Hail and Damaging Winds in Texas, March 24 to 25, 2019

Area Forecast Discussion
National Weather Service Fort Worth TX
331 PM CDT Sun Mar 24 2019

.SHORT TERM...
/Through Tonight/

Thunderstorms are expected to accompany a cold frontal passage
tonight, the bulk of the activity east of the I-35 corridor. Some
of the storms may be severe, with large hail and damaging winds
the primary hazards.

The cold front has made only slow southward progress this
afternoon, with both parallel flow above the boundary and
insolation in the cold sector impeding its movement. A narrow
corridor of westerly flow between the front and the more humid air
to the southeast has diminished the thermal discontinuity at the
edge of the better moisture, and the veered flow ahead of this
dryline continues to negate any potential convergence. The
downslope winds within the humid air have warmed temperatures
into the 80s, the thin boundary layer moisture yielding only some
innocuous cumulus clouds. The more favorable instability is deeper
into the warm sector, along the I-35 corridor, where MLCAPE
values have topped 1000 J/kg. However, newly reinvigorated
westerly flow has re-established a weak cap that should prevent
any ambitious thermals from reaching their convective potential
this afternoon.

Our focus instead will remain farther east along the boundary,
specifically from Lake Texoma into southeastern Oklahoma, where
deeper moisture should allow for the initial precipitation-
producing convective elements. These discrete cells will intensify
quickly, initially posing a hail threat. The proximity of the
surface boundary may enhance the sub-cloud helicity, but the
veered flow and cloud bases near 3000 ft should limit the
tornadic potential. With increasing storm duration, there will
also be an attendant wind threat. Into the evening hours, the
resulting outflow will enhance the frontal boundary, and a steady
transition to a linear MCS should occur as the activity passes
south of the I-20 corridor. The maintenance of this cold pool will
allow the complex to survive well beyond its separation from the
upper support (that will remain primarily north of the Red River
and into the Ark-La-Tex). Backbuilding will increase as the line
moves south into the deeper moisture, potentially impacting areas
west of the I-35 corridor (particularly those areas that are also
south of I-20), but the western reaches of the line may struggle
to maintain their intensity. Although the severe potential will
diminish during the early morning hours, the line may continue to
pose a damaging wind threat into the predawn hours in our
southeast zones.

25

&&

.LONG TERM...
/This Week into Next Weekend/

Following our bout of strong to severe storms across parts of the
region tonight, conditions will clear across North and Central
Texas on Monday. A few lingering showers and isolated storms may
affect the Brazos Valley through mid-morning, but with a front
continuing south, precipitation should be clear of our southern
counties by mid-day. While a strong storm or two cannot be ruled
out during the early morning hours, the severe threat will most
likely have diminished.

Surface ridging will build across much of Texas through Tuesday,
bringing near to slightly below normal temperatures during the
first half of the week. Skies should be considerably clearer than
prior days as well. However, we may have to watch the potential
of some lower-level cloud cover sneaking into the Red River Valley
and East Texas Monday and Tuesday, associated with cold-air
advection trailing weak impulses in cyclonic flow aloft.

Heights build over Texas mid-week and beyond, yielding a low-level
return flow regime and increasing moisture/multi-layered clouds
through the end of the week. A weak impulse and an uptick in
warm-air advection may promote a few showers Thursday, but chances
appear quite low and thunder seems unlikely, with only shallow
convective processes at work.

Rain and thunderstorm chances increase Friday into Saturday as
parcel buoyancy builds and the region remains under the influence
of west/southwesterly flow aloft. However, deterministic/ensemble
guidance still exhibit wide spread in the evolution of a sharp
impulse over the central Plains, the amplification of the
northern stream, and how amplified/active the southern stream
remains upstream of us. Regardless, the interaction of all these
features should allow a stout cold front to drive south across our
area late Friday into early Saturday, and this is generally when
the highest PoPs are forecast to exist. There is a possibility of
stronger storms, but widespread severe weather remains far from
certain (or even likely), as robust deep-layer ascent could very
well remain north of our area. This would lead to shallow frontal
ascent within a somewhat capped environment, which would likely
favor more anafrontal development. Still, the severe-weather
potential bears watching.

Temperatures fall noticeably behind the cold front next weekend,
and highs are expected to be several degrees below normal.

