257
FXAK69 PAFG 271520
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
720 AM AKDT Thu Jun 27 2024

.SYNOPSIS...
Today looks to be one of the most impactful weather days of the
summer. Hot and dry conditions will persist across the Interior
and North Slope with even some windy areas in the northern
Interior. Areas of dense smoke from fires burning will reduce
visibility along the Elliott, Steese, and Richardson Highways.
Scattered thunderstorms are expected from the Western Brooks Range
to Fairbanks to the Alcan Border, with strong thunderstorms
continuing overnight on the North Slope. Isolated dry
thunderstorms are expected from Central north to Fort Yukon.
Southeast winds 15 to 25 mph will persist on the west coast south
of Nome bringing elevated water 1 to 2 feet above the normal high
tide line south of the Bering Strait through Friday.

&&

.DISCUSSION...

Analysis and Model Discussion...

A strong ridge of high pressure aloft remains over the eastern
half of Alaska. The high center has shifted north to be over the
eastern North Slope. This brought very warm temperatures across
all of northern Alaska on Wednesday with areas on the North Slope
and Arctic Coast even reaching into the 70s and 80s. The Interior
was mostly in the mid to upper 80s, with low 80s in areas with
smokey skies. The ridge will weaken just slightly on Thursday with
temperatures remaining warm to downright hot. A strong vertically
stacked low will remain in the central Bering Sea. A number of
shortwaves will move through the convergence zone between the low
and the ridge on Thursday afternoon bringing scattered
thunderstorms from the western North Slope southeast to Tanana.
Another shortwave will rotate around the high center to provide
the forcing for scattered thunderstorms over the central and
eastern Interior south of the White Mountains. Isolated dry
thunderstorms are expected from Central north to Fort Yukon. Fortunately,
LCLs look to be substantially lower with more influence from the
Gulf of Alaska tomorrow over the Upper Tanana Valley and storms
there and across the rest of the area should be wet. Perhaps the
most intriguing development in the forecast is the likelihood of
very strong thunderstorms on the North Slope Thursday afternoon
through Friday afternoon. Models continue to indicate areas of
CAPE >1000 J/kg with Lifted Indices as low as -4. Have issued a
Special Weather Statement for this. This is all associated with
both shortwaves moving through the convergence zone and the
shortwave moving around the high to the east. Storms will likely
continue all night Thursday night into Friday and may reach the
coast. These storms may produce hail up to half an inch in
diameter and outflow winds as high as 40 mph.

On Friday, the focus of convection in the Interior shifts to the
Yukon Flats as a shortwave aloft from the south moves over that
area off the high center. Temperatures will be 3 to 5 degrees
cooler than Thursday except in the Yukon Flats, though
temperatures look to warm back up on Saturday. Convection on
Saturday looks to just be isolated over the eastern Interior but
widely scattered right along the Alcan Border and in the SE Brooks
Range.

Models initialized very well with respect to observations aloft
and at the surface, however the HRRR smoke model continuies to
struggle, still showing very dense smoke over the Fairbanks area
despite much of it being cleared out by outflow boundaries
Wednesday evening. Forecast models show above average agreement
aloft through Sunday morning and few differences at the surface
and in precipitation fields. We will use a blend of models for
this forecast package with the changes noted above.

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

&&

.FIRE WEATHER...

Red Flag Warnings are in effect for hot, dry, and windy conditions
today across the northern Interior, and for lightning across the
Central and Eastern Interior. Sustained winds will be around
10-15 mph in the Northern Interior but thunderstorms can cause
erratic wind gusts. A ridge of high pressure in the Interior and
a trough of low pressure in the Bering Sea will create a boundary
from the NW Arctic to the SE Interior where strong, scattered
thunderstorms are expected this afternoon. Most of these
thunderstorms will be wet, however widely scattered to isolated
dry thunderstorms are also possible from Central to Fort Yukon.
Expect today to be one of the biggest thunderstorm days of the
summer across northern Alaska, with strong storms even possible on
the North Slope.

On Friday, a Red Flag Warning is in effect for lightning for the
Yukon Flats and SE Brooks Range where we expect scattered wet
thunderstorms, though an isolated dry storm is possible.
Temperatures will cool slightly and RHs will moderate.

On Saturday, the thunderstorm threat moves to the AlCan border
and remains in the Eastern Brooks Range. For now, widely scattered
wet thunderstorms are expected.

&&

.HYDROLOGY...
Glacial fed rivers including the Tanana are beginning to rise as
warming temperatures lead to increased high elevation snowmelt.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Red Flag Warning for AKZ911-933.
     Red Flag Warning for AKZ912-913-919-931>935-939-943-944-946.
     Dense Smoke Advisory for AKZ834.
     Dense Smoke Advisory for AKZ839-840-844-845.
PK...Small Craft Advisory for PKZ801-802-850-851.
     Small Craft Advisory for PKZ816.
&&

$$

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