Aug 20, 2018 0600 UTC Day 2 Convective Outlook
Updated: Mon Aug 20 05:55:22 UTC 2018 (20180820 0600Z Day 2 shapefile | 20180820 0600Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20180820 0600 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 64,974 13,703,475 Washington, DC...Pittsburgh, PA...Richmond, VA...Arlington, VA...Alexandria, VA...
MARGINAL 211,309 30,352,698 Baltimore, MD...Charlotte, NC...Cleveland, OH...Virginia Beach, VA...Colorado Springs, CO...
Probabilistic Graphic
20180820 0600 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 % 64,974 13,703,475 Washington, DC...Pittsburgh, PA...Richmond, VA...Arlington, VA...Alexandria, VA...
5 % 211,508 30,360,077 Baltimore, MD...Charlotte, NC...Cleveland, OH...Virginia Beach, VA...Colorado Springs, CO...
   SPC AC 200555

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1255 AM CDT Mon Aug 20 2018

   Valid 211200Z - 221200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
   NORTH-CENTRAL APPALACHIANS/MID-ATLANTIC STATES AND THE SOUTH-CENTRAL
   HIGH PLAINS...

   ...SUMMARY...
   Severe thunderstorms will be possible on Tuesday, especially during
   the afternoon and evening across portions of the
   Appalachians/Mid-Atlantic States as well as the south-central High
   Plains.

   ...Appalachians/Upper Ohio River Valley and Mid-Atlantic States...
   Although the primary surface cyclogenesis will be focused north of
   the International border, a semi-amplified belt of seasonally
   strong/cyclonically curved westerlies will overspread much of the
   region on Tuesday coincident with an eastward-moving cold front.
   Relatively widespread early-day convection and lingering cloud cover
   limits confidence in appreciable destabilization and may somewhat
   curb the overall magnitude of Tuesday's severe risk.

   However, relatively strong low-level shear and upwards of 35-40 kt
   effective shear suggests the potential for sustained multicells and
   some supercells where adequate (even modest) diurnally enhanced
   destabilization occurs Tuesday afternoon. This currently appears
   most probable across far eastern Ohio/western Pennsylvania southward
   into parts of Maryland/Virginia. Elsewhere, at least isolated severe
   storms may occur as far south as the Carolinas/southern Appalachians
   under a more modestly strong flow regime.

   ...South-Central High Plains...
   Moist low-level upslope flow will be focused on Tuesday to the north
   of a southern High Plains surface low. This will be in  conjunction
   with a moderately strong (25-30 kt at 500 mb) belt of westerlies to
   the north of the southern High Plains-centered upper-level ridge.
   While initial storm development Tuesday afternoon is expected over
   the Front Range/foothills vicinities, it appears a sub-regional area
   of more favorable deep-layer shear and buoyancy coincident with
   probable storm development will exist across far southeast Colorado
   and neighboring areas including far southwest Kansas and the western
   Oklahoma Panhandle. Both severe-caliber wind gusts and hail will be
   possible across the region.

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

   ..Guyer.. 08/20/2018

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z