Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 281735
AFDLSX

Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
1235 PM CDT THU JUL 28 2016

.UPDATE...
Issued at 1235 PM CDT Thu Jul 28 2016

Rain chances look on target today with both an upper level
disturbance (located currently over central MO) and a surface cold
front (currently located from east-central IL thru STL metro and
into south-central MO) providing plenty of focusing mechanism with
the weak CINH, moderately moist and unstable environment in place.
Adding in weak bulk shear to the mix, and severe threat will be
minimal, although with reports of cold air funnels once again in
central IL, this alternate issue will need to be monitored
closely.

Max temps also look on target for 85-90.

TES

&&

.SHORT TERM...  (Through Late This Afternoon)
Issued at 301 AM CDT Thu Jul 28 2016

Convection across northeast MO and west central IL has dissipated
early this morning. Most of the convection was southeast of the
forecast area, associated with a slow moving, compact upper level
low/vorticity maximum.  Additional scattered convection will
develop late this morning and this afternoon as the atmosphere
destabilizes ahead of a weak northwest flow shortwave. It appears
that the best coverage of showers/storms will occur across
southeast MO and southwest IL. High temperatures today will be
similar to yesterdays highs, maybe a degree or two cooler.

GKS

.LONG TERM...  (Tonight through Wednesday)
Issued at 301 AM CDT Thu Jul 28 2016

Convection tonight may be mainly during the evening hours, with
slightly cooler low temperatures due to potentially less cloud
cover. The threat for convection will continue on Friday and
Friday night as shortwaves carve out an upper level trough over
the central US. Temperatures on Friday should be slightly cooler
due to the increased cloud cover and potentially better coverage
of precipitation. There may be less chance of convection on
Saturday and Saturday night as the upper level trough axis shifts
east of the region and a surface ridge noses into our area from
the Great Lakes region. Precipitation chances may increase again
for Sunday and Sunday night due to low-mid level warm air
advection and as a warm front shifts northeastward through our
area. Convection should become more suppressed for the first half
of the next work week as an upper level ridge tries to build
northeastward into our area. This along with southerly surface
winds will lead to warmer temperatures rising above normal values.

GKS

&&

.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1235 PM CDT Thu Jul 28 2016

VFR conditions and light NW surface winds are expected to prevail
at the TAF sites for much of the valid period. There is potential
for VSBY reductions in mist once again tonight, and depending on
exactly how the specifics play out, could lead to some IFR VSBYs
in spots. For now, have added MVFR VSBYs into most TAFs, save STL
for being a bit warmer, and COU because of anticipated additional
clouds reaching them earlier overnight. Rain chances continue to
look enough to warrant mention for all sites this afternoon,
with the better chances shifting off to the south and east late
this afternoon and into tonight, as both the upper level
disturbance and surface cold front should both be at least there
by that time. Rain chances look much more uncertain heading into
late tonight and Friday, with latest model trends showing that the
late tonight-early Friday event may be more deflected to the south
of our area. Prefer to leave out of TAFs given event today and
this new uncertainty on Friday.

TES

&&

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

$$

WFO LSX


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