Picca

&&

.AVIATION... /Issued 124 PM CDT Sun Mar 24 2019/
/18Z TAFs/

Thunderstorm potential tonight with wind shift. VFR Monday.

Despite southwest winds, moisture trapped beneath a nocturnal
inversion resulted in temporary MVFR ceilings. Surface heating has
eroded this inversion, and deeper mixing will continue to lift and
scatter these clouds. With abundant moisture still upstream,
ceilings will be more persistent at Waco, but a transition to VFR
should still occur by mid-afternoon.

Thunderstorms may begin to clutter the northeast arrival corridor
before 00Z. The window for convective impacts at Metroplex
airports remains the same, but with increasing confidence, the 18Z
package introduces a TEMPO for TSRA. A permanent wind shift will
occur by midnight. At this time, it appears the linear complex
along the advancing front will remain east of Waco. This potential
will continue to be monitored, but any convective impacts would
likely occur before the tower opens Monday morning.

25

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    55  71  48  69  49 /  60   5   0   0   0
Waco                59  74  48  70  48 /  30  10   0   0   0
Paris               52  68  45  66  44 /  80  10   0   0   0
Denton              52  70  45  69  48 /  50   0   0   0   0
McKinney            53  69  45  67  47 /  70   5   0   0   0
Dallas              57  72  48  69  49 /  60   5   0   0   0
Terrell             57  71  46  69  46 /  70  10   0   0   0
Corsicana           60  73  48  67  47 /  60  20   0   0   0
Temple              61  74  49  70  48 /  20  10   0   0   0
Mineral Wells       50  72  44  69  47 /  20   0   0   0   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&

11/30

Hazardous Weather Outlook
National Weather Service Fort Worth TX
332 PM CDT Sun Mar 24 2019

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-251100-
Montague-Cooke-Grayson-Fannin-Lamar-Young-Jack-Wise-Denton-Collin-
Hunt-Delta-Hopkins-Stephens-Palo Pinto-Parker-Tarrant-Dallas-
Rockwall-Kaufman-Van Zandt-Rains-Eastland-Erath-Hood-Somervell-
Johnson-Ellis-Henderson-Comanche-Mills-Hamilton-Bosque-Hill-Navarro-
Freestone-Anderson-Lampasas-Coryell-Bell-McLennan-Falls-Limestone-
Leon-Milam-Robertson-
332 PM CDT Sun Mar 24 2019

This Hazardous Weather Outlook is for North and Central Texas.

.DAY ONE...This Afternoon and Tonight.
Thunderstorms are expected to develop late this afternoon and into
the evening hours ahead of an advancing cold front. Areas that are
both east of I-35 and north of I-20 are the most likely to be
impacted by the storms this evening. Some of the storms may be severe
with large hail and damaging winds the primary hazards. Although
there may initially be discrete supercells near the boundary, veered
surface flow and elevated cloud bases will limit the tornado
potential.

The thunderstorms will likely transition into a linear complex after
midnight, primarily impacting areas that are both east of I-35 and
south of I-20. Although the severe potential will diminish during the
early morning hours, the line may continue to pose a damaging wind
threat.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.
A line of thunderstorms may continue to impact portions of Central
and East Texas during the Monday morning commute before exiting the
region. Strong gusty winds and heavy rain will be the primary
hazards with these storms.

Thunderstorm chances return Friday and Saturday.

.SPOTTER INFORMATION STATEMENT...
Spotter activation will likely be requested this evening in areas
that are both east of I-35 and north of I-20.

Special Weather Statement
National Weather Service Fort Worth TX
520 PM CDT SUN MAR 24 2019

TXZ093-242245-
Grayson TX-
520 PM CDT SUN MAR 24 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN GRAYSON COUNTY UNTIL
545 PM CDT...

At 520 PM CDT, Doppler radar was tracking a strong thunderstorm near
Dorchester, or near Sherman, moving east at 20 mph.

Nickel size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

Locations impacted include...
Sherman, Howe, Whitewright, Bells, Tom Bean, Savoy, Knollwood,
Dorchester, Southmayd and Luella.

A Severe Thunderstorm Watch remains in effect until midnight CDT for
north central Texas.

LAT...LON 3377 9642 3375 9641 3373 9638 3348 9638
      3350 9679 3361 9679 3371 9670 3377 9650
      3378 9646 3378 9644
TIME...MOT...LOC 2220Z 249DEG 18KT 3358 9668

Dunn