Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 291739

Area Forecast Discussion
National Weather Service Goodland KS
1139 AM MDT Wed Mar 29 2017

Issued at 553 AM MDT Wed Mar 29 2017

Just completed an update. Main change was to adjust timing of the
arrival of the next main band of rainfall, which was slower than
previously expected, and because of this later arrival and slower
movement of the system, to hold onto the higher pops, especially
in the eastern half of the area, for longer than what the
initially had. High resolution model is matching current radar
trends, and all show the trends mentioned above.

Also added patchy fog for this morning.


.SHORT TERM...(Today through Friday night)
Issued at 341 AM MDT Wed Mar 29 2017

Forecast concerns will be winds today, the end of the current
precipitation event, and the next storm system to affect the area at
the end of this period. Satellite showing a progressive flow over
the Pacific which then changes to a slower split flow and amplified
over the country. Current system affecting the area is over eastern
New Mexico and western Texas and is beginning to move northeast.

Models having trouble with catching the details of the jet over the
western and central portion of the country. In general they tended
to be too far east with the features. The Canadian and Gfs were
starting out the best. Models were also difficulties at mid levels
with the Ecmwf and Gfs doing the best.

Today/tonight...There has been a reprieve in the heavier
precipitation due to an earlier dry slot and the area waiting for
the next shortwave to rotate into the area as the upper low itself
moves northeast closer to the area. The far western portion of the
area will see a brief period of a rain and snow mix with no
accumulation expected.

Through the morning, models still showing mid level forcing and
depth of upslope increasing. Through the day, models in good
agreement showing the southeast portion of the area getting the most
of precipitation, moderate at time, with lighter precipitation over
the northern and western sections. Far western sections of the area
this afternoon will see an end of the precipitation. Rainfall ends
gradually from west to east during the night with the area being
precipitation free by the time the sun comes up.

Very tight pressure gradient develops over the area this morning on
the west side of the upper system. Winds will be in the breezy to
windy category. Temperatures will be cool today once again as do not
expect much of a rise due to cloud cover and ongoing precipitation.

Thursday/Thursday night...With a lot more sun than the previous few
days, temperatures will be warmer, and saw no reason to make changes
to what the builder gave me.

The reprieve from precipitation will be shorter than previously
expected. Models are now bringing in next system faster than last
night. A preliminary shortwave that rotates ahead of the main upper
low, affects the far northwest portion of the area late in the
night. There is some instability aloft that is not too far away plus
theta-e lapse rates are favorable for a good response to the lift.
Based on that and collaboration with neighbors, kept the slight
chance pops that are in there.

Also the models continue to show the low level air mass nearly
saturated after midnight. So at this time will continue the fog
after midnight.

Friday/Friday night...Will continue the fog through mid morning. Jet
associated with the next storm system will have a left front
quadrant near to the western end of the area or already affecting
the northwest portion throughout the day with the lift getting
better as the day goes. Mid level moisture also increases through
the day as well. Right now the forecast builder gave me slight
chance to chance pops in the far west and that seems reasonable at
this time.

Left front quadrant of the jet looks to affect the area along with
diffluence aloft. Also the upper low keeps getting closer. As a
result the lift and moisture gets better through the night with
favorable theta-e lapse rates in place. So the high pops the builder
gave me looks reasonable. During the last half of the night, a rain
and snow mix will be possible over much of the western portion of
the area. No accumulation expected.

.LONG TERM...(Saturday through Tuesday)
Issued at 341 AM MDT Wed Mar 29 2017

Model solutions are in somewhat better agreement than yesterdays
solutions, but still diverge somewhat towards the end of the long
term period.  The pattern remains active as a series of low pressure
systems moves out of the Rockies and across the plains.

The upper low that moved into New Mexico Friday night remains over
the state through Saturday as it becomes somewhat detached from the
upper flow. The low begins moving across the Texas panhandle and
into Oklahoma on Sunday as a kicker moves into the Pacific
Northwest. The surface low associated with the upper low moving
across Texas moves well south of the area across Mexico and south
Texas on Saturday and Sunday. The upper trough over the Pacific
Northwest continues inland on Sunday night and moves into the
Intermountain West on Monday as the upper low initially over Texas
moves east across the Southern Plains and the surface low lifts
northeast into the central Mississippi Valley region.

As a result of the slow moving low over New Mexico, light
precipitation continues across the forecast area on Saturday and
Saturday night with rain mixing with and changing to light snow
Saturday night.  Precipitation moves out of the area by early Sunday.

Between the low pressure area over the Eastern Plains and the
incoming trough over the Rockies, a weak higher pressure area moves
over the High Plains on Monday. This will keep the forecast area
mostly dry through Monday with temperatures rising back up into the
lower to mid 60s.

High pressure is replaced on Tuesday by the upper trough and
associated surface low pressure area moving east of the Central
Rockies and into the Central and Southern High Plains regions. Light
rain once again spreads across the area from Tuesday into Wednesday
with a possibility of mixing with and turning to light snow Tuesday


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1139 AM MDT Wed Mar 29 2017

Rain continues to rotate across southwest Nebraska and northwest
Kansas at TAF issuance, with several breaks in coverage primarily
at KMCK where light fog developed. This activity will slowly
decrease in coverage through the afternoon and early evening with
VFR conditions eventually returning and winds decreasing below
12kt by the middle of the evening. Low level moisture lingers on
the back side of the precip field, and this will allow for fog and
possibly stratus redevelopment after 09z. Guidance is showing the
better chance for reduced visibilities along the CO border
including KGLD. I have less confidence at KMCK, but this can`t be
ruled out, and models are at least showing stratus redevelopment
in southwest Nebraska.




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