Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 250432

Area Forecast Discussion
National Weather Service Topeka KS
1132 PM CDT Thu May 24 2018

...Update to aviation forecast discussion...

.DISCUSSION...(This evening through Thursday)
Issued at 300 PM CDT Thu May 24 2018

Little overall change from the previous forecasts for the
upcoming week. Ill-timed chances of showers and thunderstorms
continue through Friday and prolonged summer-like temperatures
build in for the holiday weekend.

Early afternoon water vapor imagery showed an upper-level low
lifting northward into the northern Dakotas with an attendant
trough arcing southwestward into the High Plains. This wave was
working through a broader longwave ridge that encompassed much of
the CONUS. A remnant MCV was lifting through central Kansas with
showers and thunderstorms developing on the eastern flank of the
low and additional cells blossoming ahead of the complex in a
region of very weak isentropic upglide with minimal inhibition.
MLCAPE values of 1500 to 2000 J/kg were fostering initially robust
updrafts, but the lack of deep shear in the column was hampering
cell organization and longevity.

The threat for scattered pulse thunderstorms will continue east
of Manhattan for the remainder of the daytime hours with small
hail and localized downburst winds the main threats. Attention
then turns to whether the afternoon High Plains convection can
sustain itself into the CWA tonight. Confidence is low in the
evolution of this system with the majority of the upper level
shortwave support lifting north of the area. HREF reflectivity
field variability is rather high, but do show an overall trend of
the convective complex dissipating as it reaches central Kansas
around midnight, but with new development initiating shortly
thereafter downstream of the remnant system that persists past
sunrise. For this reason, have maintained a band of POPs moving
from west to east overnight, but the actual event will likely not
be a contiguous line of storms. As with the earlier convection,
gusty winds and small hail will be the main threats.

Additional peak heating storms are possibly Friday afternoon in
eastern portions of the CWA before upper level ridging becomes re-
established over the central U.S. H850 temps climb to +20 to +24
C over the holiday weekend with resultant surface temperatures
pushing the low to mid 90s. Heat indices will flirt with 100 in a
number of locations given the dewpoints in the upper 60s to low
70s. Warm southwest flow persists into early next week before
temporarily breaking down on Tuesday/Wednesday, which will be the
next modest chance of storms.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1120 PM CDT Thu May 24 2018

isolated to scattered thunderstorms may develop after 7Z FRI near
or at the terminals and may last through the mid morning hours of
Friday. Ceilings will remain VFR, however visibilities may drop
to 4SM in thunderstorms. Expect VFR conditions to continue
through Friday evening. There may be an isolated late afternoon
shower or thunderstorms near the KTOP and KFOE terminals.




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