Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 170738

Area Forecast Discussion
National Weather Service Goodland KS
138 AM MDT Thu May 17 2018

.SHORT TERM...(This evening through Thursday)
Issued at 236 PM MDT Wed May 16 2018

Latest satellite imagery shows afternoon cumulus clouds developing
east of a weak front.  A more defined line of cumulus clouds has
developed near Akron, CO. Upper level analysis shows a short wave
trough moving onto the High Plains.

For the rest of the afternoon have low confidence of storms moving
into Yuma County due to a lack of upper level support.  Further east
have low confidence of any storms developing, let alone a severe
thunderstorm.  Isentropic analysis shows weak lift occurring east of
Highway 27, east of the weak front. The environment is suitable for
a super cell to form due to effective shear close to 40 kts and
around 1000 j/kg of CAPE with no CINh. Given this, am thinking that
hail up to half dollar size and 60 MPH wind gusts are the threats
with the strongest storms, should a severe storm form. Any storms
that develop will end by 8 PM MT.

Thursday an upper level short wave trough deepens over far Eastern
Colorado by early evening.  The dry line just west of Kit
Carson/Cheyenne counties should serve as a focus for storm
development.  Effective shear will be around 40 kts, same as today,
but the low level jet will be much stronger than today.  Low level
helicity will be supportive of tornadic development.  Based on
climatology, the window of opportunity for tornadic development will
begin around 5 PM MT and last well into the evening.  Climatology
supports baseball size hail, possibly even as large as 3" in
diameter.  Wind gusts of 70 MPH will also be likely with any storms
that develop during the late afternoon and into the evening.

.LONG TERM...(Sunday through Wednesday)
Issued at 138 AM MDT Thu May 17 2018

High pressure builds into the High Plains on Sunday as a low
pressure system exits region, leading to dry conditions during the
day. Meanwhile, an upper trough begins to develop over the west

The first of several waves ejects from the trough and across the
region Sunday night into Monday, bringing chances for showers and
thunderstorms back to the forecast. Additional disturbances eject
from the system as a closed low forms aloft through Wednesday. On
and off chances for thunderstorms persist through this extended
timeframe. Differences among guidance regarding the path and timing
of the waves bring uncertainty to the forecast at this time. Will
continue to monitor as discrepancies are resolved.

Slightly cooler temperatures (highs in the mid 60s to low 70s) are
anticipated on Sunday following the previous day`s frontal passage.
A warming trend is expected thereafter, with highs mainly in the 70s
on Monday and in the 80s on Tuesday and Wednesday. Low temperatures
will generally be in the upper 40s through upper 50s throughout the


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1114 PM MDT Wed May 16 2018

VFR expected at both KGLD and KMCK through Thursday afternoon.
Isolated thunderstorms will developed after 21z Thursday afternoon
in northeast Colorado and move northeast, but probably not impact
either terminal until after 00z Thursday evening.




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