Storm Warning 20, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
256 PM AKDT Wed Oct 9 2019

.SHORT TERM...Little in way of changes to the forecast package as
the newer model solutions maintained good agreement. First trough
for the NE gulf coast region tonight with a developing system
moving through the central gulf going towards Prince William Sound
deepening in the upper 970s Thursday. Moisture flow plumes
indicated a substantial amount of available to move through the
panhandle with second wave. The tight pressure gradient ahead of
the front will have strong Gale force to Storm force for Thursday
night and Friday, so will maintain the Wind Watch for the coastal
area from southern Baranof Island to Cape Suckling for the
potential gusts to 60 mph.

Current forecast of increasing winds and rains for the panhandle
looks to be good yet, and then post frontal shower activity into
the panhandle and southern section of the northeast gulf coast
Friday night. Forecast tended to favor the NAM/ECMWF in the model
solutions at present, although GFS not to far off the idea.

.LONG TERM.../Friday through Tuesday as of 10 PM Tuesday/...
Progressive pattern will continue through the next week as a
series of fronts and lows will bring rain to Southeast AK. The
upper level trough will most likely have moved into the E gulf by
Friday morning with an upper low located over the far N gulf.
Strong shortwave vorticity will be rotating around the low
providing the dynamic support within the SWLY flow to bring heavy
rain across much of the panhandle Friday. At the surface a strong
front is looking very likely that it will move across the E gulf
towards the panhandle early Friday morning pushing onshore by
Friday afternoon. The rain will be heavy at times as the front
moves across the panhandle with some gusty winds. At this time
forecasting strong Gales along the front just offshore through
Friday morning, but a few models are hinting at the possibility
that wind speeds may possibly reach storm force. Most inner
channel locations will also see an increase in south and easterly
winds before diminishing late Friday.

Rain will likely be diminishing through the weekend from north to
south. A secondary northerly-stream shortwave will dive SE across
the gulf Saturday. The surface low will move S along with the wave
and weaken, possibly into a trough. By Sunday could possibly see
some light low level offshore flow especially across the N
panhandle as a flat upper ridge moves over rather quickly. Did
decrease POP Sunday but kept areas mostly cloudy. By Monday
another upper trough moves into the gulf likely interacting with
another southern stream wave. Models are in fair agreement of a
low pressure system moving from the NPAC into the gulf early next
week. Still much uncertainty with the evolution of this low
especially with a very strong upper jet forecast to stream across
the Aleutians Monday through Tuesday. Do think rain chances
increase Monday into Tuesday across the panhandle from south to
north. Overall forecast confidence is average.

&&

.HYDROLOGY...Rivers and streams are not threatening flooding
issues for next 24 hours. Increased rainfall amounts for the
Thursday to Friday system as the system moves out of the central
Pacific. Event rainfall looks to be roughly 2 to 4 inches as the
strong system move into the area. Will need to keep an eye on this
situation as we fine tune the rainfall amounts and how the streams
will react going into Friday.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from Thursday morning through Thursday afternoon for
     AKZ019-025.
     High Wind Watch from Thursday evening through Friday morning for
     AKZ017-022-023.
MARINE...Gale Warning for PKZ043-052.
     Small Craft Advisory for PKZ012-013-021-022-031-041-042-051-053.

&&

Bezenek/DDH

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