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.
SPC AC 010530
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 AM CDT Sat Aug 01 2020
Valid 011200Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE OHIO VALLEY INTO NORTHWEST VIRGINIA...
...SUMMARY...
Strong thunderstorms are possible later today from parts of the Ohio
and Tennessee Valleys to the Mid Atlantic. The primary threat is
damaging wind gusts. A few gusty storms may also be noted across the
southern Rockies.
...OH/TN Valley to Mid Atlantic...
Large-scale height fields are not expected to change appreciably
during the day1 period; although, a short-wave trough will advance
slowly east across the OH/TN Valley period during the over night
hours. In advance of the short wave, a weak surface low is forecast
to track along the OH River from western KY into southwest OH by
early evening. This feature will aid low-level convergence necessary
for potentially robust convection. Latest model guidance suggests
30-35kt of 500mb flow will translate across middle TN into WV by
peak heating. 850mb flow is also expected to increase along this
corridor which will enhance wind profiles for potential storm
organization. Models are not too aggressive destabilizing this
region but some surface heating is expected south of a weak warm
front as it advances north, ultimately draping itself across central
OH-northern WV-northern VA by 02/00z. This warm-frontal corridor may
locally enhance the prospect for a few supercells, and perhaps one
or two tornadoes. Otherwise, damaging winds could accompany
scattered thunderstorms that develop across this region. Convective
temperatures should be breached fairly early (between 17-19z) and
subsequent storm mergers and multi-cell clusters appear possible, in
addition to a few supercells.
...Southern Rockies...
Upper ridge is forecast to hold across the western US today with
somewhat stronger mid-level flow expected across the Rockies from WY
into NM along the front side of the ridge. Strong surface heating
will once again prove instrumental in convective development over
the higher terrain. The most likely area for strong convection
should be across the southern Rockies where PW-values should be on
the order of 1-1.25 inches. Gusty winds are the primary threat.
...Hurricane Isaias...
Hurricane Isaias continues moving steadily northwest toward the FL
Atlantic Coast. 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
changes, the tornado threat over land should remain too low to
warrant severe probs.
..Darrow/Wendt.. 08/01/2020
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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