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Area forecast discussion
National Weather Service Kansas City/Pleasant Hill MO
1159 PM CDT Wed Jun 19 2019

Discussion...
issued at 324 PM CDT Wednesday Jun 19 2019

Message of the day: rain chances continue through the evening
hours, mainly east of I-35. Moderate to heavy rainfall is
expected in northeast MO, with another inch or so of rain
possible.

A shortwave trough and surface low have been taking their time
moving through the area today. This has kept the shower and storm
chances lingering throughout the day today. The best chance for rain
and is in northeast MO. An area of showers has already
redeveloped on the nose of a strengthening (albeit still weak) low level jet
and will slowly move through northeast MO this afternoon and
evening. No severe weather is expected in this area, but moderate
to heavy rain is a concern. Precipitable water values are around 1.6- 1.7 which
is well above normal. As a result, another inch of rain is
possible across northeast MO today, on top of the 1-2 inches that
already fell this morning. Therefore, a Flash Flood Watch has been
issued for Chariton, Linn, Schuyler, Adair, Macon, and Randolph
County in MO. Remember if approaching a flooded roadway, to turn
around don't drown. Additional rain development with isolated
thunder in central MO is also expected today. No severe weather is
expected with this activity.

High pressure will build in tonight, with the center of the high
over the area around sunrise. The calm to light winds and moisture
near the surface will likely result in patchy fog across the area
in the morning, with more dense fog possible in northeast MO. Any
fog that develop should diminish not long after sunrise.

The high pressure will move out quickly Thursday, with a surface
low on its heels. In the upper levels, we will be under a weak ridge
with energy ejecting into the upper Midwest from a closed low over
the northwest U.S. Right now, the surface low looks to move
northeast through central Kansas into northeast Kansas/southeast NE. This
will result in a southwest to northeast oriented cold front just to
our west and a west to east oriented warm front across our northern
counties. As for the upper level support, it appears a subtle
shortwave trough will move through over our northern counties,
though the better upper level support will remain well north of MO
and Kansas on Thursday. The 15z hrrr and rap, as well as the namnest,
NAM, and GFS all depict isolated storm development in northwest MO
and northeast Kansas in the late afternoon and early evening Thursday.
The environment is this area is also supportive of strong to
severe storms. Cape values will approach 4000 j/kg with 0-6 km
shear around 40 kts and steep low-level lapse rates. While
damaging winds and large hail are the main concerns, can't
completely rule out an isolated tornado or two with the warm front
in close proximity, low local heights, srh around 150 m2/s2, and
0-1 km shear around 15 kts. The main limiting severe weather factor
to keep in mind though is heights will generally be rising in the
upper levels.

Thursday night into Friday morning, a more robust shortwave trough
will eject east from the main upper level low to our northwest,
with the surface low and associated boundaries essentially
stalling across the region. The low level jet should strengthen, helping
develop an mesoscale convective system that should make it to our area Friday morning
around sunrise. However, the Canadian and European model (ecmwf) want to move the
mesoscale convective system north of the area. Will have to monitor future runs to see if
a greater consensus is reached among the models. If the mesoscale convective system does
move into the area though, damaging winds will be the main
concern, but can't rule out large hail and an isolated tornado. A
favorable environment for severe weather could continue into
Friday afternoon and evening, mainly north of I-70; however, that
will depend on morning activity and resultant boundaries and if we
can destabilize. If we can get storm development Friday afternoon,
all modes of severe weather will be possible.

Friday and Saturday temperatures are, for the first time for many
areas, forecast to reach 90 degrees. Dew points will also be high,
the upper 60s to low 70s, helping heat indices reach the mid to
upper 90s across the area. Given that this is the first time this
year we are expected to experience the Summer heat, care needs to be
taken when doing outdoor work/activities. Make sure to drink plenty
of water and take frequent breaks.

Storm chances will continue through the weekend, until the
aforementioned upper level low finally moves through the central
U.S., Helping move the surface low and cold front through the
region. This will provide a break from storm chances and relief
from the above normal temperatures.

&&

Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1159 PM CDT Wednesday Jun 19 2019

Gradually clearing skies are expected tonight, as well as
diminishing winds as surface high pressure moves over the area.
Patchy fog will be possible at all taf sites, but particularly at
kstj around 12z. Fog should gradually mix out after 13z, leaving
VFR conditions for the remainder of the taf period.

&&

Eax watches/warnings/advisories...
Kansas...none.
MO...none.
&&

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