Dec 4, 2017 1300 UTC Day 1 Convective Outlook
Updated: Mon Dec 4 13:00:58 UTC 2017 (20171204 1300Z Day 1 shapefile | 20171204 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20171204 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 86,145 5,325,196 Little Rock, AR...Springfield, MO...Columbia, MO...Fort Smith, AR...Fayetteville, AR...
Probabilistic Tornado Graphic
20171204 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
2 % 44,136 2,696,356 Springfield, MO...Fort Smith, AR...Fayetteville, AR...Springdale, AR...Conway, AR...
Probabilistic Damaging Wind Graphic
20171204 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
5 % 86,145 5,325,196 Little Rock, AR...Springfield, MO...Columbia, MO...Fort Smith, AR...Fayetteville, AR...
Probabilistic Large Hail Graphic
20171204 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 041300

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0700 AM CST Mon Dec 04 2017

   Valid 041300Z - 051200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
   OKLAHOMA AND THE ARK-LA-TEX REGION INTO MISSOURI...

   ...SUMMARY...
   Isolated strong to severe thunderstorms are expected across eastern
   Oklahoma and the Ark-La-Tex region into Missouri late this afternoon
   and evening.

   ...Eastern OK/Ark-La-Tex to Middle Mississippi Valley...
   Strong mid-level height falls will spread across the central Plains
   toward the Upper Midwest through tonight with a 90+ kt mid-level jet
   translating across northern KS into IA/northeast MO by early
   evening. A surface low near the NE/IA border early this evening will
   deepen and progress northeastward, with rapid surface cyclogenesis
   particularly occurring tonight from the Upper Midwest into northern
   Ontario through early Tuesday.
    
   Ahead of a cold front (and pre-frontal trough across the
   south-central Plains), moisture characterized by upper 50s/lower 60s
   F surface dewpoints will continue to gradually spread
   north-northeastward through the day. Weak surface-rooted buoyancy
   will evolve along a pre-frontal corridor from eastern OK into MO and
   south-central IA by mid/late afternoon. While only several hundred
   J/kg SBCAPE is expected in most areas, strong large-scale forcing
   for ascent suggests convection will initiate and intensify along the
   surging cold front by mid/late afternoon. 

   The initial deeper convective development should occur across far
   eastern Oklahoma and southwest/central Missouri as early as late
   afternoon (roughly 21Z-23Z). Forecast soundings and large-scale
   forcing suggest thunderstorms will quickly develop into a squall
   line before advancing into central MO/western AR. Convection is
   expected to weaken farther east due to limited buoyancy and cooling
   boundary layer. Damaging winds are the primary threat although at
   least some tornado risk may exist as well given adequate moisture
   and strong low-level shear/SRH. Portions of the region will be
   reevaluated in subsequent outlooks for the possibility of a
   categorical Slight risk pending destabilization trends.

   ...Upper Midwest...
   A couple of stronger storms could materialize late this afternoon
   and evening across parts of Wisconsin and/or western Upper Michigan
   in conjunction with the steadily approaching/deepening cyclone and
   cold front. Steepening mid-level lapse rates and modest elevated
   buoyancy could support the possibility of at least some small hail
   and/or thunderstorm-enhanced wind gusts, although the potential for
   severe-caliber storms currently appears low.

   ..Guyer/Dial.. 12/04/2017

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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