Damaging Wind and High Wind in Texas, June 24 to 25, 2018

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
927 PM CDT Sun Jun 24 2018

.UPDATE...
We have expired the heat advisory as well as trimmed PoPs/Wx and
adjusted several other near term grids.

A strong outflow boundary, dryline and intense heating were not
enough to overcome an impressive cap across the South Plains this
afternoon and evening. Temperatures peaked at a scorching 105 to
110 degrees over much of the central and southern South and
Rolling Plains. Officially Lubbock reached 108 degrees, just 2
degrees from the record set back in 1990. The hottest temperature
in our CWA was at Lake Alan Henry where it hit 112 degrees.

The heat was sufficient to break the cap across the eastern
Permian Basin and Big Country where a few stronger storms have
developed. This activity will largely stay to our south before
diminishing later tonight, though it could still seed a rogue
shower/storm into the southern Rolling Plains late this evening.
Hence we have maintained a minimal thunder mention over the
southern Rolling Plains through 06Z.

Otherwise, our attention turns to the north as the next MCS is
already well underway across southeast CO into western KS, with
recent development on its southern flank into the OK Panhandle.
Lastly, isolated convection has recently tried to develop just
east of Fort Sumner. If this activity can persist it could move
into our northwestern zones later tonight. Although the MCS
currently appears to be propagating mostly eastward, recent RAP
and HRRR runs continue to suggest an outflow aided front along
with glancing lift from the upper low emerging across the central
High Plains will be enough to spur additional convective
development southward through much of the western Texas Panhandle
over the next few hours. This seems plausible given the
strengthening southerly to southeasterly LLJ. Eventually the cap
and growing displacement from the upper support should thwart the
southward development of convection, though the southern flank of
the MCS could skirt our far northern zones. Should this happen,
the southern Texas Panhandle counties could see strong to severe
wind gusts, marginally severe hail and brief heavy rain before
the activity quickly shifts eastward toward dawn Monday. Hence, we
have trimmed the southern extent of mentionable PoPs, though we
have maintained solid chance values across the northern/northeastern
zones from 06-12Z.

Outside of storm chances through tonight, the main story will be
the "cold" front which will help knock temperatures back close to
average on Monday.

&&

.PREV DISCUSSION... /issued 643 PM CDT Sun Jun 24 2018/

AVIATION...
Outflow has passed south of KPVW and KCDS with gusty easterly
winds in its wake. The outflow and/or retreating dryline should
bring gusty southeast winds to KLBB in the next couple of hours.
An isolated storm could still develop on these boundaries and
affect any of the terminals this evening, though current trends
don't look favorable for this. Instead, the winds may back more
southeast to southerly as a stout southerly LLJ cranks up.
However, an outflow aided cold front will then follow moving
through the terminals after midnight. Current guess has the FROPA
around 07Z at KPVW and KCDS and 08Z at KLBB, though this could
change a bit either way, depending on the magnitude of the outflow
push. Gusty northerly to northeasterly winds will follow the
FROPA. In addition, there is a chance the convective complex
moving across the Panhandles could graze the northern terminals,
KCDS appears to have the best chance of being impacted and we have
included a VCTS for now. The post-frontal winds will gradually
ease through the day on Monday, but a period of sub-VFR ceilings
look like a decent bet at the terminals.

PREV DISCUSSION... /issued 349 PM CDT Sun Jun 24 2018/

DISCUSSION...
Outflow boundary from storms passing through central Oklahoma
today has been stronger than previously forecast. As such it has
stabilized areas in the Panhandle and northeast Rolling Plains.
Also, dryline has pushed east through most of the South Plains.
For this afternoon main concern is over the Rolling Plains along
and south of the boundary...threatening areas from Guthrie
southward. Very warm middle atmosphere temperatures...around 16C
at 700mb...working as strong cap. As such, remains questionable as
to whether or not convection will break through the cap forming
storms. If they do form, convective potential energy is very high
and as such storms could produce damaging wind gusts.

Overnight tonight...vorticity max passing around southern edge of
an upper low moving SE into Nebraska is expected to form complex
of storms over eastern Colorado that should move southeast through
parts of the Panhandle and possibly parts of our forecast area.
Developing low level jet over Rolling Plains and eastern South
Plains should feed strong moisture plume into the storms overnight
keeping the storms going. Main question will be how far south the
area of storms will extend. Other than the southeast Panhandle,
the chances of overnight storms should be 20 percent or less.

The complex of storms to our north overnight will drive a
front/boundary well south through the area for tomorrow. As such
temperatures across the South Plains are forecast to be somewhat
cooler than today with highs mostly in the 90s. The remaining
boundary will leave the area with a slight chance of storms Monday
night extending from southern Oklahoma back through the Rolling
Plains into the South Plains.

For Tuesday and on through the remainder of the week, the upper
high will rebuild over the area providing mostly dry weather with
rain chances generally well below 20 percent. Temperatures will
remain on the hot side with highs from the mid 90s to near 102.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&

23

Hazardous Weather Outlook...UPDATED
National Weather Service Lubbock TX
854 PM CDT Sun Jun 24 2018

TXZ021>044-251400-
Parmer-Castro-Swisher-Briscoe-Hall-Childress-Bailey-Lamb-Hale-
Floyd-Motley-Cottle-Cochran-Hockley-Lubbock-Crosby-Dickens-King-
Yoakum-Terry-Lynn-Garza-Kent-Stonewall-
854 PM CDT Sun Jun 24 2018

This Hazardous Weather Outlook is for the South Plains, Rolling
Plains and the far Southern Texas Panhandle.

.DAY ONE...Tonight

A complex of thunderstorms may graze the southern Texas Panhandle
late tonight, bringing with it the threat for wind gusts in excess
of 50 mph, small hail and locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

No hazardous weather is expected at this time.