Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS11 KWNS 192153
SPC MCD 192152
Mesoscale Discussion 0189
NWS Storm Prediction Center Norman OK
0352 PM CST Sun Feb 19 2017
Areas affected...Edwards Plateau...TX Hill Country
Concerning...Severe potential...Watch possible
Valid 192152Z - 192345Z
Probability of Watch Issuance...40 percent
SUMMARY...A few strong to severe storms capable of hail and damaging
wind gusts are possible during the next few hours and trends will be
monitored for a possible watch.
DISCUSSION...Recent surface analysis places a dryline from just west
of DYS southwestward into far western portions of Val Verde county.
Regional radar and satellite data have shown an increase in
attempted convection initiation over the past 30 minutes but no
sustained storms have been able to overcome the low-level warm layer
(i.e. around 850 mb) yet. However, filtered sun has resulted in
modest diurnal heating and, despite some low-level mixing, this
heating coupled with steep mid-level lapse rates continues to
support gradually increasing instability across the region.
The stronger synoptic forcing for ascent remains back west but the
persistent attempts at convection initiation and the approaching
dryline suggest that a few discrete storms may develop within the
next few hours. Overall kinematic environment is supportive of
organized storms with a primary threat of hail and damaging wind
gusts. While the tornado threat is non-zero, the weak low-level flow
across the area suggests the tornado threat will be very low.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 29760144 29860174 30790119 31310071 31509958 30719914
29149981 28900047 29210075 29610128 29760144