Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 282340
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
540 PM MDT Wed Jun 28 2017

.SHORT TERM...(This evening through Thursday)
Issued at 228 PM MDT Wed Jun 28 2017

Latest upper air analysis shows a deepening short wave trough over
Central Colorado.  Satellite imagery shows cumulus clouds increasing
in coverage over the mountains, with some storms developing on the
plains.  At the surface the cold front from this morning was
difficult to find due to the gradual cooling temperatures behind the
pre-frontal trough extending from near Liberal northeast to near
Hays. The dry line was running parallel along the pre-frontal
trough.

For the rest of the afternoon, isolated thunderstorms will continue
to develop over Eastern Colorado near the deepening upper level
short wave trough and where weak surface convergence will occur as a
surface low deepens.  The storms will increase in coverage due to
the short wave trough deepening.  Most of these storms are not
expected to become severe due to CINH capping off any mixed layer or
surface CAPE. However if storms develop as far south as I-70 or
further south, they may become severe due to very little CINH in
place there.

This evening the upper level short wave trough will continue to
deepen as it moves east.  Storms developing ahead of it will
increase in coverage as they move out of Colorado and into higher
CAPE in Kansas.  As the storms move east into higher instability the
threat for large hail will increase.  Meanwhile elevated CAPE will
develop near the warm front and nose of the low level jet over the
southeast part of the forecast area.  As the upper level short wave
trough progresses east, should see a second group of storms develop
along the warm front which will also coincide with an axis of
higher theta-e.  Am anticipating hail up to hen egg size with these
storms, although cannot rule out hail larger than that east of
Highway 83.  Severe winds will be possible with any storms that move
into Kansas.  Looking at 0-1 and 0-3 KM helicity and EHI, there is a
potential for a tornado to develop in the vicinity of the warm front
before midnight CT.  Have low confidence of this occurring, but
still bears mentioning.  However if severe weather is going to occur
it will be mainly in Northwest Kansas in the evening.

As the evening progresses the two groups of storms should merge into
a MCS or some sort of cluster before the overnight hours.  As the
storms merge into more a cluster, the size of the hail should become
smaller with severe winds becoming more of a threat along with heavy
rainfall.  Don`t have the confidence to issue a flood watch, since
the storm complex should be moving fast enough to negate flooding.

During the overnight hours the elevated CAPE shifts north into
Nebraska.  This may cause the severe thunderstorm activity to
transition north as the storm complex moves east.  However when the
CAPE axis shifts north it may be behind the storm complex. Generally
the later past midnight the lower the chance for large hail to occur
as the CAPE axis shifts north of the forecast area.

Thursday looks like another repeat of today with storms forming in
Eastern Colorado ahead of a deepening upper level short wave trough.
Isolated storms should begin to form in the early afternoon then
increase in coverage over East Central Colorado as they move east
later in the afternoon.  Main threat with these storms will be
large hail and damaging winds.

.LONG TERM...(Thursday night through Wednesday)
Issued at 127 PM MDT Wed Jun 28 2017

At the start of this extended period the models are showing an
amplified upper level trough moves out of the Central Canada with an
associated cold front and into the High Plains on Thursday. This
system looks to have enough instability to support the development
of super cell activity and possible MCS development over the region
Thursday night and into early Friday morning. There is still a
question in regard to what impact this system will have on the local
area as the track could shift to the south or east of our CWA. After
frontal passage, there will still be some lingering showers or weak
thunderstorms on Friday with temperatures reaching the upper 70s to
lower 80s.

Over the weekend, an increase in stable air mass and large scale
subsidence should support dry conditions on Saturday and into the
afternoon on Sunday. High temperatures will start out in the middle
80s on Saturday followed by the lowers to middle 90s on Sunday. Late
Sunday afternoon a chance of showers and thunderstorms return to the
local area as a surface trough combined with an upper level
shortwave approaches the area from the west.

Next week high temperatures look to maintain in the lower to middle
90s. Upper level troughs will pass over the local area on Monday and
will aid in producing another afternoon and evening of showers and
thunderstorms. As for the 4th of July, and the rest of this extended
period, the blended model is showing dry conditions. at this time I
see no reason to change anything.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 522 PM MDT Wed Jun 28 2017

VFR conditions are expected at MCK and GLD through the TAF period.

Isolated to scattered thunderstorms will move through the
vicinity of MCK and GLD overnight between 04Z-10Z with storms
being slightly more numerous and warranting a TEMPO group at GLD
between 06-07Z. Storms should move east and dissipate after 10Z
with light and variable winds turning more northerly and
increasing through the day on Thursday.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...JTL
LONG TERM...BW
AVIATION...LOCKHART


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