Note: This will be a running blog post where updates are added throughout the day. Please use the timestamps on the left hand side of the update, which will be in CDT.

Final Note: Here’s all the images we ended up posting today. The time (UTC) is the title name.

5:15 PM: After several hours of activity in Alabama a W. Georgia we’re generally in a lull now (SW GA being the exception). I’ve updated the gallery below with all the images taken throughout this afternoon. Here’s a satellite image taken around 5 PM showing where we’re watching for new developing. An expansive CU field is obvious from LA/AR all the way east to AL. We’re just waiting for the storms to pop. All parameters are favorable for significant severe weather including supercells.

12:50 PM: So it begins… We’ll be running with a gallery type system from this point out so we can speed up the process. Stay tuned!

1:30 AM: SPC indicates a Tornado Watch will be issued for MS/AL/GA shortly.

1:25 AM: The new SPC outlook is out and has increased the tornado probabilities across NE MS and AL. Those areas now have a 15% chance of seeing a tornado within 25 miles of any given point. Here’s the new outlook and graphic.


...THERE IS A MDT RISK OF SVR TSTMS PARTS OF CENTRAL AND NORTH AL  
AND NORTHEAST MS...  

...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE LWR MS VLY  
EWD INTO AL/GA/SC...  
   
..SYNOPSIS  

S/WV TROUGH CENTRAL PLAINS EMBEDDED IN FAST ZONAL FLOW WILL CONTINUE  
EAST ACROSS MS INTO TN VALLEY BY THIS EVENING. FROM THE SURFACE LOW  
OVER SERN OK A NEARLY STATIONARY FRONTAL ZONE  EXTENDS EWD ACROSS  
SRN AR AND NRN GULF STATES JUST TO N OF BHM TO NEAR ATL. COLD FRONT  
TRAILS SWWD FROM SURFACE LOW ACROSS NWRN INTO SWRN TX.  

THE WARM SECTOR OVER CENTRAL GULF STATES FROM ERN TX TO AL AND  
SPREADING EWD INTO SRN GA S OF FRONTAL ZONE IS BECOMING VERY  
FAVORABLE FOR DEVELOPMENT OF SEVERE THUNDERSTORMS INCLUDING  
SUPERCELLS THIS AFTERNOON.  

IN ADDITION TO THE E/W FRONTAL ZONE ACROSS NRN GULF STATES PROVIDING  
A FOCUS FOR SURFACE BASED CONVECTIVE INITIATION THE WARM SECTOR  
ACROSS CENTRAL AL/MS THROUGH HEATING WILL LEAD TO POTENTIAL OF  
DISCRETE SEVERE THUNDERSTORMS AS CINH DISSIPATES BY MID AFTERNOON.  
STEEP MID LVL LAPSE RATES AND RELATIVELY COOL PROFILES WILL SUPPORT  
MDT INSTABILITY WITH MLCAPES AOA 2000 J/KG FROM LWR MS VLY TO  
CENTRAL AL THIS AFTERNOON.  
   
..PARTS OF CENTRAL/NRN AL INTO NRN MS  

WITH 30-40KT LOW LEVEL WSWLY FLOW VEERING SHEAR PROFILES WILL BE  
QUITE FAVORABLE FOR SUPERCELLS INCLUDING TORNADOS AND VERY LARGE  
HAIL.  IT NOW APPEARS THAT SURFACE BASED INITIATION WILL BE ABLE TO  
OCCUR BY MID AFTERNOON IN THE WARM SECTOR WHICH INCREASES THE THREAT  
OF LONG-LIVED SUPERCELLS AND ASSOCIATED TORNADOES.  THE AREA OF  
GREATEST RISK OF THIS OCCURRENCE HAS BEEN UPGRADED TO A MDT  
RISK...ALTHOUGH THE GREATER POTENTIAL COULD EXTEND EVEN INTO WRN GA  
IF SUFFICIENT INSTABILITY DEVELOPS . THERE IS THE THREAT OF STRONG  
TORNADOES WITH ANY SUSTAINED SUPERCELLS.  
   
..SRN/ERN AR/NRN LA EWD ACROSS AL/GA AND SC  

FURTHER W THE INITIALLY STRONGER CAP THROUGH THE PROCESS OF HEATING  
AND ASCENT ALONG THE COLD FRONT WILL WEAKEN BY LATER THIS AFTERNOON  
TO ALLOW SEVERE THUNDERSTORM DEVELOPMENT FROM SRN AR INTO NRN LA.  
WHILE LOW LEVEL SHEAR WILL NOT BE QUITE AS FAVORABLE AS FURTHER  
E...MLCAPES IN EXCESS OF 2000 J/KG...BRN SHEAR OF 40-50KT ALONG WITH  
THE VERY STEEP MID LEVEL LAPSE RATES WILL ALSO SUPPORT SUPERCELLS.   
IN ADDITION TO THE VERY LARGE HAIL THREAT...A FEW TORNADOES ARE ALSO  
LIKELY.  

OVERNIGHT THE STORMS THAT DEVELOP OVER AL/MS THIS AFTERNOON WILL  
HAVE SPREAD EWD ACROSS GA WITH AT LEAST A THREAT OF LARGE HAIL AND  
DAMAGING WINDS IN PARTS OF WRN SC WHERE AIR MASS WILL BE MORE  
MARGINALLY UNSTABLE. MEANWHILE THE COLD FRONTAL INITIATED ACTIVITY  
WILL MAINTAIN A SEVERE THREAT INCLUDING SUPERCELLS AND ISOLATED  
TORNADOES EWD ACROSS CENTRAL MS/AL AND POSSIBLY  INTO SRN GA BY  
EARLY SUN.  

