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 1982
< Previous MD         Next MD >
MD 1982 graphic

   MESOSCALE DISCUSSION 1982
   NWS STORM PREDICTION CENTER NORMAN OK
   0419 AM CST TUE DEC 23 2014

   AREAS AFFECTED...PORTIONS OF SOUTHEAST MISSISSIPPI AND SOUTHEAST
   LOUISIANA

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 231019Z - 231215Z

   PROBABILITY OF WATCH ISSUANCE...5 PERCENT

   SUMMARY...SOME STRONG-THUNDERSTORM RISK WILL EXIST DURING THE
   PRE-DAWN HOURS. IN THE SHORT-TERM...WW ISSUANCE WILL NOT BE
   NECESSARY.

   DISCUSSION...SFC ANALYSES INDICATE MOIST...MARINE-MODIFIED AIR
   CONTINUING TO ADVANCE NWD...WITH MIDDLE-60S DEWPOINTS SPREADING NWD
   ACROSS SERN LA/SERN MS. RICHER...MORE STRONGLY MODIFIED GULF
   MOISTURE -- E.G. SFC DEWPOINTS IN THE LOWER 70S -- RESIDES S OF A
   WARM FRONT ANALYZED JUST OFFSHORE FROM SERN LA. THE EARLIER 00Z LIX
   RAOB AND MODIFICATIONS TO THIS SOUNDING SUGGEST THAT SUFFICIENTLY
   HIGH THETA-E EXISTS IN THE BOUNDARY LAYER FOR 500-1000 J/KG OF
   MLCAPE WITH SFC-BASED EFFECTIVE INFLOW LAYERS...ESPECIALLY WITHIN
   ABOUT 100 MILES OF THE COAST. AREA RADARS AND LIGHTNING DATA
   INDICATE A RECENT UPTICK IN CONVECTION W AND N OF LAKE
   PONTCHARTRAIN. THIS ACTIVITY IS LIKELY ASSOCIATED WITH A NARROW
   FILAMENT OF MID-LEVEL ASCENT PROGRESSING NEWD ON THE SERN PERIPHERY
   OF BROADER CYCLONIC FLOW OVER THE CNTRL CONUS...PER MOISTURE-CHANNEL
   IMAGERY.

   UNTIL LARGER-SCALE ASCENT INCREASES LATER IN THE MORNING...ONLY A
   GRADUAL INCREASE IN CONVECTIVE COVERAGE AND INTENSITY IS EXPECTED
   DURING THE NEXT FEW HOURS UNDER THE INFLUENCE OF THE AFOREMENTIONED
   ASCENT FILAMENT. LIX AND JAN VWPS SAMPLE OVER 50 KT OF MID-LEVEL
   SWLYS THAT WILL OFFER SUFFICIENT DEEP SHEAR FOR SUSTAINED/ORGANIZED
   CONVECTION. LOW-LEVEL FLOW IS PRESENTLY MODEST...THOUGH SUFFICIENT
   DIRECTIONAL SHEAR EXISTS FOR THE POSSIBILITY OF GENERALLY WEAK
   STORM-SCALE CIRCULATIONS AND PERHAPS A BRIEF/WEAK TORNADO.
   CONVECTION EVOLVING ACROSS MARION AND JEFFERSON DAVIS COUNTIES IN
   SERN MS HAS ALREADY EXHIBITED WEAK/ELONGATED CYCLONIC SHEAR ZONES.
   SIMILAR TRENDS WILL LIKELY BE NOTED WITH CONVECTION ACROSS THE
   REGION BEFORE DAWN. HOWEVER...NOTHING MORE THAN A BRIEF/WEAK TORNADO
   OR PERHAPS A STRONG WIND GUST ARE EXPECTED WHILE LOW-LEVEL FLOW
   REMAINS WEAK AND LARGE-SCALE ASCENT MODEST.

   ..COHEN/EDWARDS.. 12/23/2014


   ATTN...WFO...MOB...JAN...LIX...LCH...

   LAT...LON   29239240 29739290 30469199 31878985 31808866 30028855
               28908935 29239240 

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 23, 2014
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities