Small Craft Advisory 385, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
229 PM AKDT TUE MAY 13 2014

.ANALYSIS AND UPPER LEVELS...

UPPER LEVEL RIDGE IS OVER THE EASTERN HALF OF THE BERING AND
SOUTHWEST AK THIS AFTERNOON...WITH LOWS OVER THE EASTERN GULF AND
SOUTHWEST OF ATTU. A RAPIDLY MOVING SHORTWAVE IS FAST APPROACHING
THE ALCAN. AT THE SURFACE...A LARGE REGION OF HIGH PRESSURE COVERS
THE EASTERN BERING AND MOST OF MAINLAND AK. A LOW SOUTHWEST OF
ATTU IS ASSOCIATED WITH A FRONT OVER THE WESTERN BERING...AND A
SMALL LOW IS OVER THE SOUTHEASTERN GULF. A FRONT IS DRAPED FROM
THE NORTHERN ALCAN TO THE ALASKA RANGE AND KUSKOKWIM MOUNTAINS.

&&

.MODEL DISCUSSION...

MODELS ARE IN AGREEMENT THAT THE FRONT DRAPING ACROSS MUCH OF
ALASKA AND THE FOLLOWING HIGH WILL BE IMPORTANT FEATURES FOR THE
NEXT COUPLE OF DAYS. AS THE FRONT MOVES ACROSS THE KUSKOKWIM
VALLEY AND ALASKA RANGE IT WILL PROVIDE WIND THAT WILL MIX THE
LOWER LEVELS AND KEEP TEMPERATURES FROM COOLING...AND ALSO PROVIDE
LOWER DEWPOINT AIR TO KEEP RELATIVE HUMIDITIES FROM RECOVERING
OVERNIGHT. ON WED THE STRONGEST WINDS WILL MIX DOWN TO THE SURFACE
AND BE FOLLOWED DURING THE AFTERNOON WITH LIGHTER WINDS AS THE
HIGH BUILDS...BRINGING WARM AND EXTREMELY DRY CONDITIONS. THE
HIGH WILL CONTINUE TO BUILD OVER THE MAINLAND INTO FRI BEFORE
DRIFTING WEST.

DURING THE SAME TIME PERIOD THE FRONT OVER THE WESTERN BERING AND
ALEUTIANS WILL MOVE TO THE CENTRAL BERING BEFORE SLAMMING UP
AGAINST THE EASTERN BERING RIDGE. THE FRONT WILL REMAIN IN PLACE
AND EVENTUALLY DECAY BY FRI.

THE FORECAST UTILIZES THE EC WITH SOME GFS AND NAM FOR DETAIL.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...

AS THE FRONT PASSES THIS EVENING WINDS WILL BEGIN TO
INCREASE...PEAKING WED MORNING. AS WINDS DIMINISH ON WED
TEMPERATURES WILL INCREASE WITH MUCH DRIER DEWPOINTS...RESULTING
IN RH VALUES IN THE TEENS. ON THU AND FRI OFFSHORE FLOW WILL
BEGIN TO WEAKEN WITH SOME MOISTURE RETURNING TO THE LOWER LAYERS.
EXCEPT FOR A FEW SHOWERS THIS EVENING OVER THE AK RANGE AND
TALKEETNA MOUNTAINS...CONDITIONS WILL BE WARM AND DRY THROUGH THE
END OFF THE WEEK. HOWEVER...FIRE WEATHER CONCERNS OVER MUCH OF
SOUTH CENTRAL WILL BE CAUSED INITIALLY BY WIND AND LOW RH...AND
THEN ON WED BY LOW RH ALONE. SUFFICIENT ONSHORE FLOW ON THU SHOULD
KEEP RH VALUES ABOVE RED FLAG CRITERIA.

SOUTHWEST ALASKA...

AFTER SOME WIND TONIGHT...THE SOUTHWEST WILL BE WARM AND DRY
THROUGH THU WITH INCREASING CLOUDS ON FRI. WIND AND LOW RH WILL
BRING FIRE DANGER TO THE KUSKOKWIM VALLEY AND INTERIOR PORTIONS
OF THE BRISTOL BAY ZONE THIS AFTERNOON AND EVENING...WITH ONLY LOW
RH CONCERNS ON WED.

BERING SEA/ALEUTIANS...

RAIN AND WIND WILL AFFECT THE WESTERN BERING AND ALEUTIANS THROUGH
FRI AS THE FRONT STALLS AND DECAYS OVERHEAD. THE EASTERN BERING
WILL BE DRY WITH SOME FOG BENEATH THE HIGH.

&&

.LONG TERM FORECAST...

STILL ANTICIPATING A SIZABLE LOBE OF ENERGY DROPPING FROM THE HIGH
ARCTIC TO THE SOUTHERN MAINLAND/GULF LATE WEEKEND INTO EARLY NEXT
WEEK. THE DETAILS OF THIS REMAIN FUZZY...BUT SUFFICE TO SAY A
SIZABLE PATTERN SHIFT APPEARS ON THE HORIZON. WELL ABOVE
TEMPERATURES AND DRY WEATHER INCREASINGLY LOOKS TO TREND CLOUDIER
AND COOLER WITH MORE SIZABLE CHANCES FOR WETTING RAINS AS THIS
LARGE LOW MEANDERS AROUND WITH IT'S CYCLONIC FLOW ALOFT. FEW
CHANGES OVERALL TO THE SENSIBLE WEATHER IN THE BERING SEA/ALEUTIAN
REGION. THE UPPER HIGH IN THE EASTERN PART OF THE BERING SLIDES TO
THE WESTERN PORTION OR WEAKENS A BIT...BUT DOESN'T BREAK
COMPLETELY. THUS TYPICAL CLIMATOLOGICAL WEATHER (MORE FOG/STRATUS)
CAN BE ANTICIPATED.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...RED FLAG WARNING 101 111 121 141 146 152 161

&&

DS/JAM MAY 14