Warren Faidley
Supporter
A timely discussion given the current forecast for the end of May.
This is a good reference to get the discussion going:
This is a good reference to get the discussion going:
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- Science and Storm Chasing
- Advanced weather & chasing
Northwest Flow Severe Weather Events
- Thread starter Warren Faidley
- Start date
Jason Boggs
EF4
I actually love NW flow events. They are generally slow moving, easy to chase, and sometimes very photogenic storms. The 100 million dollar hailstorm in west Amarillo back in June 21, 2004 was NW flow.
Jason N
EF4
NW, SW, I think this just changes more of the where in the country I'll be located in
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JamesCaruso
Staff memberI find NW flow events disorientingā¦ Are they ever prolific tornado producers? I can see getting some good supercell structure in eastern CO or the TX panhandle, but itās not the type of thing any of us are really hoping for when we go out thereā¦ Itās a consolation prize at bestā¦ I canāt recall any particularly memorable NW flow supercell events in all my years of chasing.
Jason Boggs
EF4
I'm sure the Campo event was NW flow.
JamesCaruso
Staff member
HAHA, well maybe you got me thereā¦ I was on Campo, but I didnāt remember it as a NW flow eventā¦ I will have to go back and confirm. If so, Iāll feel much better about NW flow
Although, one event in 25 yearsā¦
Kem Poyner
EF2
I have photographed tons of tornados over the past 29 years. A money shot of a bare bones LP supercell has eluded me. Maybe later this season??
Bill Hark
EF5
I really hate NW flow and will skip those set ups unless I am stuck out on the Plains with nothing better to do. In the Mid-Atlantic, NW is a little better at producing decent storms and I'll chase those set ups.
Warren Faidley
SupporterCampo was zonal flow.
JamesCaruso
Staff member
Thanks Warren, I thought that was the caseā¦ Glad I wasnāt misremembering what was probably my #1 all-around most memorable chase!
Warren Faidley
SupporterNW flow is especially productive if there are any existing boundaries, e.g., MCS, from the prior day.
Jason Boggs
EF4
Absolutely!
Jason N
EF4
If I am not mistaken, Zonal to NW flow was also responsible for the Memorial Day Nocturnal EF-3/4 Tornadoes in Dayton, OH. 2019.
Plainfield, IL in 1990 was a NW flow event. The Chicago NWS office has a great 30-year review of it here: 30 Years Later: The August 28, 1990 F-5 Plainfield Tornado
Very interesting to look at the reanalyzed large-scale fields, as they show nothing synoptically evident of the potential of a high-end tornado. That goes to show you that EF5-potential setups are likely present more often than we may suspect, but that actually getting such a high-end tornado depends on factors far below the synoptic scale. I suspect the extreme total instability, low LCL & LFC heights, and degree of 3-km CAPE played a significant role in getting such a strong tornado.
Andy Wehrle
EF5
Midsummer NW flow setups have produced other notable violent tornadoes in the Midwest, such as the July 13, 2004 Roanoke, IL F4 and I believe the July 18, 1996 Oakfield F5 (northwest flow assumed from the track maps which showed the tornadoes that day moving NW-SE).
However as @Jeff Duda noted above, violent tornadoes from such setups are certainly the rare exception and it's pretty much impossible to pick out ahead of time which ones will produce one.
JamesCaruso
Staff member
Despite a northwesterly component to the winds at certain levels, I donāt think 6/15/23 would be considered a true NW flow eventā¦
Jason N
EF4
You know, after this 12 to 18 June period of going back and forth on whether to go or not to go and then deciding not to.. there was certainly some chaseable structure days without question based on all of the Twitter postings over the last week. But the overall quality was lacking so I kinda feel mixed about it.Similar threads
