Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 222338

Area Forecast Discussion
National Weather Service Goodland KS
538 PM MDT THU SEP 22 2016

Issued at 525 PM MDT Thu Sep 22 2016

Increased POPs for this evening to low chance in western areas and
isolated in central and northern areas. Showers and thunderstorms
associated with shortwave trough ejecting ahead of the main upper
low in the Great Basin will continue to move very quickly out of
northeast Colorado. Other more isolated thunderstorms may develop
along a retreating warm front roughly along Interstate 70. Latest
SPC mesoanalysis shows decent instability along and south of the
front, but decreasing rapidly north of the front, as well as
increasing CIN north of the front. There may be a narrow band
along and just north of the front where both instabilty and deep
layer shear will be enough to support a brief severe threat.
Storms are relatively high based at about 6kft, suggesting
damaging winds may be the main hazard. This is also supported by
DCAPE values near and south of the front. This rather marginal and
localized severe threat will quickly diminish with loss of surface
heating by mid evening as storms dissipate.


.SHORT TERM...(This evening through Friday)
Issued at 1243 PM MDT Thu Sep 22 2016

General clearing will continue this afternoon along the western
fringes of an area of retreating high pressure. A large upper low
will approach the CWA overnight and into Friday. The entrance region
of the jet will be positioned over the region, providing very good
forcing in the presence of 50 to 60 kts of bulk shear and CAPE
around 1200 J/Kg. Based on the soundings, any thunderstorm activity
would likely be elevated as LCLs are quite high with the inverted V
sounding profile. Mode of convection should begin as multi-cell
cluster type storms that will form into a line preceding a dry line.
Best storm chances will be during the middle afternoon and will
persist through the evening from west to east. At this time,
damaging wind gusts will be the main concern as DCAPE values will be
in the 1200 to 2000 J/Kg range as the boundary moves through the
CWA. Large hail will be the secondary threat.

Temperatures are forecast to reach the upper 80s to near 90 degrees
this afternoon; however, low fog and stratus prevailed through just
before midday thus we could see slightly lower values. For Friday,
we will see temperatures soar once more into the upper 80s to near
90 degrees with a sharp drop toward the afternoon as much cooler air
is advected into the region. Lows tonight will fall into the 60s
across the entire CWA.

.LONG TERM...(Friday night through Thursday)
Issued at 120 PM MDT Thu Sep 22 2016

For the extended period...the focus for the first portion of the
forecast...Friday night into Saturday...will be the passage of a
cold front associated with the upper low that models do shift from
the Rockies into the Northern Plains during this time. Models do
shift from previous runs in that there is a bit more progression
eastward with this system for the latter portion of the extended.
The blocking upper ridge/low over the Midwest to the East does break
down/give way. This is occurring as a stronger H5/H7 ridge builds
further eastward behind exiting upper low.

For precip...only precip expected in the Extended will coincide with
the ongoing cold frontal passage Friday night into Saturday. The
entire CWA will remain under a Marginal risk for potential severe wx
thru 06z Saturday...tapering to general thunder conditions as precip
wanes going into Saturday morning. Front will linger over extreme SE
portions of the CWA during the day Saturday but the overall trend is
for clearing late there. With the upper ridge building into the
region from the latter half of the upcoming weekend into next
Thursday...dry conditions will be expected.

For temps...early highs in the 75-80F range on Saturday with the
passage of the cold front. By Sunday as the ridge begins to build
into the plains region...wind shift from the NW initially will bring
cooler air with highs Sunday/Monday in the 60s...then increasing for
the remainder of the period into the 70s which will be near to above
normal for next Wed/Thurs.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 525 PM MDT Thu Sep 22 2016

Widely scattered thunderstorms through mid evening have a low
probability of directly impacting either KGLD or KMCK. They will
be capable, however, of producing locally strong downburst winds.
Storms will dissipate by midnight with VFR expected through the
remainder of the period. Friday will see gusty south winds develop
by mid to late morning as pressure gradient increases ahead of an
approaching cold front in eastern Colorado. Some wind gusts Friday
afternoon may approach 40kts at KGLD...which may create areas of
blowing dust and reduced visibility.


.GLD Watches/Warnings/Advisories...


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