Special Weather Statement, NWS Topeka, KS

Area Forecast Discussion
National Weather Service Topeka KS
343 PM CDT Sun Jul 19 2020

.SHORT TERM...(This evening through Monday)
Issued at 342 PM CDT Sun Jul 19 2020

Currently, the upper air patter continues to feature the main belt
of the Westerlies well north of the area around the Canadian border.
As shortwave energy continues to lift into the northwestern Great
Lakes region, the associated weak surface cold front has settled
across the forecast area.  This boundary is fairly hard to analyze
but it is roughly from just north of Kansas City trailing just north
of Manhattan and then points west into north Central Kansas.  This
boundary is expected to continue to be the focal point for any
storms to develop off of this afternoon with favored areas generally
from Topeka and points east with the best overall - but still weak -
convergence as well as higher theta-e airmass with higher mixing
ratios generally above 15 g/kg.

Overall, dewpoints are slightly lower than yesterday with some areas
being impacted by old outflow boundaries from overnight convection
that moved into the area.  Also, lower dewpoints reside on the north
side of this frontal boundary across the area.  As a result, heat
indicies across the area are now in the upper 80s to upper 90s.
Still very uncomfortable but some relief from the oppressive heat.
Winds remain light, so still exercise caution when working or
playing outdoors.

As hinted at before, storms should still develop this afternoon
generally through 6 or 7 pm from Topeka and points east then down
into areas of east Central KS into the Emporia area.  While severe
storms are not all that likely, there could be one or two develop
with downburst winds being a concern before storms develop off of
the outflows and propagate east of the area before dark.

Overnight, isentropic ascent should increase as night falls and a
LLJ develops over western KS.  As storms grow upscale, veering of
the LLJ should favor advection into the forecast area.  Slow storm
motions and backbuilding suggests that heavy rain would be possible.
 Not entirely sure about overall coverage though if the LLJ does
progressively veer sooner than expected, so not going with a broad
brush Flood Watch for now.  Still coordinated with WPC and the
slight area was not upgraded to a Moderate area for flash flooding
concerns.  Still would not rule out a flash flood warning or two may
be needed tonight with some locally high rainfall amounts.
Antecedent conditions also precluded any enhanced flood concerns at
this time.  Favored areas remain along the weak boundary extending
from area just east of Concordia into east Central KS where some of
the highest amounts may be possible.

.LONG TERM...(Monday night through Sunday)
Issued at 342 PM CDT Sun Jul 19 2020

Into the day on Monday, showers and storms should tend to weaken and
partial clearing could take place into part of the afternoon.  Right
now the a similar pattern appears to be the likely scenario with no
significant change in the synoptic pattern.  One enhancement that
would favor later afternoon storm development and continue to at
least part of the overnight period is that slight amplification of
the upper level energy north of the area may allow for a subtle
shortwave to translate into the area which would foster ascent and
help encourage storm development along with increasing instability
across much of northeastern and east central KS.  A LLJ along with
isentropic ascent into the overnight period would help support more
widespread and heavy rainfall potential once again into the
overnight period.  Moisture flux trajectories look to favor mass
flux into the east Central KS counties.  This would add to overnight
totals from tonight.  At this point the exact amounts are unknown
but the general 48 hour total could be up to around 5 inches or more
over some of these east central areas.  Therefore, expect that some
minor to moderate river flooding could take place and locally high
amounts would lead to potential flash flood warnings as the main
hazards.  Afternoon storms could certain pose a similar downburst
wind risk as well.

For the rest of the week, the upper pattern begins to amplify with a
ridge becoming more pronounced over the central Plains and heat
returning into the upcoming weekend once again with heat index
values topping out around 100 at this point.  Periods of showers and
storms appear possible but low chance due to minor perturbations
along the right flank of the ridge which could impact at least
portions of the area.  A dirty ridge should be the story regardless,
as monsoonal moisture trajectory remain into the general regional
area.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1235 PM CDT Sun Jul 19 2020

Bottom line is uncertainty remains with this overall forecast.
Best guess right now for any storms formation would be in the
vicinity of the KTOP/KFOE terminals as soon as mid afternoon. The
best convergence is east of the KMHK terminal, so that is on of
the main reasons for an eastward focus area. Later, shower and
storm development appears to be increasing in confidence during
the overnight period with the stalled frontal boundary essentially
remaining near the terminals. Into the overnight period, more
widespread showers and storms could be supported, so have
increasing intensity with potentially heavy rain. Not expecting
overall low CIG/VIS restrictions, but this could need refining
with heavier rain. Overall, the wind appears to remain generally
below 10kts but an strong wind gust or two this afternoon with any
storm wouldn't be ruled out.

&&

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

SHORT TERM...Drake
LONG TERM...Drake
AVIATION...Drake

Hazardous Weather Outlook
National Weather Service Topeka KS
346 PM CDT Sun Jul 19 2020

KSZ008>012-020>024-026-034>040-054>056-058-059-202100-
Republic-Washington-Marshall-Nemaha-Brown-Cloud-Clay-Riley-
Pottawatomie-Jackson-Jefferson-Ottawa-Dickinson-Geary-Morris-
Wabaunsee-Shawnee-Douglas-Lyon-Osage-Franklin-Coffey-Anderson-
346 PM CDT Sun Jul 19 2020

This hazardous weather outlook is for east central...north
central and northeast Kansas.

.DAY ONE...This Afternoon and tonight.

There may be a few strong to severe thunderstorms this afternoon
and Tonight. The main hazard will be damaging wind gusts this
afternoon with the focus changing to heavy rainfall overnight.
Localized flooding may be possible.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

A few strong to severe thunderstorms will be possible again on
Monday afternoon and possibly on Tuesday. The main hazards will
be damaging winds once again in the afternoon with heavy rainfall
into the overnight period on Monday which may lead to localized
flooding once again.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

&&

More detailed information can be accessed at...
http://www.weather.gov/top/sitrep