Shreveport, LA...Waco, TX...Killeen, TX...Wichita Falls, TX...College Station, TX...
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...New Orleans, LA...Tulsa, OK...Wichita, KS...Baton Rouge, LA...
SPC AC 181656
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1156 AM CDT Sun Mar 18 2018
Valid 181630Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
SOUTHERN PLAINS TO THE SOUTHEAST STATES...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
CENTRAL/SOUTHERN PLAINS TO THE SOUTHEAST STATES...
Thunderstorms with large hail and a tornado risk are possible
especially across North and East Texas late this afternoon into
evening, with additional severe thunderstorms possible across other
parts of the south-central Plains to Southeast States.
...North/East Texas and far Southern Oklahoma to ArkLaTex...
The potential exists for locally intense storm development later
this afternoon/early evening, but a number of questions remain
regarding the likelihood and locations/coverage of deep convective
development. Along these lines, various convection-allowing models
have shown semi-dramatic sub-regional spatial shifts between 00Z and
12Z of preferred severe corridors later today, while various HRRR
runs have also exhibited considerable run-to-run variability
(supercells vs. essentially no development) this morning.
Scattered showers and some thunderstorms along with multi-layer
cloud cover remain prevalent across the region at midday, related to
east/northeastward-transitioning southern-stream forcing for ascent
embedded with a strong (100+ kt at 250 mb) subtropical jet stream.
In the wake of this scattered precipitation/thicker clouds, cloud
breaks and some additional low-level moist influx should allow for
relatively rapid destabilization especially across
north-central/east-central Texas to the near/east of a dryline and
along/south of an east/southeastward-extending front.
But given some hindered heating through early afternoon and the
early timing of the aforementioned southern-stream impulse, the
likelihood and extent of deep convective development later today
remains questionable, particularly given that areas such as
north-central Texas may be influenced by subsidence aloft during
peak heating. Accordingly, the overall scenario seemingly remains
largely conditional, with the notion that any sustained
surface-rooted development could evolve into supercells capable of
very large hail and some tornado risk in the presence of steep
mid-level lapse rates, moderate buoyancy, and favorable hodographs
for large diameter (potentially significant 2+ inch) hail.
Further outlook refinements/adjustments can be expected with the 20Z
...Lower Mississippi Valley to Southeast States...
A weak impulse or two (and/or MCV) should semi-focus thunderstorm
clusters across the region today, such as is occurring across
southern Mississippi at midday. While buoyancy will not be overly
strong, 40+ kt effective shear could support some bowing segments
and possibly even a transient supercell or two. Damaging winds and
possibly some hail should be the primary concerns.
...Portions of Texas Panhandle/western Oklahoma into Kansas...
At least some severe-weather potential should exist later this
afternoon through early evening with anticipated low-topped storm
development across the region. Very limited moisture will exist
within/north of a narrowing warm sector, but steep lapse rates and
moderately strong wind profiles could support some strong to severe
storms across the Texas Panhandle/northwest Oklahoma northeastward
into southern Kansas.
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z