771 
FXUS63 KLSX 012015
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
315 PM CDT Tue Aug 1 2017

.SHORT TERM...  (Through Late Wednesday Afternoon)
Issued at 314 PM CDT Tue Aug 1 2017

A shortwave continues to move through the area with scattered 
showers and thunderstorms chances continuing into the evening.  The 
loss of daytime heating and CAPE will allow for thunderstorms to 
taper off to just showers late tonight. Any remaining scattered 
showers will dissipate before daybreak Wednesday morning. The 
combination of light winds over rivers with warm water temperatures 
will lead to some valley fog with patchy fog possible elsewhere. Any 
fog that does form will dissipated by mid morning. Temperatures will 
be within seasonal normals through Wednesday afternoon with light 
and variable winds. 

Kelly

.LONG TERM...  (Wednesday Night through Next Tuesday)
Issued at 314 PM CDT Tue Aug 1 2017

There may be isolated showers/storms Wednesday evening in the warm, 
moist and unstable atmosphere, but the better chance for convection 
will occur Thursday afternoon and evening as a deepening upper level 
low moves eastward through the northern Plains into the Great Lakes 
region and sends a cold front southeastward through our forecast 
area Thursday afternoon and evening.  Cooler and less humid air will 
filter southeastward into the region Thursday night and Friday after 
the passage of the cold front with northwest upper level flow on the 
backside of the upper level trough/low over the Great Lakes region. 
Temperatures will be about 10 to 15 degrees below normal for early 
August Thursday night through Friday night. Good radiational cooling 
conditions Friday night with a clear sky, light surface wind and 
relatively low surface dew points will lead to the coolest 
temperatures.  The next chance of rain will occur late Saturday 
night and Sunday due to low-mid level warm air advection ahead of 
another approaching upper level trough.  The chance of rain will 
continue Sunday night and possibly into Monday until the upper level 
trough shifts east of the region and a cold front shifts southeast 
of the forecast area.  The ECMWF model is a little quicker ending 
precipitation by late Sunday night, while the GFS has QPF over our 
area until Monday evening.  For now will just keep slight chance 
pops over southeast MO and southwest IL on Monday.

GKS

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1148 AM CDT Tue Aug 1 2017

Scattered|showers and thunderstorms over the region will lead to
brief periods of MVFR and IFR condition during the afternoon and
early evening hours. Some MVFR fog is expected Wednesday morning with
light winds.

SPECIFICS FOR KSTL: 
Scattered showers and thunderstorms possible this afternoon into
the early evening hours. Some MVFR fog is possible on Wednesday 
near the terminal with light winds.  

Kelly

&&

.PRELIMINARY POINT TEMPS/POPS...
Saint Louis     70  88  71  89 /  30  10  10  30 
Quincy          64  86  67  83 /  20  20  10  50 
Columbia        64  86  67  84 /  20   5   5  40 
Jefferson City  65  87  67  86 /  30   5   5  40 
Salem           65  86  67  87 /  20  30  20  30 
Farmington      64  86  66  88 /  20  40  20  20 

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX