Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 271604
SWOMCD
SPC MCD 271603
TXZ000-271730-

Mesoscale Discussion 0216
NWS Storm Prediction Center Norman OK
1003 AM CST Mon Feb 27 2017

Areas affected...north central and northeast TX

Concerning...Severe potential...Watch possible

Valid 271603Z - 271730Z

Probability of Watch Issuance...40 percent

SUMMARY...Potential exist for isolated supercells to develop over
north central TX by late morning and continue into a portion of
northeast TX this afternoon. Primary threat will be large hail
though a brief tornado cannot be ruled out.

DISCUSSION...Isolated storms are developing over north central TX
this morning within a weak warm advection regime. Objective analysis
shows the atmosphere to be moderately unstable with around 1500 J/kg
MUCAPE, but the storms are currently elevated. Widespread clouds
will slow boundary-layer warming. However, unidirectional wind
profiles with effective bulk shear of 40-45 kt and moderate
instability is sufficient to support updraft rotation with these
cells including potential for left splits which may augment the
threat for large hail. With time, a gradual warming and moistening
of the boundary layer may result in surface based activity. The 0-1
km hodograph size is relatively small except in vicinity of warm
front/outflow boundary over northeast TX where the boundary layer is
stable. A threat for a tornado will exist if low-level
destabilization occurs in vicinity of this boundary during the
afternoon as storms move east and interact with it. Subsidence
drying aloft and warming due to eastward advection of elevated mixed
layer plume will eventually cap the atmosphere from the west with
time, suggesting a relatively small window for storms to organize
and become severe in this region.

..Dial/Hart.. 02/27/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...SHV...FWD...

LAT...LON   32319790 33199678 33149498 32669431 31929486 31649749
            32319790



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