Area Forecast Discussion - Northern


FXAK69 PAFG 240008
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
408 PM AKDT MON MAY 23 2016
.DISCUSSION...
The 12 Z operational models initialized well and are in good
agreement in the short term and stay in reasonably good agreement
through Wednesday. The models depict a generally wet and active
pattern for the upcoming week.

Looking at the current upper air pattern, there is a 526 dam low
at 500 hpa over the Chukotsk Peninsula. There is a trough
extending from the low into central Alaska. The upper level low
will move northwest tonight with the trough pushing to the north.
An upper level ridge will move over the eastern Aleutians on
Tuesday and will move to Bristol Bay by Wednesday and will
continue moving to the northeast. 

At the surface a 1028 mb area of high pressure centered 600
nautical miles north of demarcation point will gradually
strengthen and drift southeast through Tuesday. A 1009 mb low
over the northern interior will move over the eastern north slope
on Tuesday. A trough currently over the west coast this evening
will push into the western interior overnight.

For the north slope precipitation is the biggest short term
concern. As the trough pushing through the region will bring
precipitation to the central and eastern Brooks Range beginning
tonight. The snow level in the Brooks Range will be around 3000
feet. In the Brooks Range above 3000 feet tonight we are expecting
snow. We are expecting 3 to 5 inches of snow at pass level in
Atigun Pass though Tuesday afternoon. Up to 7 inches of snow is
possible in high elevations in the central and eastern Brooks
Range. We didn't issue any warnings for the snowfall because the
heaviest amounts will be limited to the highest elevations in the
range wall above pass level. We did issue an updated SPS this
afternoon discussing the potential for snowfall. The precipitation
will spread northward onto the coastal plain Tuesday morning. We
are currently expecting any precipitation below 3000 feet in
elevation to be in the form of rain. There is however, at least a
chance that there could be some light freezing rain from Barrow
east. NAM and GFS forecast soundings both show a shallow layer of
cold air (right near freezing) associated with the marine layer
with warmer air aloft. SREF probability products also show at
least a chance of freezing rain in the morning Tuesday from Barrow
east.

For the Interior, moist flow will keep the forecast wet though
Friday. Scattered showers will continue across the Interior this
evening and again on Tuesday. A heavier push of moisture will
arrive on Thursday; however, right now there are significant
differences in the timing and placement of this feature in the
models. Snow levels will remain around 3000 feet through
Wednesday.

West coast and the western interior will continue to be wet with
the next surge of moisture continuing to push into the west
coast this evening. Rain associated with this wave moves rapidly
north and east into the western Brooks Range and the northern
portions of the western interior tonight and into the central
interior Tuesday. Next round of rain moves onto the west coast
Wednesday morning and into the central interior Wednesday evening.


&&
.FIRE WEATHER...
Fire weather concerns will be generally limited due to the wet
pattern. Moist southwest flow will keep RH values up through the
end of the week. 

&&
.HYDROLOGY...
The Flood Watch for the Colville River Delta remains in effect
through Wednesday Morning. The water level on the Colville River
at Umiat has increased 6 feet at Umiat since Saturday due to
Snowmelt. Water levels are now beginning to rise on the Delta.
See the latest flood advisory product for more detailed
information.

The Flood Advisory still remains in effect for the Kuparuk River.
Water is no longer flowing over the roadway; however the river
remains high. See the latest flood advisory product for more
detailed information.  

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Flood Watch for AKZ203.

Small Craft Advisory for PKZ210-PKZ220-PKZ225.
&&

$$

MAY 16