Topic: Severe Weather Forecast western Central Plains 11th to 12th March 2006

[David C]

Hi guys,

Forget about science, if you were a betting man you'd have to put your money on some very strong tornadoes occurring on one or both of these days. These are potent upper level disturbances! So far (over the past several days) they have yielded jack squat w/r to significant tornadoes!

In anycase, what else is there to say - if storms break the cap as expected there will be some significant tornadoes tomorrow and again (even more so) on Sunday there.

Something has to give!

FORECAST SOUNDINGS YIELD A
DANGEROUS COMBINATION OF CAPE AND SHEAR /MLCAPE GREATER THAN 2000
J/KG AND EFFECTIVE SHEAR IN EXCESS OF 60 KT/...WHICH WILL LIKELY
SUPPORT TORNADIC SUPERCELLS SHOULD CAP BREAK AS EXPECTED.  IN
ADDITION...STORM MODE IS EXPECTED TO REMAIN DISCRETE WITH SUBSEQUENT
ENHANCED RISK OF TORNADOES GIVEN FORECAST 200+ M2/S2 0-1 KM SRH AND
LOW LCL HEIGHTS.

[Jimmy Deguara]

Hi David,

I recall seeing this scenario a couple of days back - good pattern setup. Apparently there was a nice supercell with flying eagle signature today in Oklahoma - Marshall county.

Regards,

Jimmy Deguara

[David C]

 

[David C]

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[David C]

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[David C]

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[Jimmy Deguara]

To back up David's research in finding appropriate maps, here is the Storm Prediction Center's analysis and forecast discussion for the Day 1 outlook period

DAY 1 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0159 PM CST SAT MAR 11 2006:

WATER VAPOR IMAGERY CURRENTLY SHOWS SOUTHWEST FLOW IN PLACE ACROSS
   THE REGION WITH A SHORTWAVE TROUGH IN OK. THIS FEATURE WILL FOCUS
   LARGE-SCALE ASCENT AS IT MOVES NEWD ACROSS ERN OK...NW AR AND MO
   LATE THIS AFTERNOON CAUSING STORM COVERAGE TO QUICKLY EXPAND. A
   LARGE MCS ASSOCIATED WITH WIDESPREAD SEVERE WEATHER SHOULD GRADUALLY
   DEVELOP THIS AFTERNOON AND EVENING ACROSS THE REGION.
   
   OBJECTIVE ANALYSIS CURRENTLY SHOWS A BROAD WARM SECTOR EXISTS ACROSS
   THE ERN PART OF THE SRN PLAINS EXTENDING NNEWD ACROSS THE OZARK
   PLATEAU AND LOWER TO MID MS VALLEY. THE AIRMASS IS CHARACTERIZED BY
   MODERATE INSTABILITY WITH 0-6 KM SHEAR VALUES GENERALLY RANGING FROM
   50 KT ACROSS THE OZARK PLATEAU TO 70 KT ACROSS THE OH VALLEY. THIS
   SUGGESTS SUPERCELLS WILL BE LIKELY WITH STORMS THAT REMAIN DISCRETE.
   AS STORM COVERAGE EXPANDS THROUGH EARLY EVENING...BOW ECHOES AND
   MULTICELLS WILL BECOME LIKELY WITH LINEAR STORM CLUSTERS. THE
   GREATEST SEVERE WEATHER THREAT LATE THIS AFTERNOON WILL LIKELY BE
   ACROSS MO...ERN OK...WRN AR AND NE TX WHERE FORECAST SOUNDINGS
   SUGGEST LAPSE RATES WILL STEEPEN OVER THE NEXT FEW HOURS. THE
   MODERATE INSTABILITY AND VERY STRONG VERTICAL SHEAR SHOULD BE
   SUFFICIENT FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL. IN
   ADDITION...THE TORNADO THREAT WILL INCREASE THROUGH EARLY THIS
   EVENING AS THE LOW-LEVEL JET STRENGTHENS AND THE LOW-LEVEL SHEAR
   BECOMES MORE FAVORABLE. A THREAT FOR TORNADOES AND WIND DAMAGE WILL
   EXPAND EWD AS A LARGE LINEAR MCS DEVELOPS THIS EVENING AND MOVES
   ACROSS MO...IL AND WRN AR. A FEW SIGNIFICANT TORNADOES WILL BE
   POSSIBLE WITH SUPERCELLS AND/OR WITH THE STRONGER BOW ECHOES
   EMBEDDED IN OR AHEAD OF THE LINE. THE GREATEST TORNADO THREAT SHOULD
   BE IN THE 00Z TO 06Z TIMEFRAME EXTENDING NEWD FROM NRN AR ACROSS
   CNTRL AND ERN MO INTO THE ST. LOUIS AREA. THE BROAD WARM SECTOR
   SUGGESTS A SEVERE WEATHER THREAT WILL CONTINUE WITH THE LINEAR MCS
   AS IT MOVES EWD INTO THE OH VALLEY AND NEARS THE MS RIVER LATE
   TONIGHT.

[Jimmy Deguara]

Updated: Sat Mar 11 20:02:16 UTC 2006    (Day 1 outlook)

Public Severe Weather Outlook

The SPC is forecasting an enhanced risk of severe thunderstorms today and tonight across portions of the United States. This is an extremely dangerous situation. Please read the latest public statement about this event.

My take on this is the threat for significant tornadoes (F2 to F5 tornadoes).

