Tornado Outbreak April 29-May 2, HIGH RISK AR, TN, MS

[apocalypt-flyer]

Oh dear, this is going to a LONG NIGHT.

[brunota2003]

How often do they state they are definitely going to issue a PDS, prior to the actual issuance?

[Texas Snowman]

When I hear forecasters say that long-tracked and strong tornadoes are possible, I often think of conditions that are ripe for the formation of EF-5 type tornadoes. Right or wrong, I guess it's the default setting my brain has concerning those terms.

So out of curiosity, went and looked up to see if any F5 or EF-5 twisters have ever been recorded in Arkansas.

Couldn't find any. None for Tennessee or Missouri either.

Dumb question I guess, but I know there are many here who have forgotten more about the weather than I'll ever know.

So dumb question or not, I'll ask: is that just pure luck or is there some meterological explanation that I can't think of?

[CrazyC83]

New watch by 3 pm, which will be a PDS Tornado Watch. Probably with huge tornado probs like 95/90 or something I would guess.

MESOSCALE DISCUSSION 0445
NWS STORM PREDICTION CENTER NORMAN OK
0137 PM CDT SAT MAY 01 2010

AREAS AFFECTED...NERN TX...NRN LA...MUCH OF AR

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 011837Z - 011930Z

...PDS TORNADO WATCH WILL BE ISSUED BY 20Z ACROSS MUCH OF AR/NRN LA
AND NERN TX...

How many PDS tornado watches is that in the last 7-10 days? More than is normal for an entire year isn't it?

This will be the 6th one issued. Last year, only 6 PDS TOR watches (and 5 PDS SVR watches) were issued, but that was WAY below average.

[CrazyC83]

When I hear forecasters say that long-tracked and strong tornadoes are possible, I often think of conditions that are ripe for the formation of EF-5 type tornadoes. Right or wrong, I guess it's the default setting my brain has concerning those terms.

So out of curiosity, went and looked up to see if any F5 or EF-5 twisters have ever been recorded in Arkansas.

Couldn't find any. None for Tennessee or Missouri either.

Dumb question I guess, but I know there are many here who have forgotten more about the weather than I'll ever know.

So dumb question or not, I'll ask: is that just pure luck or is there some meterological explanation that I can't think of?

Tennessee had an F5 south of Nashville on April 16, 1998. Speaking of Nashville, a tornado warned-storm is coming into the southern suburbs now, although it doesn't look all that great on radar.

[Texas Snowman]

When I hear forecasters say that long-tracked and strong tornadoes are possible, I often think of conditions that are ripe for the formation of EF-5 type tornadoes. Right or wrong, I guess it's the default setting my brain has concerning those terms.

So out of curiosity, went and looked up to see if any F5 or EF-5 twisters have ever been recorded in Arkansas.

Couldn't find any. None for Tennessee or Missouri either.

Dumb question I guess, but I know there are many here who have forgotten more about the weather than I'll ever know.

So dumb question or not, I'll ask: is that just pure luck or is there some meterological explanation that I can't think of?

Tennessee had an F5 south of Nashville on April 16, 1998.

Guess I missed that one...

[KWT]

I think by strong tornadoes they tend to mean EF3 or above I'd have thought, thats always what I imagined as being a strong tornado anyway?

As others have said, going to be a very long day and night...

[KWT]

Impressive wind damage here from this report:

0145 PM TSTM WND DMG RIPLEY 34.73N 88.94W
05/01/2010 TIPPAH MS TRAINED SPOTTER

SPOTTER REPORTS ROOFS PEELED OFF HOME IN RIPLEY ON HWY 15.

[CrazyC83]

WWUS54 KMEG 011901
SVSMEG

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
201 PM CDT SAT MAY 1 2010

MSC003-117-139-TNC109-011930-
/O.CON.KMEG.TO.W.0051.000000T0000Z-100501T1930Z/
ALCORN MS-TIPPAH MS-PRENTISS MS-MCNAIRY TN-
201 PM CDT SAT MAY 1 2010

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 230 PM CDT FOR
SOUTHWESTERN MCNAIRY...NORTHWESTERN PRENTISS...EAST CENTRAL TIPPAH
AND ALCORN COUNTIES...

AT 200 PM CDT...NEW ALBANY POLICE DEPARTMENT REPORTED ROOFS REMOVED
FROM HOUSES AND DOWNED TREES ALONG THE PATH OF THE TORNADO BETWEEN
RIPLEY AND DUMAS. THIS TORNADO WAS LOCATED 6 MILES SOUTH OF
PEOPLES...OR 8 MILES EAST OF RIPLEY...MOVING NORTHEAST AT 30 MPH.

