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Severe Weather Threat May 7th - 13th


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under a big honkin ridge with no upper support but still, the new hotness.

I believe this is MUCAPE, and the scale maxes at 3000J/Kg, but it appears the warm sector, despite intense CAPE, will be capped if this GFS forecast is correct.

GFSCN_CE2011050412F162.gif

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GFS showing the low passing through N Central IL?

Doesn't bode well for severe up this way, at least not with that run...

The solutions on the GFS/ECMWF have been changing, which is expected several days out...

So I wouldn't buy into anything yet.

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The solutions on the GFS/ECMWF have been changing, which is expected several days out...

So I wouldn't buy into anything yet.

Not really buying into it, but, keeping a wary eye on the changes run to run. Hopefully we get a northward shift. NWS is forecasting 70's for Monday and Tuesday, and the possibility of thunderstorms for Tuesday/Tuesday night...

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I believe this is MUCAPE, and the scale maxes at 3000J/Kg, but it appears the warm sector, despite intense CAPE, will be capped if this GFS forecast is correct.

This would only be fitting for 2011. My expectations are tempered, to say the least, for this entire upcoming string of days. The effects of the severe south-central US drought should not be underestimated. The last time a major western CONUS trough evolved (April 6-10), there were two major factors that helped put the kabosh on widespread or significant Plains activity:

1. Extremely hot EML advecting over the warm sector, which is likely a function of the extreme drought conditions over NM and adjacent parts of Mexico. That situation certainly has not improved since then.

2. Low-level moisture holes developing daily over TX and then advecting N through the warm sector, such that even after three or four days of persistent southerly flow, good moisture is never a given. Central TX has at least seen some rainfall of significance since then, thankfully.

How big a role will these factors play this time around? Hard to say, but I have a feeling that the encouraging look of the H5 progs belies the magnitude of what's actually likely to happen, at least in the TX/OK/KS area.

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Not really buying into it, but, keeping a wary eye on the changes run to run. Hopefully we get a northward shift. NWS is forecasting 70's for Monday and Tuesday, and the possibility of thunderstorms for Tuesday/Tuesday night...

They're advertising a nice stretch of weather, especially away from the immediate lakefront.

Before the switch to a cooler setup, the ECMWF was forecasting temps in the 80's to around 90F for early next week...with dp's around/in the 70's.

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This would only be fitting for 2011. My expectations are tempered, to say the least, for this entire upcoming string of days. The effects of the severe south-central US drought should not be underestimated. The last time a major western CONUS trough evolved (April 6-10), there were two major factors that helped put the kabosh on widespread or significant Plains activity:

1. Extremely hot EML advecting over the warm sector, which is likely a function of the extreme drought conditions over NM and adjacent parts of Mexico. That situation certainly has not improved since then.

2. Low-level moisture holes developing daily over TX and then advecting N through the warm sector, such that even after three or four days of persistent southerly flow, good moisture is never a given. Central TX has at least seen some rainfall of significance since then, thankfully.

How big a role will these factors play this time around? Hard to say, but I have a feeling that the encouraging look of the H5 progs belies the magnitude of what's actually likely to happen, at least in the TX/OK/KS area.

Can I come visit you next May to make up for this one?

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This would only be fitting for 2011. My expectations are tempered, to say the least, for this entire upcoming string of days. The effects of the severe south-central US drought should not be underestimated. The last time a major western CONUS trough evolved (April 6-10), there were two major factors that helped put the kabosh on widespread or significant Plains activity:

1. Extremely hot EML advecting over the warm sector, which is likely a function of the extreme drought conditions over NM and adjacent parts of Mexico. That situation certainly has not improved since then.

2. Low-level moisture holes developing daily over TX and then advecting N through the warm sector, such that even after three or four days of persistent southerly flow, good moisture is never a given. Central TX has at least seen some rainfall of significance since then, thankfully.

How big a role will these factors play this time around? Hard to say, but I have a feeling that the encouraging look of the H5 progs belies the magnitude of what's actually likely to happen, at least in the TX/OK/KS area.

My concerns for the upcoming pattern are mainly in the upper level support. It looks much more subtle than the last few events, with jet level winds AOB 40 knots over the warm sector. If that's the case and capping is an issue this will evolve into a more of a nowcasting severe event. The instability looks like it will certainly be there, so even subtle waves will be able to fire something off.

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Can I come visit you next May to make up for this one?

LOL... well, I could easily be wrong... and even if I'm not, there will likely still be good ops somewhere in the Midwest and Upper MS Valley. There are definite advantages of chasing vacation-style rather than living here and trying to weigh the cost of pursuing each opportunity (not just financially, but the drain on your time/schoolwork too), and mobility/range is probably the biggest. If the worst-case scenario with next week's ops come true, though, I'll probably feel bad enough to let you take me up on that. :lol:

You guys still in KS? I might be able to recommend some mildly interesting sightseeing and photography spots around the S Plains if you're interested.

