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MAR 19, 2020 | [UPDATED] Thursday Storm to Bring Rain, T-storms to Wisconsin

LAST UPDATE : MAR 20, 2020

12:25PM WEDS - Multi-facet system coming in for Thursday.

Latest models continue to trend slowly north/warmer. What looked like a winter storm for northern WI has been reduced to a rain/snow mix - for now. The potential for accumulating snow still there in the north, however rain is expected for most of Wisconsin, and perhaps a thunderstorm south. It doesn't appear that anything significant is in store for Wisconsin however certainly an impactful weather producer for the state.

SNOW - Latest models continue to weaken the snow threat. They are warmer increasing the rain potential across Wisconsin. It seems the cold front will be delayed into Friday. The trend has been for lowered amounts. GFS/EC/NAM keep the heaviest amounts in the snow belt of western Upper Michigan/far N WI so I constrained the higher 5-8" zone there. Will take the risk of locally higher amounts. Felt the NAM was a bit of an outlier at this stage but I'm not willing to rule it out yet. 00EC is was the snowiest...not too confident in it as more recent GFS/NAM runs have been weaker. Best chance for snow on the back end of the system.

RAINFALL - I've kept the 0.5-1.0" zone, shifted it a little north. Potential there for an inch or more in some areas but I'm not confident in the exact location of the heaviest amounts so I broad-brushed the state. Most of the rain will come during the morning hours with the main surge. The afternoon rainfall will be decided by t-storm activity in the south. In a holding pattern regarding the rainfall forecast.

T-STORMS - I included more of southern WI in the strong storm zone but I'm not too concerned at the moment. Models in the worst case scenario suggest that a couple elevated hailers could develop along the elevated warm front across far southern WI. We need to monitor the surface warm front location and whether it sneaks further north with moisture near to the boundary. Still think Iowa is most at risk on Thursday afternoon/evening. NAM might be too far north...typically is. We'll see!

I've updated the maps to reflect latest thoughts.

Thursday will not be windy. Friday will be the windy day so I will separate that out.

***PREVIOUS ****

1:48PM TUES - warmer today across all models but not necessarily more intense. Watching southern WI for threat of strong thunderstorms Thursday afternoon/evening(t-storm activity possible during the AM) Wind shear profiles looks pretty strong but worry moisture and thermodynamics might be lacking. In the wash it might just come out to be a strong t-storm or two across northeast IA? Will be watching closely!

10:26PM MON - 18GFS just a touch warmer but not enough to make changes tonight. Next update late AM Tuesday.

8:30AM MON - Watching the evolution of this system on last several runs. Seems to be steering away from a major storm event in favor of a moderate impact/progressive system. Little janky/disorganized at times. The storm looks somewhat mature/even occluded at it's peak over Wisconsin which tends to lead to a narrowing of the main precip band and dry air pockets/issues. Still this system could have a decent impact with several inches of snow north. Rain. Maybe some t-storms south? I'm going to stay away from strong verbiage even if it's bringing late season snow to portions of the state. Confidence is normal today.

06GFS is the furthest north (like usual). GFS ensembles put the heaviest through northern Wisconsin. The last few runs of the EC were slightly colder but. I guess the difference relates to the overall strength of the system where GFS tends to be stronger at this forecast hour thus taking further north. If you compare the EC to the GFS ensembles...not too much difference on the big picture with snow north. The NAM at 84hrs looks similar to the GFS. Regarding amounts... this looks like a 4-9" event for northern WI if models hold. I won't rule out higher amounts somewhere but not drawing attention to that. Will need to better constrain those snow amounts zones later.

RAIN/T-STORMS? - The EC is most aggressive with a thick beefy rain band sliding through southern WI. GFS/CAN not so much which introduces some doubt. There is likely to be dry air narrowing the main W->E precip band through WI and infiltrating the band itself in spots. Still I've gone with a 0.5-1.0" zone to factor in convective precipitation. Perhaps as we get closer I can get more specific. As for thunder...yea, maybe a few embedded rumbles in the far south Thursday afternoon! Not expecting severe weather in Wisconsin right now but it could be a close call. GFS does show a weak pocket of instability slipping through that should be monitored. If models trend warmer then southern WI will need to be reevaluated for severe threat. I've highly the first t-storm zone of the year (see maps). Possibly the first storm chase the season.

In conclusion; trying to approach this carefully. I don't think the verbiage needs to be very strong yet. Will keep an eye on it.

PREVIOUS

1:20AM SAT 3/14 - Eyeing up this timeframe for a long time. Models bring a strong low through. Looks to be in fairly significant occlusion/mature phase by the time it arrives which will likely mean dry air issues. Reminds me of Mar 13, 1990 event. Not sure what that event brought for rain or snow but I know it was a severe wx outbreak to the SW of WI. Similarites.

Will attempt an update this weekend. My youngest is sick now joining my oldest and I threw my back out earlier tonight. Fun times!

