Oct 22, 2017 0600 UTC Day 1 Convective Outlook
Updated: Sun Oct 22 05:44:31 UTC 2017 (20171022 1200Z Day 1 shapefile | 20171022 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20171022 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 41,169 4,386,073 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Gulfport, MS...
Probabilistic Tornado Graphic
20171022 1200 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 41,258 4,387,295 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Gulfport, MS...
Probabilistic Damaging Wind Graphic
20171022 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 41,199 4,386,309 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Gulfport, MS...
Probabilistic Large Hail Graphic
20171022 1200 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 41,199 4,386,309 New Orleans, LA...Baton Rouge, LA...Mobile, AL...Metairie, LA...Gulfport, MS...
   SPC AC 220544

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1244 AM CDT Sun Oct 22 2017

   Valid 221200Z - 231200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE CENTRAL GULF COAST REGION...

   ...SUMMARY...
   A couple of marginally severe storms will be possible Sunday
   afternoon and evening near the central Gulf Coast.

   ...Synopsis...
   Upper ridging is forecast to prevail over the eastern U.S. through
   the period, though will be gradually shunted east by the steady
   advance of central U.S. troughing.  Meanwhile, flat/zonal flow
   initially expected over the West will gradually turn anticyclonic,
   as ridging amplifies upstream of the central U.S. trough.

   At the surface, a cold front is forecast to advance eastward across
   the Mississippi Valley during the day, and then continue across the
   Ohio and Tennessee Valleys/Central Gulf Coast states through the
   remainder of the period.

   ...Central Gulf Coast region...
   Showers and thunderstorms are forecast to be ongoing early in the
   period near and ahead of the advancing surface cold front, west of
   the lower Mississippi Valley area, while more isolated/pre-frontal
   convection is expected over portions of the MRGL risk area.  

   While generally weak lapse rates aloft will prevail across the
   region, a very moist low-level airmass will combine with some
   heating to support modest diurnal destabilization.  As the front
   crosses the lower Mississippi Valley through the late morning and
   early afternoon hours, the gradual increase in CAPE over the area
   should support an uptick in convective coverage and intensity.

   With weakly veering/increasing flow with height expected atop the
   region -- particularly as the front advances, a few severe storms
   may emerge from amidst the broader area of convective activity. 
   Risk for a locally stronger/damaging gust or two may evolve during
   the afternoon, and possibly some marginal hail and even a tornado
   with one or two of the strongest cells.  At this time however, it
   still appears that the weak lapse rates/limited CAPE expected should
   hinder overall degree and coverage of severe risk, warranting
   maintenance of MRGL risk level at this time.

   ..Goss.. 10/22/2017

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z