Skip Navigation Links weather.gov 
NOAA logo-Select to go to the NOAA homepage NOAA's National Weather Service   Select to go to the NWS homepage
Storm Prediction Center
navigation bar left  
  navigation bar end cap


 
USA.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

Mesoscale Discussion 1979
< Previous MD         Next MD >
MD 1979 graphic

   MESOSCALE DISCUSSION 1979
   NWS STORM PREDICTION CENTER NORMAN OK
   0438 PM CST MON DEC 15 2014

   AREAS AFFECTED...PORTIONS OF MISSISSIPPI...WESTERN
   ALABAMA...SOUTHEAST LOUISIANA

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 152238Z - 160045Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...THE RISK FOR A WEAK TORNADO/STRONG WIND GUST WILL NOT BE
   ENTIRELY NEGLIGIBLE INTO THE EARLY EVENING...THOUGH WW ISSUANCE WILL
   NOT BE NEEDED.

   DISCUSSION...VIS SATELLITE IMAGERY AND SFC OBSERVATIONS INDICATE
   ISOLATED TO WIDELY SCATTERED LOW-TOPPED CONVECTION PRODUCING LITTLE
   TO NO LIGHTNING EVOLVING IN TWO REGIMES:

   /1/ ALONG A REMNANT TROUGH/WIND-SHIFT AXIS ANALYZED ALONG THE MS
   RIVER FROM THE GREENVILLE AREA SWWD INTO CNTRL LA -- WHICH IS
   SHIFTING EWD...
   /2/ ALONG A CONFLUENCE AXIS ANALYZED TO THE E OF THE TROUGH --
   EXTENDING FROM S-CNTRL LA INTO CNTRL MS E OF JACKSON TO NEAR
   STARKVILLE.

   MOISTURE-CHANNEL IMAGERY INDICATES A PROMINENT DRY SLOT SPREADING
   ACROSS THE AREA...WITH LARGE-SCALE DCVA BEING RELEGATED TO HIGHER
   LATITUDES /E.G. MID MS VALLEY/. THIS IS LARGELY LIMITING THE
   CONVECTIVE COVERAGE. HOWEVER...WITH 30-40 KT OF 1-2-KM FLOW SAMPLED
   BY THE JACKSON VWP...SUFFICIENT LOW-LEVEL SHEAR EXISTS FOR A FEW
   ROTATING CONVECTIVE ELEMENTS -- E.G. ONE CURRENTLY ALONG THE
   SIMPSON/JEFFERSON DAVIS COUNTY LINE. MODIFICATIONS TO THE 12Z
   JACKSON RAOB TO ACCOUNT FOR MODEST BOUNDARY-LAYER MOISTENING AND
   DIURNAL DIABATIC HEATING SUGGEST AROUND 500 J/KG OF SBCAPE E OF THE
   WIND-SHIFT AXIS. THIS COULD SUPPORT A FEW MORE INSTANCES OF MODESTLY
   ROTATING UPDRAFTS...WITH THE RISK FOR A WEAK TORNADO/STRONG WIND
   GUST NOT ENTIRELY NEGLIGIBLE. HOWEVER...PROMINENT CAPPING LAYERS
   BETWEEN H7 AND H6 WILL LARGELY STUNT VERTICAL VORTICITY
   STRETCHING/STORM-INDUCED MID-LEVEL HYDRODYNAMIC PRESSURE
   PERTURBATIONS THAT WOULD OTHERWISE YIELD A MORE SUBSTANTIAL SVR-TSTM
   RISK. ANY SVR RISK WILL QUICKLY CEASE FOLLOWING DUSK.

   ..COHEN/EDWARDS.. 12/15/2014


   ATTN...WFO...BMX...MOB...MEG...JAN...LIX...

   LAT...LON   33699001 33908893 33598823 32448820 31198908 30659003
               30629113 31029161 31609150 32709087 33699001 

Top/All Mesoscale Discussions/Forecast Products/Home
Weather Topics:
Watches, Mesoscale Discussions, Outlooks, Fire Weather, All Products, Contact Us

NOAA / National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.
spc.feedback@noaa.gov
Page last modified: December 16, 2014
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities