National Weather Service
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Severe Storm Outlook Narrative (AC)
acus11 kwns 211509
spc mcd 211509
txz000 - arz000 - okz000 - 211645-
mesoscale discussion 0749
nws storm prediction center norman ok
1009 am cdt tue may 21 2013
areas affected ... much of nrn tx
concerning ... severe potential ... watch likely
valid 211509z - 211645z
probability of watch issuance ... 95 percent
summary ... storms will increase in coverage and intensity over the
next 1 - 2 hrs ... and particularly damaging winds are expected to
affect much of nrn tx. in addition ... a few tornadoes and very large
hail will all be possible. a watch will be issued shortly.
discussion ... an outflow boundary currently extends from wrn ar wwd
along the red river to just w of abilene tx ... joining with a
developing cold front which will continue swd across w tx. to the
e ... an extremely moist and unstable atmosphere was in place ... with
midlevel lapse rates of 8. 0 - 9. 0 c/km.
storms will rapidly develop along the advancing cold front which
also intersects the outflow boundary in the next few hours ... and are
expected to quickly grow upscale into a damaging mcs. wind gusts
over hurricane force ... wind driven hail ... and a few tornadoes will
be possible as the system matures and forward propagates across a
large part of nrn tx and into the arklatex this evening.
although mainly a linear storm mode is eventually expected ... initial
development may be supercells with an enhanced tornado threat. when
storms do merge ... there will likely be areas of rotation embedded
within the advancing line ... perhaps producing swaths of particularly
.. jewell/kerr.. 05/21/2013
... please see www. spc. noaa. gov for graphic product...
attn ... wfo ... shv ... tsa ... hgx ... fwd ... oun ... sjt...
lat ... lon 31970006 32929962 33939680 33899492 33579436 33179426
32169421 31459469 31169556 31329716 31479905 31970006