650
FXAK69 PAFG 052301
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
301 PM AKDT Wed Jun 5 2024

.SYNOPSIS...
As of this afternoon, scattered showers and thunderstorms have
developed over the central, east-central, and southeastern
Interior Alaska some with frequent lightning, heavy rainfall,
gusty winds, and some small to moderate sized hail. The
thunderstorm risk continues through that region into Friday with
diminishing intensity and coverage through that timeframe.

&&

.DISCUSSION...
Analysis...A weakening upper level low remains over the northern
Gulf, which has generally been helping to give the interior
southeasterly flow. Multiple rounds of shortwave troughs with
associated vort-maxes will traverse the region through the end of
the work-week providing additional lift for showers and
thunderstorm development. The strongest shortwave trough of low
pressure currently centered over the eastern Interior will
continue its trek northwestward while weakening and eventually
getting absorbed into the flow through Friday off the NW coast. A
few weaker shortwave troughs will follow shortly behind it which
will help provide some lift for some more showers and
thunderstorms into Friday. Friday and beyond, higher pressure
looks to build in from the east, which will act to dry out the
region.

Central and Eastern Interior...
This afternoon, we are seeing showers and thunderstorms develop
and traverse northwestward through the area. A shortwave moving
over the area from the east is acting to enhance development of
the cells. Showers moistening the SFC over the area overnight and
this morning, CAPE values of up to around 1,000 J/kg with todays
wave with LI values of down to around -3 have the local atmosphere
essentially primed for scattered to numerous thunderstorm
development this afternoon. Some areas may receive  to around 1
inch of rainfall with the heavier and more persistent storms,
which may cause some urban and small stream flooding concerns,
especially in the Fairbanks area. Topographic enhancement may also
occur in some areas in the region with some showers and
thunderstorms. Frequent lightning, strong winds, and small to
moderate sized hail of less than 1 inch in diameter are occurring
and hail up to 1.25 inches is also possible with these storms.
Easterly winds increasing with height will also help to allow a
westward tilt of the thunderstorm column, which will increase the
likelihood of hail in any strong enough thunderstorms that do
develop. The following weaker shortwave troughs moving through the
area into Friday look quite a bit less impactful as far as
intensity and coverage of shower and thunderstorm development. A
Wind Advisory also remains in effect from 6AM Thursday until 4 AM
Friday for gusts up to 60 mph for the Eastern Alaska Range north
of Trims Camp. High temperatures over the area will remain warm
through the period with some areas continuing to reach into the
70s through the next several days.

West Coast and Western Interior...
There is a chance for isolated thunderstorms for the western
Interior as peak heating of the day approaches this evening. These
storms will be weaker than the ones over the Central and Eastern
Interior as you progress westward and may contain brief heavy
rainfall, gusty winds, and small hail. The cause of these storms
will be the shortwave moving westward over this area into
Thursday. Friday, a drying trend begins with only a few showers
possible.

North Slope and Brooks Range...
Once again, fog and low stratus will remain as general onshore
flow continues through the period from the sea ice, which will
keep temps lowered to near their dewpoints. High temperatures will
range from the 30s and 40s along the coast and reaching into the
60s in the Brooks Range. Isolated showers and thunderstorms are
possible for the central and eastern Brooks Range through
Thursday. Friday will be more benign with isolated showers in the
west as the shortwave drifts northwestward away from the region.
SW flow begins on Friday, which will work to erode cloud cover
near North Slope coastal areas, which will allow temperatures to
rise well into the 40s.

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

&&

.FIRE WEATHER...

SFC moisture and RH values are improving for the Yukon Flats area.
Showers that moved yesterday through the overnight have helped
that situation. Temperatures will be slightly cooler, but remain
on the warm side through the next several days. Some of the
scattered to numerous thunderstorms through this evening may
produce frequent lightning, which could act to spark a wildfire or
2. Model forecast CAPE of around 1,000 J/kg and LI values down to
around -3 will help produce thunderstorms with locally heavy
rainfall with up to around an inch of accumulation with the
heavier more persistent storms and with local enhancement from a
topography that the storms experience. Gusty winds and small to
moderate hail are also possible. Storms originate in the Tanana
Valley and push northwestward through the evening.

&&

.HYDROLOGY...

Recently received snowfall present in the Brooks Range / North Slope
area along with warming temperatures will promote snowmelt,
giving the potential for high water for the Colville, Sag, and
Kuparuk rivers and their tributaries. There are some ice jams
present on the Colville, which will enhance any flooding threat.
Water levels are expected to crest by the end of this week into
the weekend. The water level in Fort Yukon will continue receding
very slowly. Satellites and ground observations continue to
indicate plenty of snow in the Porcupine Mountains. As
temperatures continue to warm over the next few days, snowmelt
could lead to continued high water for streams in that area.

Widespread showers and scattered thunderstorms are developing
early this afternoon over the Interior from Denali Park to
Fairbanks to the White Mountains. Areas of heavy rain bring the
risk of small stream flooding over steep terrain in the hills
north and east of Fairbanks and the Alaska Range near Denali Park
this afternoon and evening. There is the possibility of urban
street flooding should the heavy showers fall over Fairbanks and
North Pole this afternoon and evening. People in the Eastern
Interior should be alert to severe weather this afternoon and
evening. The storms will move northwest this evening over the
Central and Northern Interior, and storms should diminish from
Fairbanks south by 9 pm.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Wind Advisory for AKZ849.
PK...Small Craft Advisory for PKZ806-854-856.
     Small Craft Advisory for PKZ810-811-857.
     Small Craft Advisory for PKZ816-817-851.
     Brisk Wind Advisory for PKZ859-860.
     Brisk Wind Advisory for PKZ861.
&&

$$