Categorical Graphic 20200801 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 49,316 12,456,808 Columbus, OH…Washington, DC…Arlington, VA…Alexandria, VA…Columbia, MD…
MARGINAL 262,177 29,648,256 Baltimore, MD…El Paso, TX…Albuquerque, NM…Virginia Beach, VA…Raleigh, NC…
Probabilistic Tornado Graphic 20200801 2000 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 % 60,232 15,127,404 Columbus, OH…Washington, DC…Pittsburgh, PA…Arlington, VA…Alexandria, VA…
Probabilistic Damaging Wind Graphic 20200801 2000 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 % 49,316 12,456,808 Columbus, OH…Washington, DC…Arlington, VA…Alexandria, VA…Columbia, MD…
5 % 262,184 29,684,637 Baltimore, MD…El Paso, TX…Albuquerque, NM…Virginia Beach, VA…Raleigh, NC…
Probabilistic Large Hail Graphic 20200801 2000 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
5 % 37,270 1,252,399 Albuquerque, NM…Santa Fe, NM…Rio Rancho, NM…South Valley, NM…Alamogordo, NM…
   SPC AC 012000

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0300 PM CDT Sat Aug 01 2020

   Valid 012000Z - 021200Z

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

   ...SUMMARY...
   Scattered damaging winds and a brief tornado remain possible through
   this evening, centered on portions of the Upper Ohio Valley into the
   northern Virginia and western Maryland vicinity.

   ...20Z Update...
   The only substantial change was to expand the Slight Risk to include
   more of western MD into the DC metro area. Latest short-term
   guidance suggests that low-level shear should modestly strengthen
   later this afternoon into the evening across this region. Any storms
   that can remain sustained along/near a northward-moving warm front
   may be capable of producing damaging wind gusts and perhaps a
   tornado or two. For more information on the near-term severe threat
   across the upper OH Valley into the adjacent Appalachians, see
   recently issued Severe Thunderstorm Watch 409.

   ..Gleason.. 08/01/2020

   .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 01 2020/

   ...Ohio Valley east to central/northern Virginia...
   A surface low was located near the KY/IL border and should lift
   northward into western OH tonight. As a broad upper-level trough
   amplifies today, an increase in low/mid-level wind fields will
   result in shear profiles supportive of multicells and a couple
   supercells across the Ohio Valley and mid-Atlantic region. An
   increase in storm coverage/intensity is expected by early-mid
   afternoon across northern KY/southern OH vicinity along a nearly
   stationary front, while a second area of severe storms should
   develop over eastern WV/northern VA by late afternoon. Damaging
   winds will be the primary risk though a tornado or two cannot be
   ruled out, especially east of the surface low where low-level flow
   will be more favorable.

   A cluster of storms is also expected over eastern portions of NC/SC,
   aided in part by a remnant outflow boundary and strong instability. 
   Weak wind fields will limit storm organization, but wet downbursts
   capable of isolated strong wind gusts will be possible.  

   ...New Mexico/southeast Arizona/far West Texas...
   A belt of enhanced mid-level northerlies will lie across the 
   central/eastern portions of the area between upper-level high 
   centered over the Lower CO Valley and a trough near the MS Valley. 
   Buoyancy will be slightly lower compared to yesterday due to a drier
   boundary-layer. Nevertheless, weak MLCAPE should contribute to a
   couple updrafts with mid-level rotation off the Sangre de Cristo and
   Sacramento Mountains with a risk for isolated severe hail.
   Otherwise, the steep lapse rate environment will contribute to a
   risk for locally severe wind gusts with isolated to scattered storms
   that should peak in the late afternoon to early evening.

   ...East-central FL Coast...
   Hurricane Isaias continues moving steadily northwest toward the FL 
   Atlantic Coast. The more favorable shear profiles supportive of a
   risk of tornadoes should remain offshore through 12z Sunday.

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z