Jul 21, 2019 1730 UTC Day 2 Convective Outlook
Updated: Sun Jul 21 17:25:44 UTC 2019 (20190721 1730Z Day 2 shapefile | 20190721 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190721 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 16,131 16,690,418 Philadelphia, PA...Baltimore, MD...Toms River, NJ...Edison, NJ...Columbia, MD...
MARGINAL 194,601 43,957,684 New York, NY...Memphis, TN...Washington, DC...Nashville, TN...Virginia Beach, VA...
Probabilistic Graphic
20190721 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
15 % 15,843 16,400,350 Philadelphia, PA...Baltimore, MD...Toms River, NJ...Edison, NJ...Columbia, MD...
5 % 195,411 44,433,763 New York, NY...Memphis, TN...Washington, DC...Nashville, TN...Virginia Beach, VA...
   SPC AC 211725

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1225 PM CDT Sun Jul 21 2019

   Valid 221200Z - 231200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE MID-ATLANTIC...

   ...SUMMARY...
   Thunderstorms associated with a wind damage threat will be possible
   on Monday across parts of the Mid-Atlantic. A few marginally severe
   wind gusts are also possible from the mid Mississippi Valley into
   the central Appalachians.

   ...Central Appalachians/Mid-Atlantic...
   An upper-level trough will move across the Great Lakes region on
   Monday as west-southwesterly mid-level flow remains over the
   Mid-Atlantic states. At the surface, a cold front will advance
   southward across the central Appalachians with a moist airmass in
   place south of the front. Surface dewpoints should be in the lower
   70s F will contribute to the development of moderate instability
   ahead of the front by late morning. Convection is first expected to
   initiate in the higher terrain of the central Appalachians around
   midday. Other storms should develop during the afternoon eastward
   along the front across the Atlantic Coastal Plains. NAM forecast
   soundings along this part of the front at 21Z on Monday have 0-6 km
   shear in the 40 to 50 kt range and show very steep low-level lapse
   rates suggesting severe storms will be possible. The problem is that
   the overlap between the strongest instability and deep-layer shear
   is forecast be narrow. Cells that initiate right along the front and
   move parallel to the boundary may have potential for damaging wind
   gusts and hail. Although the threat area is small, the models are in
   reasonable agreement and enough potential exists in the Mid-Atlantic
   to add a small slight risk area from northern Maryland into New
   Jersey. The slight risk is oriented along the forecast position of
   the front during the afternoon.

   ...Mid Mississippi and Ohio Valleys...
   An upper-level trough will move eastward across the Great Lakes and
   mid Mississippi Valley on Monday. At the surface, a cold front is
   forecast to advance southward into Arkansas, far southeast Missouri
   and Kentucky. Ahead of the front, surface dewpoints in the upper 60s
   and lower 70s F should result a corridor of instability by midday.
   As surface temperatures warm and low-level convergence increases
   along the front, scattered thunderstorms appear likely to develop
   during the afternoon. Although deep-layer shear should be relatively
   weak, steep low-level lapse rates should be enough for marginally
   severe wind gusts. The potential should be greatest with cells
   develop within the strongest instability.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   2%     - Marginal
   Wind:     15%     - Slight
   Hail:      5%     - Marginal

   ..Broyles.. 07/21/2019

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z