171
FXAK69 PAFG 290933
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
133 AM AKDT Wed May 29 2024

.SYNOPSIS...
More summer-like weather returns to the Mainland as we head into
the weekend, with chances for Interior thunderstorms and heavier
rain showers, along with warmer temps. Today will be an active
weather day for the entire S Interior as heavy showers and an
isolated thunderstorm will be possible by late afternoon. Recent heavy
rains over the E Alaska Range and SE Interior will shift westward
and come to an end for the time being.

&&

.DISCUSSION...

Upper Levels and Analysis...
Weak ridging has built over the Mainland with a 555 dam ridge now
in place with that center over the E Brooks Range, but extending
south to include the entire Mainland. There is a departing 526 dam
arctic low over the Chukotsk Peninsula, with another departing
Gulf of AK low, with that center now analyzed around 549 dam.
There is a 531 dam low over the E Aleutians. A weak shortwave
trough, an easterly wave, is moving west over the S Yukon Terr.

Model Discussion...
The models are in much better agreement for the next few days with
only minor discrepancy expected with summer-time convective
season. There will be daily chances for showers and thunderstorms
so a blend of models is favored, as small ripples of energy move
through the flow. This is normal for an easterly flow pattern. We
will favor the hi-res models for winds and a blend of the GFS and
ECMWF for the general details.

Central and Eastern Interior...
Fairly nice day today with warming temps to near 70 over much of
the Interior, then an increasing chance for isolated to widely
scattered thunderstorms in the afternoon, initiating over the
higher terrain east of the Tanana Valley and then moving west
during the late afternoon and evening. Some showers will be rather
heavy and may produce heavy rainfall across the S Interior into
the overnight hours. Thursday will be 5 or so degrees cooler
across the S Interior as south winds push through the Alaska Range
gaps, bringing cooler and more moist marine air inland. Showers
and isolated thunderstorm chances mainly move north of the White
Mtns to the Yukon Flats and Upper Koyukuk Valley. Friday warms
back up into the lower 70s with chances for showers and an
isolated thunderstorm, focused over the E Interior and higher
terrain.

West Coast and Western Interior...
Warming temps today with values approaching 70 over the Interior
and 60s over parts of the Seward Pen. Showers and isolated
thunderstorms are likely late this afternoon over the Kuskokwim
Valley and into the Lower Yukon. Some stronger showers and storms
may push out toward the Delta and to the coast. Showers and
thunderstorm chances continue on Thursday and will move north
including the N Interior and Seward Peninsula, which may even see
a thunderstorm or two given the easterly flow aloft. Friday looks
less active, but there will still be an isolated thunderstorm
threat over the Interior to the S Brooks Range, but temps will be
a few degrees cooler.

North Slope and Brooks Range...
Clouds have briefly cleared out over the Arctic as a weak high as
allowed for winds over the immediate coast to switch from onshore
to offshore. Later today and tonight the high builds offshore
which means the low level winds switch back around to northeast,
so expect more widespread stratus and fog to move back in, and
eventually shift all the way down to the slopes of the Brooks
Range. Winds over the W Arctic increase to 25 to 35 mph tonight
through Friday from the northeast.

Extended Forecast Days 4-7...
The suite of global models and their ensembles are beginning to
show a clearer picture of the pattern after Friday, with a large
low over the Gulf of AK and weak Interior ridging building in
slightly from the Yukon, along with another arctic trough digging
into the NW Arctic and then down the West Coast as we head into
the next week. This pattern looks to bring warming temps to
Interior Alaska with widespread values above seasonal norms by
Saturday or Sunday. It also looks more active for thunderstorm
chances. Out west, it looks like a return to north winds and
slightly cooler temps, but otherwise probably on the sunnier side.

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

&&

.FIRE WEATHER...
Isolated to widely scattered wet thunderstorms are expected today
as an easterly wave moves across the E Interior and across the S
Interior. The best chance for thunderstorms will generally remain
over the higher elevations east of the Tanana Valley, with heavier
rain showers as they move into the valley. Any storms will be very
wet. Early afternoon temps will push into the 70s before clouds
and showers drop those values. Out west, a secondary thermal
trough will spark of isolated wet thunderstorms over the Kusko
Valley to the Lower Yukon. It too will be warmer today before
cooling tomorrow as the thermal trough lifts north toward the
Middle Yukon Valley to the Yukon Flats. Expect the S Interior to
be cooler Thu before warming back up Fri.

By this weekend, it looks to be warming above seasonal norms for
the Interior for several days, along with increased chances for
thunderstorms.

&&

.HYDROLOGY...
The water level in Fort Yukon will crest the mid-week. Minor
flooding will continue through at least the middle of the week,
with water receding very slowly by late in the week. Satellites
and ground observations continue to indicate abundant snow in the
Porcupine Mountains. As temperatures warm this week, snowmelt
could lead to continued high water along the Porcupine and the
interrelated sloughs.

Rainfall has resulted in some minor stream flooding in the E
Alaska Range where 1 to 2 inches of rainfall has fallen along with
higher elevation snow. A flood advisory is out for the E Alaska
Range from just east of the Richardson Highway to north and east
of Mentasta Pass. With less rainfall projected in the next 72
hours, water levels should come down. There are no significant
hydro concerns for now for the larger stem rivers as they remain
low.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Flood Warning AKZ833
PK...Small Craft Advisory for PKZ806.
     Brisk Wind Advisory for PKZ807.
     Small Craft Advisory for PKZ816-817.
     Small Craft Advisory for PKZ851.
     Small Craft Advisory for PKZ854.
     Brisk Wind Advisory for PKZ856.
&&

$$

Ahsenmacher