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Major Severe Weather Outbreak November 17

Hoosier

By Hoosier,
in Weather Forecasting and Discussion

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Stebo

Stebo

Posted
Posted 
DAY 1 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   1152 PM CST SAT NOV 16 2013   VALID 171200Z - 181200Z   ...THERE IS A HIGH RISK OF SVR TSTMS ACROSS PARTS OF ERN IL...IND   AND FAR SW LOWER MI...   ...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF IL...LOWER   MI...OH...IND...KY AND WRN TN......   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE MID TO   UPPER MS VALLEY...OH VALLEY...SRN GREAT LAKES AND TN VALLEY...   ...TORNADO OUTBREAK WITH MULTIPLE SIGNIFICANT TORNADOES AND   WIDESPREAD DAMAGING WINDS EXPECTED ACROSS THE OH VALLEY AND SRN   GREAT LAKES REGION TODAY...   AN IMPRESSIVE NEGATIVELY-TILTED UPPER-LEVEL TROUGH AND POWERFUL 80   TO 100 KT MID-LEVEL JET WILL MOVE ACROSS THE NCNTRL U.S. TODAY. AT   THE SFC...A LOW WILL TRACK NEWD INTO THE UPPER MIDWEST AS A COLD   FRONT ADVANCES EWD INTO THE MID TO UPPER MS VALLEY. AHEAD OF THE   FRONT...STRONG MOISTURE ADVECTION WILL OCCUR DUE TO A WELL-DEVELOPED   AND BROAD 60 TO 75 KT LOW-LEVEL JET. AN EXTENSIVE AREA OF   THUNDERSTORMS WITH AN ISOLATED SEVERE THREAT SHOULD BE ONGOING ALONG   THE ERN EDGE OF THE LOW-LEVEL JET FROM NE AR NEWD INTO SRN IND AT   DAYBREAK WITH THIS ACTIVITY MOVING EWD AWAY FROM THE INSTABILITY   AXIS THIS MORNING. FURTHER TO THE WEST...THE LOW-LEVEL JET WILL   TRANSPORT LOW TO MID 60S F SFC DEWPOINTS INTO THE MID MS VALLEY AND   OH VALLEY RESULTING IN A CORRIDOR OF MODERATE INSTABILITY FROM NE AR   NNEWD INTO CNTRL IL BY MID MORNING. DUE TO STRONG LARGE-SCALE ASCENT   ASSOCIATED WITH THE UPPER-LEVEL TROUGH...SFC-BASED CELL INITIATION   SHOULD OCCUR AHEAD OF THE FRONT BY MID MORNING ACROSS NRN AND CNTRL   IL WITH STORM COVERAGE EXPANDING EWD INTO IND AND LOWER MI BY EARLY   AFTERNOON. ALTHOUGH CELLS MAY REMAIN DISCRETE THROUGH MUCH OF THE   AFTERNOON...THE DEVELOPMENT OF A SQUALL-LINE APPEARS LIKELY DURING   THE LATE AFTERNOON ACROSS THE OH VALLEY WITH THE LINE DEVELOPING SWD   INTO THE TN VALLEY DURING THE EARLY EVENING.   FORECAST SOUNDINGS AT URBANA IL AND INDIANAPOLIS IND IN THE 18Z TO   21Z TIMEFRAME SHOW SBCAPE NEAR 1500 J/KG...0-6 KM SHEAR AROUND 70   KT...LOW-LCL HEIGHTS AND LONG LOOPED HODOGRAPHS SUGGESTING   SUPERCELLS AND TORNADOES WILL BE LIKELY AS DISCRETE CELLS INTENSIFY.   0-3 KM STORM RELATIVE HELICITIES OF 400 TO 450 M2/S2 WILL BE   FAVORABLE FOR STRONG TORNADOES WITH SEVERAL LONG-TRACK DAMAGING   TORNADOES EXPECTED TO OCCUR FROM ERN IL ENEWD ACROSS MUCH OF WRN AND   CNTRL IND FROM LATE MORNING INTO EARLY AFTERNOON. AS CELL COVERAGE   INCREASES AHEAD OF THE FAST MOVING FRONT...A SQUALL-LINE SHOULD   ORGANIZE LATE THIS AFTERNOON. WIDESPREAD WIND DAMAGE WILL BE   ASSOCIATED WITH THE LINE ALONG WITH TORNADOES WITH ROTATING CELLS   EMBEDDED IN THE LINE. THE SEVERE THREAT SHOULD RAMP UP SOUTH OF THE   OH RIVER DURING THE LATE AFTERNOON AS CELLS INITIATE SWD ALONG THE   FRONT. THE POTENTIAL FOR WIND DAMAGE AND TORNADOES SHOULD DEVELOP AS   A FAR SOUTH AS THE TN VALLEY DURING THE EVENING AS AN EXTENSIVE LINE   OF SEVERE STORMS MOVES EWD INTO THE UPPER OH VALLEY AND CNTRL   APPALACHIAN MTNS.   SEVERAL FACTORS APPEAR TO BE COMING TOGETHER FOR A TORNADO OUTBREAK   ACROSS THE OH VALLEY. THE FIRST FACTOR IS THAT THE SYSTEM IS   NEGATIVELY-TITLED AND VERY WELL-ORGANIZED. THE SECOND IS THAT THE   LOW AND MID-LEVEL JETS WILL BECOME FAVORABLY COUPLED IN THE OH   VALLEY TODAY COINCIDING WITH AN OUTBREAK OF STORMS ACROSS THE WARM   SECTOR. THE THIRD IS THAT SUPERCELLS ARE EXPECTED TO REMAIN DISCRETE   INTO THE MID-AFTERNOON. THESE FACTORS COMBINED WITH EXTREMELY   FAVORABLE LOW-LEVEL SHEAR PROFILES JUSTIFIES THE ISSUANCE OF A HIGH   RISK ACROSS ERN IL...IND AND SW LOWER MI.