..HALES/ROGERS.. 03/26/2011  

1:00 AM: SPC and several NWS offices are now using the Palm Sunday Tornado Outbreak back in March of 1994 as an analog to today’s event. Today has the potential to produce devastating tornadoes across MS/AL. Those in mobile homes should spend the day at a more reliable structure, such as a church, city building, or a friend’s house. Today is the day where you could get a lot of fatalities if a tornado goes through a mobile home park.

10:25 AM: The Storm Prediction Center is upgrading their convective outlook to the “Moderate’ level due to an increased tornado threat this afternoon and evening. Reference the graphic and text below.

   1630 UTC DAY 1 CONVECTIVE OUTLOOK WILL BE UPGRADING PARTS OF NE MS
   AND CNTRL/NRN AL TO A MODERATE RISK.  CATEGORICAL RISK WILL BE
   DRIVEN BY 15 PERCENT TORNADO PROBABILITIES.  REFER TO GRAPHIC FOR
   DETAILED AREA.

   DETAILS WILL BE FORTHCOMING IN SWODY1 BY 1630 UTC.

1:45 AM: The NSSL (National Severe Storms Lab) high resolution WRF shows an extremely dangerous situation across Mississippi and Alabama by 8 PM tonight, with the model actually showing a tornadic supercell with a hook in MS with all the parameters off the chart. Another cell is over Central Alabama at this point. This won’t play out exactly how it is shown on the graphic below, but it is indicative of the dangerous potential today holds.

1:05 AM: The Storm Prediction Center has issued a high-end standard risk of severe weather today from SE Arkansas all the way into Western Georgia. Here’s the discussion and associated risk graphic.

GREATEST POTENTIAL FOR SFC-BASED SVR TSTM DEVELOPMENT...INCLUDING
   SUPERCELLS WITH TORNADOES...LARGE HAIL AND DAMAGING GUSTS...WILL BE
   DURING MIDDAY THROUGH EARLY EVENING ACROSS CORRIDOR OF MAX
   PROBABILITIES...ALONG AND S OF IMMEDIATE SFC FRONTAL ZONE.  FRONT
   SHOULD BE ALIGNED CLOSE TO MEAN WIND VECTOR...IN ENVIRONMENT
   CHARACTERIZED BY INCREASING DIURNAL INSTABILITY...FAVORABLE
   DEEP-LAYER SHEAR...AND ENHANCED HODOGRAPH SIZE/SRH ALONG BOUNDARY.
   AS SUCH...ANY RELATIVELY DISCRETE STORMS THAT CAN INTERACT WITH
   FRONT MAY SPEND A LONG TIME IN ITS VORTICITY-RICH ENVIRONMENT...WITH
   ENHANCED TORNADO RISK.

   MAIN UNCERTAINTY IS IN POSITION OF WARM/STATIONARY FRONT E OF LOW.
   SOME LATITUDINAL MARGIN FOR ERROR IS NEEDED IN SVR PROBABILITIES
   ATTM GIVEN WIDE VARIATION IN PROGGED TIMING/COVERAGE OF PRECIP N OF
   FRONT...IN TURN INFLUENCING EFFECTIVE BOUNDARY LOCATION DURING PEAK
   CONVECTIVE PERIOD.  SCATTERED-NUMEROUS TSTMS IN CLUSTERS ARE
   PROBABLE ACROSS PORTIONS AR AND MID-SOUTH DURING MORNING AND
   AFTERNOON...CARRYING OVER FROM BEFORE 26/12Z.  ADDITIONAL ACTIVITY
   MAY FORM THROUGHOUT PERIOD N OF FRONT AS ELEVATED WAA/MOISTURE
   TRANSPORT REGIME SHIFTS EWD ACROSS SRN APPALACHIANS.

   S OF FRONTAL ZONE...IN ABSENCE OF APPRECIABLE MID-UPPER
   PERTURBATIONS...CONVECTIVE INITIATION AND COVERAGE DEPEND ON
   MESOSCALE SUBTLETIES AND CAPPING ISSUES NOT NECESSARILY WELL FCST BY
   SYNOPTIC MODELS.  VERTICAL SHEAR PROFILES CERTAINLY WILL BE
   FAVORABLE FOR SUPERCELLS...HOWEVER...SO ANY CONVECTION THAT CAN
   DEVELOP OVER CENTRAL/SRN PORTIONS AL...WRN GA AND MS S OF FRONT WILL
   POSE TORNADO/HAIL/WIND THREAT AS WELL.  CENTRAL/SRN AL MAY REPRESENT
   RELATIVE MAX OF POTENTIAL S OF FRONT...SINCE IT WILL RESIDE E OF
   STRONGEST ELEVATED MIXED LAYER AIR...WHERE CINH WILL BE WEAKENED
   MOST READILY VIA AFTERNOON HEATING AND CONVECTIVE PROCESSES.  SVR
   PROBABILITIES SHOULD LESSEN WITH TIME AND EWD EXTENT ACROSS GA
   OVERNIGHT AS INSTABILITY WEAKENS...BUT NOT DISAPPEAR ALTOGETHER.

   UNCERTAINTIES REGARDING MORE PRECISE FRONTAL POSITION...BAND
   COVERAGE S OF FRONT...PRECLUDE PROBABILITIES SUPPORTING CATEGORICAL
   MDT RISK ATTM.  HOWEVER...UPPER-END SLGT EASILY MAY BE UPGRADED ONCE
   SOME OF THESE UNCERTAINTIES ARE BETTER RESOLVED.

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