Alaska, 2017

High Wind in Alaska, July 8, 2017

July 8, 2017 · NWS AFG · 1 event in 1 county or zone

An unusually strong bow echo signature cluster of thunderstorms produced strong winds for portions of the southern Interior centralized around the Delta Junction Area, Fort Greely and Quartz Lake. Straight-line winds from the east peaked at 50 to 60 mph with heavy rain and numerous lightning strikes during the early evening of July 8th.

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS AFG wrote it up.

An unusually strong bow echo signature cluster of thunderstorms produced strong winds for portions of the southern Interior centralized around the Delta Junction Area, Fort Greely and Quartz Lake. Straight-line winds from the east peaked at 50 to 60 mph with heavy rain and numerous lightning strikes during the early evening of July 8th. |The quick moving storms produced significant damage to power lines and cellular towers. 12 transformers needed repairing due to downed trees. Power outages lasted 24 hours for some residents.

Zone 223: U.S. Army Fort Greely mesonet reported 58 mph (51 kt).

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Fairbanks, AK wrote its last area forecast discussion before the first event at Jul 8, 12:28 PM AKST, 6 hours 8 minutes earlier.

Area forecast discussion, Jul 8, 12:28 PM AKST, 6 hours 8 minutes before
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
128 PM AKDT Sat Jul 8 2017

.DISCUSSION...
Active weather pattern continues over the interior with a triple
shot of weather systems bringing periods of rain over the
southeastern interior and Alaska Range through Wednesday of next
week. The triple shot of precipitation will add to ongoing
elevated water levels along streams and rivers draining the Alaska
Range and southeastern interior. Fire weather remains active with
persistent hot, dry and windy weather conditions and ongoing Red
Flag Warnings over the northeast interior. In addition another
active thunderstorm day is expected late late afternoon and
evening along a line from near Eagle to Fairbanks to near Lake
Minchumina with the potential for hail, heavy rain and strong
winds.

Aloft at 500 mb, an eat-west oriented ridge stretches along a Nome
to Fort Yukon line and will continue to move slowly north over
the next several days to be located along the crest of the Brooks
Range Sunday and over the North Slope and McKenzie Delta Monday.
As the ridge moves slowly north a series of shortwaves will
move from east to west along the southern boundary of the ridge.
The timing and track of each of these waves varies slightly with
each model run and model family however the concensus of the
models indicate a very wet weekend and start to the work week for
the southern interior and Alaska Range.

Multi rain events to impact the southeast interior and eastern
Alaska Range. The first rain event will move over the Alaska
Range this evening. The heaviest rain is expected over the Alaska
Range and areas just north of the range. Special Weather
Statements covering rapidly rising water levels, elevated water
levels and outdoor activities have been issued. The first round of
rain should be winding down mid day Sunday with storm totals on
in the Alaska Range expected to be in the 1 to 1.5 range. The
second round of rain is expected to begin late Sunday night and
continue into Monday. Areas just north of the Alaska Range are in
the cross hairs on this event with storm totals on this event
reaching 0.5 to 1 inch by mid day Monday. The latest models
continue to indicate yet another round of rain moving over the
southeast interior and eastern Alaska Range Tuesday and Wednesday.
Favorable upslope flow for the Eastern Alaska Range could produce
another 1 to 1.5 inches of rain on Tuesday and Wednesday.

Over the northeast interior Hot, dry and breezy conditions will
continue today with Red Flag Warnings ongoing for the southeast
Brooks Range as well as for the Yukon Flats and surrounding
uplands. Temperatures will climb again today into the 80s while
minimum relative humidities fall into the 20s this afternoon and
evening. Winds are expected to increase this afternoon and
continue overnight as a pressure gradient between a 1016 mb high
over the North Slope and a devloping 1006 low over the southeast
interior increases. Humidity levels will increase on Sunday as the
rain maker over the southern interior pulls in a more moist
airmass into the northern interior. Red Flag criteria for minimum
humidity is not expected to be reached Sunday or Monday.
Thunderstorm activity over the northeast interior and southeast
interior is expected to increase Sunday and Monday as the capping
upper level ridge moves north and low level moisture moves into
the area.

