Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 200859

Area Forecast Discussion
National Weather Service Goodland KS
259 AM MDT Fri Oct 20 2017

.SHORT TERM...(Today and tonight)
Issued at 258 AM MDT Fri Oct 20 2017

Latest upper air analysis shows the trough moving toward the Plains.
Within the flow satellite imagery shows scattered clouds.  At the
surface south winds were breezy due to a tight pressure gradient.

Today southerly winds will increase in the afternoon as warming
temperatures allow some of the strengthening low level jet to mix to
the ground.  Am a bit concerned the cloud cover will serve to
prevent the winds from being as strong as they could be by limiting
the mixing potential.  Most model data indicate winds peaking at 25
MPH along the southeast part of the forecast area.  However
soundings show winds of 30-40 MPH in the mixed layer.  Hesitant to
go too high above guidance given the scattered cloud cover, so
forecast winds are a few MPH above guidance given the much stronger
winds shown in the soundings.  The winds will increase to the east
this afternoon.

Tonight southerly winds will quickly decline in the early evening,
but remain breezy through the night due to the tight surface
pressure gradient in place.  These winds will help keep the low
temperatures quite warm for this time of year.

.LONG TERM...(Saturday through Thursday)
Issued at 258 AM MDT Fri Oct 20 2017

Saturday morning the cold front will move through.  Northwest winds
will not increase too much until mid morning when the warming
temperatures allow some of the low level jet behind the front to mix
to the ground.  Winds will be strongest in the morning then
gradually decline in the afternoon.  The strongest winds will be
over the west 2/3s of the forecast area.  The windy conditions and
low relative humidity values may lead to a fire weather concern. See
fire weather section for further information.

There will be a slim chance for rainfall in the early morning over
Yuma County between the front and the upper level short wave trough
following the front.  Lift with the upper level short wave trough
will trigger a line of storms just east of the forecast area, but
Graham County may catch the west edge of the storms that develop.

Saturday evening the winds will become light.  With a colder, drier
air mass in place lows will be near normal.  Dew points will be in
the teens and low 20s.  With conditions looking favorable for
radiational cooling, am thinking the lows may be too warm.  If this
is the case, a freeze watch may be needed for counties east of the
Colorado border where a hard freeze has yet to happen for this
growing season.

Sunday/Sunday night warm air advection will warm temperatures
compared to Saturday.  Winds will be light to breezy.  Dry northwest
upper level flow will move over the forecast area behind the trough
from Saturday.

An active and dynamic pattern will prevail Monday through Thursday
with alternating periods of near normal to above normal temperatures
and generally dry weather. Northwest flow aloft will dominate on
Monday, gradually becoming northerly as we head into Tuesday. This
will be in response to a cold front that will push through the
region late Monday night and early Tuesday morning. Due to lack of
antecedent moisture advection, this passage will likely be dry and
windy. I increased winds on Tuesday beginning around mid morning as
pressure rises will be a bit sharp on the trailing side of lowered
heights associated with a deep trough to our east. Could see gusts
approaching the 40 to 45 mph range with 20 to 25 mph sustained north
to northwest winds. Also adjusted temps down slightly from guidance
as very strong CAA will prevail through the day.

The upper flow will shift back to westerly as we go into Wednesday
with weak high pressure briefly traversing the central High Plains.
Another cold front will push through the area on Thursday and once
more we will not have much moisture to work with as this happens.
There will be only a slight chance of precipitation as the front
moves across the region; however, breezy conditions are expected as
a sharp pressure gradient will trail the frontal passage. This front
could bring widespread freezing temperatures to the region; however,
a hard freeze is not likely as of today`s guidance.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1141 PM MDT Thu Oct 19 2017

40-45KT low level jet is in place over both KGLD and KMCK and low
level wind shear will remain possible at both terminals through
sunrise Friday morning. Winds will increase by early Friday
afternoon, with daytime gusts possibly exceeding 35kt at times.
Winds decrease after sunset Friday, however this will correlate
with low level wind shear possibly redeveloping. VFR conditions
should prevail at both terminals, though there is still a small
possibility for MVFR cigs/vis at KGLD. Confidence is still low,
and most models do not favor this.


Issued at 258 AM MDT Fri Oct 20 2017

Wind gusts of 20-35 MPH will occur over East Central Colorado
Saturday afternoon while relative humidity values will fall to the
upper teens.  Am expecting the winds to decline through the
afternoon, but they will not be declining fast enough to avoid
occurring with the low relative humidity values.  Currently the
relative humidity looks to remain above 15 percent.  Even if the
relative humidity fell to less than 15 percent, it may not be for
long enough before the winds cease to be a concern.  Am not
anticipating a fire weather product needing to be issued, but this
day will need to be watched in case dew points fall faster behind the
front than currently forecast.




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