Storm Australian Severe Weather Forum
Severe Weather Discussion => Tornado Alley Outbreaks and Severe Weather Worldwide => Topic started by: David C on 07 June 2007, 06:59:19 AM
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The 6th is looking quite interesting. 0-6km shear will be off the scale. According to GFS, there are significant issues however with respect to storms materialising for chasers over the northern Plains down into Nebraska.
First, it will be a particularly warm atmosphere during the afternoon and in particular with very high temperatures from 850 to 700mb - ie an very strong cap will be in place through the day. The upper level low really does not make an impact and destabilise things until after dark say 03-06z. Despite there being good foci's for development over the plains (dryline), without a cooling atmosphere until after dark the CAP looks insurmountable based on the temperature profiles forecast during the afternoon/evening.
In addition, SPC is questioning moisture return progged by the models, which of course would be disastrous in creating significant dewpoint deficits and hence high LCLs. GFS appears to have downgraded instability from the previous run I looked at and suggests that the boundary layer RH will be at best moderate over the region. With initiation over the high plains further west (Montana etc) perhaps during the afternoon, given proximity to height falls there, high based storms might fire up in numbers there and produce in inhibitory cold pools while the CAP suppresses convection further east in the favourable environment. So a complex might develop before any isolated supercells get the chance to. Either way, that will be after dark by the looks of it. Of course, if the upper low is more progressive and dewpoints in the upper 60s (at least) are realised during the afternoon, gosh, there could be some big storms on the go when I next log on tomorrow morning.
Any other thoughts? It's a long drive for a bust but you could hardly turn down the chance given that things might fall into place.
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Hi David,
It seems various variables did not come together favourably for an outbreak of sorts. Not sure about the 7th June event yet but it was anticipated to be well to the east of the region.
Regards,
Jimmy Deguara