-JP

Forecast Maps

Thunderstorm Outlooks

Thunderstorms
General
Strong
Severe
Significant

Snow


Heavy Rain

Heavy Rain
0.5-1.0"
1-2"
2-3"
3-6"
6-10"
10"+

Verification


Storm Details

Hazards
Heavy Rain, Heavy Snow, T-Storms
Start
THU 7:00 AM - Mar 19, 2020
End
FRI 8:00 AM - Mar 20, 2020
Confidence Level
Storm Class

Posts

latest models showing up to an inch or so in portions of central or even southern WI into early tomorrow AM. Could be similar to the light snow we saw earlier this week. Little to nothing across northern WI (away from the snow belt).
the most active day we've had across the region in awhile. Severe thunderstorms possible across Iowa as storms currently in Nebraska shift east tonight. Still think it will be a near miss for Wisconsin on the strong/severe threat. Will keep an eye on far southern WI tonight anyway. For WI overall it's really the snow/rain activity coming from the west that will slide through tonight. An additional inch or two of snow could fall as far south as southern WI by early Friday morning.
Will be working through over the next few hours. Severe weather not expected with this round however cannot rule out small hail.
Good Morning! Rain & storms will arrive during the mid-day hours and hang with us throughout the evening. Broken line of tstorms currently moving into Iowa. We're next in line.
Snowing pretty good in spots around southern WI. 2.2" in Oshkosh so thinking about up to 3" based on that one single report I have. This morning snow will gradually end or turn to rain as the system slides east.

Archives

March 19, 2020

24HR Radar Loop
24HR Radar Loop
Snow Accumulation 24Hr
Wind Gusts
Storm Reports

March 20, 2020

24HR Radar Loop
24HR Radar Loop
Snow Accumulation 24Hr
Wind Gusts
Storm Reports

Storm Reports

HEAVY RAIN (13)
Heavy Rain
HEAVY RAIN
OAKFIELD, WI
2.53"
HEAVY RAIN
HEAVY RAIN
WRIGHTSTOWN, WI
1.5"
Heavy Rain
HEAVY RAIN
OSHKOSH, WI
1.48"
HEAVY RAIN
HEAVY RAIN
7 WNW SPRING GREEN, WI
1.38"
HEAVY RAIN
HEAVY RAIN
2 SW FOND DU LAC, WI
1.15"
HEAVY RAIN
HEAVY RAIN
7 SE MOSINEE, WI
1.05"
HEAVY RAIN
HEAVY RAIN
3 SW DE PERE, WI
1.03"
HEAVY RAIN
HEAVY RAIN
OSHKOSH, WI
1.02"
HEAVY RAIN
HEAVY RAIN
STILES, WI
0.98"
HEAVY RAIN
HEAVY RAIN
GREEN BAY, WI
0.93"
HEAVY RAIN
HEAVY RAIN
EASTMAN, WI
0.88"
HEAVY RAIN
HEAVY RAIN
SINSINAWA, WI
0.17"
Heavy Rain
HEAVY RAIN
MARKESAN, WI
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SNOW (40)
HEAVY SNOW
HEAVY SNOW
GILE, WI
6.5"
SNOW
SNOW
1 NW HURLEY, WI
6.0"
SNOW
SNOW
PENCE, WI
4.5"
SNOW
SNOW
3 SW BAYFIELD, WI
2.2"
SNOW
SNOW
3 WNW CLAM LAKE, WI
1.8"
SNOW
SNOW
5 WSW INO, WI
1.5"
SNOW
SNOW
STURGEON BAY, WI
1.5"
SNOW
SNOW
6 SW BUTTERNUT, WI
1.4"
SNOW
SNOW
2 E LA CROSSE, WI
1.3"
SNOW
SNOW
2 NNE BLACK RIVER FALLS, WI
1.3"
SNOW
SNOW
3 NNW FRENCHVILLE, WI
1.2"
SNOW
SNOW
7 NNE MERCER, WI
1.1"
SNOW
SNOW
1 SSW BLACK RIVER FALLS, WI
1.1"
SNOW
SNOW
1 SW SPARTA, WI
1.0"
SNOW
SNOW
1 ESE MAUSTON, WI
1.0"
SNOW
SNOW
2 N MOQUAH, WI
1.0"
SNOW
SNOW
2 SSE WINTER, WI
1.0"
SNOW
SNOW
CATARACT, WI
1.0"
SNOW
SNOW
3 NNW BUTTERNUT, WI
1.0"
SNOW
SNOW
5 WSW WARRENS, WI
0.9"
SNOW
SNOW
1 S DE SOTO, WI
0.8"
SNOW
SNOW
1 S PHILLIPS, WI
0.8"
SNOW
SNOW
1 WNW FRIENDSHIP, WI
0.8"
SNOW
SNOW
2 SSE HOLMEN, WI
0.7"
SNOW
SNOW
TOMAH, WI
0.7"
SNOW
SNOW
ASHLAND, WI
0.7"
SNOW
SNOW
PHILLIPS, WI
0.6"
SNOW
SNOW
2 WSW GALESVILLE, WI
0.6"
SNOW
SNOW
1 E VIROQUA, WI
0.6"
SNOW
SNOW
2 SW BAYFIELD, WI
0.6"
SNOW
SNOW
2 NNE FRENCH ISLAND, WI
0.6"
SNOW
SNOW
2 SW MELVINA, WI
0.5"
SNOW
SNOW
1 WSW MAPLE, WI
0.5"
SNOW
SNOW
SEELEY, WI
0.5"
Snow
SNOW
OSHKOSH, WI
0.5"
SNOW
SNOW
PARK FALLS, WI
0.4"
SNOW
SNOW
2 WNW SEELEY, WI
0.3"
SNOW
SNOW
4 NNE SARONA, WI
0.2"
SNOW
SNOW
EASTMAN, WI
0.2"
SNOW
SNOW
3 E SAND BAY, WI
0.1"
OTHER (1)
Lightning
LIGHTNING
MARKESAN, WI
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