Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 231157
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
657 AM CDT THU JUN 23 2016

.SHORT TERM...  (Through Late This Afternoon)
Issued at 317 AM CDT Thu Jun 23 2016

Cold front extending from a surface low over northern IN southwest
to near UIN and MCI will move southeastward through the forecast
area today. Do not see much convection this morning as the
atmosphere is initially capped with warm 700 mb temperatures.
Scattered convection should break out this afternoon along and
south of the front as the atmosphere become very unstable across
southeast MO and southwest IL, south of I-70. High temperatures
will be a little cooler across northeast MO and west central IL
behind the cold front with surface dew points also gradually
lowering across this area. Temperatures will be quite hot again
across southeast MO and southwest IL with high values of humidity
again today leading to heat indices approaching 105 this
afternoon. For this reason will issue a heat advisory this
afternoon across parts of southeast MO and southwest IL.

GKS

.LONG TERM...  (Tonight through Wednesday)
Issued at 317 AM CDT Thu Jun 23 2016

Scattered convection may linger tonight across southeast MO,
otherwise surface high pressure building southward into the area
behind the cold front will lead to cooler and more normal low
temperatures tonight. Although an upper level ridge will try to
build back over the region on Friday, a weak shortwave along with
a return southerly low level flow on the backside of the retreating
surface ridge may bring scattered showers/storms to central and
southeast MO on Friday and to most of the area Friday night.
Scattered mainly afternoon and early evening convection is
expected on Saturday and Saturday night. An upper level trough
will move eastward through the northern Plains and into the Great
Lakes region Sunday through Monday with a weakening cold front
dropping southeastward through the region. This front will be the
focus for more showers and storms Sunday through Monday. Should
see at least slightly cooler temperatures beginning Monday night
after a warm weekend, and these cooler temperatures should
continue for the rest of the extended forecast as we get into a
more northwesterly upper level flow pattern as the upper level
ridge retrogrades into the southwestern US with upper level
troughing over the Great Lakes region. A surface ridge will also
build southeastward into our region from the northern Plains.

GKS

&&

.AVIATION...  (For the 12z TAFs through 12z Friday Morning)
Issued at 614 AM CDT Thu Jun 23 2016

A cold front will continue sinking southward into the region
today. Winds will be southwesterly ahead of the front, then turn
northwesterly to northerly after fropa. Winds will continue
veering and become northeasterly late in the TAF period. Isolated
SHRA/TSRA are possible this afternoon near the front, but
confidence is too low to include in the TAFs attm.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Heat Advisory from noon today to 7 PM CDT this evening for Iron
     MO-Madison MO-Reynolds MO-Saint Francois MO-Sainte
     Genevieve MO.

IL...Heat Advisory from noon today to 7 PM CDT this evening for
     Randolph IL-Washington IL.

&&

$$

WFO LSX


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