Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 231731
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1231 PM CDT Thu Apr 23 2015

.DISCUSSION...
Issued at 348 AM CDT THU APR 23 2015

The main focus for this forecast issuance will be thunderstorm
chances tonight through Saturday, and especially the strong/severe
storm potential on Friday evening. A shortwave trough will lift out
of the four corners region today and out into the Plains by late
tonight, helping to kick lee-side low pressure out of the High
Plains and into central Kansas by Friday. Ahead of this system, a
round of showers and thunderstorms are expected to develop late
tonight along the low-level jet axis, mainly from eastern NE through
central KS and into north central OK. These showers and storms will
roll east during the morning hours, likely impacting our forecast
area between sunrise and late morning before dissipating and exiting
to the east as the LLJ shifts and weakens. Meager instability and
the elevated nature of storms should keep activity non-severe in our
area during the morning hours, although a few stronger storms are
possible to our west.

After these storms clear out of the region, the primary focus for
potentially strong to severe convection will be a northeastward-
lifting warm front. There remains some uncertainty in the timing and
track of the front as the surface low tightens and pushes eastward
on Friday and Friday night, but most model solutions bring the
surface boundary at least to the MO River by 10 PM Friday before
pushing out to the east. Instability parameters are a bit difficult
to discern due to the response of convective parameterization in the
models throughout the day, but it seems likely that at least a weak
cap may be present, in addition to the capping inversion resulting
from the elevated warm front north of the surface boundary. MUCAPE
values should be less than 1000 J/kg along and north of the front,
and will quickly diminish from south to north. However, lift
resulting from the upper jet, shortwave trough, and surface front
will likely be more than sufficient to support convection throughout
the region, but the strongest convection will be along the warm
front where lift and low-level shear are strongest, and potentially
in the warm sector where more instability may build. Supercells are
possible along and south of the warm front, and a few tornadoes will
be possible if robust convection can survive along the surface
boundary. The slightly later timing may slightly decrease potential
tornadic activity, but convection may remain rooted longer than the
diurnal cycle typically allows for due to the dynamics of the system.

Heavy rain continues to be a concern on Friday night if storms train
along the warm front, and in areas that see multiple rounds of
convection Friday and Friday night. However, the threat for flooding
appears too low for any sort of watch product at this time, and left
QPF amounts more representative of widespread amounts than of the
potential for localized higher values.

Storms along the front and ahead of the surface low will push out to
the east by Saturday morning, then some light wrap-around showers
are possible Saturday, mainly east of Highway 65. Temperatures on
Saturday afternoon will depend both on the amount of clearing that
occurs and the track of the surface low, but it looks likely that
areas south of the MO River and west of Hwy 65 may clear out enough
to reach 70 degrees before cooler air starts to move in Saturday
night into Sunday.

Fairly seasonable temperatures and a few low-end chances for rain
showers continue for next week; however, rain would be light and
short-lived if it occurs beyond the Friday/Friday night system.
Overall, quiet conditions are expected for Saturday evening and
beyond.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1228 PM CDT THU APR 23 2015

VFR conditions expected through the afternoon and likely through the
overnight. Main concern is timing any potential shower/convection
late tonight/early tomorrow morning. Activity looks to be fairly
scattered from a few hours before sunrise through late morning so
feel just carrying a VCTS group is warranted still.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

DISCUSSION...Laflin
AVIATION...CDB





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