Buffalo Grove, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

044
FXUS63 KLOT 102317
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
617 PM CDT Sun Aug 10 2025

.KEY MESSAGES...

- Periodic bouts of scattered showers and isolated to scattered
  thunderstorms can be expected through the first half of the
  upcoming work week, probably followed by a few quieter days.

- Any stronger thunderstorms the next few days will be capable
  of producing torrential downpours and localized flooding.

&&

.DISCUSSION...
Issued at 301 PM CDT Sun Aug 10 2025

Through Monday:

In the wake of the earlier showers and storms, convective coverage
has greatly diminished as of this writing, owing to likely
subsidence amidst marginal mid-level lapse rates. Isolated to
widely scattered showers and perhaps a few isolated thunderstorms
should be the theme for the rest of the afternoon hours. Can`t
completely rule out an isolated thunderstorm as far southeast as
the Kankakee River Valley of northwest Indiana over the next
few hours.

Looking off to the west of the MS River, a slow moving MCV over
eastern Iowa has recently resulted in the initiation of scattered
convection. Given the worked over and more stable conditions over
much of northern Illinois, along with this wave approaching
after dark, how much bonafide deep convection is able to
develop in our CWA is a big question mark. The next shift will
be able to better refine things per observational trends this
evening. Given the uncertainty, weak lapse rates, unfavorable
timing, and only modest forcing, kept thunder chances in the
slight chance range through tonight and into Monday morning. Our
highest forecast PoPs (30-50%) for shower activity regardless
of thunder chances/coverage are once again focused
near/northwest of I-55.

The slow moving cold front up across the upper MS Valley will
gradually progress southeast through Monday. Specifics regarding
shower and thunderstorm trends in the afternoon are unclear.
However, outflow could push the effective boundary farther
south resulting in better chances for scattered showers and
thunderstorms farther south than previous forecast thinking.
Exactly how things play out overnight into the morning hours
will help determine how the rest of the day goes.

All in all, weak forcing, possible cloud cover effects, and
increased uncertainty necessitated lowering PoPs down into the
30-40% range through the day on Monday. If and where thunderstorms
develop, coverage now appears more likely to be widely scattered
in nature. Marginal mid-level lapse rates and sub marginal deep
layer shear should further limit the threat for any damaging
downburst winds on Monday. Slow storm motions and high PWATs will
keep the threat for localized torrential downpours and flooding
going, however. Aside from the uncertain convective details on
Monday, it will be another warm and humid day, especially near and
southeast of I-55 (upper 80s to around 90F).

Castro


Monday Night through Sunday:

The potential for continued off-and-on rounds of showers and
thunderstorms will persist through Tuesday night/Wednesday as an
axis of high theta-e air with PWATs near 2 inches remains
nearly quasistationary overhead. Several perturbations will
slingshot their way through fairly active southwest flow during
this time frame, as a robust shortwave drops out of southern
Canada and sweep through the northern Plains.

Timing each of these individual perturbations remains
challenging, as, to some degree, convective augmentation will
take place each day with successive rounds of thunderstorm
development. That said, there is a decent signal in latest model
guidance that a synoptic wave (positively tilted in most
guidance) may impinge on the region Monday evening and
overnight, yielding an uptick in broad warm and moist advection
and an associated increase in shower and some thunderstorm
activity. The ensemble signal remains fairly strong that the
greatest potential coverage during this period overnight Monday
night into Tuesday morning will remain near and northwest of
I-55, within the core of the modeled deepest tropospheric
moisture.

While 925-850 mb southwesterly flow will be seasonably
strong (near 35 kts at times), not currently seeing signs of
particularly robust convergence axes which would spell more of a
concerning heavy rain and flood scenario. Some training of
individual convective clusters will be possible with cloud-bearing
flow generally southwest to northeast, aligned parallel with the
main moist axis, but nothing currently stands out as overly
concerning from a widespread flash flood perspective into Tuesday.
Guidance remains in decent agreement that a cold front will press
south through the region during the Tuesday night/Wednesday
timeframe. This should shift the shower and thunderstorm chances
southward Tuesday afternoon and eventually bring an end to the
daily convective potential. If the front gets hung up in our far
south on Wednesday, isolated afternoon showers and thunderstorms
will be possible.

Moisture and instability looks like it`ll end up sloshing back
across the region towards next weekend. Current extended
guidance suggests that our region may remain on the northern
periphery of lingering subsidence with a belt of stronger
cyclonic mid and upper level flow displaced across northern
Wisconsin and the UP of Michigan. This may end up keeping the
more appreciable storm chances to our north, although there are
some signals that the mid-level ridge could break down towards
the Saturday night - Monday time frame ahead of another front
which could open us up to the next round of MCS chances.

Carlaw/Castro

&&

.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 617 PM CDT Sun Aug 10 2025

A warm and moist airmass remains stalled over the region ahead
of a stationary front draped across the Upper Mississippi River
Valley. Small-scale perturbations and axes of confluence will
afford periodic opportunities for showers and thunderstorms
amidst otherwise prevailing dry conditions. One such confluence
axis has recently allowed for isolated showers and storms to
develop from IJX to ARR. This activity should lift east-
northeastward and threaten DPA/ORD and possibly MDW between 00
and 02Z. Meanwhile, an MCV in eastern Iowa is supporting the
development of a broken band of showers and storms near the
Mississippi River, which will threaten RFD between 02 and 04Z.
For both of these areas, will introduce TEMPO groups at
DPA/ORD/RFD. Thereafter, will revert to a strategy of prevailing
dry conditions until new mechanisms to initiate convection
become apparent or trends dictate otherwise.

Winds through the TAF period are expected to remain out of the
southwest. Periods of mid to upper level clouds will prevail.
High resolution guidance suggests a period of IFR cigs may
develop in the vicinity of RFD overnight in response to weak
winds, moist soils, and low pressure troughing in southern
Wisconsin. At this point, confidence is not high enough to
introduce a formal mention of such in the outgoing TAF package.

Borchardt

&&

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

&&

$$

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