Small Craft Advisory 102, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
125 PM AKDT FRI AUG 5 2016

.DISCUSSION...

UPPER AIR...
An upper low centered west of Bristol Bay will move on a wobbly
track to near Dall Point by Sunday evening, then drift slowly
southward to the Yukon Delta area by Monday afternoon. Current
models runs are in good agreement through Sunday afternoon. By
Monday afternoon the current solutions diverge, with the ECMWF and
Canadian runs taking the low center towards Bristol Bay while the
NAM has less southward movement and the GFS keeping the low center
nearly stationary. All of the models maintain a light mainly south
to southeast flow pattern over the interior and the Arctic Slope.
850 mb temperatures over the eastern interior will warm to
midsummer levels Saturday, with the above normal temperatures
continuing through Monday.

SURFACE...
An elongated 1000 mb low centered about 50 nm west of
Nunivak Island will deepen to 993 mb by Saturday afternoon
then weaken to a 998 mb center near Nunivak Island by Sunday
afternoon. Current model runs are similar through Sunday
afternoon, then diverge by Monday afternoon, with movement
of the weakening surface low center similar to that of the
associated upper low. A 1030 mb high centered 200 nm east
northeast of Barter Island will weaken to a 1026 mb high
centered near Banks Island by Saturday afternoon, then move to
near 78N/110W in the northwestern Canadian Archipelago
by Sunday afternoon. Current deterministic model runs indicate
the extratropical remnants of typhoon "Omais" could move into the
western Bering Sea by Thursday evening. GFS and ECMWF models agree
well at 162 hours/06Z Friday with about a 980 mb center near
55N/173E, which is slightly east of the GEFS ensemble mean
position. The GEFS ensemble mean indicates a lower central
pressure at this time, about 993 mb. There is still quite a
bit of spread between the individual ensemble members at the 162
hr projection. After 162 hrs, the current deterministic model
runs become considerably divergent. Since this is still far out
in time, forecast confidence is low but at this time it appears
unlikely there will be any impact from this system anywhere in
our forecast area.

WEST COAST...
Showers from the southern Seward Peninsula northward will
spread over most of the remainder of the area and continue
through Sunday night.

WESTERN INTERIOR...
Rain or showers will develop over the lower Yukon Valley
tonight, spreading to the middle Yukon and lower Koyukuk
Valleys Saturday and continuing Saturday night, with a
chance of showers in areas farther to the north.

CENTRAL AND EASTERN INTERIOR...
Mainly isolated to scattered showers over the Alaska Range
and southeastern areas tonight. A chance of showers over
most areas Saturday and Saturday night, except in the
northeastern interior and areas just to the north of the Alaska
Range. South winds mainly 15 to 25 mph continuing in Alaska Range
passes west of the Tok Cutoff. Temperatures will be warmer over
the weekend, with highs mostly in the 70s. High temperatures in
the middle Tanana Valley will climb into the mid to upper 70s over
the weekend. Slightly cooler but still a few degrees above normal
temperatures are expected Tuesday through the remainder of the
week.

ARCTIC COAST...
No precipitation is expected through Sunday. East winds 15 to 25
mph over most areas continuing through tonight, with winds
gradually decreasing from the west Saturday through Saturday
night.

Coastal Hazard Potential Days 3 and 4...None.

&&

.FIRE WEATHER...
Warmer and slightly drier conditions are expected over the
weekend...but minimum RH values are expected to remain near
or above 40 percent. Isolated thunderstorms in parts of the
western, central and southeast interior Saturday afternoon
and evening. Isolated thunderstorms over many parts of
the interior and southern inland west coast areas Sunday
afternoon, and over southern parts of the western interior
and inland west coast areas Sunday evening. Isolated
thunderstorms are expected over most interior and inland
west coast areas Monday afternoon and evening.

&&

.HYDROLOGY...
Water levels are expected to remain high on the Chena River near
the Moose Creek Dam through Sunday evening...then begin to
decreases as the water level in the holding pond begins to fall.
Shower activity is expected to continue over much of northern
Alaska from the Brooks Range southward. Rainfall amounts for the
next 48 hours are expected to range from 0.25 inch up to locally
0.75 inch over most of the western interior and along the west
coast from the Seward Peninsula southward. Over the central and
eastern interior, rainfall amounts for the next 48 hours are
expected to be less than 0.25 inch. Expected rainfall amounts are
not expected to be high enough to create any flooding issues.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Small Craft Advisory for PKZ235-PKZ240-PKZ245.
Flood advisory for the Chena River near the Moose Creek Dam.

&&

RF AUG 16