667
FXAK69 PAFG 080006
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
406 PM AKDT Tue May 7 2024

.SYNOPSIS...
Cool and wet conditions continue today into Wed AM, with drying
and warming Wed PM along with southerly Chinook winds gusting to 50
mph along the Alaska Range Wed night into Thu AM. At this time it
looks like strong winds will be late Wed night and early Thu AM so
not anticipating Red Flag conditions at this time, but expect near
Red Flag conditions from Delta Junction to Donnelly Dome early Thu
afternoon.

A band of rain and snow (with all snow above 2000 ft and north of
the Yukon River) that lies from Delta Junction to Ft Yukon will
move the Yukon River Bridge to Atigun Pass Tue night, and over
the Northwest Alaska and the Western North Slope on Wed, then
remaining over NW AK Wed night and Thu. Expect 1-2 inches of snow
above 2000 ft north of Fairbanks and north of the Arctic Circle
with this feature tonight into Wed, and could see 2-4 inches in
the Brooks Range from Atigun pass West.

A thermal low pressure trough developing over the Tanana Valley
Wed will persist into Wed night then move north over the NE
Interior on Thu. High pressure building south of the Alaska Range
Wed and Wed night will weaken on Thu. These features, combined
with southerly Chinook winds wed night, will cause warm, dry and
windy conditions over the SE Interior near the Alaska Range Wed
night and Thu AM.

A weather front moving NE across the Interior Thu PM and Fri will
cause rain and snow over the SE Interior Thu night and Fri as the
Chinook winds end.

Cool and showery conditions will remain over most of Northern
Alaska through the weekend into early next week.

&&

.DISCUSSION...
Models initialize well at 12Z. The GFS quickly becomes the outlier
solution aloft after 00Z today, moving the short wave over the SE
Interior to the Northwest more quickly and weaker than the ECWMF,
NAM and Canadian models. Prefer a blend of the NAM and ECMWF for
features aloft through Fri. Prefer a blend of the NAM and ECMWF
for precip as well. At the surface models verify well at 15Z. Will
use a blend of the NAM and Canadian for surface features and
winds through Fri.

Aloft...
The long wave pattern consists of a deep trough over Western
Alaska and the Western Bering Sea and a strong ridge over Western
Canada and NE Alaska. This pattern retrogrades over the next
through Wed as the long wave trough moves over the Bering and
Western AK by Wed and the ridge builds over NE AK. This will cause
SE flow with several short waves moving NW across Interior AK.
Each of the short waves will bring several inches of snow or mixed
rain and snow to the elevated areas of the Interior and North
Slope through Wed, with moderate strength southerly chinook winds
developing across the Alaska Range Wed night and continuing into
Thu AM. This will cause a drying and warming trend over the SE
Interior Wed into Thu.

At the surface...
An Arctic front stretching from Circle to Ambler to King Salmon
will move to Old Crow to Kotzebue to King Salmon by 4pm Wed.
The front will then weaken after that.

A thermal low pressure trough developing over the Tanana Valley
Wed will persist into Wed night then move north over the NE
Interior on Thu. High pressure building south of the Alaska Range
Wed and Wed night will weaken on Thu. These features, combined
with southerly Chinook winds wed night, will cause warm, dry and
windy conditions over the SE Interior near the Alaska Range Wed
night and Thu AM.

A weather front moving NE across the Interior Thu PM and Fri will
cause rain and snow over the SE Interior Thu night and Fri as the
Chinook winds end.

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

&&

.FIRE WEATHER...
Cool and wet conditions continue today into Wed AM, with drying
and warming Wed PM along with southerly Chinook winds gusting to 50
mph along the Alaska Range Wed night into Thu AM. At this time it
looks like strong winds will be late Wed night and early Thu AM so
not anticipating Red Flag conditions at this time, but expect near
Red Flag conditions from Delta Junction to Donnelly Dome early Thu
afternoon.

A band of rain and snow (with all snow above 2000 ft and north of
the Yukon River) that lies from Delta Junction to Ft Yukon will
move the Yukon River Bridge to Atigun Pass Tue night, and over
the Northwest Alaska and the Western North Slope on Wed, then
remaining over NW AK Wed night and Thu. Expect 1-2 inches of snow
above 2000 ft and north of the Arctic Circle with feature tonight
into Wed and could see 2-4 inches in the Brooks Range from Atigun
pass West.

A thermal low pressure trough developing over the Tanana Valley
Wed will persist into Wed night then move north over the NE
Interior on Thu. High pressure building south of the Alaska Range
Wed and Wed night will weaken on Thu. These features, combined
with southerly Chinook winds wed night, will cause warm, dry and
windy conditions over the SE Interior near the Alaska Range Wed
night and Thu AM.

A weather front moving NE across the Interior Thu PM and Fri will
cause rain and snow over the SE Interior Thu night and Fri as the
Chinook winds end.

&&

.HYDROLOGY...
As of 2pm Tuesday, ice was moving past Circle and the break up
front with high water is upstream but approaching Circle. No
overbank flooding has been reported yet. As the breakup front
moves downstream, it is likely that small jams may form and
release, leading to fluctuating water levels and potential minor
or moderate flooding at Circle today into tonight.

The break up front on the Yukon River will approach Ft Yukon on
Wed or Thu. Downstream of Ft Yukon most ice remains in place on
the Yukon River at this time.

The Tanana and Upper Kuskokwim River are mostly open.

Rivers north of of the Yukon River have mostly intact ice.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Flood Watch for AKZ833.
PK...Heavy Freezing Spray Warning for PKZ801-802.
     Heavy Freezing Spray Warning for PKZ803.
     Heavy Freezing Spray Warning for PKZ806.
     Small Craft Advisory for PKZ806.
     Heavy Freezing Spray Warning for PKZ810.
     Heavy Freezing Spray Warning for PKZ816.
     Heavy Freezing Spray Warning for PKZ850.
     Small Craft Advisory for PKZ851.
     Heavy Freezing Spray Warning for PKZ851.
     Brisk Wind Advisory for PKZ854.
&&

$$

JB