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Arctic April

Just noticed on the Euro that it looks like it’s trying to bring back the severe weather threat for the weekend. Could be something to watch.
 
Just noticed on the Euro that it looks like it’s trying to bring back the severe weather threat for the weekend. Could be something to watch.

Yep, the threat it showed a few days ago has come back. The environment verbatim is excellent, nearly 40 knots of 0-1 shear and 300-400 01-km SRH coupled with CAPE anywhere from 500 j/kg further north near the low center to nearly 2000 j/kg on the Gulf coast. This is a sounding near Mobile, AL

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Despite the lack of internal consistency in the models right now, one thing is basically set in stone already, any synoptic-scale low pressure system and warm sector convection that comes along will be fueled an the left exit region (which enhances upper level divergence & forces ascent) of an exceptionally strong jet streak within the subtropical jet.

A 135-140 knot jet streak in the subtropical jet is very unusual at any time of the year really, much less in mid April when the polar jet usually starts moving north & weakens, not to mention this is happening when many of us are approaching our peak severe and tornado climo.

We really need to keep a very close eye on this the next few days.

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This one is near Charlotte a few frames later. Just your casual 600 0-1 SRH and 50 knots of low level shear coupled with nearly 1000 j/kg CAPE.

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Geez and I thought that setup in February that produced tornadoes around CLT looked bad, this is sum else, also that’s impressive CAPE For the morning time, just one run of the euro but this one has the highest ceiling of any threat we’ve seen this year atm...
 
Also back to that little Monday threat, NAM3km still shows it, mixed out BLs/dry subcloud layers and low freezing levels along with 30kts+ of 0-6KM shear May allow some decent storms
Dcapes up near 1000 too. Models have a very modest bit of energy at h5 cresting the ridge and moving in. That may help organize things tomorrow afternoon instead of a hodgepodge of intermittent storms along outflows and convergent boundaries moving SE.
 
NAM 3KM has solid profiles on Tuesday, could be a few scattered storms on tuesday aswell 1586100972554.png
 
geez even Wednesday south of CLT, im loving this pattern lol, can see nice EML advection with that sounding supportive of large hail
1586101242469.png
 
Despite the lack of internal consistency in the models right now, one thing is basically set in stone already, any synoptic-scale low pressure system and warm sector convection that comes along will be fueled an the left exit region (which enhances upper level divergence & forces ascent) of an exceptionally strong jet streak within the subtropical jet.

A 135-140 knot jet streak in the subtropical jet is very unusual at any time of the year really, much less in mid April when the polar jet usually starts moving north & weakens, not to mention this is happening when many of us are approaching our peak severe and tornado climo.

We really need to keep a very close eye on this the next few days.

View attachment 38387

To put into perspective how unusual this is, based on a sounding climo out of New Orleans, LA, a 135-140 knot jet streak on the Gulf coast would be record breaking at certain points in the heart of the winter, & it's 15-20 knots higher than the previous record of 120 knots at this time of the year. We're meeting or exceeding the boundaries of the "typical" outbreak parameter space in some aspects, but synoptic & mesoscale details will determine if this massive ceiling is realized.

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Nice pattern
 
The difference between a severe outbreak and nothing next week pretty much hinges on how much stream separation we get in the medium range between the SW US s/w and the big vortex over the Lakes (sounds familiar lol?). More stream separation & stronger/slower SW US shortwave increases the chances of a severe &/or tornado outbreak by keeping the parent s/w & QG forcing for ascent more in-tact, allowing the s/w to tilt more neutrally/less positive and shifting the eventual surface low further NW >>> more of the SE US in a more robust warm sector of a stronger mid-latitude cyclone.

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1586107478701.png
 
The difference between a severe outbreak and nothing next week pretty much hinges on how much stream separation we get in the medium range between the SW US s/w and the big vortex over the Lakes (sounds familiar lol?). More stream separation & stronger/slower SW US shortwave increases the chances of a severe &/or tornado outbreak by keeping the parent s/w & QG forcing for ascent more in-tact, allowing the s/w to tilt more neutrally/less positive and shifting the eventual surface low further NW >>> more of the SE US in a more robust warm sector of a stronger mid-latitude cyclone.

View attachment 38400



View attachment 38401

Model trends are well on their way towards it being a nothingburger locally.
 
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