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

&&

.FIRE WEATHER...
Fire weather concerns continue to focus on the northeast interior
as Hot, dry and breezy conditions continue today. Red Flag
Warnings are ongoing for the southeast Brooks Range as well as
for the Yukon Flats and surrounding uplands. Temperatures will
climb again today into the 80s while minimum relative humidities
fall into the 20s this afternoon and evening. Winds are expected
to increase this afternoon and continue overnight as a pressure
gradient between a 1016 mb high over the North Slope and a
devloping 1006 low over the southeast interior increases. Humidity
levels will increase on Sunday as the rain maker over the
southern interior pulls in a more moist airmass into the northern
interior. Red Flag criteria for minimum humidity is not expected
to be reached Sunday or Monday. Thunderstorm activity over the
northeast interior and southeast interior is expected to increase
Sunday and Monday as the capping upper level ridge moves north and
low level moisture moves into the area.

&&

.HYDROLOGY...
Multiple rain events to impact the southeast interior and eastern
Alaska Range through Wednesday of next week. The first rain event
will move over the Alaska Range and adjacent areas to the north this
evening. The heaviest rain is expected over the Alaska Range and
areas just north of the range. Special Weather Statements covering
rapidly rising water levels, elevated water levels and outdoor
activities have been issued. The first round of rain should be
winding down mid day Sunday with storm totals on in the Alaska
Range expected to be in the 1 to 1.5 range. The second round of
rain is expected to begin late Sunday night and continue into
Monday. Areas just north of the Alaska Range are in the cross
hairs on this event with storm totals on this event reaching 0.5
to 1 inch by mid day Monday. The latest models continue to
indicate yet another round of rain moving over the southeast
interior and eastern Alaska Range Tuesday and Wednesday. Favorable
upslope flow for the Eastern Alaska Range could produce another 1
to 1.5 inches of rain on Tuesday and Wednesday.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning for AKZ218-AKZ220.
&&

CCC JUL 17

In the hours before

Special weather statement, Jul 8, 1:56 PM AKST, 4 hours 40 minutes before
Special Weather Statement
National Weather Service Fairbanks AK
256 PM AKDT Sat Jul 8 2017

AKZ221>224-100200-
Central Interior-Middle Tanana Valley-Deltana and Tanana Flats-
Upper Tanana Valley and the Fortymile Country-
Including Nenana, Anderson, Tanana, Minto, Manley Hot Springs,
Rampart, Lake Minchumina, Livengood, Fairbanks, Fort Wainwright,
Eielson AFB, Ester, North Pole, Moose Creek, Two Rivers, Fox,
Chatanika, Chena Hot Springs, Sourdough Camp, Salcha,
Delta Junction, Fort Greely, Harding/Birch Lake, Dry Creek,
Dot Lake, Healy Lake, Tok, Tanacross, Eagle, Tetlin, Northway,
Alcan, Chicken, and Boundary
256 PM AKDT Sat Jul 8 2017

...Rising Water Levels on the Tanana River...

The Tanana River will gradually rise through next week and may
approach bankfull levels in some locations. This rise in water
levels is due to recent heavy rain in the Eastern Alaska Range and
warm temperatures which have increased glacial runoff. Several
weather systems are forecast to move into the eastern Interior
this weekend and early next week and bring more rain to the
region. In addition to rising water levels, bank erosion is
expected to increase and most sandbars will be covered with water
through much of next week.

CCC
Special weather statement, Jul 8, 5:12 PM AKST, 1 hour 24 minutes before
Special Weather Statement
National Weather Service Fairbanks AK
612 PM AKDT Sat Jul 8 2017

AKZ223-224-090415-
Deltana and Tanana Flats-
Upper Tanana Valley and the Fortymile Country-
Including Salcha, Delta Junction, Fort Greely,
Harding/Birch Lake, Dry Creek, Dot Lake, Healy Lake, Tok,
Tanacross, Eagle, Tetlin, Northway, Alcan, Chicken, and Boundary
612 PM AKDT Sat Jul 8 2017

...Strong to Severe Thunderstorms Possible this Evening...

At 545 pm, a line of strong to severe thunderstorms was detected
by radar about 10 miles east of Healy Lake, moving west at 30 mph.
If this line of thunderstorms can maintain strength, they will
impact the Delta Junction area around 7 pm this evening. Residents
in the Delta Junction area should monitor weather conditons
closely and be alert for possible warnings this evening.

Event by event

1 high wind. Local standard time, as filed.

High Wind, Deltana and Tanana

When
July 8, 6:36 PM AKST to 7:00 PM AKST
Where
Deltana and Tanana forecast zone
Measured
51 kt (59 mph) measured gust
Reported by
Mesonet

What these are

High Wind
Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Alaska in 2017Every state in 2017This day in weather historyWarnings in Alaska, July 2017

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 716384.