554
FXAK69 PAFG 291431
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
631 AM AKDT Mon Apr 29 2024

.SYNOPSIS...
Temperatures will remain cooler than normal most areas through
Tue, warm closer to normal on Wed, then warm to well above normal
by the end of the week south of the Brooks Range. Conditions will
become more cloudy most areas on Tue and Wed with areal coverage
of showers increasing slightly each day today through Wed.

Expect Isolated showers near the ALCAN Border today, and Isolated
snow and rain showers over the NW Interior and Central Brooks
Range today. Expect isolated showers over most of the Interior
East of McGrath to Anaktuvuk Pass Tue with scattered showers along
and just east of Denali to Fairbanks to Circle. Expect scattered
showers southeast of the YK Delta to Bettles to Old Crow on Wed
with isolated showers in the the chinook shadow of the AK Range
from the Tanana River south on Wed.

Expect northeast winds 15-25 mph from St Lawrence Is to the
Bering Strait then over NW AK to Point Lay on Tue and Wed.
Expect South winds 15 mph gusting to 30 mph through AK Range
Passes on Wed, with those winds increasing slightly and
continuing into Thu, then becoming stronger on Fri and Sat as a
moderate to strong southerly chinook flow develops across the
Alaska Range.

At the surface...
An Arctic weather front that lies from Point Lay to Chicken will
persist into Tue and then move to the Yukon Delta to Circle on
Wed. A cool Arctic Airmass will keep temperatures below normal
north of this front. Any precipitation north of this feature
should remain as snow.

High pressure over the Chukchi Sea will strengthen into Tue and
then persist. This will cause Northeast winds to increase over NW
AK and the West Coast of AK tonight into Tue and persist into Wed.
This is causing Stratus and fog along the Arctic Coast from
Utqiagvik east.

A secondary Arctic Cold front over the Northern Beaufort Sea will
move along the Eastern Arctic Coast of Alaska late tonight and
move over the eastern Beaufort Sea on Tue. This will bring mid to
low levels clouds and periods of light snow, and lift stratus
slightly.

A strong low southwest of Shemya will move to near Shemya on Tue,
and to the Southeast bering Sea on Wed.

High pressure building over the Copper River Basin on Wed will
cause southerly gap winds through Alaska Range Passes Wed.

&&

.DISCUSSION...
At 00Z, models initialize well aloft. Models show similar
solutions aloft through 4AM Tue. After that time the ECMWF
becomes the outlier solution aloft as it pushes short wave energy
from the Beaufort Sea south over NE Alaska as a low aloft, while
other models split the short wave energy with some energy dropping
SW across Western Alaska while the other energy moves SE across
NW Canada. Given the weak ridging over southern Alaska, expect the
splitting of short wave energy shown by the GFS/ NAM and Canadian
models to be the most likely solution. The ECWMF solution of a
low aloft developing over NE Alaska as the short wave moves south
seems very unlikely. Will use a blend of the NAM, GFS and Canadian
for features aloft through Wed.

The long wave pattern consists of a trough from the Canadian
Archipelago southwest over northern AK and over NW Canada, with a
ridge over the Bering and Chukchi Seas, and a second trough over
the Sea of Okhotsk and the NW Pacific. This pattern will
retrograde over the next several days as a strong short wave moves
from the high Arctic south over Northern AK and Western AK and
another strong short wave moves from the NW Pacific east
undercutting the long wave ridge and forming a deep low aloft over
the southern Bering Sea by Tue PM. By Tue night and Wed there is
a long wave trough from the Beaufort Sea SW across NW AK to the
Bering Sea. This will cause the current weak west flow aloft
across Northern AK to persist today, then turn northeast across NW
AK on Tue and SW across the Interior on Tue. Flow will become
weak south over the Interior on Wed and weak northeast across NW
AK on Wed. Southerly flow will increase over the Interior from Thu
into Fri and possibly into Sat.

This upper level pattern means that temperatures will remain
cooler than normal most areas through Tue, warm closer to normal
on Wed, then warm to well above normal by the end of the week
south of the Brooks Range. This also means that conditions will
become more cloudy most areas on Tue and Wed with precipitation
areal coverage increasing slightly on Tue and Wed.

With precipitation, will use a blend of the NAM and GFS for areal
coverage. Main feature is that areal coverage will increase
slightly each day today through Wed. Expect Isolated showers near
the ALCAN Border today, and Isolated snow and rain showers over
the NW Interior and Central Brooks Range today. Expect isolated
showers over most of the Interior East of McGrath to Anaktuvuk
Pass Tue with scattered showers along and just east of Denali to
Fairbanks to Circle. Expect scattered showers southeast of the YK
Delta to Bettles to Old Crow on Wed with Isolated showers in the
the chinook shadow of the AK Range from the Tanana River south on
Wed.

At the surface at 06Z, models verify well over Alaska. Will use a
blend of the NAM and Canadian for surface features and winds
through Wed. Highlights include: N 15 to 25 mph along Capes of the
West Coast and NE 10-15 through Brooks Range Passes today. NE
15-25 mph from St Lawrence Is to the Bering Strait then over NW AK
to Point Lay on Tue and Wed. South winds 15 mph gusting to 30 mph
through AK Range Passes on Wed.

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


&&

.FIRE WEATHER...
Temperatures will remain cooler than normal most areas through
Tue, warm closer to normal on Wed, then warm to well above normal
by the end of the week. RH will remain dry today, in the 20-40%
range driest from Denali to Fairbanks to Ft Yukon. Conditions
will become more cloudy with slightly higher RH on Tue and Wed.
Expect light Isolated showers near the ALCAN Border today, and
Isolated snow and rain showers over the NW Interior and Central
Brooks Range today. Expect isolated light showers over most of the
Interior east of McGrath to Anaktuvuk Pass Tue with scattered
showers and possible wetting rain east of Denali to Fairbanks to
Circle. Expect scattered showers southeast of the YK Delta to
Bettles to Old Crow on Wed with Isolated showers in the the
chinook shadow of the AK Range from the Tanana River south on
Wed.

South winds 15 mph gusting to 30 mph through AK Range Passes
expected on Wed, with those winds increasing slightly and
continuing into Thu, then becoming stronger on Fri and Sat.
RH expected to be above 25% Wed and Thu, but Fri and Sat could see
near red flag conditions near Delta Junction as a moderate to
strong southerly chinook flow develops across the Alaska Range.

&&

.HYDROLOGY...
No issues at this time. Yukon River ice still in place.
Cooler than normal temperatures should keep slow melt through the
middle of this week. Warmer than normal temperature late this
week could speed up melt and flow of water into rivers by the
weekend.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Brisk Wind Advisory for PKZ806.
     Brisk Wind Advisory for PKZ807-811-854-856-857.
&&

$$

JB