Oct 17, 2019 1300 UTC Day 1 Convective Outlook
Updated: Thu Oct 17 12:49:44 UTC 2019 (20191017 1300Z Day 1 shapefile | 20191017 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20191017 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Tornado Graphic
20191017 1300 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
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20191017 1300 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
No Risk Areas Forecast
Probabilistic Large Hail Graphic
20191017 1300 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
No Risk Areas Forecast
   SPC AC 171249

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0749 AM CDT Thu Oct 17 2019

   Valid 171300Z - 181200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   Potential for organized severe thunderstorms will be minimal across
   the contiguous United States today.

   ...Synopsis/Discussion...
   The synoptic-scale, upper-air pattern this period will be
   progressive and fairly high-amplitude.  As the deep cyclone now
   centered over western New England moves slowly northeastward toward
   the Gulf of St. Lawrence, a series of variably amplified shortwaves
   will traverse the northwest flow across the Appalachians and help to
   maintain troughing near the East Coast.  Meanwhile, the upstream
   ridge -- now extending from eastern NM across the Dakotas -- will
   shift eastward across the mid/upper Mississippi Valley.  To its
   south, a currently cut-off, small cyclone is evident in moisture-
   channel imagery over west TX between DRT-MAF.  This should devolve
   into an open-wave trough and move east-southeastward across the TX
   coast by 12Z.

   Those processes will occur as heights fall across much of the West
   in association with a series of Pacific shortwave troughs.  The
   first of these -- currently located over the inland Northwest from
   central WA to central CA -- will eject northeastward across the
   northern Rockies.  Another perturbation will dig southeastward from
   offshore OR to the Sierra by 00Z, reaching portions of UT/AZ by 12Z.
   Cold air aloft and marginal midlevel moisture, amidst falling
   heights, will support isolated thunder across parts of the central
   Intermountain region this evening and tonight.  Another shortwave
   trough -- now located south of the Gulf of AK -- will move east-
   southeastward across the southern BC and WA coastlines around 06Z. 
   The latter feature may result in enough cooling aloft, prior to the
   onset of low-level cold advection, to support relatively maximized
   (but still isolated) thunder potential over parts of western WA/OR
   this afternoon.

   At the surface, the 11Z analysis showed a deeply occluded cyclone
   centered near the MA/NH line, with occluded front arching across the
   Gulf of Maine to open Atlantic waters.  The associated cold front
   trailed southwestward to central FL and the north-central Gulf,
   becoming quasistationary over the northwestern Gulf off the middle/
   lower TX and northeastern MX coasts.  The front should move slowly
   southward over the north-central/northeastern Gulf and FL today,
   becoming quasistationary by evening near Lake Okeechobee.  A few
   thunderstorms are possible along and south of the front, especially
   near the southeastern FL coastal sea breeze.  Given the rich low-
   level moisture content, 2000-2500 J/kg preconvective MLCAPE, and a
   shallow but well-mixed boundary layer, isolated strong/briefly
   damaging gusts cannot be ruled out in heavily water-loaded
   downdrafts.  However, the severe potential appears too isolated and
   conditional to warrant a categorical outlook area at this time.

   ..Edwards.. 10/17/2019

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z