Oct 23, 2017 0730 UTC Day 3 Severe Thunderstorm Outlook
Updated: Mon Oct 23 06:50:01 UTC 2017 (20171023 0730Z Day 3 shapefile | 20171023 0730Z Day 3 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
0730 UTC Day 3 Outlook Graphic
Day 3 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 5,502 3,071,690 Boston, MA...Providence, RI...Brockton, MA...New Bedford, MA...Fall River, MA...
Probabilistic Graphic
20171023 0730 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 3 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 5,359 2,636,924 Providence, RI...Brockton, MA...New Bedford, MA...Fall River, MA...Plymouth, MA...
   SPC AC 230650

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0150 AM CDT Mon Oct 23 2017

   Valid 251200Z - 261200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEDNESDAY ACROSS
   EASTERN PORTIONS OF SOUTHERN NEW ENGLAND...

   ...SUMMARY...
   Thunderstorms may impact eastern portions of southern New England
   Wednesday, accompanied by at least some risk for potentially
   damaging wind gusts.

   ...Synopsis...
   Model output indicates increasing uncertainty concerning short wave
   developments within the larger-scale flow during this period.  In
   general, though, the pattern appears likely to remain amplified, but
   initial large-scale upper troughing over the East may slowly begin
   to lose some amplitude and accelerate northeast across the Atlantic
   Seaboard.  This is expected to occur as an upstream short wave
   trough begins to amplify southeastward across the central
   Canadian/U.S. border and northern Rockies.  A cold front associated
   with the remnant Eastern troughing may be in the process of
   advancing into New England, east of much of the mid and southern
   Atlantic coast, and through the southern Florida Peninsula, by 12Z
   Wednesday.  It is expected to advance east of the New England and
   southeast Florida coast by the end of the period.  In its wake,
   generally dry and stable conditions will prevail across much of the
   nation.

   ...New England...
   Within a narrow plume of seasonably moist air ahead of the cold
   front, an environment characterized by weak boundary layer
   instability and strong lower/mid tropospheric wind fields (40-60+ kt
   in the 850-500 mb layer) may still support a risk for convection
   capable of producing potentially damaging wind gusts across eastern
   portions of southern New England.  This could include the
   Boston/Providence area through midday, and the Cape Cod area through
   Wednesday afternoon.  Destabilization to support an appreciable risk
   for severe convective gusts remains more unclear farther to the
   north, across coastal/Downeast Maine.

   ..Kerr.. 10/23/2017

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z