Columbus, OH...Oklahoma City, OK...Kansas City, MO...Tulsa, OK...Cincinnati, OH...
Probabilistic Damaging Wind 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.
Oklahoma City, OK...Kansas City, MO...Tulsa, OK...Wichita, KS...Overland Park, KS...
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SPC AC 191959
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 PM CDT Fri May 19 2017
Valid 192000Z - 201200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
NORTH TEXAS AND SOUTHERN OKLAHOMA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
SOUTHERN PLAINS TO THE MID MISSISSIPPI VALLEY...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE OHIO VALLEY...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
TEXAS TO SOUTHERN NEW ENGLAND...
Severe thunderstorms are possible this afternoon into tonight across
parts of the central and southern Plains through portions of the
Ozark Plateau and middle Mississippi Valley. Particularly across
parts of northern Texas into southeastern Oklahoma, some of these
may be accompanied by large hail, damaging wind gusts and a couple
...Portions of the southern Plains...
No significant changes are made to the ongoing risk areas. A
somewhat nebulous convective evolution lends some uncertainty
regarding the severe potential this afternoon and evening.
Nonetheless, surface heating and dew points in the upper 60s/lower
70s are maintaining moderate surface-based buoyancy across portions
of north Texas into southeast Oklahoma. Across this area, large hail
(with an isolated report over 2 inches in diameter), damaging winds,
and a couple tornadoes remain possible. Farther north into central
Oklahoma, while air mass recovery has been stunted by convection to
the south, storms developing over northwest Texas will potentially
push east/northeast and pose a threat of large hail.
...Portions of the Ohio Valley...
The Slight Risk is expanded farther east, as a stationary front
focuses convection along/ahead of a larger-scale complex progressing
east. Mixed-layer CAPE around 500-1500 J/kg and sufficient westerly
flow aloft will support a few damaging wind gusts. A tornado may be
possible as well in the vicinity of the front, where storm-relative
helicity may be slightly enhanced.
.PREV DISCUSSION... /ISSUED 1115 AM CDT Fri May 19 2017/
Within the southern branch of split westerlies emanating from the
mid-latitude Pacific, models continue to indicate that large-scale
troughing will gradually redevelop northeastward out of the
Intermountain West and Rockies into the Plains, with an embedded
closed low migrating out of the Colorado Rockies into the central
Plains. At the same time, a significant upper trough within the
northern branch appears likely to dig across the Canadian Maritimes
and New England. In between, mid/upper ridging is forecast to build
north and east of the middle Mississippi Valley through the Great
Lakes and Mid Atlantic region.
In lower-levels, a significant surface cold front associated with
the northern branch trough has advanced into the Northeast, Ohio and
middle Mississippi Valleys, and central/southern Plains. While this
front is stalling across the central Plains into the Ohio Valley, it
is expected to advance across the remainder of New England and
northern Mid Atlantic Coastal areas by late tonight. Across the
Plains, in response to forcing associated with the southern branch
impulse, modest surface frontal cyclogenesis appears possible later
today into tonight, from parts of western Oklahoma through the
middle/lower Missouri Valley.
...Central and southern Plains into middle Mississippi Valley...
The ongoing southward frontal surge across the Texas Panhandle and
south Plains, the presence of significant outflow from prior
convection across the Ozark Plateau into the Red River area,
southward into northwest Texas, and the presence of considerable
ongoing storm development above/to the cool side of this outflow
across northwest Texas into Oklahoma, all are adding uncertainty to
severe weather potential for today into tonight.
Ongoing storms across northwest Texas appear to be supported by warm
advection on the northern periphery of a plume of warmer and more
strongly capping elevated mixed layer air. Little further
northeastward advection of this air mass may occur, and this may
remain the focus for the primary thunderstorm development through
the remainder of this period, as a short wave impulse pivots
northeast of the southern Rockies.
The eventual upscale growth of a large mesoscale convective system
appears possible this afternoon and evening across northern Texas
into southeastern Oklahoma. In the presence of thermodynamic
profiles characterized by steep mid-level lapse rates and moderately
large CAPE, large hail and damaging wind gusts are expected. Deep
layer and low-level shear may remain sufficient to support a risk
for tornadoes, particularly with any initial discrete supercell
development, and possible continuing supercell development near or
just ahead of the evolving convective system.
Farther north, into the central Plains, potential for significant
destabilization is becoming more unclear, but the developing frontal
wave may provide another focus for strong/severe storm development
late this afternoon and evening. If sufficient destabilization can
occur, deep layer wind fields and shear probably will become
supportive of organized storm development, including supercells.
...Ohio Valley into Mid Atlantic and New England...
Low severe probabilities have been extended northward into parts of
southern New England, where the pre-frontal environment now appears
at least conditionally supportive of storms capable of producing
Farther south and west, into the Mid Atlantic and Ohio Valley, more
uncertainty exists concerning severe storm potential, in the
presence of rising mid-level heights beneath the building upper
ridge. However, it appears at least possible that forcing
associated with a remnant convectively enhanced impulse, could
support and enhance thunderstorm development near the stalling front
across the middle Ohio Valley region this afternoon.
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