NOAA Storm Prediction Center
Convective Outlooks
Convective Outlooks
The convective outlooks serve as guidance to the local NWS forecast offices and are used by emergency managers, private sector meteorologists, media, and other weather customers concerned with public safety. Three separate risk areas (slight, moderate, and high) are used to describe the expected coverage and intensity for the categorical severe weather threat on days 1-3 along with severe weather probabilities for the potential threat.
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Categorical Day1 1200Z Outlook
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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.
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Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.
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Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point.
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Images courtesy of the NWS Storm Prediction Center
000
ACUS01 KWNS 060533
SWODY1
SPC AC 060532
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1232 AM CDT Thu Aug 06 2020
Valid 061200Z - 071200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE PLAINS...SOUTHEAST...AND MIDDLE ATLANTIC...
...SUMMARY...
Isolated, strong to potentially severe, storms are possible from
Montana to the southern Plains. Localized damaging gusts may also
occur across parts of the Southeast and Middle Atlantic.
...Plains...
Upper ridging is forecast to dominate the High Plains from the
western Dakotas to northwest TX. Due to large-scale ridging,
weak-negligible forcing for ascent will be noted across this region
through the period. As a result, strong diurnal heating will prove
instrumental in convective development along a lee trough, just east
of the higher terrain. One exception will be across western MT where
deep-layer flow is forecast to increase ahead of a notable
short-wave trough that will advance into the northern Rockies by
early evening. Leading edge of this feature should encourage
high-based convection along/ahead of a surface front as it
progresses east of the mountains. Forecast soundings ahead of the
front suggest organized multi-cell updrafts are possible, and the
primary threat should be gusty winds.
Farther south, isolated high-based storms will once again develop
across eastern WY/CO. Some of this activity could be maintained well
into the overnight hours as it advances east due to expected
increase in nocturnal LLJ.
Latest model guidance suggests a corridor of somewhat stronger
mid-level flow will arc along the NM/CO border into northern OK
where 500mb flow is forecast to approach 30kt. A weak surface
boundary will advance slowly north across OK during the day with
strong boundary-layer heating expected to allow surface temperatures
to warm well into the mid 90s south of the wind shift. While
significant upper support will be lacking, convective temperatures
may be breached along this wind shift where wind profiles would
favor multi-cell updrafts, and perhaps weak supercells. Have opted
to extend low severe probs east across OK to account for this
scenario, though it's not entirely clear how much convection will
actually develop along the boundary.
...Southeast/Middle Atlantic...
Weak upper trough will translate into the OH/TN Valley region later
today. 20kt southwesterly 500mb flow will extend downstream across
the southern Appalachians into the southern Middle Atlantic where
forecast buoyancy should be adequate for robust convection. Gusty
winds are the primary threat with the strong storms.
..Darrow/Wendt.. 08/06/2020
$$
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