Aug 1, 2020 1300 UTC Day 1 Convective Outlook
Updated: Sat Aug 1 12:44:20 UTC 2020 (20200801 1300Z Day 1 shapefile | 20200801 1300Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20200801 1300 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 52,366 9,198,344 Columbus, OH...Centreville, VA...Dale City, VA...Reston, VA...Burke, VA...
MARGINAL 255,264 31,895,568 Baltimore, MD...El Paso, TX...Washington, DC...Albuquerque, NM...Virginia Beach, VA...
Probabilistic Tornado Graphic
20200801 1300 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 % 53,402 11,638,846 Columbus, OH...Washington, DC...Pittsburgh, PA...Arlington, VA...Alexandria, VA...
Probabilistic Damaging Wind Graphic
20200801 1300 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 % 52,366 9,198,344 Columbus, OH...Centreville, VA...Dale City, VA...Reston, VA...Burke, VA...
5 % 254,921 31,842,655 Baltimore, MD...El Paso, TX...Washington, DC...Albuquerque, NM...Virginia Beach, VA...
Probabilistic Large Hail Graphic
20200801 1300 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 % 37,413 1,252,968 Albuquerque, NM...Santa Fe, NM...Rio Rancho, NM...South Valley, NM...Alamogordo, NM...
   SPC AC 011244

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0744 AM CDT Sat Aug 01 2020

   Valid 011300Z - 021200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS UPPER OH VALLEY TO
   NORTHERN VA...

   ...SUMMARY...
   Scattered damaging winds and a brief tornado are possible, centered
   on portions of the Upper Ohio Valley into northern Virginia from
   mid-afternoon through this evening.

   ...OH Valley to western/northern VA...
   A broad mid-level trough over the Mid-MS Valley will slowly move
   northeast across parts of the Midwest through early Sunday.
   Attendant 1008-mb surface cyclone near the confluence of the MS/OH
   rivers will evolve northeast, reaching western OH tonight. A broad
   belt of 30-40 kt 700-mb southwesterlies should shift from the Deep
   South and TN Valley northeast towards the central and southern
   Appalachians. 

   Scattered thunderstorm development is expected this afternoon near
   and well east of the surface cyclone across the OH Valley, and
   within a separate corridor off the central Appalachians/Blue Ridge
   in western/northern VA and the eastern WV Panhandle. Although
   mid-level lapse rates will remain poor (well sampled by regional 12Z
   soundings), surface dew points around 70 should support modest
   buoyancy with MLCAPE increasing to 500-1500 J/kg. Along the northern
   periphery of the amplifying 850-700 mb flow regime, several small
   clusters and a few transient supercells may develop to the northeast
   with a primary risk of scattered damaging winds. A brief tornado is
   possible as well, mainly during the evening when low-level shear
   increases.

   ...NM...
   A belt of enhanced mid-level northerlies will lie across the
   central/eastern portions of the state between an anticyclone
   centered over the Lower CO Valley and a trough near the MS Valley.
   While buoyancy is not expected to be as robust as yesterday, owing
   to a drier boundary-layer, 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 foster a
   predominant 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...
   T.C. Isaias continues moving steadily northwest toward the FL
   Atlantic Coast. The eastern hemisphere of this tropical system is
   forecast to remain offshore through the period, along with the more
   favorable shear for potential tornadoes. Unless the track of Isaias
   shifts farther west, the tornado threat over land should remain too
   low to warrant probabilities.

   ..Grams/Jewell.. 08/01/2020

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