Fond Lac, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

463
FXUS63 KMKX 191446
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
946 AM CDT Sat Jul 19 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms will develop across
  central Wisconsin this morning (40 to 50 percent chance), with
  widespread light to moderate rainfall and embedded lightning
  across southwestern to southeastern Wisconsin through the
  remainder of this morning. An isolated storm may develop near
  the Illinois border and produce gusty winds.

- Isolated showers and thunderstorms are possible late this
  afternoon and early evening along a cold front, especially
  across central Wisconsin. Storms may produce gusty winds and
  small hail.

- Chances for storms develop on and off Tuesday through late
  next week, but timing and intensity remain uncertain at this
  time.

- Heat builds back into the region, with highs in the upper 80s
  to lower 90s Tuesday into the end of the week.

&&

.UPDATE...
Issued 945 AM CDT Sat Jul 19 2025

Increasing instability this morning as solar heating increases,
with a large batch of rain containing isolated lightning bolts
progressing from west to east across the region. Embedded
thunderstorms along the back of the rainfall produced wind
gusts of 40 to 50 mph across Iowa, with expectations remaining
steady that a few similar gusts may occur along the Illinois
border as this activity moves eastward (bulk shear values in the
30 to 40 kt range). In addition, a few thunderstorms are
developing along the leading edge of the broad area of rain
across the remainder of southern Wisconsin. Modeling is
struggling to latch on to the amount of stratiform
precipitation, which may create a bias toward higher CAPE
without that potential being realized (i.e., storms in central
to southeastern Wisconsin remain weak and transient).

The cold front farther to our northwest is beginning to
show its hand, with a few scattered showers developing across
southeastern Minnesota to northwestern Wisconsin even within an
overcast region. However, it will be moving into an area of
increasingly stable air as it enters Iowa and southern Wisconsin
where morning storms were most widespread. Meso models continue to
show only isolated showers and storms along the cold front. If
some CAPE can build back into the area, could see an isolated
stronger storm along the front itself, especially toward central
Wisconsin where widespread rainfall did not occur during the
morning hours. Main concerns would be gusty winds and small
hail once again.

MH

&&

.SHORT TERM...
Issued 323 AM CDT Sat Jul 19 2025

Today through Sunday:

The thunderstorm complex of interest is currently over north
central IA and is slowly making progress east-southeastward.
This is slower than what was previously forecast. There are a
few small thunderstorms out ahead of the intense cluster within
a region of warm air advection, low level frontogenesis, and mid
level vorticity advection. Mid level lapse rates are fairly
steep over southeast MN and that is expected to advect into
northeast IA and southwest WI through 8AM. The MLCAPE gradient
is along an axis from southeast MN to east central IA, but this
is also expected to shift eastward into south central WI through
mid morning. The surface-based CAPE is farther west, aligned
with the storm complex. This is not expected to make it into
south central WI until late morning, and by that time, the storm
complex should ride the gradient south-southeast through
eastern IA.

The HRRR model seems to be doing well and has a reasonable
solution to keep the main storm complex just to our southwest.
Several other models also agree with this solution. The
northeast edge of the complex will probably clip southwest and
south central WI. However, we will still have a chance of storms
through late morning due to the warm air advection and vorticity
advection. These should be on the weaker side, but cannot rule
out a stronger storm or two due to tall, skinny cape and modest
bulk shear. The limiting factor on scattered storms with this
forcing in the mid to late morning is a weak cap.

It is still uncertain how long the clouds will hang around
during the day. If clouds dominate, which upstream satellite
suggests, then there will not be enough afternoon/evening
instability to support showers and storms when the actual
surface cold front drops through the area. The meso models have
been showing this scenario for a couple of days now - little to
no convection along the front over southern WI. If storms do
develop, then brief gusty winds and small hail are the threats.

North to northeast winds are expected to rush down the lake in
the wake of the cold front late this evening. Gusts up to 25 kt
and higher waves are anticipated through the night and into
Sunday morning. A moderate to high swim risk is possible, mainly
south of Milwaukee.

The frontal boundary will stall over northern IL late tonight
through Sunday. Showers and storms developing along the front
may clip far southern WI, so there is a chance for showers
mentioned.

Cronce

&&

.LONG TERM...
Issued 323 AM CDT Sat Jul 19 2025

Sunday night through Friday:

High pressure will slowly move to the east of the region Sunday
night into Monday, with light east to southeast flow helping push
most of the precipitation chances to the south and west of the
area. Temperatures should be near seasonal normal values. The
influence of the high may keep Monday night relatively dry as
well, as southeast winds start to increase.

The axis of the 500 mb ridge remains to the south of the region
Tuesday into Wednesday, with more zonal flow over the area. Warm
air advection develops in earnest later Tuesday into Wednesday, as
a warm front shifts through and winds shift to the south. This
should be a period for showers and thunderstorms to move through
the area. This will also help bring very warm and humid
conditions into the area Tuesday into Wednesday, which have been
supported by ensemble member trends for the past several model
runs.

Periodic chances for showers and thunderstorms are then forecast
through the remainder of the week, as the area remains in the more
zonal flow aloft with systems moving through the region at times.
Ensembles support this fairly active weather pattern, with a
majority of members suggesting measurable precipitation for most
days during this period. Warm and humid conditions should prevail
for most of this period as well, with ensemble members still
showing above normal temperatures.

Wood

&&

.AVIATION...
Issued 945 AM CDT Sat Jul 19 2025

MVFR to VFR ceilings in most areas, with brief pockets of IFR
conditions beneath storms. An area of rain with isolated
lightning will progress west to east through this morning,
with a few stronger storms across south-central to southeastern
Wisconsin as solar heating increases by midday. Gusty winds up
to 40 kt and local small hail are possible within stronger
storms during the late morning to midday timeframes. After the
morning to midday convection moves through, expect southwesterly
breezes to develop and VFR conditions to prevail. A cold front
will then move northwest to southeast, bringing isolated to
scattered showers and thunderstorms along it, especially in
central Wisconsin. Brief periods of MVFR conditions beneath
heavier showers/thunderstorms are possible. Winds shift to
become northwesterly behind the front, then northeasterly
tonight. As winds shift to northeasterly, low clouds off of Lake
Michigan are expected to progress inland. Ceilings in around
1000 ft are expected.

MH

&&

.MARINE...
Issued 323 AM CDT Sat Jul 19 2025

A warm front extending from low pressure developing in the lee
of the Colorado Rockies is situated across northern Wisconsin
and the Upper Peninsula of Michigan. This will bring showers and
thunderstorms to the north half of the lake today. Additional
thunderstorm development is possible across the southern half of
the lake later this morning.

Winds become southwesterly as the showers and storms end by
midday, then become northerly behind a cold front as it tracks
north to south this afternoon and evening. A few thunderstorms
are possible along this front. Gusts up to 25 kt are likely
behind the front tonight, so a Small Craft Advisory may be
needed. High pressure will settle back into the region on
Sunday, slowly departing into Monday and shifting winds to
easterly. A low pressure trough will cross the Upper Midwest on
Tuesday, bringing southeasterly winds.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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