Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 12/11/22
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
415 PM AKST Sat Dec 10 2022
.SHORT TERM.../Through Sunday night/...A developing low south of
the Alaska Peninsula as of this afternoon will track to the
northeast and intensify to storm force during this short term
forecast period. The associated front will produce heavy snow over
the northeast Gulf Coast beginning Sunday afternoon and a winter
storm warning has been issued through Sunday night. There will be
a rapid transition to rain early on Monday on top of the snow
which will complicate snow removal. Further east, snow will begin
Sunday evening and spread south through Monday evening. The
potential for heavy snow is greatest over the northern third of
the Panhandle with a 24 hour total of 6 inches or more.
Accordingly, a winter storm watch has been issued for Sunday
evening through Monday evening for the northern outer coast and
inland locations north of Tenakee Inlet and Tracy Arm.
.LONG TERM...As the main parent low in the northern central gulf as a weather front moves
across SEAK. A low will try to develop along the front as it drifts
into the eastern gulf. With that said, precipitation will continue to
fall across the region with most of this precipitation falling as snow
across the central and northern panhandle while coastal areas and the
southern panhandle will see more rain or a rain snow mix during the day
on Monday. Went ahead and issued a winter storm watch for the Icy
Strait corridor and N Lynn Canal locations for the potential of
accumulating snow throughout the day on Monday of 6 to 12 inches.
Precipitation type will switch over to rain as a wave rotates around
the parent low for most locations through late Monday afternoon as
winds mix down to scour out any cold air that was left neat the
surface. Some locattions will change later that will affect snow
accumulations. Winds during this time will strengthen as they are able
to mix throughout the area Monday evening with south marine winds
increasing along with land wind gusts. Winds offshore will be Gales
throughout the day Monday before weakening behind the front. The
exception for this will be locations that do not see the winds mix into
the area which will stay as a mix or straight snow during this time. As
the front moves through, precipitation will become more showery during
the day on Tuesday. Expect to see a switch back to mix or straight snow
throughout the day Tuesday across the Panhandle with the exception of
the far Southern Panhandle which will remain as rain.
Throughout the week, the pattern looks to remain unsettled with
showers remaining across the region. An exception to this right now
looks to be the Yakutat region as precipitation looks to be more
uniform for this area and less showery in nature. Towards the end of
the week, the pattern changes from a more wet pattern to a drier
trend with most places drying out by the end of the week. Current
CPC guidance points towards a cooler and drier pattern for the next
six to ten days for SE AK.
&&
.AVIATION.../Through 00Z Monday/...VFR CIG and VIS conditions are
expected to continue through the 24-hour period as the region will
remain under the influence of a strong dominant ridge of high
pressure centered over the Canadian Yukon. The only exception will
be the Yakutat area as a frontal system will be approaching and
bringing chances of snow to that area, lowing CIG and VIS conditions
to within the MVFR category by the late morning / early afternoon
timeframe. Continued strong northerly outflow winds over the
northern Inner Channels, blowing at an increased magnitude out of
interior Passages, from a tight pressure gradient between the
aforementioned area of high pressure and lower pressure poised south
of the Panhandle may cause impacts in terms of low-level turbulence
via increased winds blowing out of interior passages such as the
Taku and Taiya Inlets along with several others adjacent to those
may create moderate turbulence for low-flying aircraft into Sunday
morning. These winds will begin diminishing Sunday morning and will
continue diminishing to benign magnitudes through the end of the
period.
&&
.MARINE...Prior to the arrival of the front discussed above,
gales will continue over Lynn Canal tonight with freezing spray
expected north of Berners Bay as well as in Taku Inlet. Winds will
diminish through the day Sunday, weakening to 20 kts by late
Sunday afternoon. On the outside, winds will begin to increase
through Sunday night, reaching storm force west of Icy Bay Prior
to Monday morning. Gales will extend south past Cape decision by
Monday afternoon before diminishing early on in the extended range
forecast period.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning from 3 PM Sunday to 6 AM AKST Monday for
AKZ317.
Winter Storm Watch from Sunday evening through Monday evening
for AKZ318>322-325.
Strong Wind until 3 PM AKST this afternoon for AKZ319-325.
MARINE...Gale Warning for PKZ012-013-031-052.
Small Craft Advisory for PKZ011-021-022-032>034-041>043-051-053.
&&
$$
SHORT TERM...Fritsch
LONG TERM....ABJ/SEF
AVIATION...JLC
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