Archive Severe threat April 26-27, 2011

[TW Archive]

natedogg
Posted 26 April 2011 - 12:38 PM

So where do yall think we will see a high risk tomorrow and if so where does it look to be.
Edited by natedogg, 26 April 2011 - 12:42 PM.

 

[TW Archive]

Tyler Penland
Posted 26 April 2011 - 12:40 PM

natedogg, on 26 April 2011 - 12:38 PM, said:

So where do yall think we will see a hih risk tomorrow and if so where does it look to be.

Central/Northern AL maybe TN/NW GA but those will be conditional. I can see the MOD going east and south both by tomorrow.

 

[TW Archive]

TimHSV
Posted 26 April 2011 - 12:41 PM

Concerning today's High Risk out west:



"It's a very dangerous day," said AccuWeather.com Senior Meteorologist Henry Margusity. "It's the kind of day where tornadoes could cause massive destruction."
Edited by TimHSV, 26 April 2011 - 12:42 PM.

 

[TW Archive]

Tyler Penland
Posted 26 April 2011 - 12:41 PM

natedogg, on 26 April 2011 - 12:38 PM, said:

So where do yall think we will see a hih risk tomorrow and if so where does it look to be.

Central/Northern AL maybe Central TN/NW GA but those will be conditional. I can see the MOD going east and south both by tomorrow.

 

[TW Archive]

SWL
Posted 26 April 2011 - 12:43 PM

natedogg, on 26 April 2011 - 12:38 PM, said:

So where do yall think we will see a high risk tomorrow and if so where does it look to be.

Central AL up to S TN

 

[TW Archive]

superjames1992
Posted 26 April 2011 - 12:44 PM

Looks like a decent shot at some thunderstorms tomorrow evening for central/eastern North Carolina. I am somewhat doubtful, though, and only went for a 70% POP for tomorrow in our NCSU forecast contest. The models seem to be insistent on weakening the squall line as it moves off to the east. We can just hope that it doesn't weaken too much. If it holds together, the severe weather could be pretty bad Wednesday evening. There's certainly enough moisture around.

We also had a brief thundershower pass through Raleigh about an hour ago. There was a little thunder, but not much.

 

[TW Archive]

Harlequhn_Boy
Posted 26 April 2011 - 12:46 PM

I think people in the Mid South are a little storm weary at this point.

Sitting in a HIGH with 30% tornado probs and 60% damaging winds; wonder which will end up being the big story in MEG's CWA.
Edited by Harlequhn_Boy, 26 April 2011 - 12:47 PM.

 

[TW Archive]

Stormnow
Posted 26 April 2011 - 12:49 PM

MichelleH, on 26 April 2011 - 12:36 PM, said:

I know exactly how you feel! There is a met that I won't name either who I know does the very same! Could be the same one! LOL It drives me crazy because I believe he is putting people in danger.

I agree, is the met we will not name in B'ham or Hsv?

 

[TW Archive]

SD
Posted 26 April 2011 - 12:49 PM

superjames1992, on 26 April 2011 - 12:44 PM, said:

Looks like a decent shot at some thunderstorms tomorrow evening for central/eastern North Carolina. I am somewhat doubtful, though, and only went for a 70% POP for tomorrow in our NCSU forecast contest. The models seem to be insistent on weakening the squall line as it moves off to the east. We can just hope that it doesn't weaken too much. If it holds together, the severe weather could be pretty bad Wednesday evening. There's certainly enough moisture around.

We also had a brief thundershower pass through Raleigh about an hour ago.

There was a little thunder, but not much.
It looked like the 12z models today had the line moving through 12-18z Thursday now unless im looking at it wrong. Tomorrow would be most likely airmass convection or driven by a remnant MCV from tonight.

 

[TW Archive]

weatherguy
Posted 26 April 2011 - 12:50 PM

Looks like they where considering a high risk for day 2, so if things look more clear on the models for them tonight we could easily be put under a high risk then.

