809
FXAK69 PAFG 111324
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
524 AM AKDT Tue Jun 11 2024

.SYNOPSIS...
Showers and thunderstorms will remain possible the next few days over
most of the S Interior and Alaska Range. It will also be a little bit
cooler from the recent very warm temps. Some rains may be locally
heavy, especially across the Alaska Range where a couple inches or
more of rainfall is possible.

&&

.DISCUSSION...

Upper Levels and Analysis...
There is a strong high latitude blocking high over the arctic with
an undercutting upper low digging into the eastern Interior. There is a
very large closed low over the Gulf of AK. There is a weak easterly
wave over the western Interior, with another one over the ALCAN border
near Eagle. A weak remnant thermal trough is in place over the southern
Interior.

Model Discussion...
The models remain in good agreement overall, but they are still not
in great agreement with the heavier precipitation potential across
the Alaska Range and southern Interior, with enough variance to keep the
forecast somewhat uncertain on exactly where the heaviest precipitation
will fall. For now, we will continue with moderate precipitation over the
entire Alaska Range and across most of the southern Interior. We favor a
blend to all models for precipitation , thunderstorm chances, and temperatures.
We favor the NAM-Nest for winds.

Central and Eastern Interior...
Cooler and showery weather continues today with heavier
showers over the Alaska Range, with the general pattern persisting
into Wednesday. Ridging aloft will slowly build in Thursday and
temps will be warming up over the Interior, with showers still
over the Alaska Range and far S Interior. Isolated thunder chances
will be possible on Thursday, as well, pretty much across the entire
Interior with the warming temperatures.

West Coast and Western Interior...
Warming temps over the Interior and Seward Peninsula will allow
for afternoon and evening thunderstorms, which will move across
the Peninsula and into Norton Sound this evening. Some storms may
be strong. Isolated thunderstorms will continue to be possible
over the Interior along a weak thermal trough through Wed. North
winds over the Bering Strait continue, with periods of fog and
stratus. The pattern changes on Wed night and Thu as a cold front
moves in from the south and temps fall a bit.

North Slope and Brooks Range...
Once again, more stratus and fog moved in during the evening and
overnight for the North Slope. There is very little change in weather
the next few days, with persistent 15 to 30 mph northeast winds,
strongest over the western Arctic.

Extended Forecast Days 3-6...Temperatures are warming again as
ridging aloft develops Friday into Saturday. Massive global model
differences develop by late weekend as some of the models are now
trying to crash in a strong Arctic trough into the Mainland,
looping the West Coast trough inland. The ECMWF and Canadian
models are doing this, with the GFS/GEFS/Icon, and ECMWF AI
machine learning models not showing anything of the sort, and
instead depict strong ridging and considerable warming. The
forecast discrepancy is fairly stark, and while the arctic trough
scenario almost seems implausible in mid-June, we cannot
completely ignore that scenario, only saying that there is a much
higher probability of the ridging scenario. Either way, it does
look cooler out west as south winds will advect marine air
northward and onto the coast.

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

&&

.FIRE WEATHER...
Cooler and wetter over the S Interior to Alaska Range, with good
chances of wetting rains through Wednesday south of the White
Mtns. Today and Wednesday, the thermal trough will weaken, but
there will still be isolated thunderstorms across most of the S
Interior to the Yukon Valley, with an area of widely scattered
thunder over the Fortymile Uplands. Temps across the board are
cooler and it will be much damper, with the lone region of 20
percent RHs over the Yukon Flats.

&&

.HYDROLOGY...
Heavy showers over the next few days will result in the potential
for 1-3 inches of rainfall across parts of the Alaska Range, which
will likely result in fast stream rises and overall rises along
all rivers draining the Alaska Range. Residents should be aware of
the possibility of quick river rises with heavy rainfalls
generally lasting into Wednesday evening.

High water from snowmelt will make its way down rivers on the
Central North Slope over the next several days, and minor flooding
remains possible.

The Sagavanirktok River near Pump Station 3 crested on Saturday,
and that high water is expected to reach the coast Tuesday. Water
will be near bankfull, with minor flooding of low lying areas
downstream of Pump Station 3 possible over the next several days.

The Colville River at Umiat crested Monday, and that high water
will reach the coast on Wednesday. Ice jams on the Colville River
downstream of Nuiqsut this past weekend may remain in place, so as
the high water gets there late today and Wednesday, it is
possible that minor flooding could occur.

On the Kuparuk River at the Bridge, moderate flooding is occuring
and the roads approaching the bridge are closed due to high
water. An ice jam appears to be 1 mile downstream of the bridge,
but the location is uncertain. If additional ice and high water
from upstream cause the jam to shift, it is possible the water
could rise further at the bridge. There is a Flood Warning for
this location through 930 PM Tuesday.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ806-854-856.
     Brisk Wind Advisory for PKZ807.
     Small Craft Advisory for PKZ812-857-858.
     Brisk Wind Advisory for PKZ814.
&&

$$