THIS IS AN EXTREMELY DANGEROUS SITUATION WITH A TORNADO ON THE
GROUND CAUSING DAMAGE.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO CORINTH...
GLEN...HINKLE...JUMPERTOWN...KOSSUTH...RIENZI...THEO...WENASOGA...
CHEWALLA...CYPRESS...PEOPLES...LONE PINE...GIFT AND FARMINGTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

.HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. TAKE COVER NOW.

&&

LAT...LON 3487 8836 3463 8871 3478 8881 3474 8888
3484 8887 3508 8872 3489 8835
TIME...MOT...LOC 1900Z 236DEG 27KT 3472 8878

$$

[CrazyC83]

WWUS54 KMEG 011917
SVSMEG

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
217 PM CDT SAT MAY 1 2010

MSC003-117-141-011945-
/O.CON.KMEG.TO.W.0052.000000T0000Z-100501T1945Z/
ALCORN MS-TISHOMINGO MS-PRENTISS MS-
217 PM CDT SAT MAY 1 2010

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 245 PM CDT FOR NORTHERN
PRENTISS...WEST CENTRAL TISHOMINGO AND SOUTHEASTERN ALCORN
COUNTIES...

AT 215 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A TORNADO ON THE
GROUND 5 MILES SOUTH OF BIGGERSVILLE...MOVING EAST AT 45 MPH.
THIS IS A DANGEROUS AND LIFE THREATENING SITUATION...AS THIS STORM
HAS HAD A HISTORY OR PRODUCING DAMAGE.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BOONEVILLE...
BURNSVILLE...HINKLE...JUMPERTOWN...LEEDY...MIDWAY...RIENZI...
THRASHERS...HOLTS SPUR...WALKER SIDING...HOLCUT AND GASTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

.HEAVY RAINFALL MAY HIDE THIS TORNADO. DO NOT WAIT TO SEE OR HEAR THE
TORNADO. TAKE COVER NOW.

&&

LAT...LON 3491 8831 3473 8819 3463 8866 3474 8867
TIME...MOT...LOC 1915Z 252DEG 37KT 3474 8853

$$

[Calasanjy]

When I hear forecasters say that long-tracked and strong tornadoes are possible, I often think of conditions that are ripe for the formation of EF-5 type tornadoes. Right or wrong, I guess it's the default setting my brain has concerning those terms.

So out of curiosity, went and looked up to see if any F5 or EF-5 twisters have ever been recorded in Arkansas.

Couldn't find any. None for Tennessee or Missouri either.

Dumb question I guess, but I know there are many here who have forgotten more about the weather than I'll ever know.

So dumb question or not, I'll ask: is that just pure luck or is there some meterological explanation that I can't think of?

Tennessee had an F5 south of Nashville on April 16, 1998.

Guess I missed that one...

And in Missouri, there was the infamous May 20, 1957 Ruskin Heights F5 tornado, which crossed into the state from Kansas. And it's also worth mentioning the March 18, 1925 "Tri-State Tornado", which developed in Missouri before tracking through southern Illinois into southern Indiana.

I believe that "strong" tornadoes refer to those of (E)F2+ tornadoes, whereas (E)F4 and F5 tornadoes are considered "violent" tornadoes. I think it would be extremely presumptuous for the SPC to mention violent tornadoes in a convective outlook, and therefore they probably only say "strong" meaning the potential exists for several tornadoes of EF2 class or higher.

[KWT]

Just watching one of the chase teams from the UK moving through NE AR and the clear slot is really evident to see on the stream.

Still lots of very heavy rain falling as well with the big MCS feature further east.

[CrazyC83]

I'm looking at the meso-analyses, and a secondary area to watch may be way up north, in the upper Great Lakes...

http://w1.spc.woc.noaa.gov/exper/mesoan ... underlay=1

[KWT]

Will certainly be a big geographical spread if that happened Crazy!


MESOSCALE DISCUSSION 0446
NWS STORM PREDICTION CENTER NORMAN OK
0254 PM CDT SAT MAY 01 2010

AREAS AFFECTED...NRN MS/AL...WRN/CNTRL TN

CONCERNING...TORNADO WATCH 124...

VALID 011954Z - 012100Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 124 CONTINUES.

