEA BREEZE DEVELOPMENT AT VALDEZ...SEWARD...AND
HOMER. THE RIDGE ORIENTATION WILL NOT BE QUITE AS FAVORABLE FOR
OUTFLOW WINDS TODAY...SO TYPICAL SEA BREEZES SHOULD KEEP
TEMPERATURES SEVERAL DEGREES COOLER. ON THE OTHER HAND...INLAND
LOCATIONS COULD SEE TEMPERATURES A FEW DEGREES WARMER AS THE HIGH
ASSERTS ITS DOMINANCE. OVER THE EASTERN BERING...STRATUS IS THE
RULE. IT WILL BE MORE CHALLENGING FOR IT TO MAKE A PUSH INLAND
TODAY AS SOME OFFSHORE FLOW STARTS TO GET PICK UP OVER THE LOWER
KUSKOKWIM AND BRISTOL BAY. THE CENTRAL AND WESTERN BERING REMAIN
UNDER THE INFLUENCE OF A NEARLY STATIONARY FRONT. WINDS HAVE
ALREADY STARTED TO DECREASE ALONG THIS BOUNDARY AND WILL CONTINUE
TO DO SO TODAY.

&&

.MODEL DISCUSSION...MODELS ARE HANDLING THIS BLOCKING PATTERN
QUITE WELL. IT IS TRULY THE FINER DETAILS OF THE FORECAST THAT WE
FOCUSED ON THIS MORNING AND WE RELIED ON THE HIGHER RESOLUTION
GUIDANCE FOR THE MOST PART. THE STRATUS OVER THE BERING CONTINUES
TO BE TOUGH TO PINPOINT...BUT SOME OF THE HIGHER RESOLUTION MODELS
ARE STARTING TO GET A BETTER HANDLE ON IT. NUMERICAL GUIDANCE
REMAINS SOMEWHAT FLIPPANT ON TIMING AND STRENGTH OF SEA BREEZE
DEVELOPMENT LATER TODAY...BUT THEY DO LOOK LIKELY AFTER SEEING HOW
THEY PANNED OUT ON SATURDAY. MODELS ARE STARTING TO COME INTO
BETTER AGREEMENT HANDLING THE WAVE COMING OVER THE RIDGE TUESDAY
AFTERNOON-EVENING. THE GFS HAD BEEN THE MOST BULLISH IN STRENGTH
WITH THIS FEATURE WHILE THE EC WAS THE FURTHEST TO THE WEST. THE
NAM AND THE GFS WERE USED TO HANDLE IT WITH THIS PACKAGE AND SOME
EVENING CONVECTION STILL LOOKS POSSIBLE AS IT CROSSES THE
MOUNTAINS.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2...SUN AND
MON)...HIGH PRESSURE WILL KEEP THINGS DRY AND WARM THROUGH THE
START OF THE WEEK. 850 MB TEMPERATURES OVER ANCHORAGE WERE NEAR 0
DEGREES C ON FRIDAY. YESTERDAY AFTERNOON...THEY WERE CLOSE TO 6C.
THEY SHOULD CONTINUE TO RISE WARMER AND WARMER WITH 15 C PROJECTED
FOR MONDAY. TODAY MARKS THE ALL-TIME RECORD FOR ANCHORAGE...85
DEGREES AT ANCHORAGE INTERNATIONAL SET BACK IN 1969. DO NOT THINK
WE WILL CLIMB QUITE THAT WARM...BUT INLAND AREAS WITH LESS MARINE
INFLUENCE COULD SEE HIGHS IN THE LOW 80S THE NEXT COUPLE OF DAYS.
SEA BREEZES SHOULD HELP TO KEEP COASTAL AREAS A FEW DEGREES COOLER
THAN SATURDAY. THE NEXT CHANCE FOR PRECIPITATION WILL BE FROM
CONVECTION COURTESY OF AN UPPER LEVEL WAVE DROPPING THROUGH THE
COPPER RIVER BASIN LATE TUESDAY.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2...SUN AND
MON)...THE CLOSED HIGH CURRENTLY CENTERED OVER THE EASTERN
ALEUTIANS WILL SHIFT TO THE NORTHWEST TODAY. THIS COUPLED WITH A
DEVELOPING TROUGH OF LOW PRESSURE IN THE NORTHERN GULF OF AK WILL
CREATE A FAIRLY TIGHT GRADIENT ACROSS MUCH OF THE AREA. OFFSHORE
WINDS WILL START TO DEVELOP TODAY AND SHOULD ONLY INCREASE AS WE
MOVE INTO MONDAY AS THE HIGH SLIDES FARTHER NORTH. THIS WILL CAUSE
A FEW DIFFERENT THINGS TO HAPPEN. FIRST...OFFSHORE FLOW SHOULD
START TO INCREASE TODAY. THIS SHOULD LIMIT THE INLAND PUSH OF MUCH
LOW STRATUS AND FOG. ANY SPOTS THAT DO SEE IT DEVELOP SHOULD BURN
OFF RATHER QUICKLY. SECOND...THOSE WINDS WILL BECOME GUSTY IN THE
AFTERNOON AND WILL DEFINITELY HELP TO DRY THE AIRMASS OUT VERY
QUICKLY. WINDS SHOULD DIE OFF OVERNIGHT BUT THEN RETURN EARLY
MONDAY ONCE THE SUN HEATS THINGS UP ENOUGH.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2...SUN AND
MON)...THE FRONT DRAPED ACROSS THE CENTRAL ALEUTIANS WILL CONTINUE
TO WEAKEN AND SHIFT TO THE WEST THROUGH THE DAY. A NEW AREA OF LOW
PRESSURE WILL APPROACH THE WESTERN ALEUTIANS MONDAY. IT WILL
SPREAD ANOTHER ROUND OF RAIN TO THE ISLANDS FROM ADAK TO ATTU.
SMALL CRAFT WINDS WILL ACCOMPANY THIS FRONT AS WELL.
MEANWHILE...THE CLOSED HIGH WILL SHIFT TO THE NORTHERN BERING BY
TUESDAY. THIS SHOULD ALLOW THE AREA OF LOW STRATUS AND PATCHY FOG
TO SPREAD FURTHER WESTWARD AND POSSIBLY ALLOW A REPRIEVE TO THE
EASTERN ALEUTIANS TO START NEXT WEEK.

