Scientific Forecaster Discussion
Southeast Alaska forecast discussion
National Weather Service Juneau Alaska
405 PM akdt Wednesday Mar 12 2014
Short term...scattered showers over the eastern coastal waters
and moving into the Panhandle are generally small although a few
over the northern portion had reported some ice pellets in it.
The main low center of the next system near Cold Bay with has the
lead frontal band moving across the northern Gulf that will start
to increase the winds over the central Gulf waters and northern
coastal waters tonight. A secondary wave will swing around the
low and then push the frontal band eastward and into the
Panhandle area Thursday. Expect the winds out over the Gulf
waters will increase ahead of the main front to gale force
through early Thursday. Some gusty winds working there way into
the Inner Channels but have keep strong wind headlines at Bay for
Strong gusty winds in the Lynn Canal region this afternoon will
be subsiding through the evening with wind lowering down to a
10 to 20 range. Most of the rest of the Panhandle does not have
the gusty wind but will be increase Thursday afternoon.
The rain spreading will not be falling at the intensity of the
previous storm. Used a blend for model adjustments changes were
Long term...the second atmospheric river will get close to the
Panhandle, but the European model (ecmwf) advertising a little wiggle of a wave
along the front, that may be the reason that qpfs are more
concentrated to the south along the British Columbia coast. In addition, another
system with the momentum of an upper level low swinging eastward
will keep things moving more quickly than the event of yesterday
that gushed rainwaters of 3 to 7 inches across the southern
Panhandle...giving Klawock their 3rd wettest day on record. While
the southern Panhandle...specifically 27 and 28 ground is now
primed and saturated, we should not see the spikes with the last
system. But do expect streams and rivers to rise again Thursday
night...but will not exceed action stages. Another system, right
now, is begin watched for the weekend. This one looks a little
more like the previous system in its slow speed and orientation.
However, the model quantitative precipitation forecast is still not as impressive with this
system. However, should the ridge to the east be stronger than
expected and therefore the front makes less progress eastward and
stalls, qpfs may rise in the forecast. If things look wetter for
weekend, we may issue a hydrologic outlook to prepare the
Refined winds a little with European model (ecmwf) Thursday night across Gulf.
Northern inside passages light northerly. South of
admiralty...winds should remain southerly/easterly. Also boosted
some westerlies across Gulf in line with cold air advection
hugging the surface. 850 winds not anything too strong, but if
hugging the surface, could mean solid small craft for Gulf waters.
Violated the gradient a bit through central regions...as made Icy
Strait westerly with this surge Saturday and Friday night for
northern Chatham making them southerly with 850 winds as opposed
to gradient. Watch for strong winds possible with this front
Thursday evening on Baranof and Prince of Wales islands.
Another front in line for Monday which looks to develop a wave
that may keep qpfs higher than this weekend's system. Ec pointing
a little more for northerly Panhandle while GFS deflects
southward. Differences will be ironed out later.
Some snow may begin to mix with rain Saturday afternoon for much
of the northern Panhandle...and more confident Friday night as the
showers diminish. 850 temperatures still low for south late Friday
night...but southerly winds may keep snow mixing for the evening
and go all rain late. Extended forecast has lots mention of
snow...but in truth, we may be a little on the snowy side...colder
air may be more marine and most snow to fall may be on the wetter
side for sure.
European model (ecmwf) used for model of choice, but most wind changes made for
local effects...although did nudge gradient Thursday night and Friday
public...strong wind until 7 PM akdt this evening for akz018.
Marine...Gale Warning for pkz041>043-051-052.
Small Craft Advisory for pkz011>013-021-022-033>036.
Small Craft Advisory due to seas for pkz053.