Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO
1144 PM CDT Friday Jul 31 2015

issued at 319 PM CDT Friday Jul 31 2015

Storm chances across far northern Missouri will be the main concern
this weekend, mainly this evening and again Saturday evening into
Saturday night. A few storms have already begun to initiate across
eastern NE this afternoon, and a cu field continues to expand south
and east of ongoing storms, edging into the far northwest corner of the
County Warning Area. Moisture pooling in the local area and temperatures in the
upper 80s have resulted in 3000+ j/kg cape; however, model soundings
show a weak capping inversion lingering around 900-875 hpa that may
prevent widespread storm development. 0-6 km shear values remain
marginal at best with only about 20 kts of flow at 6 km, then winds
begin to increase dramatically above about 8 km, possibly causing
updrafts to shear off and making storm organization difficult. Above
All, the baroclinic zone supporting storm initiation continues to
weaken, and very weak surface winds indicate very little surface
focus and convergence to support ci; thus, storm coverage may be
isolated this evening. Storms will also be diurnally driven and any
southeastward progress into the rest of the County Warning Area brings storms into a
less supportive environment, so do not expect any convection south
of the Hwy 36 corridor this evening, nor any overnight storm

Another round of storms is possible again in a similar setup
Saturday afternoon and evening, but initiation may occur a bit
further to the north where a shortwave trough will slide across
northeast Nebraska into northern Iowa. Southward sagging of any
convection or outflow boundaries could take storms into northern
Missouri after sunset, but have once again confined pops mainly to
the Hwy 36 corridor and northward, and taper chances back after
midnight when forcing for storms exits the region and diurnal
instability is eliminated. Better shear may support more organized
storms, but the possibility of storms staying completely north of
the County Warning Area prevents any widespread concern for strong/severe storms.

For the remainder of the forecast area, the only real concern this
weekend will be heat as temperatures and moisture very slowly climb.
Highs in the lower 90s and dewpoints in the lower 70s will spell
heat indices maxing out around 100 most afternoons, which is not
enough for heat advisory concerns but will still be uncomfortable
for those with outdoor plans. Overnight lows will also linger in the
upper 60s to mid 70s, providing little relief during the night.
Surface winds will also remain fairly light as surface high pressure
drifts and expands east.

Storm chances continue to look a bit higher into next work week as a
slow-moving boundary drapes somewhere in the County Warning Area and upper-level
flow flattens, supporting the transport of a few weak shortwave
troughs through the area. Models still differ a bit on the timing
and location of shortwave troughs, but storms are still possible in
almost any period with ample moisture and the surface boundary
present. Temperatures will be impacted by any clouds/precipitation
and also the eventual position of the boundary, but should generally
be a bit cooler in the majority of the County Warning Area during the daytime hours.


Aviation...(for the 06z tafs through 06z Saturday night)
issued at 1143 PM CDT Friday Jul 31 2015

Aside from some fog at stj around sunrise, VFR conditions are
expected at all terminals. Light winds will persist through the
forecast but may become southerly with time. There may also be enough
lower level moisture to get some afternoon cumulus to form with bases
generally above 5k ft.


Eax watches/warnings/advisories...



National Weather Service Glossary of Abbreviations