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LOL... well, I could easily be wrong... and even if I'm not, there will likely still be good ops somewhere in the Midwest and Upper MS Valley. There are definite advantages of chasing vacation-style rather than living here and trying to weigh the cost of pursuing each opportunity (not just financially, but the drain on your time/schoolwork too), and mobility/range is probably the biggest. If the worst-case scenario with next week's ops come true, though, I'll probably feel bad enough to let you take me up on that. :lol:

You guys still in KS? I might be able to recommend some mildly interesting sightseeing and photography spots around the S Plains if you're interested.

We're in Blackwell OK now.. I didn't want to stay in Wichita again... figure might as well see different places if nothing else, plus hoping we'll have some dryline though that might be lost hope. Not sure what the plan is at this pt, talked about going to Norman or just chilling and seeing how/if things come together. The worst part is that if nothing much happens I'll have to do it again in the future. ;)

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We're in Blackwell OK now.. I didn't want to stay in Wichita again... figure might as well see different places if nothing else, plus hoping we'll have some dryline though that might be lost hope. Not sure what the plan is at this pt, talked about going to Norman or just chilling and seeing how/if things come together. The worst part is that if nothing much happens I'll have to do it again in the future. ;)

Tour the National Weather Center if you haven't because it's pretty sweet...

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the days 4-8 outlook

......... TUE AND WED APPEAR TO HAVE AGREATER TORNADO THREAT THAN ON SUN/MON WITH HIGHER THETA-E AIR AND

BETTER HODOGRAPHS. AN ISOLATED STRONG TORNADO MAY OCCUR...ESPECIALLY

ON TUE WHEN A STRONG NOCTURNAL LOW LEVEL JET RESPONSE IS FORECAST TO

OCCUR DURING THE EVENING.

post-556-0-14372100-1304665770.gif

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DTX saying that the cold following the low may help to get rid of the cap Wednesday night/ Thursday

TUESDAY AND WEDNESDAY FEATURE A CONTINUED UNSETTLED PATTERN AS BROAD LOW PRESSURE APPROACHES FROM THE CENTRAL PLAINS. THIS WILL BE ACCOMPANIED BY UPPER LEVEL RIDGING...KEEPING A LIMIT TO THE LAPSE RATES AND ALSO USHERING IN WARMER AIR FROM THE SOUTH. WE MAY MAKE A RUN TO NEAR 80 DEGREES IN LENAWEE COUNTY. WARMEST FORECAST TEMPERATURES ARE DEPENDENT ON THE LACK OF PERSISTENT RAIN OR THUNDERSTORMS. SE MI SHOULD RESIDE IN THE WARM SECTOR OF THE LOW FOR TUESDAY BUT THINKING WARM AIR ALOFT MAY CAP THE THUNDERSTORM POTENTIAL. COLDER AIR MASS WILL FOLLOW THE LOW SO MAY SEE BETTER SEVERE THREAT AFTER WEDNESDAY NIGHT. MAIN FORECAST POINTS ARE TO INCREASE TEMPS AND MAINTAIN THUNDERSTORM CHANCES.
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FWIW, I was able to see the full 00z ECMWF output this morning and it showed convective initiation on Sunday, Tuesday, and Wednesday afternoons in the Plains. Precipitation on Wednesday was fairly widespread, and that's the day I see as most likely to produce something substantial.

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Good reply.

I'm sure you're aware of the fact we have seen numerous high CAPE events not produce do to capping, though it's more of an issue in the summer months.

With this event we will likely see at least some development.

In any case, hopefully you guys catch a few nice slow moving supercells down there. :thumbsup:

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The cap should break in spots with that much instability. Just a question of where/when.

That's what they said about April 10th... and it produced bupkis.....

We shall see, though. GFS took it back north, way north, in fact, to C WI....Wonder if that is the trend, or if it will jump it back south.

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That's what they said about April 10th... and it produced bupkis.....

We shall see, though. GFS took it back north, way north, in fact, to C WI....Wonder if that is the trend, or if it will jump it back south.

Models have been consistent in building a ridge and showing only modest upper support for convection in IL/IN until possibly the middle of the week. Weak waves ejecting from the large scale trough could be enough of a trigger but they are notoriously difficult to resolve this far in advance. Going to be a reservoir of strong instability south of the front so whatever fires will have the potential to be severe, but sluggish wind fields aloft are still a bit of a concern.

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Im excited about weds looking at the 18z GFS...one of those days where were already up to 3500 j/kg of SBCAPE by 18z with all of northern IL completely in the warm sector and bump that up to 5000 j/kg by late afternoon with better mid-level flow approaching the area during that time with dew points in the low 70's.

Still days away but just the fact that it looks like its going to be very humid and unstable excites me. Now we just need a subtle s/w to ripple on through to set off something fun.

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