Rich,
Come on out. See you at the field.
Aviation weather concerns this period consist of:
* Lake breeze and an ENE wind shift late this AM/early PM
* Developing soaking rain this evening and overnight with MVFR and
potentially IFR cigs/vsbys
* Low potential for some RASN for a brief period late tonight,
mainly RFD and DPA.
* Gusty easterly winds tonight into Sunday morning
Light and variable winds will start the day off along with some
very patchy/shallow BR at outlying airports. A freshening lake
breeze will switch winds easterly/northeasterly, first at GYY, and
then into MDW and ORD around 17-19z. Winds will then remain east
or northeast through the rest of the TAF period.
Rain chances look to increase quickly this evening, although there
remains some level of uncertainty regarding just how quickly the
low-levels saturate with the latest thinking that it may take a
little longer at ORD/MDW/RFD than currently indicated by some of
the more aggressive hi-res guidance. Eventually, MVFR vsbys/cigs
should be commonplace, with a potential for IFR conditions. Have
introduced TEMPO groups for a period where the steadiest/heaviest
rainfall is currently expected, and these may need to be moved to
prevailing groups if confidence increases. Latest guidance
suggests that a cold rain should prevail at ORD/MDW, with some
potential for a brief rain/snow mix developing at RFD and DPA.
This potential still seems pretty low right now, but perhaps just
high enough at RFD to justify a brief PROB30.
Precipitation chances will begin to trend downwards through Sunday
morning and certainly through the early-mid afternoon hours with
some improvement to cigs/vsbys during this time.
Carlaw