...SYNOPSIS...
...OUTBREAK OF SEVERE THUNDERSTORMS POSSIBLE...
MODELS INDICATE THAT THE LARGE UPPER TROUGH...NOW EVOLVING OVER THE
CENTRAL U.S...WILL SLOWLY LIFT ACROSS AND EAST OF THE MISSISSIPPI
VALLEY DURING THIS PERIOD. AS IT DOES...IT APPEARS LIKELY TO TAKE
ON AN INCREASING NEGATIVE TILT...AS A STRONG SHORT WAVE IMPULSE
LIFTS OUT OF ITS BASE...AND GRADUALLY PIVOTS AROUND THE EASTERN
PERIPHERY OF A DEVELOPING CYCLONIC CIRCULATION OVER THE UPPER
MISSISSIPPI VALLEY/GREAT LAKES REGION. THIS SHOULD BE ACCOMPANIED
BY STRENGTHENING CYCLONIC MID/UPPER FLOW FIELDS IN THE WARM SECTOR
OF A SURFACE CYCLONE PROGGED TO DEEPEN AS IT MIGRATES NORTHEAST OF
THE OZARK PLATEAU TOWARD THE GREAT LAKES. THIS PROBABLY WILL
INCLUDE A 90-100 KT 500 MB JET CORE NOSING ACROSS THE TENNESSEE AND
OHIO VALLEYS BY LATE AFTERNOON.

VARIABILITY EXISTS AMONG THE MODELS CONCERNING THE DETAILS OF THIS
CYCLOGENESIS...PERHAPS IN PART DUE TO THE INFLUENCE OF CONVECTION
...WHICH COULD BE EXTENSIVE AND ONGOING AT 12Z WEDNESDAY. HIGH
RESOLUTION MODEL DATA IS STRONGLY SUGGESTIVE THAT A SIGNIFICANT
CLUSTER OF STORMS COULD BE IN PROGRESS WEDNESDAY MORNING EAST OF THE
MIDDLE AND LOWER MISSISSIPPI VALLEY. IF THIS VERIFIES...IT IS
UNCERTAIN WHAT INFLUENCE IT WILL HAVE ON SUBSEQUENT BOUNDARY LAYER
DESTABILIZATION ACROSS THE OHIO/TENNESSEE VALLEY REGION. THIS
UNCERTAINTY PRECLUDES AN OUTLOOK UPGRADE TO HIGH RISK PROBABILITIES
AT THE PRESENT TIME. HOWEVER...MOST OTHER INDICATIONS ARE STRONGLY
SUGGESTIVE THAT A MAJOR OUTBREAK OF SEVERE THUNDERSTORMS COMMENCING
TONIGHT ACROSS PARTS OF THE OZARK PLATEAU/LOWER MISSISSIPPI VALLEY
WILL CONTINUE AND EXPAND NORTHWARD AND EASTWARD TOWARD THE
APPALACHIANS DURING THE DAY WEDNESDAY. THIS WILL INCLUDE THE
POTENTIAL FOR LONG-LIVED SUPERCELLS CAPABLE OF STRONG
TORNADOES...AND ORGANIZED STORM CLUSTERS CAPABLE OF STRONG DAMAGING
WIND GUSTS.

...EASTERN U.S...
IN AREAS NOT IMPACTED SIGNIFICANTLY BY EARLY MORNING CONVECTION...
PRE-FRONTAL BOUNDARY LAYER MOISTURE OVER A BROAD AREA EAST OF THE
MISSISSIPPI VALLEY INTO THE APPALACHIANS...AND PERHAPS EAST OF THE
APPALACHIANS...WILL BE SUPPORTIVE OF CAPE ON THE ORDER OF 1000 TO
2000 J/KG WITH SURFACE HEATING. IN THE PRESENCE OF WIND PROFILES
CHARACTERIZED BY STRONG DEEP LAYER SHEAR...AND LARGE CLOCKWISE
CURVED LOW-LEVEL HODOGRAPHS BENEATH A BROAD 50-70 KT SOUTHERLY
LOW-LEVEL JET...A SIGNIFICANT TORNADIC SUPERCELL THREAT COULD BE
ONGOING OR RAPIDLY DEVELOP BY LATE MORNING ACROSS PARTS OF
NORTHEASTERN MISSISSIPPI/NORTHERN ALABAMA THROUGH WESTERN/MIDDLE
TENNESSEE AND WESTERN/CENTRAL KENTUCKY. HOWEVER...THIS WILL BE
LARGELY CONTINGENT ON EVOLUTION OF OVERNIGHT CONVECTION. IF AN
LARGE CLUSTER OF STORMS DEVELOPS AS SOME GUIDANCE SUGGESTS...AN
EXPANSIVE SURFACE COLD POOL COULD SLOW DESTABILIZATION AND MITIGATE
THE SEVERE POTENTIAL.
Edited by weatherguy, 26 April 2011 - 01:00 PM.

