CheeselandSkies
Member
Here's MKX's thoughts on the remainder of this afternoon/tonight for southern Wisconsin. Appreciate the detailed breakdown; like I mentioned in a post a few days ago there were several years where they weren't really doing that.
.SHORT TERM...
Issued 153 PM CST Fri Mar 6 2026
This afternoon through Saturday:
Watching an effective warm front wiggle northward through the
Mississippi Valley this afternoon, with expectations of a brief
period of peeks of sunlight and higher clouds this afternoon
as a much warmer airmass arrives in the southern two tiers of
Wisconsin counties. As temperatures rise, isolated to scattered
thunderstorms may develop in the warm sector along the effective
warm front. A few of these cells have already developed in
northern Illinois, with expectations that as the front moves
northward this isolated to scattered activity will develop
across far southern Wisconsin. Within these cells, without much
steering flow, expecting more pulse-tyle convection with primary
hazards of hail and gusty winds. CAPE nearing 500 J/kg, bulk
shear around 35 kt, and moderate mid level lapse rates of 6-7
degrees C/km along with freezing levels near convective cloud
base will set the stage for isolated cells to be able to tap
into all the dynamics and instability this afternoon.
Significant turning in the lowest 5000 ft may allow for an
isolated supercell to develop, but confidence is low. Expecting
isolated storms with hail up to 1 inch and gusty winds.
A brief break in precipitation may develop around sunset into
the early overnight hours as the surface warm front weakens with
the lack of solar heating, and the developing low remains to the
southwest. However, going into the 10 PM to 3 AM timeframe,
expecting the low to rapidly lift northeastward, bringing
convection through all of southern Wisconsin. With LLJ dynamics
in play (nearing 60 kt nosing across far southern Wisconsin,
nearing 50 kt in central Wisconsin), expecting this prefrontal
convection to have plenty of lift (frontal boundary), shear
(bulk shear values near 50 kt, 0-3 helicity 300-400 m2/s2), and
moisture to work with (PWATs nearing 1.5 inches). MUCAPE will
also continue to increase through the overnight hours, nearing
1000 J/kg by the time the prefrontal convection moves in. With
all these ingredients in play, expecting a squall line type
feature with low topped convection and potential for QLCS
tornadoes along the leading edge where individual bowing
segments turn northeastward (along the 0-3 shear vector). Even
with a stable layer near the surface, strong enough cells
embedded in the line are expected to punch through to the
surface, resulting in damaging wind potential along with the low
topped QLCS tornado threat. Hail is less likely for this round,
but not out of the question.
Convection will sweep eastward into the early morning hours
Saturday, with lighter rain and embedded lightning to continue
after the main band of strong thunderstorms moves through. All
activity will exit into Lake Michigan and northern Illinois by 4
AM based on current model guidance. The main cold front lags
behind the convection by several hours, allowing for slight
chances of additional showers (20-30%) through mid-morning
Saturday along the cold frontal boundary. No additional severe
storms are expected.
.SHORT TERM...
Issued 153 PM CST Fri Mar 6 2026
This afternoon through Saturday:
Watching an effective warm front wiggle northward through the
Mississippi Valley this afternoon, with expectations of a brief
period of peeks of sunlight and higher clouds this afternoon
as a much warmer airmass arrives in the southern two tiers of
Wisconsin counties. As temperatures rise, isolated to scattered
thunderstorms may develop in the warm sector along the effective
warm front. A few of these cells have already developed in
northern Illinois, with expectations that as the front moves
northward this isolated to scattered activity will develop
across far southern Wisconsin. Within these cells, without much
steering flow, expecting more pulse-tyle convection with primary
hazards of hail and gusty winds. CAPE nearing 500 J/kg, bulk
shear around 35 kt, and moderate mid level lapse rates of 6-7
degrees C/km along with freezing levels near convective cloud
base will set the stage for isolated cells to be able to tap
into all the dynamics and instability this afternoon.
Significant turning in the lowest 5000 ft may allow for an
isolated supercell to develop, but confidence is low. Expecting
isolated storms with hail up to 1 inch and gusty winds.
A brief break in precipitation may develop around sunset into
the early overnight hours as the surface warm front weakens with
the lack of solar heating, and the developing low remains to the
southwest. However, going into the 10 PM to 3 AM timeframe,
expecting the low to rapidly lift northeastward, bringing
convection through all of southern Wisconsin. With LLJ dynamics
in play (nearing 60 kt nosing across far southern Wisconsin,
nearing 50 kt in central Wisconsin), expecting this prefrontal
convection to have plenty of lift (frontal boundary), shear
(bulk shear values near 50 kt, 0-3 helicity 300-400 m2/s2), and
moisture to work with (PWATs nearing 1.5 inches). MUCAPE will
also continue to increase through the overnight hours, nearing
1000 J/kg by the time the prefrontal convection moves in. With
all these ingredients in play, expecting a squall line type
feature with low topped convection and potential for QLCS
tornadoes along the leading edge where individual bowing
segments turn northeastward (along the 0-3 shear vector). Even
with a stable layer near the surface, strong enough cells
embedded in the line are expected to punch through to the
surface, resulting in damaging wind potential along with the low
topped QLCS tornado threat. Hail is less likely for this round,
but not out of the question.
Convection will sweep eastward into the early morning hours
Saturday, with lighter rain and embedded lightning to continue
after the main band of strong thunderstorms moves through. All
activity will exit into Lake Michigan and northern Illinois by 4
AM based on current model guidance. The main cold front lags
behind the convection by several hours, allowing for slight
chances of additional showers (20-30%) through mid-morning
Saturday along the cold frontal boundary. No additional severe
storms are expected.
