Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 182045
Area Forecast Discussion
National Weather Service Goodland KS
145 PM MST Wed Jan 18 2017
Issued at 1031 AM MST Wed Jan 18 2017
Update to going forecast to add in a few isolated showers to far
E/NE locales. Latest radar loop shows scattered rain showers.
Current trend/track may pinwheel these back into E/SE zones over
the next couple hours. Adjusted sky cover to acct for more
msunny/sunny conditions over past couple hours as well.
.SHORT TERM...(Today through Friday night)
Issued at 325 AM MST Wed Jan 18 2017
Forecast concerns will be fog potential through Thursday night and
the chance of precipitation at the end of this period. Satellite
showing a progressive but somewhat amplified wave train from the
Pacific into the west coast of North America. The flow becomes more
amplified and split over the country. The models started out
well at jet level. At mid levels the Gfs, Ukmet, and Ecmwf were
doing a little better than the other output. Gfs was doing a
little better on the low level thermal field.
Today/tonight...Not a lot of fog going at this time, and it may end
up being mostly frost. There is still some potential there so kept
the mention of patchy freezing fog. Models underdid the warming
yesterday. The surface winds will not be as favorable as yesterday.
At this time I raised the high temperatures a little.
Models indicate a large increase in low level moisture during the
later half of the night. Model output shows fog developing but
differs on timing. The most aggressive, the Nam and Nmm, seem to
be a little to aggressive. However, there is enough model
consensus and supported by the Sref probabilities that fog plus
the pattern supports it as well that fog was added to the forecast
for after mid night.
As yesterday the models are showing the movement of a closed off mid
level circulation into the area, slower than yesterday, and looks
like it will be about half to two thirds of the way through the area
by the end of the night. The lift is weak and the lapse rates are
not that good. Also soundings show the moisture is shallow so
believe no drizzle or any measurable precipitation will occur in
addition to the fog.
Thursday/Thursday night...Per the discussion above, fog will
continue through mid morning with any drizzle or measurable
precipitation remaining to the east of our area.
Models showing that surface winds will be weak, especially in the
eastern portion of the area. Also models show that low level
moisture stays rather high in the eastern portion as well. At the
very least it looks like that stratus may linger well into the day
which could cut back on the heating and how warm it gets.
For the night for the eastern portion of the area, the low level air
mass does not change much with a continued light wind field. So
expect fog to develop again in the far east and introduced fog
Friday/Friday night...Fog will continue through mid morning once
again. Variable cloud cover will make it difficult to get a good
handle on the high temperatures. At this time made little to no
changes to what the forecast builder gave me.
There is now become a rather big difference in how fast the models
bring the next system through the area for this time period. Not
only that they differ on the strength, position, and how much they
close off the system as it progresses across the area.
First the models for the most part are slower in taking Thursday
system out. Very strong jet is moving into the west side of the
upper trough. At this time am leaning toward the slower arrival of
this system along with being more closed and little further
southwest. In general this would favor the Gfs. In addition model
sounding do not really saturate the column until the mid and late
afternoon hours. This would make sense since the previous would have
pulled the moisture to the east with it.
Whenever the lift and moisture arrives, favorable theta-e lapse
rates will be in place to allow a good response to that lift.
Considering the differences in timing, will keep the blend pops
confined to the afternoon hours but am thinking that precipitation
will wait to the mid and late afternoon hours. At this time will
keep the phase rain. The lift and moisture moves across the area
through the evening with some lingering in the far northeast after
midnight. There will be a transition to a mixture or to all snow.
.LONG TERM...(Thursday night through Wednesday)
Issued at 144 PM MST Wed Jan 18 2017
The extended period is fairly busy with troughs and shortwave ridges
moving over the region quickly. As well as precipitation chances
Friday and Monday night into Tuesday.
To start the period on Thursday night, there is an exiting cut off
low pressure. As this exits to the northeast a shortwave ridge pushes
into the region and quickly pushes east by the early morning hours on
Friday. In return to the ridge moving east a trough begins to push
into the region from the west. This trough is expected to move
through the area during the day and start to form a cut off low
during the late afternoon. This cut off low will push north,
northeast over the region and will create some chances for
precipitation. The afternoon will see rain shower chances and then
will transition to snow showers as the night progresses. Current
guidance does not show a significant accumulation.
Saturday will bring another shortwave ridge as that cut off low
moves out of the region. This ridge will be short lived over the CWA
and will be out of the area by late morning. Again, as the ridge
moves out another closed low pushes into the region. This trough
looks to produce a closed low but, as of current guidance, moves
south of our area. Precipitation chances are low, with the potential
for some rain/snow in our southern counties if the closed low tracks
a little more north.
Sunday and Monday will be similar. The trough on Saturday will push
east and a ridge will start to build over the region on Sunday.
Meanwhile on the west coast another trough develops. By the end of
the day on Monday, that trough will start to force itself into the
CWA. Bringing with it southwest flow and moisture. Current guidance
shows a closed low forming just east of the Rockies and moving right
over the area. This will help with the development of rain and snow.
This same trend will continue into Tuesday before the trough
completely moves out of the region by the end of the day on Tuesday.
This is the best chance for precipitation during the period.
Wednesday, will be embedded under a very broad and deep trough that
is covering a good portion of the CONUS.
Temperatures during the period will be normal Friday through Monday
in the 40s during the day. Tuesday and Wednesday will see a cool
down into the 30s during the day due to a cold frontal passage and
the trough moving over the region.
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1021 AM MST Wed Jan 18 2017
For KGLD...VFR conditions thru 03z Thursday w/ scattered high
clouds. From 03z-14z Thursday...3-6sm in light fog and scattered
low clouds. 14z Thursday onward...VFR w/ scattered mid clouds.
Winds WNW around 10kts thru 21z. 21z this afternoon thru 14z
Thursday...WSW around 10kts. 14z Thursday onward...WNW 5-10kts.
For KMCK...VFR conditions thru 02z Thursday w/ scattered high
clouds. From 02z-08z MVFR fog w/ 5sm visibility at times. From
08z-16z Thursday...IFR fog with visibility down to 2sm and
scattered low clouds. 16z Thursday onward...VFR with scattered low
clouds. Winds WSW around 5kts thru 08z Thursday...then
light/variable thru 16z w/ south winds around 5kts thereafter.