Gale Warning 162, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
255 PM AKDT Fri Jul 31 2020

.SHORT TERM.../Through Saturday night/...A low that has been
nearly stationary south of the Gulf for the past couple days has
begun to move north, bringing with it rain showers. Additionally,
easterly wave showers and some thunderstorms are tracking north
over western British Columbia. On satellite imagery, the
distinction between the easterly wave and the clouds associated
with the low is becoming more and more vague. Cloud cover over
Southeast Alaska will steadily increase this evening as the rain
showers approach. Over the inner channels, gusty winds will
accompany the stronger bands of showers as they move north and
this was depicted very well by the previous shift. Changes were
made to winds over the gulf based on very good model agreement
between the GFS and the Canadian NH, resulting in an area of gales
associated with the low as it moves north.

Very warm temperatures have been observed with at least two
locations reporting temperatures above 90 degrees as of early this
afternoon. A cooler airmass will move in behind the low. This in
addition to the increased cloud cover and precipitation will
result in significantly cooler temperatures tomorrow. Shower
activity will continue through Saturday afternoon. A developing
wave south of the Gulf will move northeast and over the southern
Panhandle by late Sunday night

Overall short term forecast confidence is average.

.LONG TERM...Sunday through Friday...As of 10PM Thu...Long term
pattern looks to provide fairly consistent wet and cool
conditions for the panhandle next week. At the onset of the
forecast, the first of three distinct rainy periods will be in
progress, brought upon by onshore flow ahead of a sfc trough just
off the coast. In terms of rain, this particular event looks to be
on of the least impactful for the week with about a half an inch
of rain or less expected across the panhandle before the trough
dissipates on Monday. A low moving through the northern Gulf
begins to exert its influence on the region on Tuesday and early
appearances indicate that this event should be a bigger rain maker
than it's predecessor. Further, while the current forecast shows
winds of 15 to 20 kt in the Gulf during this event, future
permutations of the forecast could very well see these numbers
trend upward. Yet another front begins to move in on Friday, once
again bringing an increased chance of rain and potentially windy
condition. In between these three separate systems, onshore flow
should keep shower potential alive across the panhandle.

.HYDROLOGY...A flood warning remains in effect for the Mendenhall
River due to a glacial lake outburst from Suicide basin. As of
early this afternoon, the Mendenhall Lake had risen to minor flood
stage of 9 feet. The forecast crest is 10.2 feet, or moderate
flood stage, late Friday night. A glacial lake outburst on the
Salmon River near Hyder is also still in progress. The forecast
crest for that river is between 26 and 28 feet.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Areal Flood Warning until 10 AM AKDT Saturday for AKZ025.
MARINE...Gale Warning for PKZ043-051.
     Small Craft Advisory for PKZ012-031-035-036-041-042-052.

&&

Fritsch/CDC/JDR

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

Special Weather Statement
National Weather Service Juneau AK
1019 AM AKDT Fri Jul 31 2020

AKZ029-011830-
Misty Fjords-
Including the city of Hyder
1019 AM AKDT Fri Jul 31 2020

A glacially dammed lake on the Salmon River near Hyder began to
release on Thursday, July 30th 2020. This is a yearly event
lasting 4 to 5 days. As of mid morning today, 31 July 2020, the
river stage was at 24.5 feet. The Salmon River is expected to
rise as much as 3 more feet over the next 2 to 3 days and crest
this weekend with a stage between 26 and 28 feet at the USGS river
gauge.

Anyone near the river should monitor conditions closely and expect
rising water levels, increased riverbank erosion, and potential
debris in the river. NWS Juneau will continue to monitor this
situation.

FCF