267
FXUS63 KTOP 121124
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
624 AM CDT Sun May 12 2024

.KEY MESSAGES...

- Isolated showers and thunderstorms this morning into afternoon,
then rain becomes more widespread tonight into Monday morning.

- Showers and storms continue on and off through Monday. Many places
are forecast to receive over 1" of rainfall by Tuesday morning, with
some places possibly up to 2".

- Another system is expected to bring chances for showers and
  storms Wednesday through Friday morning.

&&

.DISCUSSION...
Issued at 356 AM CDT Sun May 12 2024

08Z water vapor imagery shows a mid-level shortwave trough digging
over the Four Corners region early this morning. Another closed low
is noted over northern Manitoba about to move into Ontario, while a
low-amplitude wave can be seen off the coast of British Columbia. At
the surface, weak low pressure has begun to develop in eastern CO in
response to the aforementioned shortwave. Dew points across the
forecast area are in the upper 40s to low 50s, with 60-degree
readings still as far south as central OK.

Rain showers have been slowly working their way through western KS
early this morning with thunderstorms confined to the TX/OK
panhandles so far, where the better instability resides. There may
be enough isentropic lift this morning to bring some isolated, hit-
or-miss shower activity into the area. However, the best large-scale
lift and moisture transport with the approaching shortwave looks to
arrive late this afternoon, mainly moving through this evening and
overnight. This is when CAMs show rain becoming more widespread over
the area. Based on the latest guidance, there should be some breaks
with dry time during the day on Monday, but generally expect showers
and a few storms to continue on and off. The rain looks to taper off
toward Monday evening as the trough axis pushes east. Generally
speaking through these two days, MUCAPE looks limited to under 1000
J/kg with 0-6 km bulk shear around 20-30 kt, so the chance of any
embedded thunderstorms becoming severe looks low. Ensemble data
shows most areas are likely (60-80%) to see at least 1" of QPF by
Tuesday morning with lesser confidence for any particular point to
see upwards of 1.5". That said, ensemble plumes across the area do
show a decent number of solutions between 1.5 and 2", suggesting
there could be some pockets of amounts such as these. This idea is
supported by the HREF as well.

We look to get a break from the rain on Tuesday before the next
Pacific trough moves through the area Wednesday through Friday.
There are still some differences among models regarding the timing
and strength of this system, so it is unclear at this time whether
we dry out before Friday, but PoPs remain in the forecast through
Friday for now. Adjustments can be expected as we get closer to that
time frame. Instability and shear look similar to the first system,
so not anticipating severe weather at this time, but again it will
be something to monitor.

Clouds and rain will likely be the main influence on temperatures
for much of the week. Highs are generally forecast in the upper 60s
to low 80s this week, with temperatures expected to be on the lower
end of that range on the days with more cloud cover and rain.
Forecast lows are mainly steady in the 50s.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 624 AM CDT Sun May 12 2024

VFR conditions look to continue at least for the first half of
the period. Scattered showers move in during the afternoon,
then become more widespread this evening and overnight. While an
isolated thunderstorm can`t be ruled out, coverage of storms
doesn`t look to be widespread enough to justify mentioning in
TAFs at any specific time. Seems like a situation where
monitoring and amending as needed might be more prudent. MVFR
cigs are expected late tonight, and some vis reductions are
possible within heavier pockets of rain as well. There are hints
of cigs dropping to IFR overnight, but confidence isn`t high
enough to introduce in TAFs yet.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Picha
AVIATION...Picha