Severe Weather Threat 4/28-4/30

Note the addition of a 10% hatched risk in western Oklahoma on the 1300 update.

Also, the wording used in the discussion makes me think the forecasters would love to have that 5% hatched tornado option to use today for southern Iowa through NE Kansas. Sounds like the possibility of one or two isolated supercells there could be very dangerous were they to fire and sustain.
 
Wind Driven Coconut said:
Note the addition of a 10% hatched risk in western Oklahoma on the 1300 update.

Also, the wording used in the discussion makes me think the forecasters would love to have that 5% hatched tornado option to use today for southern Iowa through NE Kansas. Sounds like the possibility of one or two isolated supercells there could be very dangerous were they to fire and sustain.
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Yeah, we saw what one isolated supercell can do last night in this kind of environment.
 
I appreciate MPX's forecast discussion on today. It's not anything new to those of us following this, but it does an excellent job breaking things down in easy-to-grasp language, I feel like.

After the morning convection dies off and moves out, there will be a few hours of tranquility at the surface, the calm before the storm, if you will. However, the atmosphere will be doing all but remaining calm in preparation for round 2. In some scenarios, morning convection can dampen the potential for redevelopment later in the day. In today's scenario, morning convection may actually aid in creating a better environment for round 2. How is that so? The morning storms will allow the strong inversion to remain in place. Maintaining this inversion causes surface winds to respond more to the deepening pressure gradient. Additionally, a roaring low-level jet will have no issue re-energizing the atmosphere after morning storms roll through. Southerly winds will advect warm and moist air into southern Minnesota beneath the elevated mixed layer. This difference in conditions (dry air in the EML and moist air at the surface) creates the instability needed for storms. The HREF is forecasting MUCAPE values of 2000-2500 J/kg, dewpoints in the mid 60s, mean deep layer shear around 50kts, and breakable CIN (-30 J/kg or less) through around 6PM. With this in mind, most of the conditions needed for severe storms will be present, but it`s the initial trigger mechanisms that are needed to actually get storms to initiate. This is where the conditional threat comes in. IF that trigger occurs (breaking any potential cap) ahead of the squall line anticipated to ride the cold front later in the evening, then strong tornadoes are possible with discrete supercells. This potential for strong tornadoes is what is driving the Moderate Risk (4/5). It is entirely possible the trigger never happens and the only convection we see in round 2 is with the passage of the cold front this evening. Tornadoes would still be possible with this scenario, but the storm mode would be linear (QLCS) versus discrete (supercells). This typically translates to brief spin-ups and the the primary threat transitions to damaging wind along the line of storms.

The takeaway from today's severe storm potential is to remain vigilant of the potential for storms to go up quickly. This may mean checking your phone more often or keeping an eye to the sky, but don't let your guard down in this environment.

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DISCUSSION...PV
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That's a dangerous-looking environment out there being advertised by the HRRR for a lot of real estate, including Minneapolis-St. Paul, today. The obvious question is how many storms take advantage of it, and where. Regardless, I would definitely be erring on the side of caution in the risk area today - kinematics and thermodynamics are improving and making their way up into the core of the MDT risk area, though not quite as quickly as RAP has modelled. Hopefully we get some photogenic storms that tear up some cornfields and nothing more. Wishing everyone up there the best today.
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This may be a dumb question, but I'm planning on chasing tomorrow's threat and I don't want to stray too far from my location. Would the highlighted area be worth chasing, or is most of the interesting activity going to be outside of this area?
All I'm really looking for is interesting storm structure, not really any tornadoes specifically.
 
Maxis_s said:
View attachment 40570
This may be a dumb question, but I'm planning on chasing tomorrow's threat and I don't want to stray too far from my location. Would the highlighted area be worth chasing, or is most of the interesting activity going to be outside of this area?
All I'm really looking for is interesting storm structure, not really any tornadoes specifically.
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Well if you want the best storm structure I recommend eastern Ohio and Western Pennsylvania, but I don't see why storm structure up there wouldn't be pretty good.
 
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