FXUS63 KTOP 150733

Area Forecast Discussion
National Weather Service Topeka KS
233 AM CDT Wed Jul 15 2020

.SHORT TERM...(Today and tonight)
Issued at 229 AM CDT Wed Jul 15 2020

At the time of this update (07Z), a large area of shower and
thunderstorm activity was located in central Kansas and progressing
toward the northeastern portion of the state. The cluster of
precipitation had developed into an MCV with broad-scale cyclonic
rotation noted on the radar loop. Surface analysis shows a boundary
draped across the area from far northeast KS southward into south-
central KS. Over the next several hours, the system will move along
the boundary and interact with a moist and unstable airmass over the
CWA. Mesoscale analysis at 07Z showed MLCAPE values as high as 3500
J/kg over central KS, decreasing northward. Shear is not as
impressive with effective bulk shear values around 25 to 30 kts.
Pwats were up to 2.0 inches, which is near record levels
climatologically. Based on this analysis, damaging wind gusts (up to
70 mph) and locally heavy rainfall leading to flooding will be the
main concerns with this system through the night and early morning
hours. Given the high pwats and slow movement of the system, many
locations could receive one to two inches of rain, with locally
higher amounts likely. The system should exit the area to the
east/northeast by midday with the RAP and HRRR both showing
northerly winds area-wide by that time.

Cloud cover is expected to linger much of the day, holding
temperatures down compared to recent days. Highs should range from
near 80 degrees close to the NE border, to the mid 80s in east-
central KS. Dewpoints, however, will continue to be oppressive in
the low 70s.

.LONG TERM...(Thursday through Tuesday)
Issued at 229 AM CDT Wed Jul 15 2020

The general upper level pattern through the long-term period looks
fairly zonal with a ridge suppressed over the southern US and low
amplitude waves traversing the northern US/southern Canada

Some models are showing a shortwave moving across southern KS on
Thursday. I went ahead and lowered highs a bit to account for
additional cloud cover should these models verify with precip to
our south. Weak waves in this kind of flow can be difficult to
forecast at this range but there appears to be another signal, at
least from the NAM, for a complex of storms late Friday into early
Saturday. Other models show a very subtle wave with an 850mb jet
kicking in Friday night. Will have to monitor trends for the
potential of another MCS impacting the area Friday night, however,
confidence is not currently high enough to include categorical

As of right now, the weekend is looking dry and very hot. Forecast
highs will approach 100 degrees with heat index values as high as
110 at times. If this forecast holds (pending any possible impact
from precip chances Saturday morning), an Excessive Heat Watch
might need to be considered. Our next surface boundary looks to
approach the area from the north through the weekend and possibly
sag into northern KS by early next week. That might become our
next best chance for another round of wet weather.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1142 PM CDT Tue Jul 14 2020

Based on current trends and latest short-term guidance, have
narrowed the timing of storms into the most likely windows for all
sites with confidence slightly higher at MHK. Reductions in
cigs/vis accompany storms with rain clearing the area in the mid
to late morning. MVFR cigs look to linger into at least part of
the afternoon. Some models show VFR conditions returning earlier
in the day, but will keep the greatest confidence at 21Z.




LONG TERM...Teefey

NWS TOP Office Area Forecast Discussion