Jan 3, 2018 0600 UTC Day 1 Convective Outlook
Updated: Wed Jan 3 05:56:36 UTC 2018 (20180103 1200Z Day 1 shapefile | 20180103 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180103 1200 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
20180103 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
No Risk Areas Forecast
Probabilistic Damaging Wind Graphic
20180103 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
No Risk Areas Forecast
Probabilistic Large Hail Graphic
20180103 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
No Risk Areas Forecast
   SPC AC 030556

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1156 PM CST Tue Jan 02 2018

   Valid 031200Z - 041200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   A few thunderstorms are expected across the central and northern
   California coastal areas late this afternoon and evening.
   Other/ongoing showers and a couple of thunderstorms may persist
   early along a portion of the east Florida coast.

   ...Synopsis...
   Slow progression of the highly amplified upper flow field over the
   U.S. will continue today, with both the western ridge and eastern
   trough advancing gradually eastward.  Within the longer-wavelength
   flow, two faster-moving short-wave troughs are evident that will
   affect the convective forecast.  One, approaching the lower
   Mississippi Valley at this time, will sweep quickly east across the
   northern Gulf of Mexico and across the Florida peninsula during the
   afternoon.  A second -- moving northeast across the eastern Pacific,
   will affect the West Coast mainly during the second half of the
   period.  

   At the surface, a clipper-type front will cross the Great Lakes
   region, while low pressure develops early in the period off eastern
   Florida ahead of the upper trough.  With time, this low is forecast
   to move northward along the Gulf Stream and deepen rapidly. 
   Elsewhere across the U.S., high pressure will largely prevail.

   ...Coastal central California...
   Showers -- possibly with occasional/embedded lightning -- will
   approach, and then reach, portions of coastal central California by
   late afternoon, and then expand northward overnight, in conjunction
   with passage of the aforementioned upper trough.  

   ...Coastal eastern Florida...
   Showers -- and possibly a couple of thunderstorms, may affect
   portions of eastern Florida, mainly early in the period.  Greater
   coverage of convection should, however, remain offshore, with any
   inland threat likely ending by mid afternoon at the latest.

   ..Goss/Cook.. 01/03/2018

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