Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion...updated aviation 
National Weather Service Saint Louis MO
608 am CDT Tuesday Jul 26 2016

Short term... (through late this afternoon)
issued at 309 am CDT Tue Jul 26 2016

A few storms were across southwest IL, northeast of stl early this
morning. This activity appeared to be associated with a surface
dewpoint gradient and along the 850 mb front. A surface ridge
centered over eastern Nebraska and Iowa was bringing slightly
cooler air and lower humidities to northeast MO and west central
Illinois along with a clear sky. The chance of showers and storms will
continue today, mainly across southeast MO and southwest IL,
south of stl near a weakening cold front and where low-mid level
moisture and instability will be maximized.

Gks

Long term... (tonight through monday)
issued at 309 am CDT Tue Jul 26 2016

The threat for convection should be mainly confined to southeast
MO and southwest Illinois tonight into Wednesday, then across most of
the forecast area by Wednesday night and Thursday as the weak
front lifts back northward as a warm front and the surface ridge
shifts east of the area allowing low level moisture and
instability to spread northward. Shortwave energy will also be
carving out an upper level trough over the central US by Thursday
leading to more cloud cover and possibly slightly cooler high
temperatures. This upper level trough should bring another cold
front slowly southeastward through our area by Thursday night.
This may eventually shunt much of the convection south of our
forecast area by Friday night with surface ridging moving slowly
eastward through the Great Lakes region, or at least to parts of
southeast MO and southwest Illinois. Temperatures Friday and Saturday
may be slightly below normal, but then return to near normal
values by Sunday as southerly surface/low level flow returns.

Gks

&&

Aviation... (for the 12z tafs through 12z Wednesday morning)
issued at 550 am CDT Tue Jul 26 2016

Specifics for KUIN, kcou: there is a possibility for MVFR fog at
kcou and KUIN this morning before 14z. VFR conditions are expected
for the rest of the day. Fog is possible again after 27/06z.

Specifics for kstl, ksus, kcps: MVFR fog/stratus was noted this
morning on area metars near the terminals. Conditions should
improve by 14z with VFR conditions then expected for the rest of
the day. Although rain showers/thunderstorms and rain chances are higher for locations
farther south and closer to a stalled cold front, isolated
rain showers/thunderstorms and rain cannot be ruled out this aftn near the St. Louis Metro
area terminals. Fog is possible again tonight after 27/06z.

Kanofsky

&&

Lsx watches/warnings/advisories...
MO...none.
Illinois...none.
&&

$$

Weather forecast office lsx

National Weather Service Glossary of Abbreviations