Regards,

Jimmy Deguara
 

[Jimmy Deguara]

Hi,

There is now a high risk of severe weather and tornadoes some significant across the central mid-west (Missouri, Illinois and Iowa mostly being affected). Let us hope there are no fatalities.

Here is the updated public weather statement:

PUBLIC SEVERE WEATHER OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0346 AM CST SUN MAR 12 2006
   
   VALID 120946Z - 121745Z
   
   ...SEVERE THUNDERSTORM OUTBREAK EXPECTED OVER PARTS OF THE LOWER
   MISSOURI AND MID MISSISSIPPI RIVER VALLEYS LATER TODAY AND
   TONIGHT...
   
   THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE
   DEVELOPMENT OF A FEW STRONG...LONG-TRACK TORNADOES OVER PARTS OF THE
   LOWER MISSOURI AND MID MISSISSIPPI RIVER VALLEYS LATER TODAY AND
   TONIGHT.
   
   THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE
   
          FAR SOUTHERN IOWA
          WEST CENTRAL ILLINOIS
          MISSOURI
   
   SURROUNDING THE HIGH RISK AREA...THERE IS A MODERATE RISK OF SEVERE
   THUNDERSTORMS FROM EASTERN OKLAHOMA AND KANSAS INTO THE MID SOUTH
   AND OHIO RIVER VALLEY.
   
   A VOLATILE SITUATION IS EXPECTED TO UNFOLD OVER EASTERN PORTIONS OF
   THE CENTRAL PLAINS AND MUCH OF THE LOWER MISSOURI...MID MISSISSIPPI
   AND OHIO RIVER VALLEYS TODAY AND TONIGHT.  A VERY STRONG UPPER LEVEL
   STORM SYSTEM AND ASSOCIATED JET MAX WILL QUICKLY OVERSPREAD AN
   UNSEASONABLY WARM AND MOIST SURFACE AIR MASS THIS AFTERNOON.  WE
   EXPECT THAT SEVERAL AREAS OF SIGNIFICANT SEVERE WEATHER WILL DEVELOP
   DURING THE PERIOD.  THE MOST SIGNIFICANT OF WHICH MAY OCCUR OVER THE
   NORTHERN HALF OF MISSOURI/FAR SOUTHERN IOWA INTO WEST CENTRAL
   ILLINOIS AHEAD OF A STRENGTHENING LOW PRESSURE CENTER AND ITS
   ACCOMPANYING WARM FRONT.  THIS ACTIVITY IS EXPECTED TO DEVELOP
   DURING THE EARLY TO MID AFTERNOON AND RACE EAST-NORTHEASTWARDS
   THROUGH THE EVENING IN THE FORM OF TORNADIC SUPERCELLS...MANY OF
   WHICH COULD BECOME QUITE STRONG AND LONG-LIVED.  OTHER POTENTIALLY
   TORNADIC SUPERCELLS ARE EXPECTED TO DEVELOP LATE TODAY AND THIS
   EVENING ALONG A DRY LINE EXTENDING INTO FAR EASTERN OKLAHOMA AND
   NORTHEASTERN TEXAS.  THESE WILL SPREAD A THREAT OF SEVERE
   WEATHER...INCLUDING DAMAGING TORNADOES...ACROSS ARKANSAS INTO THE
   MID SOUTH/LOWER OHIO RIVER VALLEY THROUGH THE NIGHT.
   
   THIS IS POTENTIALLY A VERY DANGEROUS SITUATION. THOSE IN THE
   THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER SAFETY RULES AND
   TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER RADIO FOR
   POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

[Jimmy Deguara]

Here are the graphics outlining the risk areas, the probabalistic tornado, hail and wind areas:

[David C]

Sit back and watch now - this could be major.
I think Carson's comment regarding sitting back and watching a few wedges race by will apply tomorrow :-)

[Jimmy Deguara]

Hi,

2 PDS Tornado Watches have been issued - in other words :

http://www.spc.noaa.gov/products/watch/ww0073.html

http://www.spc.noaa.gov/products/watch/ww0074.html

Let's hope if storms become tornadic they don't pass through major populated areas. The fast pace of these tornadoes will make evacuation and warnings difficult to monitor for the general public. Fatalities could result!

Regards,

Jimmy Deguara

[Jimmy Deguara]

Hi,

Kansas City web cam

http://www.kctv5.com/Global/story.asp?S=2611457&nav=1PuZ

One has been supplied here for a virtual chase:)

[Jimmy Deguara]

A TVS signature on doppler radar at the moment with a large hook. A confirmed half mile wide tornado on the ground

* AT 409 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
  A CONFIRMED LARGE AND EXTREMELY DANGEROUS TORNADO 6 MILES EAST OF 
  GREEN RIDGE...OR 8 MILES SOUTHWEST OF SEDALIA. DOPPLER RADAR       
  SHOWED THIS TORNADO MOVING NORTHEAST AT 55 MPH.

* THE TORNADO WILL REMAIN OVER MAINLY RURAL AREAS OF NORTHWESTERN
  MORGAN COUNTY.

NUMEROUS REPORTS OF EXTENSIVE DAMAGE HAVE BEEN RECEIVED FROM
SOUTHERN PETTIS COUNTY. SPOTTERS ARE REPORTING A LARGE ONE HALF MILE
WIDE TORNADO ON THE GROUND!

Regards,

Jimmy Deguara

[David C]

That supercell has just crossed I70 just west of Columbia MO