Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 050722
SPC MCD 050722

Mesoscale Discussion 1783
NWS Storm Prediction Center Norman OK
0122 AM CST Tue Dec 05 2017

Areas affected...Portions of far eastern Texas...central/northern

Concerning...Severe potential...Watch unlikely

Valid 050722Z - 050845Z

Probability of Watch Issuance...5 percent

SUMMARY...A brief tornado could occur over the next 1-2 hours.
However, the threat should be relatively transient/confined,
precluding watch issuance.

DISCUSSION...Regional radar data illustrate a cluster of convective
cells from eastern Texas to northern Louisiana early this morning,
ahead of a cold front pushing southeast across the Arklatex.
Developing within a modest low-level warm-advection/confluent
regime, these cells are likely being aided by a weak southern-stream
impulse currently crossing the upper Texas coast. KPOE VWP data
depict some veering with height through the lowest 2 km, with 0-1km
storm-relative helicity around 150 m2/s2. Several of these cells
have occasionally exhibited weak rotation, and this trend may
continue for the next hour or two. Therefore, despite weak buoyancy
(evidenced by a lack of CG lightning), a favorably moist boundary
layer may support a brief tornado. However, as low-level flow
continues to veer this morning, this potential should diminish with
decreasing shear.

..Picca/Guyer.. 12/05/2017

...Please see for graphic product...


LAT...LON   31039460 32039326 32109250 32019193 31709153 31339148
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