 

 

Figured I would add the discussion to the thread, this is one of the strongest worded discussions I have ever seen issued.

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stormtrackertf

stormtrackertf

Posted
Posted

Figured I would add the discussion to the thread, this is one of the strongest worded discussions I have ever seen issued.

How do you feel about our chances for some widespread wind damage in the Detroit metro area today? Been a while since we've had an old fashioned derecho roll through town.

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nwohweather

nwohweather

Posted
Posted

One of the largest areas of 15% hatched I've seen in the Great Lakes/Ohio Valley... not to mention a very large high risk area. Certainly does not bode well for later today. 

 

One of, if not the most impressive setup I have ever seen for our region. Granted I am in my early 20s but still, this seems to possibly take the cake from November 2002

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stormtrackertf

stormtrackertf

Posted
Posted

Latest I can ever remember was (I believe) October 24th, 2001.


To add on to this, the setup was actually quite similar to this one although it didn't pan out so much in the tornado aspect. I think there were around 20 tornadoes, the highest being rated F3, but hundreds of high wind reports and widespread damage.

This was the SPC outlook that day, also somewhat similar:

post-7696-0-13666600-1384669088_thumb.gi
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cyclone77

cyclone77

Posted
Posted

I'm rather surprised at the 30% hatched.  I guess they didn't think too much of that potential veer-back-veer profile or any other factor inhibiting a tornado outbreak.

 

 

Normally I hate the ol' veer-back-veer profile, but with the tremendous mid-upper velocities it shouldn't be a factor.  Most of the time the VBV setup is associated with much less upper level support.  With these stretched out, and highly curved hodos the VBV isn't too much of a factor. 

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Stebo

Stebo

Posted
Posted

How do you feel about our chances for some widespread wind damage in the Detroit metro area today? Been a while since we've had an old fashioned derecho roll through town.

I think the damaging wind potential is very good locally, and our tornado potential is decent as well, not nearly as good as just west of here but still pretty solid.

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tornadotony

tornadotony

Posted
Posted

Normally I hate the ol' veer-back-veer profile, but with the tremendous mid-upper velocities it shouldn't be a factor.  Most of the time the VBV setup is associated with much less upper level support.  With these stretched out, and highly curved hodos the VBV isn't too much of a factor. 

Plus, the overall VBV component is pretty small, even on the model where it's the most substantial (NAM).

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Memphis Weather

Memphis Weather

Posted
Posted

To add on to this, the setup was actually quite similar to this one although it didn't pan out so much in the tornado aspect. I think there were around 20 tornadoes, the highest being rated F3, but hundreds of high wind reports and widespread damage.

This was the SPC outlook that day, also somewhat similar:

attachicon.giff3-day1otlk_1200.gif

 

Ahh, back in the days where a High risk without a surrounding Moderate was somewhat common. I think that may have been the last High risk ever to feature that...

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stormtrackertf

stormtrackertf

Posted
Posted

I think the damaging wind potential is very good locally, and our tornado potential is decent as well, not nearly as good as just west of here but still pretty solid.

I'm fine with the lesser tornado threat. This time of year, with the speed these storms are going to be moving at and the likely strength of them out further west...that's a potential doomsday scenario for a big metro area. Hopefully everyone gets plenty of warning time IF the threat materializes. If I remember correctly, that Van Wert, OH tornado in November of 2002 narrowly missed leveling a theater with about 50 people inside, I wouldn't want to count on that kind of luck again if I were in the line of fire this time.

I could see a bunch of tornado warnings in our area mostly based off the potential for spin-ups on the leading edge of the main line of storms that rolls through with damaging winds being the highest threat, with maybe a few brief tornadoes mixed in.

 

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AppsRunner

AppsRunner

Posted
Posted

I'm fine with the lesser tornado threat. This time of year, with the speed these storms are going to be moving at and the likely strength of them out further west...that's a potential doomsday scenario for a big metro area. Hopefully everyone gets plenty of warning time IF the threat materiaizes. If I remember correctly, that Van Wert, OH tornado in November of 2002 narrowly missed leveling a theater with about 50 people inside, I wouldn't want to count on that kind of luck again if I were in the line of fire this time.

I could see a bunch of tornado warnings in our area mostly based off the potential for spin-ups on the leading edge of the main line of storms that rolls through with damaging winds being the highest threat, with maybe a few brief tornadoes mixed in.

The van wert f4 did hit a theater, but the manager moved everyone to safety. There's pictures somewhere of cars that were lifted into front row seats of the theater itself
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