Editing Storm Prediction Center (section)

==Mesoscale discussions==
SPC mesoscale discussions (MDs) once covered [[Atmospheric convection|convection]] (mesoscale convective discussions [MCDs]) and [[precipitation]] (mesoscale precipitation discussions [MPDs]); MPDs are now issued by the [[Weather Prediction Center]] (WPC). MCDs generally precede the issuance of a tornado or severe thunderstorm watch, by one to three hours when possible.<ref name="mesoscale discussions"/> Mesoscale discussions are designed to give local forecasters an update on a region where a severe weather threat is emerging and an indication of whether a watch is likely and details thereof, as well as situations of isolated severe weather when watches are not necessary.<ref name="mesoscale discussions"/> MCDs contain meteorological information on what is happening and what is expected to occur in the next few hours, and forecast reasoning in regard to weather watches.<ref name="mesoscale discussions"/> Mesoscale discussions are often issued to update information on watches already in effect, and sometimes when one is to be canceled. Mesoscale discussions are occasionally used as advance notice of a categorical upgrade of a scheduled convective outlook.<ref name="mesoscale discussions"/>

===Example===
[[File:2025MCD0217.png|thumb|Graphic associated with the example mesoscale discussion]]{{Quote box
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<pre>

   Mesoscale Discussion 0217
   NWS Storm Prediction Center Norman OK
   0900 PM CDT Sat Mar 15 2025

   Areas affected...much of central Alabama

   Concerning...Tornado Watch 49...

   Valid 160200Z - 160400Z

   The severe weather threat for Tornado Watch 49 continues.

   SUMMARY...The risk of strong tornadoes persists over watch area,
   especially over central Alabama.

   DISCUSSION...In the wake of tornadic storms which went across the
   BMX radar, a residual region of outflow remains across parts of
   Shelby, Talladega, Chilton and Coosa counties. Meanwhile, a very
   large complex of storms is coming up from the southwest. Very strong
   inflow winds exist ahead of this complex, which will continue to
   feed these storms and possibly enhance lift along the residual
   outflow from the earlier storms. Given over 400 m2/s2 0-1 SRH, it is
   possible that any interaction with the boundary could result in a
   strong tornado.

   The environment remains favorable extending farther south as well,
   where a north-south confluence line is noted ahead of the primary
   cold front, and including the Wilcox County cell.

   ..Jewell.. 03/16/2025

</pre>
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=== Meso-gamma mesoscale discussion ===
{{see also|List of Storm Prediction Center meso-gamma mesoscale discussions}}
SPC mesoscale discussions for a high-impact and high-confidence strong tornadoes (EF2+) or winds greater than {{convert|100|mph|km/h}} are called meso-gamma mesoscale discussions.<ref>{{cite web |last1=Lyons |first1=Andrew |title=They are called meso-gamma mcds and we do them for high impact high confidence violent tornadoes. |url=https://twitter.com/TwisterKidMedia/status/1567166503153278976 |website=Twitter |publisher=TwisterKidMedia (SPC Forecaster) |access-date=7 September 2022}}</ref><ref>{{cite web |last1=Lyons |first1=Andrew |title=Yes that's a meso-gamma mcd. They are primarily designed to deliver targeted mesoanalysis information to warning forecasters for high impact severe weather phenomenon. Ie. strong long-track tornadoes and in some cases extreme damaging winds greater than 100 mph. |url=https://twitter.com/TwisterKidMedia/status/1679651029267169281 |website=Twitter |publisher=@TwisterKidMedia |access-date=14 July 2023 |archive-url=https://web.archive.org/web/20230714011424/https://twitter.com/TwisterKidMedia/status/1679651029267169281 |archive-date=14 July 2023 |url-status=live}}</ref> Meso-gamma mesoscale discussions are rarely issued by the SPC. {{As of|2025|March}}, the Storm Prediction Center has issued 44 meso-gamma mesoscale discussions.