Area Forecast Discussion
Issued by NWS Dodge City, KS

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FXUS63 KDDC 150510
AFDDDC

Area Forecast Discussion
National Weather Service Dodge City KS
1210 AM CDT Tue Aug 15 2017

...Updated Aviation Discussion...

.SHORT TERM...(This afternoon through Tuesday)
Issued at 1255 PM CDT Mon Aug 14 2017

Plentiful sunshine and boundary layer moisture (dewpoints in the
60s) will keep instability in place through this evening. 12z NAM
forecasts CAPE of 2000 J/kg widespread by peak heating, locally
higher. The problem is the triggering mechanisms necessary for
convection are nebulous, weak and hard to identify. HRRR has shown
some consistency developing thunderstorms along an outflow
boundary along the I-70 corridor by peak heating. In the absence
of strong forcing, orographic forcing and the higher terrain will
become the primary focusing mechanism through this evening.
Confident that convection will fire in the vicinity of the Raton
Mesa soon, with subsequent propagation SE toward the TX/OK
Panhandles. SPC`s marginal 5% wind/hail probabilities for this
scenario just SW of SW KS look reasonable. 12z NAM also shows this
solution, which would keep impacts limited to nil in SW KS. With
moderate high CAPE and little shear/forcing, can`t rule out a
thunderstorm at any location, but the odds are very low. Kept pop
grids limited and conservative in the 20-30% range. Lows tonight
in the 60s (probably holding near 70 SE of Dodge City).

Tuesday...Stronger S/SE surface winds (averaging 15-25 mph) will
maintain boundary layer dewpoints in the 60s. Southerly 850 mb
flow increases progressively through the afternoon, near 25 kts,
increasing further to near 40 kts with a modest low level jet
Tuesday evening. NAM responds to this by forecasting stronger
instability late Tuesday, with CAPE of 3000-3500 J/kg. During
daylight Tuesday, forcing is still progged to be weak and less
than obvious, so kept slight chances for most locales. Convection
appears much more likely Tuesday night into early Wednesday, as
as a midlevel trough approaches from the central Rockies, and a
frontal boundary sinks south into SW KS. NAM/GFS MOS pops show a
unanimous increase Tuesday evening, with ECMWF solutions strongly
hinting at MCS generation over at least central Kansas through
Tuesday night. Given the largely nocturnal timing of Tuesday and
Wednesday`s expected convection, primary expectation is one of
strong to severe multicell convective clusters producing
marginally severe hail/wind. Highest risk will be near and NW of
our NW zones, as SPC slight risk delineates. Temperatures Tuesday
afternoon very near mid-August normals, within a few degrees of
90.

.LONG TERM...(Tuesday night through Monday)
Issued at 230 PM CDT Mon Aug 14 2017

Long term likely to start out active, as ECMWF shows strong
forcing (for mid-August standards) arriving with a Colorado
shortwave Tuesday night. MCS generation over central Kansas is
anticipated, and storms are most likely across the NE zones near
the I-70 corridor. Pop grids offered by the forecast blend are in
the 50% range, and will need to be increased into the likely
category over the next couple shifts. Areas of heavy rain and
severe weather are expected. The cold front associated with the
shortwave will usher in a northerly wind for Wednesday,
effectively scouring the instability and pushing most of the CAPE
into Oklahoma. Pops are very low Wednesday afternoon/evening, and
confined to the eastern/SE zones. A few degrees of cooling
expected Wednesday, in the mid to upper 80s, versus the lower 90s
on Tuesday.

Much of Thursday appears dry, but another round of thunderstorms
is expected Thursday evening/night. 12z ECMWF suggests heavy rain
from this probable MCS would favor the southern zones. 12z GFS in
good agreement, with another shortwave in the NW flow aloft
triggering a strong MCS along the Oklahoma border Thursday
evening. Scattered thunderstorms still expected mainly across
eastern sections late Friday.

12z MEX guidance suggests a notable warming trend this weekend,
with afternoon temperatures into the mid 90s. With such wet
ground across much of KS, and more MCSs probable between now and
then, forecast grids only show a very gradual warmup this weekend
(climbing to near/slightly above normal) by Sunday and Monday.
It is still summer.....

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1208 AM CDT Tue Aug 15 2017

00z Model soundings showing an increase in moisture in the 850mb
to 700mb level but these models are not as excited about the
return of moisture below this level given the prevailing south to
southwest flow in the boundary layer. Fog and/or stratus not
expected overnight but could see some increasing clouds towards
daybreak in the 3000ft to 8000ft AGL level. If clouds do develop
they should not last much longer than a couple of hour with clear
below 12000 expected for the remain of the day. Late day
convection developing over eastern Colorado will spread across
western Kansas overnight and with it low VFR conditions. A few
late day storms also may develop north of a warm that that will be
moving into far southwestern Kansas.

Southeasterly winds at the surface at 10 knots or less overnight
will increase into the 15 to 20 knot range by the early afternoon
as surface pressures begin to fall across eastern Colorado.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  68  92  68  88 /  10  30  50  30
GCK  67  91  65  86 /  10  30  40  10
EHA  65  91  64  85 /  20  30  50  10
LBL  68  94  67  87 /  10  30  50  10
HYS  68  89  68  86 /  10  20  50  40
P28  70  93  72  91 /  10  30  40  30

&&

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

$$

SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Burgert



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