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I giggled when I saw it but there was definitely rotation with it for a scan or two.

 

 

I was busy working for a minute, but the waterspout I saw in the Gulf was from a not super-terribly impressive cumulus, might have qualified as congestus, and I've seen a funnel from a garden variety thundershower in South Louisiana, maybe it was more like a tropical funnel.  I saw a spooky looking tropical funnel from out my window, looking close to Houston.  It was decent sized, but only halfway to the ground.

 

Never have seen a supercell tornado or even funnel cloud.  Best I've ever done locally was rapidly rising scud into a storm base but w/o rotation.

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Actually, I'm wondering why anyone has doubts about Iowa for Sunday.  With 00Z Td's in the 70's and the left front exit region of the 500mb speed max, what is the problem?

 

Backing upper level winds, which would create problems in terms of storm mode (especially with a weaker cap in this area).

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URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 166
NWS STORM PREDICTION CENTER NORMAN OK
305 PM CDT FRI MAY 17 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
CENTRAL AND NORTH CENTRAL TEXAS

* EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 305 PM UNTIL
800 PM CDT.

* PRIMARY THREATS INCLUDE...
SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 3
INCHES IN DIAMETER POSSIBLE

SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 45
STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES SOUTH OF
BROWNWOOD TEXAS TO 50 MILES NORTH NORTHWEST OF MINERAL WELLS
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

&&

DISCUSSION...CONVECTION IS DEEPENING OVER PARTS OF TX ALONG THE
DRYLINE TO THE EAST OF SJT AND EAST OF ABI. AIR MASS EAST OF THE
DRYLINE IS MOIST AND VERY UNSTABLE WITH CAPE VALUES UP TO 4000 J/KG.
ALTHOUGH WINDS ALOFT ARE RELATIVELY WEAK...VERY FAVORABLE
THERMODYNAMIC ENVIRONMENT/STEEP LAPSE RATES INDICATES THREAT FOR A
FEW STORMS TO PRODUCE VERY LARGE HAIL AND LOCALIZED DAMAGING WIND
GUSTS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 24015.

 

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Backing winds above say 500mb is not a problem, and has actually been shown to be a feature in past sig events. Where you worry about consistent veering winds is in like the lowest 300mb or so.

 

Backing mid-upper level winds are associated with cold advection and falling heights around the jet stream level

 

This is a good point, I have just noticed that the storm mode can tend to go awry with this, but this is mainly east of the MS River into the Southern Great Lakes region and Dixie Alley, although I thought I remember 5/24/11 in KS having this issue (it didn't help having a closed circulation at 700 mb so close to the warm sector in that area, either).

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This is a good point, I have just noticed that the storm mode can tend to go awry with this, but this is mainly east of the MS River into the Southern Great Lakes region and Dixie Alley, although I thought I remember 5/24/11 in KS having this issue (it didn't help having a closed circulation at 700 mb so close to the warm sector in that area, either).

 

 

I know I've seen it in a lot of events. I've read some different / mixed opinions. Regardless, most important is in the lowest half of the atmosphere anyway.

 

By the way, pretty neat site I just stumbled on: http://www.tornadohead.com/storhodos.htm

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18z NAM really puts the emphasis on Kansas for tomorrow. 

 

Really interested to see what the 00z runs do, especially since the hi-res models will be entering their "more accurate" ranges.

Wow, no kidding. I just looked at a forecast sounding for the Hays, KS area on the 18Z NAM and it is very impressive.

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Backing upper level winds, which would create problems in terms of storm mode (especially with a weaker cap in this area)

I also wouldn't be concerned with the backed winds above 500mb (as disco'ed above), but yeah, totally agree about the cap.  Good point.  Could be a lot of rain in IA though!

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The NAM seems to echo the idea of Iowa being the place to watch in terms of significant tornado activity.

 

While the northern threat area is potent looking, I think the NAM solution is looking less impressive further south due to it blowing up an MCS across KS and OK on Sunday.

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Near Pratt, KS tomorrow evening...

 

NAM_218_2013051718_F30_37.5000N_99.0000W

 

 

NAM_218_2013051718_F30_37.5000N_99.0000W

The indices here are [quite literally] off the charts. If the NAM verifies and something goes up in southern KS, it won't be pretty. (Or it will be, depending on how you look at it, of course). SWEAT of ~750 and an EHI of 21.1?

SKT_META__KPTT.png

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The 18z 4km NAM is even more impressive, blowing up supers in areas with 7000 j/KG of SBCAPE. 

 

I'll post the 00z 4km NAM when it's out later tonight. 

 

That's just insanity, as is the sounding that Jake posted.

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