Nov 9, 2017 1730 UTC Day 2 Convective Outlook
Updated: Thu Nov 9 16:50:20 UTC 2017 (20171109 1730Z Day 2 shapefile | 20171109 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20171109 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
Probabilistic Graphic
20171109 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 2 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 091650

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1050 AM CST Thu Nov 09 2017

   Valid 101200Z - 111200Z


   The risk for severe thunderstorms appears negligible across the
   U.S., Friday through Friday night.

   At mid levels, subtropical ridging may become at least a bit more
   prominent during this period, along an east-west axis across the
   Baja of California through the Florida Peninsula/Bahamas and
   Caribbean.  Otherwise, much of the remainder of North America is
   expected to remain under the influence of split mid-latitude
   westerlies, which are forecast to remain generally zonal across and
   inland of the Pacific Coast, through the western Atlantic.  

   Within this regime, models indicate that one vigorous short wave
   trough (now digging across and east of the upper Great Lakes region)
   will accelerate eastward across Quebec and the Northeast, into the
   Canadian Maritimes, during this period.  In its wake, an expansive
   area of cold surface ridging is forecast to develop across a large
   portion of the central and eastern U.S., although its center may
   rapidly shift eastward from the Upper Midwest, at 12Z Friday,
   through the lower Great Lakes/upper Ohio Valley/Mid Atlantic by 12Z

   At the same time, it appears that a significant short wave trough
   and embedded closed low (now near/west of the Pacific Northwest)
   will lose considerable amplitude while accelerating inland across
   the northern Great Basin, as another upstream wave
   develops/amplifies southeastward across the Gulf of Alaska and
   northeast Pacific.

   In response to the developing eastern U.S. surface ridging, near
   surface winds are forecast to turn to northerly/northeasterly across
   much of the Florida Peninsula and Keys by the beginning of the
   period.  Although it appears that the boundary layer will remain
   fairly moist across much of the eastern and southern portions of the
   peninsula, forecast soundings indicate that relatively warm and dry
   air at mid/upper levels will tend to suppress any attempts at
   convective development in response to surface heating.  Coupled with
   little readily apparent mid/upper support for large-scale ascent,
   the risk for thunderstorms near southeast coastal areas now appears

   ...Pacific Northwest...
   Before the upper impulse accelerates into the northern Great Basin,
   it still appears possible that destabilization beneath its modest
   associated mid-level cold core could support isolated/short-lived
   thunderstorm activity.  While this potential seems maximized
   near/west of the Oregon Cascades early Friday, an area of enhanced
   mid-level forcing for ascent overspreading the mountains of
   northeastern Oregon could provide an additional focus for weak
   thunderstorm activity late Friday morning into Friday afternoon.

   ..Kerr.. 11/09/2017