Area Forecast Discussion
Issued by NWS Dodge City, KS

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FXUS63 KDDC 091907

207 PM CDT Wed Jul 9 2014

...Updated Short Term Section...

.SHORT TERM...(This evening through Thursday)

The main challenge in the forecast tonight and Thursday is
precipitation chances, extent, and thunderstorm severity.
Surface-based thunderstorms are expected to develop across northeast
Colorado in vicinity of, or just downstream of Cheyenne Ridge. The
former runs (00Z) of the WRF-ARW and WRF-NMMB cores suggested a
small MCS would develop and roll southeast toward far west-central
Kansas. The latest 12Z runs of both the models, however, are less
aggressive with this idea. That being said, the HRRR (using WRF-ARW
core) late morning runs insist on northeast Colorado activity
evolving southeast through the evening across northeastern Kansas
and eventually into our far northwestern zones (Syracuse to Scott
City). We will maintain some Chance POPs in the far west-central
Kansas counties north of Hwy 50 and generally west of Hwy 283
through the evening.

Another MCS will either roll south-southeast out of Nebraska and
interact with the western MCS or remain a separate entity all
together and redevelop around 04-06Z across north central/central
Kansas along a strengthening zone of warm frontogenesis in the
850-750mb layer. We will have some 40 POPs from Hays to Pratt in the
05-12Z time frame, but these may need to be raised early this
evening if short term trends favor a more western scenario for
potential MCS. The overall severe weather threat looks fairly
minimal, despite a SLGT risk being issued by SPC. Any large hail
threat would be confined to areas of far west-central Kansas (but
more likely across northeastern Colorado and northwestern Kansas)
with strong straight-line winds to 65 mph the most likely threat
with any bowing segments during the mid to late evening hours. After
that, a very heavy rain threat will develop during the overnight
hours across central Kansas. It remains to be seen, though, how far
west the core of the nocturnal MCS will be. It seems most likely
this will stay across portions of central and south central Kansas
just east of our forecast area (east of a Hays to Pratt line).

Going in to the day Thursday, a warmer day is forecast with warmer
overall temperatures in the lower troposphere (to +29C at 850mb as
far east as the Hwy 283 corridor). This should allow surface
temperatures late afternoon reaching close to, if not 100F
(especially along/west of Hwy 83 where evapotransporation will be
less). A fairly strong gradient will yield a windier day with
south-southwest winds 20 to 23 knots sustained in the afternoon.

.LONG TERM...(Thursday through Tuesday)

Thunderstorms are likely across portions of central Kansas early
Thursday morning as an upper level shortwave coming off the ridge
axis across the Colorado Rockies dips southeast across the Central
Plains. Increased convergence/forcing ahead of the advancing surface
trough along with ample low/mid level moisture will be enough to
support convection across central Kansas as the aforementioned
shortwave dives southeast across the region. Drier conditions
are then likely Thursday afternoon through Friday afternoon as
the upper level ridge axis shifts eastward across the Western
High Plains. Going into the weekend, medium range models indicate
the upper level ridge breaking down somewhat as it moves further
east into the Central Plains returning a southwest flow aloft to
portions of the Rocky Mountain Region. The GFS/ECMWF hint at H5
vort maxima ejecting eastward out of the Central Rockies providing
the focus for possible thunderstorms lee of the front range Friday
night into Saturday. Although the flow aloft will remain fairly
weak, forcing associated with a surface trough and enough
instability will exist to support thunderstorm development across
eastern Colorado late Friday afternoon with storms potentially
moving into western Kansas overnight through early Saturday.

Warmer temperatures are likely Thursday as a prevailing lee side
trough continues to influence a southerly flow across western
Kansas. This will enhance warm air advection into the area with
H85 temperatures climbing into the mid 20s(C) across central Kansas
to near 30C closer to the Colorado border. Highs will reach well
into the 90s(F) Thursday afternoon with similar highs expected
each day going into the weekend as upper level ridging moves out
of the Rockies across the Western High Plains.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)

The lee trough will continue to strengthen across eastern Colorado,
increasing the pressure gradient and resulting surface winds. Wind
speeds during the afternoon hours will range from 15 to 19 knots
with gusts in the mid to upper 20s knots out of the southeast. Winds
will decrease slightly during the overnight hours. At this time,
thunderstorm activity will not be included in any three of the
terminals (DDC, GCK, HYS) given low confidence of any thunderstorm
impacts. Thunderstorms will likely make an approach to GCK late this
evening, however more than likely in a weakening state (or even
completely dissolved by the time they reach GCK). Another overnight
cluster of thunderstorms will develop across central Kansas, but HYS
appears to be on the western edge of any of this activity with a
much higher probability of thunderstorms east of HYS overnight.


DDC  67  97  72  98 /  10  10   0  10
GCK  66  98  71  99 /  20  10   0  20
EHA  68  98  71  97 /  20   0   0  20
LBL  68  99  71  99 /  10   0   0  10
HYS  66  95  72  99 /  40  10  10  20
P28  68  96  72  98 /  20  30   0  10




SHORT TERM...Umscheid
LONG TERM...JJohnson
AVIATION...Umscheid is the U.S. government's official web portal to all federal, state and local government web resources and services.