Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 180836
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
336 AM CDT Fri May 18 2018

.SHORT TERM...(Today and tonight)
Issued at 319 AM CDT Fri May 18 2018

Early this morning, main focus was on a shortwave over western NE.
Regional radar imagery showed a complex of storms on the leading
edge of this shortwave, with short-range models showing this cluster
of storms continuing to advance eastward across NE through the
morning hours.  These storms are being supported by a LLJ stretching
from western KS into western/central NE.  As these storms progress
into south central NE after sunrise and into mid-morning, there is
still uncertainty in whether or not some of these storms on the
southern edge will extend into portions of north central KS.
However, wind shear looks to be rather weak in that area with some
elevated instability of less than 1000 J/kg possible, so do not
anticipate any storms that do develop to be strong.  Due to low
confidence in the southern extent of this thunderstorm development,
only have some slight chance PoPs in for mid/late morning.  With
surface winds remaining out of the southeast and with some breaks in
the cloud cover possible (primarily across eastern KS) ahead of the
next advancing shortwave, expect high temperatures to reach into the
low to mid 80s from west to east across the CWA.

Focus tonight shifts to the deep mid-level trough over the western
U.S. as it progresses further east toward the central U.S. Models
show an embedded shortwave developing along the eastern edge of this
trough and tracking northeast into KS by Saturday morning. This
advancing trough will help to push an area of surface low pressure
into KS with an associated warm front starting to lift northward
across the CWA by Saturday morning. The LLJ should be focused more-
so across central KS tonight, with improved 0-6km bulk shear values
expected. Modest mid-level lapse rates should support MUCAPE values
of 1000-1500 J/kg late tonight through the overnight hours. With
these conditions in place, models show a complex of storms
developing with this shortwave and tracking into central KS by late
tonight and progressing eastward across the CWA overnight. Shear and
instability look more favorable across the western part of the CWA,
so cannot rule out the potential for some strong to severe storms to
develop, with hail and strong winds being the primary hazards.

.LONG TERM...(Saturday through Thursday)
Issued at 319 AM CDT Fri May 18 2018

A complex of showers and storms may be ongoing early Saturday
morning continuing through the early afternoon.  The location and
timing of this storm complex will play a role in how storms develop
in the afternoon hours of Saturday.  Overall, an upper low will be
located over the central Rockies while the intersection between a
warm front and dry line will be located near central Kansas by late
Saturday afternoon.  Dewpoints in the upper 60s will be seen across
northeast Kansas along with high temperatures approaching the upper
80s.  Am abundance of buoyancy and shear sufficient for
supercellular development will be in place by mid-afternoon when
soundings indicate the cap will be broken.  The main hazards with
any storms will be large hail and damaging winds.  Models indicate
helicity near the surface warm frontal boundary could be around 200
m2/s2 which leads to the concern for the possibility of tornadoes.
Once again, storms in the morning may still act to alter this
scenario slightly so the forecast should continue to be monitored
for any changes.

The front shifts east by Sunday morning and slightly cooler
temperatures will be seen Sunday, especially in north central Kansas
where highs may only top out in the lower 70s.  An unsettled pattern
continues for the work week with precipitation chances almost every
day.  Highs do look to reach at least 80 every day in northeast
Kansas keeping the trend of warmer than average temperatures
continuing.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1120 PM CDT Thu May 17 2018

VFR conditions expected through most of the taf period. There is
still a small chance for a high-based shower or storm in the late
morning although confidence is low and impacts should be minimal.
A stronger complex of storms looks to develop in western KS
tomorrow and move eastward in the evening. It could reach MHK
toward the end of the period. Gusty wind and heavy rain would be
the main threats if those storms reach the taf sites.


&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Hennecke
LONG TERM...Heller
AVIATION...Sanders



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