Sep 25, 2022 0600 UTC Day 1 Convective Outlook
Updated: Sun Sep 25 05:05:00 UTC 2022 (20220925 1200Z Day 1 shapefile | 20220925 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20220925 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 57,322 41,803,975 New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Newark, NJ...
MARGINAL 128,478 24,479,897 Boston, MA...Pittsburgh, PA...Richmond, VA...Providence, RI...Worcester, MA...
Probabilistic Tornado Graphic
20220925 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
2 % 74,423 51,720,121 New York, NY...Philadelphia, PA...Baltimore, MD...Boston, MA...Washington, DC...
Probabilistic Damaging Wind Graphic
20220925 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
15 % 58,496 41,993,522 New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Newark, NJ...
5 % 128,405 24,504,105 Boston, MA...Pittsburgh, PA...Richmond, VA...Providence, RI...Worcester, MA...
Probabilistic Large Hail Graphic
20220925 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
15 % 57,404 41,946,324 New York, NY...Philadelphia, PA...Baltimore, MD...Washington, DC...Newark, NJ...
5 % 125,259 21,303,755 Pittsburgh, PA...Richmond, VA...Providence, RI...Worcester, MA...Knoxville, TN...
   SPC AC 250505

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1205 AM CDT Sun Sep 25 2022

   Valid 251200Z - 261200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE NORTHERN
   APPALACHIANS INTO PARTS OF THE MID ATLANTIC AND SOUTHERN NEW
   ENGLAND...

   ...SUMMARY...
   Scattered severe storms producing large hail and damaging winds are
   expected from mid to late afternoon across the northern Appalachians
   and parts of the Mid Atlantic and southern New England through
   evening.

   ...Portions of the Appalachians, Mid Atlantic and southern New
   England...
   Within a larger-scale upper trough, a lead wave will move from the
   OH Valley to the Mid Atlantic during the day, providing cooling
   aloft and midlevel winds of 60-70 kt, enhancing shear. At the
   surface, low pressure will slowly deepen from Lake Huron into NY,
   with a front trailing southwestward across PA, WV, eastern KY and
   Middle TN by late afternoon. Meanwhile, a warm front will develop
   over southern New England, resulting in destabilization toward
   evening. Dewpoints will rise into the lower 60s F there, with upper
   50s to lower 60s F southwestward along the front where heating and
   mixing will be stronger.

   The warm sector will become uncapped by around 18Z from PA southward
   across WV, VA, KY and TN, with further destabilization 21-00Z from
   NJ into southern New England. MLCAPE of 1000 J/kg will be common,
   with locally higher values. Deep-layer shear will be strong beneath
   the upper jet, with values around 60 kt common from eastern TN to
   the DelMarVa.

   Precipitation may be ongoing from OH into PA and western NY early in
   the day, north of the midlevel jet where temperatures aloft will be
   cold, and as warm advection around 850 mb translates east. Given
   cold temperatures aloft, some of this activity could produce small
   hail. As the air mass destabilizes beneath the cold air aloft, some
   of these storms may expand and become severe across PA and NJ during
   the afternoon, producing hail and wind. Later in the evening,
   additional storms may interact with the warm front where low-level
   shear will be stronger, and a brief/weak tornado could occur,
   depending on whether surface temperatures are warm enough for
   surface-based parcels.

   Farther south, southwest winds will maintain a moist air mass along
   the Appalachian Front, and heating will aid development after 18Z.
   Long, straight hodographs should favor fast-moving storms producing
   hail and wind. Additional isolated activity may occur into northern
   GA and AL along the front, primarily late afternoon and evening.

   ..Jewell/Wendt.. 09/25/2022

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