Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 211149

Area Forecast Discussion
National Weather Service Goodland KS
449 AM MST Thu Feb 21 2019

.SHORT TERM...(Today through Saturday night)
Issued at 447 AM MST Thu Feb 21 2019

Major forecast concern will be upcoming major storm to affect the
area. Satellite showing an active and amplified flow from the
Pacific into North America. Feature of interest is the strong and
cold storm system developing over the western portion of the country.

Concern with this forecast is whether this system will end up going
too far south. Trends in the models have been going that direction.
The Nam is currently the furthest south, the Gfs the furthest north
and the most favorable for significant snow accumulation, and the
Ecmwf and Canadian in the middle. There is more support for a more
south solution due to what the height fall analysis showed. Current
pattern would also support that as well. Would like to be more
certain getting this close to the event but we are not there yet.

Today/tonight...Latest model output has pulled back from the from
the amount of fog. It still looks like the southwest corner will
have the best chance of freezing fog and kept that in through this

As seen the last few days, jet axis/right rear quadrant moves
over/affects area from late this afternoon into the night with the
strongest affects over the northwest half. From later this afternoon
through the night, a series of shortwave troughs in southwest flow
aloft move through. Later this afternoon both the Gfs and Nam show
some elevated Cape and favorable mid level theta-e lapse rates are
in place with the Nam more robust with the elevated Cape.

So later this afternoon into the middle of the night when the
deepest moisture is in place at the same time as the best forcing,
instability and lapse rates, that will be the best chance for
measurable precipitation until the main event starts. When it gets
to tonight there will be a mixed bag of precipitation along with an
isolated thunderstorm from his afternoon into this evening.

After midnight, the moisture will become more shallow and will
transition to a more freezing drizzle and fog scenario. Based on the
thick cloud cover and easterly component of the wind, I lowered the
high temperatures. Also with the major influx of low level moisture
and higher dewpoints, I raised low temperatures especially in the
eastern portions.

Friday...Depending on the temperature, fog/freezing fog and/or
drizzle/freezing drizzle will continue through the day. Also thick
cloud cover, especially looks to be in place all day, and this makes
sense with a strong lees side trough causing a more easterly
component to the winds. As a result, I lowered the high
temperatures. However I may not have lowered them but they may not
be low enough

Friday night/Saturday...Now this period is where the forecast gets
uncertain, and messy. Models have slowed down the arrival of the mid
level system along with the cold front. In general there looks to be
a mixture of precipitation types through at least midnight and
possibly late into the night due to the later arrival of the cold
front, and most of the area still being on the warm side of the
system. There will be a large influx of low level moisture which will
raise dewpoints and slow down the change in phase as well.

Considering the above plus the system possibly being further south
than what is depicted, there may not be ice in the column and a
complete change over to snow until during the morning Saturday with
Colorado counties having the longest duration of snow. So confidence
is low on snowfall amounts with confidence still low but rising in
having more freezing drizzle and freezing rain.

Based on this, and low confidence of neighbors much like myself, a
watch was not issued. We will continue to message this storm through
social media and HWO. I also will issue a SPS on this. The winds get
stronger and will probably cause issues no match how much or what
combination of ice and snow there will be. If enough snow falls,
then blowing snow will be an issue. If there is more ice on trees
and power lines, then it will be easier to have power outages.

Saturday night...Precipitation will be done, winds will decrease,
and temperatures will be cold, probably not cold enough.

.LONG TERM...(Sunday through Thursday)
Issued at 347 AM MST Thu Feb 21 2019

The extended forecast will be much quieter with below normal temperatures
persisting. The Tri-State region will be under northwest flow as
the winter storm continues to push off to the northeast. Moisture
chances will be limited on Monday to a few light snow showers.

A ridge will be in place over the western CONUS around mid-week.
Currently expecting temperatures to be a little warmer in our
Colorado counties on Tuesday and Wednesday. May need to pull
temps down a little due to snow cover from this weekend`s storm.
The next chance for moisture will be late next week as a shortwave
may develop and move through the region.


.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 445 AM MST Thu Feb 21 2019

At GLD terminal, VFR conditions are expected to prevail through this afternoon.
Southwest winds around 11 kts are expected to continue through
the forecast period. Clouds are expected to move into the region
late this afternoon/early evening with ceilings falling to MVFR
conditions around 03Z. Ceilings are expected to lower through the
evening and overnight as a potent winter storm approaches the
area. Have held off from putting in any precipitation at this
time, however, may see a few light showers in the area toward the
end of the forecast period.

VFR conditions are expected to continue through mid-afternoon at MCK terminal.
Winds will increase to around 14kts from the southeast in the
afternoon. Clouds will move into the area Thursday afternoon,
lowering ceilings to MVFR. A few showers will be possible near the
terminal as well. Conditions are expected to worsen toward the
end of the forecast period as a winter storm approaches the




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