&&

.FIRE WEATHER...HIGH PRESSURE WILL DOMINATE THE PATTERN MAKING FOR
PROGRESSIVELY WARMER AND DRIER CONDITIONS FOR JUST ABOUT ALL
AREAS THROUGH EARLY NEXT WEEK. FOR THE EAST...THE BIGGEST CONCERN
WILL BE JUST HOW DRY DO THE COPPER RIVER BASIN AND THE SUSITNA
VALLEY GET. NORTHERLY WINDS WILL BE GUSTY EACH AFTERNOON IN THESE
AREAS. SO WHILE WE MIGHT NOT REACH CRITICAL FIRE WEATHER
CRITERIA...EVERYONE SHOULD EXERCISE CAUTION WITH THESE DRY
CONDITIONS.

OUT WEST...NORTH TO NORTHEAST WINDS WILL INCREASE THROUGH THE DAY
TODAY AND PERSIST THROUGH MONDAY. THE STRONGEST WINDS WILL STAY
MOSTLY OVER HIGHER ELEVATIONS. HOWEVER...WITH VERY WARM
AFTERNOONS...SOME OF THESE STRONGER WINDS COULD MIX DOWN AND MAKE
FOR GUSTY CONDITIONS. WHILE THIS AREA HAS SEEN QUITE A BIT OF RAIN
AND MOIST CONDITIONS OVER THE PAST 2 WEEKS...OFFSHORE WINDS COULD
DRY THINGS OUT IN A HURRY.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE EXTENDED FORECAST STARTING TUESDAY AFTERNOON CENTERS AROUND
THE EVOLUTION OF THE BLOCKING HIGH CURRENTLY TAKING SHAPE OVER THE
MAINLAND. WARM AND DRY CONDITIONS WILL PREVAIL OVER MOST OF THE
SOUTHCENTRAL FROM MIDDLE TO LATE NEXT WEEK. HOWEVER...AS THE UPPER
LEVEL RIDGE SLIDES WESTWARD INTO THE BERING LATE NEXT WEEK INTO
THE WEEKEND THE CHANCES FOR MOUNTAIN SHOWERS INCREASES. DETAILS
HAVE YET TO BE RESOLVED BUT AFTERNOON AND EVENING SHOWERS ARE
INCREASINGLY POSSIBLE TOWARD NEXT WEEKEND...MAINLY OVER HIGHER
TERRAIN. TEMPERATURES WILL CONTINUE TO BE ABOVE AVERAGE THEN COOLING
SLIGHTLY OVER THE WEEKEND TOWARD AVERAGE. WINDS WILL REMAIN
GENERALLY LIGHT THROUGH THE PERIOD WITH SEA BREEZES FORMING IN
FAVORED COASTAL LOCATIONS.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...MSO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MSO
LONG TERM...MTL