957
FXUS63 KLOT 302110 CCA
AFDLOT

Area Forecast Discussion...CORRECTED
National Weather Service Chicago/Romeoville, IL
410 PM CDT Thu May 30 2024

.KEY MESSAGES...

- Dry and pleasant weather continues into tomorrow.

- Rain (possibly with a few thunderstorms) on Saturday.

- Periodic chances for showers and storms early to mid-week next
  week.

&&

.DISCUSSION...
Issued at 341 PM CDT Thu May 30 2024

Through Friday:

Another spring-like day wraps up this afternoon, as temps
climbed into the low 70s inland with 60s from the lakeshore to
a few miles inland. High pressure will continue to track
through the lower Great Lakes region into the Appalachians by
Friday. The cooler overnight temperatures linger once again with
forecast lows tonight in the upper 40s to low 50s. Easterly
winds will shift to southerly heading into Friday, ushering
warmer temperatures into the region to end the work week.
Although sustained winds will remain nearly the same as today,
some gusts in excess of 18-20 mph are anticipated Friday midday,
bringing highs in the early afternoon near 80 inland while low
to mid 70s hang around the lakeshore on the Illinois side. The
only major difference featured tomorrow will be the arrival of
clouds during the afternoon into the evening ahead of the next
weather system.

Baker


Friday Night through Thursday:

This year`s meteorological summer will start off on a crummy
note as a low pressure system lifts northeastward into the
area, encouraging an influx of moisture towards the lower Great
Lakes. Increasing mid-level DPVA and low-level isentropic
ascent/warm air advection will serve to erode dry antecedent air
and bring a relatively expansive precipitation shield into the
area overnight Friday into Saturday morning, which will then
likely linger around in some capacity through most or all of
the daytime on Saturday. Instability will remain meager at best
and should stay mainly confined to our southern counties, which
will thus stand the best chance to get a few rumbles of thunder
before the system departs to the east.

Precipitable water values as high as 1.50"-1.75" are progged to
get drawn into our forecast area on Saturday and should support
some healthy 1+" rainfall totals wherever the rain falls
steadiest and longest. The introduction of any convective
elements to locally enhance rainfall rates could lead to a need
to watch for some localized minor flooding -- particularly in
the most heavily urbanized areas of the Chicago metro -- but
otherwise, not expecting any more notable concerns on the
hydrologic front. With the rain and associated stratus expected
to linger throughout much of the day, temperatures on Saturday
should struggle to climb much above the 70 degree mark, and will
likely remain mired in the low-mid 60s closer to the lakeshore
as winds there turn northeasterly in response to the surface low
passing by.

Sunday looks like it should be dry as we find ourselves in
between weather systems, though just enough moisture may be
present to where we can`t completely rule out some isolated
showers developing during the afternoon. With the jet stream
remaining displaced to our north early to mid-week next week, it
looks like we will enter a period featuring generally above
normal temperatures and periodic shower and thunderstorm chances
originating from disturbances tracking to our northwest.

An initial shortwave trough will zip through the Upper Midwest
Sunday into Monday, spawning a surface low whose cold front
should eventually make its way towards our CWA on Monday. Much
uncertainty remains at this time about the strength of the
front, its timing of arrival, and whether a preceding outflow
boundary may be generating convection out ahead of it before it
arrives, among other things, but enough of a QPF signal exists
in the latest EPS and GEFS to continue carrying the NBM`s likely
PoPs and chance thunder probabilities in our gridded forecast
for Monday. There should be enough pre-frontal instability to
support the potential for some strong to severe storms as hinted
at in CSU`s machine learning probabilities and CIPS analog
guidance, but whether this potential will be realized will
depend on the aforementioned factors and others, and these finer
scale details probably won`t be able to be resolved for at least
a few more days. Another opportunity for thunderstorms (and
quite possibly strong to severe thunderstorms somewhere in the
region) should then come late Tuesday and/or Wednesday as a
more potent upper-level trough careens into the Upper Midwest.

Ogorek

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1202 PM CDT Thu May 30 2024

VFR conditions with cirrus are expected through the period. NE
winds around 10 knots will diminish tonight while veering SSE by
sunrise Friday. Variability between 160-190 degrees is expected
Friday morning before a lake-enhanced wind shift settles
directions ESE mid to late afternoon.

Kluber

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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