Gale Warning 167, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
307 PM AKDT Sun May 20 2018

.SHORT TERM...According to current water vapor satellite imagery,
a weakening shortwave can be seen exiting the northeast gulf and
through portions of the northern panhandle of Southeast Alaska.
Most locations are now reporting accumulating precipitation across
the area, and the wind has picked up for a few areas as the weak
front associated with this shortwave exits east through the
panhandle. In addition, our next feature, in the form of a
stronger shortwave, can be seen on satellite. It has begun to lift
northeast as well, where it will eventually cross into the
eastern gulf. This shortwave will be supported by an 85 kt jet
streak aloft, which will provide divergence aloft near the left
exit region and enhance the shortwave. Another weather front
associated with this feature, this one stronger than the previous,
will lift across the eastern gulf tonight, making its way through
the panhandle tomorrow. Conditions will remain relatively wet for
all locations throughout SE Alaska, as the front will provide the
needed lift for precipitation and as the jet streak aloft advects
additional moisture across the panhandle.

We'll see winds increase along the front as it makes its way
across the eastern gulf tonight and onshore tomorrow. High
resolution model guidance at the 925 mb level shows a low level
jet of approximately 40 to 50 kt, which should mix down and
increase winds at the surface. In addition to various marine
hazards, we currently have Strong Wind headlines for land zones
23 and 27, which includes the cities of Sitka, Craig, and
Hydaburg. Gusts at approximately 40 mph can be expected for these
areas as the front passes through. Other areas will most likely
still see windy conditions with gusts in the 30 to 35 mph.

In addition, most locations will lose their normal diurnal heating
curve in regards to temperature. Cloud cover will limit daytime
heating, and warm air advection and mixing ahead of the front
tonight will actually warm temperatures overnight, where the max
temperature actually occurs overnight. Max temps should still be
in the low to mid 50s, with lows in the mid to upper 40s.

For the rest of the timeframe, the rain should linger all the way
through into Tuesday, as the shortwave mentioned previously
stalls over the gulf. The Coast Range along the eastern border
will continue to provide the orographic lift to keep precipitation
chances high for most of the panhandle through this time period.

.LONG TERM.../Tuesday through Sunday as of 10 PM Saturday/
Continued outlook of a wet and cool pattern through next week.
Aloft an upper trough will remain over the Gulf before lifting
out Thursday morning. Meanwhile the surface low in the western
Gulf will weaken until it eventually gets overtaken by the next
front later in the week.

Overall models tend to remain fairly consistent with the idea
that skies will remain cloudy with widespread precipitation across
the panhandle Tuesday. Winds will diminish Tuesday afternoon
becoming fairly light by Wednesday morning. Used GFS/ECMWF to make
minimal changes to the forecast Tuesday and WPC solution through
the weekend. High temperatures expected to remain in the low to
mid 50s through mid-week.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from Monday morning through Monday afternoon for
     AKZ027.
     Strong Wind from late tonight through Monday afternoon for
     AKZ023.
MARINE...Gale Warning for PKZ036-041>043-051-052.
     Small Craft Advisory for PKZ011>013-021-022-031>035.
     Small Craft Advisory due to Seas for PKZ053.

&&

Voveris/DDH

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