Small Craft Advisory 80, NWS Fairbanks, AK

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
145 PM ADT FRI SEP 7 2007

.DISCUSSION...
MODELS IN DECENT AGREEMENT THROUGH ABOUT 6Z SUNDAY. AT THIS TIME
THE NAM BRINGS THE CURRENT BERING SEA LOW AND FORMS A SPIN OFF LOW
NEAR NUNIVAK ISLAND LATE FRIDAY EVENING. THEN TAKES THAT LOW FROM
SAINT LAWRENCE ISLAND OUT TO THE CHUKOTSK PENINSULA AND THEN
WESTWARD. THE GFS TAKES THE LOW FROM SAINT LAWRENCE ISLAND AND
PUSHES IT NORTHWARD TO NORTH OF POINT LAY BY 12Z MONDAY. THIS
APPEARS TO BE A MORE LOGICAL PATH AT THIS TIME. UPPER LEVEL FLOW
IS NEARLY IDENTICAL OVER NORTHERN ALASKA.

NOW...SHORT WAVE TROUGH MOVING NORTHWARD FROM ABOUT KOTZEBUE TO
TANANA AND THEN SOUTHEASTWARD. UPPER LEVEL TROUGH WILL REACH TO
ABOUT NEAR BARROW TO ABOUT FORT YUKON BY 12Z SATURDAY. WINDS ARE
BEGINNING TO INCREASE IN THE SOUTHWESTERN INTERIOR WITH
APPROACHING LOW AND FRONTAL BOUNDARY. STRATUS STILL PLAGUING THE
ARCTIC COAST EVEN THOUGH SOUTH WINDS ARE DOMINATING. WIND FLOW IS
LIGHT ALONG THE ARCTIC COAST BUT WILL PICK UP LATE THIS AFTERNOON
AND INTO THIS EVENING AS ARCTIC HIGH DROPS SOUTHWARD AND BERING
LOW MOVES NORTHWARD.

THIS FIRST IN A SERIES OF BERING SEA LOWS WILL BEGIN INFLUENCING
NORTHERN ALASKA WEATHER BY LATE THIS AFTERNOON AND EVENING WITH
PRECIPITATION SHIELD ARRIVING TO ZONES 212...214...215 AND 225 BY
LATE THIS EVENING. MODERATE UPPER LEVEL SOUTHERLY FLOW WILL RULE
NORTHERN ALASKA WHICH WILL SHADOW OUT PRECIPITATION FROM BETTLES TO
TANANA AND EASTWARD THROUGH MOST OF SATURDAY. BEFORE UPPER LEVEL
WINDS TURN MORE SOUTHWESTERLY TO LOCK OUT THE CHINOOK EFFECT. THE
GFS IS A BIT MORE VIGOROUS IN WIND MAGNITUDES IN UPPER LEVELS. THE
CENTRAL INTERIOR WILL GET IN ON THE PRECIPITATION BEGINNING
SATURDAY NIGHT AS THE UPPER LEVEL RIDGE TILTS AND ALLOWS A MORE
FAVORABLE TRAJECTORY FOR PRECIPITATION.

ALL OF NORTHERN ALASKA WILL GET IN ON THE PRECIPITATION EXCEPT FOR
POSSIBLY THE FAR EASTERN INTERIOR WHICH WILL STILL BE UNDER THE
INFLUENCE OF THE RAIN SHADOW. STRONG WINDS THROUGH THE ALASKA
RANGE PASSES TO 50 MPH WILL BE LIKELY WITH THE RIDGE BUILDING IN.

WINDS WILL REACH SMALL CRAFT ADVISORY AND EVEN GALE IN WESTERN
ZONE 210 BUT FEEL AT THIS POINT THAT THERE WILL NOT BE SUFFICIENT
SURGE VALUES TO AFFECT THE DELICATE BALANCE FOR THE THRESHOLD FOR
ANY COASTAL FLOOD POTENTIAL AT THIS TIME.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.

&&

.FIRE WEATHER...FIRE WEATHER WATCH IN EFFECT FOR ZONES 223 AND 226
FOR STRONG WIND BEGINNING SATURDAY AFTERNOON. THE WINDS WILL
LIKELY REACH THE THRESHOLD BUT THE RH VALUES WILL BE CLOSE. WITH
THE STRONG SOUTHERLY WIND WILL CAUSE THE MOISTURE CONTENT TO BE
SQUEEZED FROM THE AIR AS IT DOWNSLOPES BUT GIVEN THE AMOUNT OF
MOISTURE STILL LEFT OVER FROM BEING MOISTURE LADEN TO BEGIN
WITH...THE RH VALUES WILL BE CLOSE.

&&

.HYDROLOGY...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR AKZ225-AKZ226.

FIRE WEATHER WATCH FOR AKZ223-AKZ226.

SMALL CRAFT ADVISORY FOR PKZ200-PKZ210-PKZ215-PKZ220-PKZ225-
PKZ230-PKZ235-PKZ240-PKZ245.

GALE WARNING FOR PKZ200-PKZ210.
&&

CF SEP 07