Small Craft Advisory 106, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
247 AM AKDT FRI SEP 21 2012

.DISCUSSION...
LONG WAVE TROUGH REMAINS ENTRENCHED OVER THE BERING SEA WHILE
HIGH PRESSURE RIDGE EXTENDS FROM BC NORTHWARD THROUGH THE YUKON
AND EASTERN ALASKA. ENERGY CONTINUES TO DRIVE EASTWARD WITH STRONG
JET AND SHORTWAVE AND WILL TURN NORTHEAST THIS MORNING AND THEN
NORTHWARD THIS AFTERNOON AS SYSTEM MOVES ALONG THE BACK OF UPPER
LEVEL RIDGE. A SHORT WAVE OVER THE INTERIOR WILL CONTINUE TO MOVE
NORTH AND EAST TODAY. 500 MB WINDS NEAR 75 KTS DIMINISH AS
INTERIOR SHORTWAVE MOVES NORTH.

ON THE SURFACE A WEAK LOW ASSOCIATED WITH THE UPPER LEVEL
SHORTWAVE OVER THE INTERIOR WILL CONTINUE TO MOVE NORTH TODAY.
WIDESPREAD RAIN SHOWERS IN THE INTERIOR WILL TAPER OFF TO
SCATTERED SHOWERS AS THE LOW CONTINUES TO MOVE NORTH AND EAST.
CHINOOK FLOW ALONG THE CENTRAL AND EASTERN ALASKA RANGE WILL
DIMINISH THROUGH THE DAY AS THE INTERIOR LOW WEAKENS AND CONTINUES
TO MOVE INTO NORTHEAST ALASKA.

DENSE FOG ALONG THE CENTRAL NORTH SLOPE WILL DIMINISH THROUGH THE
DAY AS THE INTERIOR LOW MOVES ONTO THE EASTERN NORTH SLOPE. NORTH
AND NORTHWEST WINDS CONTINUE ALONG THE WEST COAST AS THE INTERIOR
LOW MOVES ONTO THE NORTH SLOPE.

UNSEASONABLE WARM TEMPERATURES ARE EXPECTED SATURDAY ACROSS THE
EASTERN INTERIOR AS UPPER LEVEL RIDGE MOVES WESTWARD.

CHINOOK WINDS ARE EXPECTED TO DEVELOP SATURDAY ALONG AND NEAR
THE ALASKA RANGE AS A 65 KT CROSS BARRIER FLOW AT 700 MB DEVELOPS
AHEAD OF THE SURFACE LOW MOVING NORTH OUT OF THE GULF OF ALASKA.
CROSS SECTION ANALYSIS REVEALS MODERATE DOWNWARD MOMENTUM BUT NO
CRITICAL LEVEL THEREFORE MINIMAL MOUNTAIN WAVE ENHANCEMENT TO WIND
SPEEDS ARE EXPECTED. WINDS ARE NOT EXPECTED TO REACH WARNING
CRITERIA HOWEVER ADVISORY LEVEL WINDS ARE EXPECTED IN ZONES 223
225 226 AND ZONE 227 NEAR THE ALASKA RANGE SATURDAY. CONTINUE TO
MONITOR LATE SEASON FIRE POTENTIAL SATURDAY AFTERNOON IN ZONES
223 AND 226 AS MIN RH VALUES ARE EXPECTED TO DROP INTO THE LOWER
30S CONCURRENT WITH ADVISORY LEVEL WINDS AND BURNABLE FUELS.

MODELS REMAIN IN GOOD AGREEMENT THROUGH EARLY NEXT WEEK WITH THE
UPPER LEVEL RIDGE REMAINING OVER WESTERN CANADA AND UPPER LEVEL
TROUGH REMAINING OVER THE BERING SEA THROUGH THE WEEKEND. BOTH THE
GFS AND ECMWF INDICATE THAT THE WESTERN CANADA RIDGE BREAKS DOWN
AND THE BERING SEA TROUGH MOVES EAST OVER ALASKA BY MID WEEK.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.HYDROLOGY...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR PKZ245.
&&

CC SEP 12