10:15PM TUES - the bulk of the event will end tonight. The next precipitation chance will be WEDS PM as a secondary low pushes through. Scattered showers and maybe a tstorm helping to round out the rainfall forecast amounts in the eastern half of WI. Windy conditions possible too.
10:40 AM TUE - small adjustments to rainfall forecast map. Previous thoughts still apply. Severe weather threat is low...chance of a weak tornado given favorable cyclonically sheared environment but otherwise non-severe today.
1:30 PM MON - Forecast models continue to bring Tropical Storm Cristobal into Wisconsin Tuesday afternoon and evening. There will be a lull on Wednesday morning before light rain wraps around the low Weds PM. The primary event will be Tues night.
(See maps) - I tried to constrain down the heaviest rainfall zone...now shaping up across western Wisconsin. I expect a narrow zone of 3-4", possibly locally higher amounts up to 5" near or west of Eau Claire. Storm track details continue to shift run to run but this the latest trends. Eastern Wisconsin has seen a decreasing trend in forecasted rainfall amounts. I'm okay with 1-2"...cozy range to go with. Really focusing on the Mississippi River with this event. I didn't want to push around the 3-6" zone too much so kept it small (and labeled 3-4"+).
Scattered thunderstorms are likely. On a regional scale I wouldn't rule out a strong t-storm somewhere(it's June after-all). This is not a great setup for severe weather given cloud cover and staking of the low. Weak tornadoes can form but that doesn't concern me as much as other things. Will keep it GENERAL with a TARGET in there to recognize the possibility of a stronger cell...but not enough to go any further right now. If weak tornado threat is legit...will push to STRONG.
SAT 3:12PM - 12z models today further west, focused more on the west side of WI or Mississippi River region. What are the odds this thing targets Minneapolis? GFS and EC basically have the same magnitude just different tracks. And the evolution for Wednesday seems to be changing...from a tropical system into a full blown extra tropical cyclone heading into Canada. Pretty interesting! Confidence level in predicted rainfall amounts is low. Will begin looking at t-storm threat closer with short range models. Stay tuned!
FRI 6/5 9:30AM - An interesting event could be on tap for next week. Tropical Depression Cristobal will track north into the U.S towards Wisconsin & Great Lakes early next week. https://www.nhc.noaa.gov/graphics_at3.shtml?start#contents .
Been watching this system for a couple days and models seem to be generally consistent on bringing it through Wisconsin despite large timing differences. The storm track has shifted back and forth from one side of the state to the other...I wouldn't expect consistent to be very good. This storm also complex in the way it interacts/integrates with the jet stream. Bit unusual. I'll keep confidence level LOW for now; not ruling anything out.
Heavy rain will be the primary hazard. 00EC was very aggressive; into the 4"+ range locally within the heaviest axis. 06GFS more modest. The GFS Ensemble mean favors eastern Wisconsin with the heaviest axis while operational models are further west. I'm not gonna get too carried away yet. Will watch over the weekend.
The WPC seems to favor the GFS Ens too. This is the 7-day total.
Severe thunderstorm threat remains low FOR NOW. Main negating factor appears to be cloud cover. On the other hand timing for Tuesday PM per the 06GFS opens the door. If clouds are thinner, more destabilization could easy lead to t-storm development. I wouldn't rule out a strong storm at this stage provided a trigger of some type. Will be watching as short range models come in.