SEVERE THREAT...INCLUDING TORNADOES...WILL CONTINUE PRIMARILY ACROSS
NRN PORTIONS OF WW124 BEYOND WATCH EXPIRATION. TORNADO WATCH WILL
BE REISSUED BY 21Z TO ADDRESS THIS THREAT.

SEVERAL LONGER LIVED SUPERCELLS...ONE PARTICULARLY TORNADIC STORM
OVER NERN MS...CONTINUE ALONG SRN FRINGE OF QUASI-STATIONARY MCS.
MODELS SUGGEST WEAK SUBSIDENCE/CAPPING WILL GRADUALLY EXPAND NWD
ACROSS MUCH OF SRN/CNTRL MS AND AL...ULTIMATELY SUPPRESSING STRONGER
CONVECTION ACROSS THESE REGIONS. DESPITE THE WEAK THUNDERSTORM
ACTIVITY LOCATED OVER CNTRL MS CURRENT THINKING IS GREATER SEVERE
RISK WILL REMAIN CONFINED TO TN AND EXTREME NRN MS/AL...THUS A NEW
TORNADO WATCH WILL BE ISSUED TO ADDRESS THIS LONGER TERM THREAT.

[CrazyC83]

Interesting thinking that makes a lot of sense, maybe issue a new watch primarily for Middle Tennessee and North Alabama now (probs around 60/40 would make most sense), and then look into a PDS Tornado Watch later for Mississippi and West Tennessee this evening.

That would be a huge spread - that is on the first warm front and trailing cold front. No one seems to be forecasting it though but the dynamics are there.

[RL3AO]

Look at the clearing over Arkansas.

[CrazyC83]

2000Z: Slight risk expanded eastward, Moderate expanded northward. No real change in the High Risk area.

[CrazyC83]

How often do they state they are definitely going to issue a PDS, prior to the actual issuance?

Very rarely, but it is a no-brainer over a High Risk area.

[CrazyC83]

SPC AC 012001

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0301 PM CDT SAT MAY 01 2010

VALID 012000Z - 021200Z

...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF NRN
LA...AR...NW MS...SE MO AND WRN TN...

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NRN LA...FAR NE
TX...AR...MS...TN...SRN IND...SRN IL AND SE MO...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...LOWER TO MID MS VALLEY...TN VALLEY AND OH VALLEY...

SEVERAL CHANGES HAVE BEEN MADE FOR THE 20Z OUTLOOK. THE FIRST IS TO
EXTEND THE HIGH RISK SLIGHTLY FURTHER NORTH ACROSS PARTS OF SERN MO
WHERE MODEL FORECASTS AND SEVERE PARAMETERS SHOW INTENSE CONVECTIVE
DEVELOPMENT. THE SECOND CHANGE IS TO EXTEND THE MODERATE RISK
FURTHER NORTHEAST INTO SRN IL AND SRN IND WHERE A SEVERE MCS IS
EXPECTED TO MOVE AFTER MIDNIGHT. THE CURRENT THINKING IS THAT A
TORNADO OUTBREAK WILL BEGIN LATE THIS AFTERNOON IN SRN AND ERN AR
WHERE LONG TRACK STRONG TO VIOLENT TORNADOES WILL BE POSSIBLE. THE
TORNADIC SUPERCELLS SHOULD MOVE NNEWD INTO SE MO THIS EVENING. THE
MCS ASSOCIATED WITH THIS CLUSTER SHOULD PERSIST NEWD ACROSS THE
MODERATE RISK AREA TONIGHT ON THE WEST SIDE OF AN IMPRESSIVE
LOW-LEVEL JET. ISOLATED STRONG TORNADOES WILL BE POSSIBLE ACROSS SRN
IL...WRN KY AND SRN IND AFTER MIDNIGHT. THE THIRD CHANGE IS TO ADD A
SLIGHT RISK AREA EWD ACROSS NRN AL AND NRN GA WHERE OBJECTIVE
ANALYSIS SHOWS MODERATE INSTABILITY AND STRONG VERTICAL SHEAR. THE
OTHER THAN THUNDER PROBABILITY ADJUSTMENTS...THE FINAL CHANGE
INCLUDES EXTENDING THE 5 PERCENT HAIL AND WIND PROBABILITIES WWD
ACROSS ERN OK.

..BROYLES.. 05/01/2010

[KWT]

The fact they are suggesting that a tornado outbreak is expected shows how serious this set-up could become really doesn't it!

Still nothing too severe out there but that clear slot won't last much longer I'd think before cells start going up.

The high risk ever so slightly expanded NE from looknig at the comprasion to the previous outlook.