Spring wx discussion 2013 edition

Toot wrote:You rarely see this even progged this time of year and normally I dont write off anything a guidance model suggests but i can assure the GFS is definately smoking CRACK!!

John1122 wrote:May 9th 1916 or so my grandpa said we had 9 inches of snow in knee high corn. I remember a May monster snow in the Smokies above 4000 or so feet. 3+ feet if I remember correctly. 40s and heavy rain in the lower elevations.

Code:

MESOSCALE DISCUSSION 0563
  NWS STORM PREDICTION CENTER NORMAN OK
  0155 PM CDT SAT APR 27 2013
 
  AREAS AFFECTED...NRN/CNTRL MS...NWRN AL...WRN TN...ERN AR
 
  CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
 
  VALID 271855Z - 272100Z
 
  PROBABILITY OF WATCH ISSUANCE...80 PERCENT
 
  SUMMARY...SEVERE TSTMS SHOULD DEVELOP ACROSS PARTS OF THE MID-SOUTH
  TOWARDS THE TN VALLEY BY LATE-AFTERNOON. A TORNADO AND PERHAPS A
  SEVERE THUNDERSTORM WATCH WILL BECOME NECESSARY AT SOME POINT...BUT
  CONFIDENCE IS LOW ON TIMING OF WW ISSUANCE THIS AFTERNOON.
 
  DISCUSSION...18Z SURFACE ANALYSIS PLACED A 1015 MB CYCLONE 30 W KHOT
  WITH A WARM FRONT EXTENDING EWD TO NEAR KMEM TO KHSV AND A COLD
  FRONT EXTENDING SWWD INTO NERN TX. ABUNDANT CLOUD COVERAGE WAS
  PREVALENT ALONG THE FRONTAL ZONES. NEVERTHELESS...SURFACE
  TEMPERATURES HAD WARMED THROUGH THE 70S IN MUCH OF THE WARM SECTOR
  INTO THE LOWER 80S ACROSS CNTRL/SRN MS...WHILE DEW POINTS HAVE HELD
  IN THE MIDDLE 60S. THIS IS FOSTERING THE INCREASING PRESENCE OF A
  MODERATELY BUOYANT AIR MASS.
 
  CONVERGENCE ALONG PRIMARILY THE COLD FRONT...AS WELL AS BANDS OF
  CONFLUENCE WITHIN THE WARM SECTOR WILL YIELD INCREASING TSTM
  COVERAGE AS THE AIR MASS CONTINUES TO DESTABILIZE. WITH A BELT OF
  STRONG 700-500 MB FLOW ATTENDANT TO THE COMPACT SHORTWAVE IMPULSE
  MOVING EWD ACROSS SRN MO...SETUP SHOULD YIELD SEVERAL
  SUPERCELLS/MULTICELL CLUSTERS CAPABLE OF LARGE HAIL AND DAMAGING
  WIND. 0-1 KM SHEAR OF 15-25 KT WILL ALSO SUPPORT A RISK FOR A FEW
  TORNADOES...MOST LIKELY NEAR THE WARM FRONT FROM ERN AR INTO WRN TN.
 
  ..GRAMS/HART.. 04/27/2013

Code:

 URGENT - IMMEDIATE BROADCAST REQUESTED
  TORNADO WATCH NUMBER 141
  NWS STORM PREDICTION CENTER NORMAN OK
  350 PM CDT SAT APR 27 2013
 
  THE NWS STORM PREDICTION CENTER HAS ISSUED A
 
  * TORNADO WATCH FOR PORTIONS OF
    EAST CENTRAL ARKANSAS
    NORTHERN MISSISSIPPI
    SOUTHWEST TENNESSEE
 
  * EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 350 PM UNTIL
    1100 PM CDT.
 
  * PRIMARY THREATS INCLUDE...
    SEVERAL TORNADOES POSSIBLE
    SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2
      INCHES IN DIAMETER POSSIBLE
    SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE
 
  THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 35 STATUTE
  MILES NORTH AND SOUTH OF A LINE FROM 50 MILES EAST SOUTHEAST OF
  JACKSON TENNESSEE TO 15 MILES SOUTH OF LITTLE ROCK ARKANSAS.  FOR
  A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
  OUTLINE UPDATE (WOUS64 KWNS WOU1).
 
  PRECAUTIONARY/PREPAREDNESS ACTIONS...
 
  REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
  TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
  AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
  THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
  AND POSSIBLE WARNINGS.
 
  &&
 
  DISCUSSION...THUNDERSTORMS ARE BEGINNING TO INTENSIFY ALONG A WARM
  FRONT EXTENDING ROUGHLY FROM A LOW NEAR LIT TO NORTH OF MEM.  A
  MOIST AND MODERATELY UNSTABLE AIR MASS LIES TO THE SOUTH OF THE
  FRONT WITH DEWPOINTS IN THE MID 60S.  DEEP EFFECTIVE SHEAR AND
  SUFFICIENT LOW LEVEL SHEAR WILL POSE A RISK OF SUPERCELLS CAPABLE OF
  LARGE HAIL...DAMAGING WINDS...AND A FEW TORNADOES.
 
  AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
  SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
  WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
  450. MEAN STORM MOTION VECTOR 24035.