Severe Thunderstorm Warning 1, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
257 PM AKDT Thu Jun 27 2019

.SHORT TERM...Seasonably warm temperatures will persist over the
next few days. This afternoon temperatures have already warmed up
beyond 80 degrees across much of southeast Alaska with a few
"cooler spots" staying in the upper 60s and low 70s. The hot
weather may be of big impact to some; however, the aspect of
today's forecast with the potentially the biggest impacts is the
thunderstorm potential.

Taking a quick glance at satellite imagery, cumulus development
can be seen over the central and southern inner channels with the
greatest development over Misty Fjords. Additionally the global
lightning detection network has picked up on a fair amount of
lightning activity out of a few of the showers over the area.
Scattered thunderstorms are expected through this evening over
Misty Fjords, with a slight chance of thunderstorms remaining in
the forecast everywhere south of Fredrick Sound.

The current satellite imagery/conditions is in good agreement with
the forecast update that was done late this morning, so no change
was made to the convective portion of the forecast. Overall
forecast confidence is high over the next 48 hours.

.LONG TERM.../ Saturday to Thursday as of 10 pm Wednesday / The
break down of the blocking ridge over the Gulf of Alaska is
expected Saturday to Sunday. This leaves a flatter ridge headed
into the western and central gulf.  Longer range solutions
started shifting its plan to a broad ridge over the western gulf
and a weak trough along the panhandle and northeast gulf coast.

Expect the temperatures to stay on the warm sides, with warm
anomalies starting at up to +4 standard deviations to +2 standard
deviations into the early the next week. Temperatures will be
above average ranging from the upper 70s to around 80, and then
slowly cooling to the upper 60s. We needed to warm the
temperatures through the weekend and needed to lower pops for the
weekend and into early next week. Right now it looks as if the
best PoPs will be 20 to 30 percent mainly near the coast mountains
or northern Lynn Canal.

Winds over the gulf also got an refresh as a surface ridge was
needed to be added to the western gulf and forced a shift in wind
directions to a southwest or west across the gulf to the
panhandle.

&&

.FIRE WEATHER...Downsloping (drying winds) will continue over the
Panhandle through tonight. This will couple with the very high
temperatures, which are in excess of 80 degrees across most of
the northern Panhandle currently. Thus the fire weather threat is
much higher than we typically see in southeast Alaska and the
Haines, Skagway, and Juneau areas all remain under a red flag
warning through 10 PM tonight. In addition, fire danger is higher
than normal (bordering red flag criteria) for areas near Yakutat,
Glacier Bay, and Chichagof Island. Another caveat to the fire
weather danger is thunderstorm activity over Misty Fjords through
this evening.

Friday winds will be a bit weaker and temperatures will be a few
degrees cooler, but further red flag warnings may be needed
tomorrow.

&&

.Hydrology...Under this prolonged warm spell of air, significant
snow and glacial melt will drive significant rises along the
Taiya River. This is expected to peak tomorrow afternoon with
minor flooding possible along the Taiya River. With a forecast
crest of 16.5 ft. portions of the Chilkoot Trail will begin to
inundate with water.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Red Flag Warning until 10 PM AKDT this evening for AKZ018-019-
     025.
     Flood Watch from Friday afternoon through Sunday morning for
     AKZ018.
MARINE...Small Craft Advisory for PKZ022.

&&

JB/Bezenek

Visit us at http://www.weather.gov/Juneau

Special Weather Statement
National Weather Service Juneau AK
108 PM AKDT Thu Jun 27 2019

AKZ019-280915-
Haines Borough and Lynn Canal-
Including the city of Haines
108 PM AKDT Thu Jun 27 2019

...RISING RIVER LEVELS THROUGH SUNDAY...

Near record high temperatures the next several days will cause
additional snow and glacial melt into the Chilkat River basin. As
a result, the river will crest higher with each day, approaching
bankful late Friday night into Saturday morning. Users in this
area should take extra caution near the river in the next few days
and over the weekend.