 

[TW Archive]

superjames1992
Posted 26 April 2011 - 12:52 PM

SD, on 26 April 2011 - 12:49 PM, said:

It looked like the 12z models today had the line moving through 12-18z Thursday now unless im looking at it wrong. Tomorrow would be most likely airmass convection or driven by a remnant MCV from tonight.

Yeah, you're right, actually. The initial line looks like it's going to die out (and you can already see it happening now). Ugh, I'm torn on what to forecast for tomorrow (well, 12z tomorrow through 12z Thursday, actually). The real line of storms looks to pass through after the forecast period ends, yet there is a good chance of convective storms. I kind of want to go gung ho on the rain chances and try to aim for the fences to try to pass my professor and get the automatic A+ in my met class (though I have an A, anyways), but if I take that swing and lose, I'll drop back to 3rd or 4th in the standings with only one forecast left.

The GFS MOS gives a 30-40% chance at precip and the NAM MOS puts that number more towards 50%, but I usually tend to think the MOS under predicts POPs in general.

EDIT: I reconsidered and lowered POPS to 50% tomorrow. The atmosphere looks kind of dry during the peak of the instability and the heating of the day and I'd rather not take unnecessary risks. I expect storms tomorrow, but I think they'll be scattered in nature.
Edited by superjames1992, 26 April 2011 - 01:12 PM.

 

[TW Archive]

MichelleH
Posted 26 April 2011 - 12:55 PM

Stormnow, on 26 April 2011 - 12:49 PM, said:

I agree, is the met we will not name in B'ham or Hsv?

Huntsville

 

[TW Archive]

sutton82
Posted 26 April 2011 - 12:56 PM

MichelleH, on 26 April 2011 - 12:55 PM, said:

Huntsville

I'll name him. Brad Huffines. He's terrible.

The only fly in the ointment I see for n. AL tomorrow is morning convection. It seems like it always hangs around longer than expected.
Edited by sutton82, 26 April 2011 - 12:57 PM.

 

[TW Archive]

bjd
Posted 26 April 2011 - 01:03 PM

From deep out in left field...

SPC has an MD out on us up here in the Frozen North; I've been keeping an eye on things ever since the sun came out after lunch and think if a tornado does happen this afternoon, it will be in Central NY -- the Finger Lakes region.


...my play is over for now. Carry on with the regularly scheduled ballgame. (Hey...tomahawk and cardinal emoticons? Just a thought.)

Barb

 

[TW Archive]

Weatherphreak
Posted 26 April 2011 - 01:04 PM

How close are we to an April 74 kind of event?

Brad Huffines is the first name that came to mind. Brad Travis is nice and balanced and Dan will get you pumped up.

 

[TW Archive]

superjames1992
Posted 26 April 2011 - 01:06 PM

Looks like some pretty significant CAPE values tomorrow afternoon/evening, eclipsing 2,500 J/kg in some spots. The lapse rate looks pretty unstable, as well. The forecasted hodograph also predicts veering winds. The atmosphere also seems to really moisten up tomorrow evening.

 

[TW Archive]

Snowowl
Posted 26 April 2011 - 01:06 PM

sutton82, on 26 April 2011 - 12:56 PM, said:

I'll name him. Brad Huffines. He's terrible.

The only fly in the ointment I see for n. AL tomorrow is morning convection. It seems like it always hangs around longer than expected.

Agreed. Thankfully he's going off the air after May 31 to "pursue other opportunities".

 

[TW Archive]

weatherguy
Posted 26 April 2011 - 01:09 PM

Dr. Greg Forbes updated north Alabama from a 7 the other day to a new forecast of 8 or 9 for Wednesday (That forecast is 90% chance of a tornado within 50 miles of any point in north AL):

http://www.weather.com/outlook/weather-news/news/articles/torcon-daily-forecast_2011-03-24
Edited by weatherguy, 26 April 2011 - 01:17 PM.

 

[TW Archive]

sutton82
Posted 26 April 2011 - 01:11 PM

Weatherphreak, on 26 April 2011 - 01:04 PM, said:

How close are we to an April 74 kind of event?

I don't think it is really possible to forecast an event of that magnitude. The set up says the possibility is there, however it will come down to mesoscale features which can not be modeled as accurately as they need to be.

I wouldn't worry about high risks or analogs (except for forecasting purposes). Just take the warnings seriously and hide if you need to.

 

[TW Archive]

Weatherphreak
Posted 26 April 2011 - 01:16 PM

"Might have some strong storms tomorrow" Huffines 2 minutes ago on the radio