577
FXAK69 PAFG 302156
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
156 PM AKDT Tue Apr 30 2024

.SYNOPSIS...

Overall upper-level pattern this afternoon is showing a trough
moving into the Gulf of Alaska with a larger trough moving into the
western Bering Sea. At the same time, ridging continues aloft over
the eastern Bering Sea. Models are in good agreement at least
through Thursday showing the upper trough over the Bearing Sea
moving eastward towards the Alaska Peninsula and eventually into the
Gulf of Alaska by Thursday afternoon. Weak energy continues to lift
into the Interior Alaska today and is evident on both satellite and
radar imagery. We have seen pretty consistent returns on radar
across the White Mountains this morning, however, there remains some
uncertainty on how much is actually reaching the ground. As the
aforementioned low reaches the Gulf of Alaska, we will see increased
southerly flow through the Alaska Range that will bring Chinook
winds that will lead to some elevated fire weather concerns on
Thursday and continuing into the weekend. This southerly flow will
actually be reinforced by another strong upper-level trough that
moves through the Bering Sea and into the Alaska Peninsula into the
weekend.

&&

.DISCUSSION...

Isolated showers will continue through the remainder of the day
today and continue into Wednesday across the interior. Despite the
chances, overall QPF amounts will remain low. There is also a chance
that as temperatures cool this evening and through the night that we
could see some snow from Galena through Tanana and then into the
White Mountains. Also can`t guarantee that a few flakes are not seen
from McGrath through Fairbanks. As southerly flow increases with the
passing of the two aforementioned upper-level troughs, we will see
some increasing Chinook winds along the northern slopes of the
Alaska Range. Because of this, wind prone areas will see wind gusts
increasing to around 30 to 50 mph, especially into the weekend. With
lower daytime humidity values, this will lead to some elevated fire
weather conditions from Thursday and only increasing into the
weekend. This will also allow for some sort of WAA for the interior
that will bring above average high temperatures.

An Arctic cold front will generally continue to impact the North
Slope through late week. This will lead to cooler than normal
temperatures across the northern slope into the weekend. We will
also see periods of light snow, fog, and low stratus through at
least Friday. Winds will begin to increase as we head into the
weekend, with gusts up to around 30 mph that will likely bring more
periods of blowing snow.

High pressure currently over the Yukon Delta will become less of an
influence as it pushes to the southeast through Wednesday. By this
time, the first upper-level trough will be in the Gulf of Alaska,
wrapping around moisture by Wednesday afternoon. It should be cold
enough that the coastal areas will see some snow while inland areas
will see periods of rain. Again, any accumulations for this area
will remain light. Still looking like a brief lull in the
precipitation for Thursday before the second upper-level trough
moves into the Gulf of Alaska that will bring another round of what
looks to be more widespread showers to the West Coast on Friday and
into Saturday. There remains some uncertainty on the timing of this
secondary precipitation as it highly depends on the track of the
second trough along with how fast it pushes east. As with the
remainder of the area, winds will also be on the increase as we move
into the weekend for the West Coast.

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

&&

.FIRE WEATHER...

Min RH values across the Upper Tanana Valley today have
generally ranged from around 15 to 25 percent with the rest of the
interior between the 25 to 40 percent range. Aside from the southern
portion of the Lisburne Peninsula, the North Slope and West Coast
have seen ranges from the 50 to 80 percent range. Similar conditions
will be seen on Wednesday in terms of min RH values, with maybe some
lowering RH across the Upper Tanana Valley into the Delta Junction
and areas to the south of here. By Thursday, min RH values from
Fairbanks into the Delta Junction and the Eastern Alaska Range and
the Upper Tanana Valley will be in the 15 to 20 percent range.
Mixing this with increasing southerly winds through the Alaska Range
passes fire weather concerns will increase. Looks like moderate
Chinook winds will develop as early as Thursday afternoon,
increasing as we move into Friday and then continuing into the
weekend. Wind gusts of 30 to 50 mph and lower humidity values will
be very near Red Flag conditions for the aforementioned areas.

&&

.HYDROLOGY...

An ice jam on the Yukon River just upstream of Eagle,
along with some ice remaining in place at Eagle, have lead to an Ice
Jam Flood Watch for Eagle. River watch teams are in the air today
and will get more information. We will continue to monitor and
update as needed.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Flood Watch for AKZ835.
PK...Small Craft Advisory for PKZ802.
     Brisk Wind Advisory for PKZ805.
     Brisk Wind Advisory for PKZ806-807-850.
     Brisk Wind Advisory for PKZ809.
     Brisk Wind Advisory for PKZ810-854-856.
     Gale Warning for PKZ811.
     Brisk Wind Advisory for PKZ812-817-851-858.
     Heavy Freezing Spray Warning for PKZ816.
     Small Craft Advisory for PKZ816.
     Brisk Wind Advisory for PKZ852.
     Brisk Wind Advisory for PKZ853.
     Brisk Wind Advisory for PKZ857.
&&

$$

BT