481
FXAK69 PAFG 102300
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
300 PM AKDT Mon Jun 10 2024

.SYNOPSIS...
Showers and thunderstorms will be possible the next few days over
most of the S Interior and Alaska Range. It will also be a bit
cooler from the recent very warm temps. Some rains will 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 572 dam high latitude block over the arctic with
an undercutting upper low digging into the E Interior. There is a
very large closed low over the Gulf of AK, with heights around 533
dam. There is a weak easterly wave over the W Interior, with
another one over the ALCAN border near Eagle. A remnant thermal
trough is in place over the S Interior with the surface pressure
around 1000 mb.

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

Central and Eastern Interior...
Showers become numerous by this evening with isolated
thunderstorms and heavy rain showers. Locally heavy rainfall will
be possible from the White Mtns southward to the Lower Tanana
Valley. Cooler and showery weather continues Tuesday 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 Thu, as well, pretty much across the entire
Interior with the warming temps.

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...
A bit of clearing skies developed overnight, but with northeast
winds and high pressure over the Arctic, more stratus and fog will
move in later today and tonight, and likely move back to the
Brooks Range. There is very little change in weather the next few
days, with persistent 15 to 30 mph northeast winds, strongest over
the W Arctic.

Extended Forecast Days 4-7...
Temps 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 can`t completely ignore that scenario, only saying
that there is a much higher prob of the ridging scenario. Either
way, it does look cooler out west as south winds will advect
marine air north 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, widely scattered thunderstorms will develop late this
afternoon and evening across the Fortymile and Upper Chena Basin
into the Tanana Valley, with another area across the W Interior to
the S Seward Peninsula. Tuesday and Wednesday, the thermal trough
is weakened, 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 beginning this evening and into Wednesday evening.

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

The Sagavanirktok River near Pump Station 3 crested on Saturday,
and that high water is expected to reach the coast late today or
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 is cresting today, 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 Tuesday 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.
     Brisk Wind Advisory for PKZ807.
     Gale Warning for PKZ811.
     Small Craft Advisory for PKZ812-858.
     Small Craft Advisory for PKZ816.
     Small Craft Advisory for PKZ817-853.
     Small Craft Advisory for PKZ856.
     Gale Warning for PKZ857.
&&

$$

Ahsenmacher
Hydro: JB