629
FXAK69 PAFG 220105
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
505 PM AKDT Tue May 21 2024

.SYNOPSIS...
Warm, windy and dry across the Eastern Interior today, becoming
slightly cooler and less windy on Wed, then much cooler and
wetter from Thu into the weekend.

The Western Interior and West Coast is will remain wet and cool
through the end of the week.

The North Slope has stratus and fog with near normal
temperatures along the Coast, while inland areas are sunny and
warmer than normal. The inland areas will cool and become wetter
on Wed night and Thu, with all areas remaining seasonally cool and
cloudy into the weekend. A chance of snow in the Brooks Range Thu
into the weekend.

Surface...
Strong high pressure north of the Arctic Coast is causing east
winds along the Arctic Coast and keeping stratus and fog in place.
Little will changes through Fri.

A 990 mb low in the southeast Bering Sea will move over the
Yukon Delta as a 1000 mb low on Wed, and then move inland Wed
night. A weather front stretching from this low to Norton Sound
then to Bristol Bay will move northeast to Kivalina to McGrath
tonight and then to Point Hope to Denali on Wed, then to Point
Hope to Northway on Thu then weaken in place through Fri. This is
bringing rain and cool temperatures to the Western Interior today
through Wed with the rain spread to the Central Interior Wed and
to the Eastern Interior Wed night and Thu. Most areas west of
Fairbanks will receive a quarter inch or more of rain between
today and Wed. Most areas from Fairbanks east will get one tenth
of an inch or more of rain between Wed night and Fri. Heavy rain
is possible in some areas of the Eastern Interior Thu into Fri but
to much uncertainty at this time to say exactly where.

Strong southerly Chinook flow across the Alaska Range ahead of
this system is causing very warm, dry and windy conditions over
much of the Eastern Interior, with the warmest and driest areas
between Nenana and Fairbanks southeast to Delta Junction.
These Chinook winds will decrease on Wed as the front moves east
and the winds drop off.

East winds of 15-25 mph are blowing ahead of the frontal system
along the West Coast and Western North Slope, with those winds
decreasing south of the front on Wed.

A strong low moving from the Bering Sea to the Yukon Delta on Fri
will keep conditions cool and wet into the weekend.

.DISCUSSION...
Models initialize well aloft and show similar solutions through
Wed night, then differ some on short wave placement and strength
over the SE Interior and SE AK from Thu into Fri. This greatly
affects precip amounts and location over the Eastern Interior Thu
into Fri. At this time we can day all of the Eastern Interior will
have rain between Wed night and Fri, with some areas getting
heavy rain but exactly where is not defined at this time.

The long wave pattern consists of a trough over the Bering and
Chukchi Seas, a ridge over the NE Pacific north over eastern
Alaska. A series of short wave troughs will move east across
southern AK from Wed through the weekend, eventually pulling the
long wave east over Mainland AK by the weekend. This will change
the current warm Eastern Interior and North Slope to cooler and
wetter later this week, while the cool and wet West Coast remain
so into the weekend.

At the surface at 18Z, models all verify 2-3 mb too weak on the
low in the Southeast Bering Sea and 4 or more mb too weak in the
high north of the Arctic Coast, and 6 mb too weak on the high
over the Wrangel Mtns. These misses explain why winds are much
stronger than forecast through AK Range Passes, and slightly
stronger than forecast along the West Coast and Arctic Coast. We
have adjusted winds from models in all these areas to reflect the
stronger than expected winds through Wed. After Wed we use a blend
of models for winds.

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

&&

.FIRE WEATHER...
Warm, windy and dry across the Eastern Interior today, becoming
much cooler and wetter from Thu into the weekend. The Western
Interior is will remain wet and cool through the end of the week.

Southerly Chinook winds across the Alaska Range are causing Red Flag
conditions now across much of the Interior from Fairbanks and Nenana
south to Delta Junction. Strong winds are occuring near Healy,
but temperatures near Healy are cooler and RH is higher there. Red Flag
conditions will end this evening as RH rises and temperature falls.

The Chinook flow will weaken from the west on Wed as a weather front
moves east across the Interior. The front will move east from Wed
through Thu before diminishing over the Eastern Interior on Fri.
This will cause winds to decrease during the day Wed and lower
temperatures about 5 degrees, and raise minimum RH 5-10 percent on
Wed. Temperatures will fall well below normal on Thu and remain
cool into the weekend.

Isolated to scattered showers will spread from west to east across the
Interior Wed with showers becoming scattered to numerous on Thu,
and then persisting into Fri. Most of the Eastern Interior can expect
wetting rain between Wed night and Fri.

A thermal low pressure trough stretching from Chicken to Bettles
will move to Chicken to Coldfoot on Wed, then to Chicken to Arctic
Village on Thu, then east of the ALCAN Border on Fri. There will be
isolated showers along this trough Wed and Thu with a few
thunderstorms along the ALCAN Border Thu PM.


&&

.HYDROLOGY...
A flood watch for ice jam flooding remains through Friday on the
Yukon River from downstream of Mountain Village to the Yukon Delta
Coast. The break up front now downstream of Mountain Village and
will likely get to the Yukon Delta at Alakanuk, Emmonak, Nunam
Iqua and Kotlik sometime between Wednesday and Fri, bringing the
risk of ice jam flooding to those areas Wed through Fri. If an ice
jam forms, water could rise rapidly at any of these locations.
The threat of flooding at Mountain Village appears to be over.

Water is moving freely past Mountain Village but remains high.
The river ice in the Yukon Delta is thicker than normal and is
more likely to jam up as this high water comes down river.
Satellite imagery depicts minimal degradation of shorefast ice
along the Yukon Delta Coast as well. This may exacerbate the
situation as shorefast ice could impede the breakup push and lead
to backwater in communities closest to the coast.

The water levels along the Porcupine River at the Border rose to
record levels over the weekend due to heavy snowmelt. This high
water is expected to reach Ft Yukon on Wed, where it will
gradually fills sloughs and swales east of Ft Yukon and eventually
bring high water into Ft Yukon late this week with high water
continuing into next week. A flood watch is valid from this Wed
through next week Wed at Ft Yukon.

There are no new reports about the Buckland River.

Rivers on the North Slope are beginning to flow with water
flowing over ice with some open water areas. Those area will
continue to see increasing melt this week.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Wind Advisory for AKZ837-849.
     Flood Watch for AKZ825.
     Flood Watch for AKZ833.
     Red Flag Warning for AKZ937.
     Red Flag Warning for AKZ939>945.
     Wind Advisory for AKZ847.
PK...Small Craft Advisory for PKZ811.
     Small Craft Advisory for PKZ812.
     Small Craft Advisory for PKZ851.
     Brisk Wind Advisory for PKZ856.
     Brisk Wind Advisory for PKZ857-858.
     Brisk Wind Advisory for PKZ861.
&&

$$