Hail and Damaging Winds in Kansas, August 10 to 11, 2017

Area Forecast Discussion
National Weather Service Dodge City KS
110 AM CDT Thu Aug 10 2017

...Updated for aviation discussion...

.SHORT TERM...(This evening through Thursday)
Issued at 345 PM CDT Wed Aug 9 2017

Scattered thunderstorms were developing across central and south
central Kansas this afternoon along a surface trough that has
moved into the area. A few storms were also developing over far
southwest Kansas in an area of weaker convergence. SPC
mesoanalysis shows MLCape values around 1500 j/kg in a band from
far southwest Kansas into the northwest/north central part of the
state. Deep layer shear across western and central Kansas was
fairly weak, save the southwest corner of the forecast area where
30-40 knots of 0-6km shear was indicated. A few storms in the
Medicine Lodge area were strengthening with some pea size hail
possible. Can't rule out a few strong storms with hail up to
quarter size along with gusty winds but overall, think the severe
threat will be fairly isolated through late afternoon.

Convective allowing models, especially the HRRR, have been showing
storms developing in this area for several runs. The current area
of showers and storms along the Highway 183/281 corridor should
continue in that area through the remainder of the afternoon
before gradually propagating east out of the area late this
afternoon and early evening. Thunderstorms developing along the OK
border over far southwest Kansas are progged to diminish by late
afternoon. The models then show some convection moving into
western portions of the forecast area from the west and north
late this evening and these should be diminishing by late tonight.

Thursday should be fairly quiet through the daytime after the
overnight convection diminishes. The GFS is warmer than the NAM
with boundary layer conditions during the day. Tend to lean toward
the GFS but overnight convective trends could definitely have
impacts. High temperatures should be in the mid 80s to around 90.
Otherwise, the models show a mid level shortwave trough dropping
out of the northern Plains in the Midwest while a cold front drops
south toward western Kansas during the day. Ahead of the front,
CAPE values increase to 1500-2000 j/kg along with 0-6km shear
around 50 kts. This should be sufficient for supercell
thunderstorms with large hail, damaging winds and possibly a
tornado. Thunderstorms should begin developing over the higher
terrain of eastern Colorado and northwest Kansas along the front
by mid afternoon.

.LONG TERM...(Thursday night through Wednesday)
Issued at 345 PM CDT Wed Aug 9 2017

Thunderstorms developing Thursday afternoon should coalesce into a
forward propagating MCS that tracks southeast across the forecast
area Thursday evening. High winds along with possible localized
flooding from heavy rain will become an increasing threat. The
models have this system moving southeast out of southwest and
south central Kansas later Thursday night. Friday should be quiet
and cooler as the upper wave moves east of the area and somewhat
cooler and stable air moves into western Kansas. Friday night
could see additional showers and thunderstorms moving out of the
eastern slopes into western Kansas. There is a little more
uncertainty as to the coverage and eastern progression of these
storms given the more stable conditions.

Another shortwave trough digs southeast through the northern
Plains into the Midwest on Saturday into Sunday. This should force
another cold front south through western Kansas along with
increasing chances for thunderstorms. The weather should quiet
down a bit early next week as an upper level ridge builds east
across the northern and central Plains. Another shortwave moving
east out of the Rockies into the northern and central Plains by
mid week could bring another round of storms to western Kansas.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 106 AM CDT Thu Aug 10 2017

Light winds or weak upslope flow and abundant low level moisture
will lead to LIFR CIGS and visbys at KGCK/KDDC and KHYS by 07-10Z.
Any fog will dissipate by 14-15z. An upper level disturbance and
plenty of low level moisture will result in thunderstorms near the
TAF sites after 21Z. These could be severe with large hail and
damaging winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  64  86  65  84 /  20  50  60  20
GCK  63  86  63  82 /  20  50  60  20
EHA  65  87  63  82 /  20  50  60  20
LBL  67  90  65  85 /  20  50  60  20
HYS  62  85  63  83 /  30  40  50  10
P28  67  89  68  85 /  20  50  70  30

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...Gerard
LONG TERM...Gerard
AVIATION...Finch

Hazardous Weather Outlook
National Weather Service Dodge City KS
1203 PM CDT Wed Aug 9 2017

KSZ030-031-043>046-061>066-074>081-084>090-101000-
Trego-Ellis-Scott-Lane-Ness-Rush-Hamilton-Kearny-Finney-Hodgeman-
Pawnee-Stafford-Stanton-Grant-Haskell-Gray-Ford-Edwards-Kiowa-
Pratt-Morton-Stevens-Seward-Meade-Clark-Comanche-Barber-
1203 PM CDT Wed Aug 9 2017 /1103 AM MDT Wed Aug 9 2017/

This hazardous weather outlook is for portions of central...south
central...southwest and west central Kansas.

.DAY ONE...This afternoon and tonight.

Day 1 Discussion
----------------

A few showers and thunderstorms will be possible this afternoon
and evening over western Kansas. Strong to severe thunderstorms
will be possible over far southwest Kansas late this afternoon.
The strongest storms will be capable of hail to half dollar size
and wind gusts to near 60 mph.

Day 1 Hazards
-------------
* Hail: Limited risk
* Thunderstorm wind damage: Limited risk
* Flooding: Elevated risk
* Lightning: Elevated risk

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Days 2-7 Discussion
-------------------

Thunderstorms are likely late Thursday and Thursday night.
Initial storms in NW Kansas are expected to be supercells, capable
of large hail and potentially a few tornadoes. This risk will be
highest across the NW zones early Thursday evening. Thunderstorms
are expected to organize into a large complex of storms and race
southeast across SW Kansas Thursday evening. If storms organize
into line and bowing segments as expected, than damaging wind
gusts can be expected. Locally very heavy rainfall is also
expected, but quick storm movement will reduce the flooding threat
at least to some degree.

Days 2-7 Hazards
----------------
* Thursday
  - Flooding: Elevated risk
  - Lightning: Significant risk
  - Severe thunderstorm: Elevated risk

* Friday
  - Flooding: Elevated risk
  - Lightning: Elevated risk

* Saturday
  - Lightning: Elevated risk

* Sunday
  - Lightning: Limited risk

* Monday
  - Lightning: Limited risk

* Tuesday
  - Lightning: Limited risk

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed along and west of US Highway
83 later this afternoon and evening.

&&

For more details visit our webpage http://weather.gov/ddc/ehwo

Gerard