Flash Flooding and Hail in Texas, November 7 to 8, 2024

Area Forecast Discussion
National Weather Service Fort Worth TX
1214 PM CST Thu Nov 7 2024

...New Short Term, Aviation...

.KEY MESSAGES...

-  Thunderstorm chances return today, become more widespread on
   Friday, and then taper off this weekend.

-  A few strong or severe thunderstorms as well as heavy rainfall
   are possible from this afternoon through early Saturday,
   particularly west of the I-35 corridor.

-  Rainfall totals will average 1-3” through Saturday. There is a
   10% chance that rainfall totals exceed 4” in parts of western
   North Texas, increasing the potential for flooding issues.

&&

.SHORT TERM... /NEW/
/Through Friday Evening/

A deep upper low currently spins just south of the Four Corners
region this afternoon. Warm/moist advection and subsequent lift
ahead of this system has led to the development of isolated to
scattered showers and thunderstorms generally along/west of the
I-35 corridor. Highest thunderstorm coverage is currently across
our far western Big Country counties where the greatest ascent is
located. Elevated instability on the magnitude of ~750-1000 J/kg
has supported a few cores capable of producing frequent lightning
and marginally severe hail. The highest thunderstorm coverage
will remain focused on our western zones through this evening and
into the overnight as the aforementioned storm system approaches
from the west. Persistent warm/moist advection, steepening lapse
rates, and sufficient shear will support a threat for marginally
severe hail generally west of the Highway 281 corridor through the
overnight.

By Friday morning, the upper low will begin its progression into
West Texas. Surface cyclogenesis will take place over the Texas
Panhandle, rapidly shifting northeast drawing a frontal boundary
east across our forecast area during the day Friday. Warm
advection showers and low stratus will be in place ahead of this
frontal passage Friday morning. Thunderstorms should take on more
linear characteristics along/ahead of the front as it enters our
western zones by mid-afternoon Friday. Depending on the degree of
destabilization (may be difficult due to morning convection
cooled-air), cells ahead of the front could intensify and pose a
severe weather threat, particularly south of the I-20 corridor and
along/west of the I-35 corridor where peak daytime heating could
lead to ~1250-1750 J/kg MLCAPE. Hail would be the primary threat
with any discrete/semi-discrete cells, however low-level wind
fields will support at least a low threat for an isolated tornado.
Damaging winds will be the primary threat with any line segments
that develop.

A messy storm mode and the likelihood of multiple storm cells
shifting over individual locations will increase the threat for
localized flash flooding through Friday. Most locations in North
and Central Texas can expect 0.5"-1.5" through Friday evening
with a 10-20% chance that totals exceed 2.5". The bulk of the
thunderstorm activity will shift into East Texas near or just
after midnight Friday night.

Langfeld

&&

.LONG TERM... /Issued 327 AM CST Thu Nov 7 2024/
/Friday Through the Middle of Next Week/

The powerful storm system to our west will be at its closest
proximity on Friday when it swings through the Texas Panhandle.
Large-scale forcing for ascent will spread deeper into North Texas
with widespread showers and storms impacting the region. At
daybreak Friday morning, warm advection showers may be streaming
northward as more robust convection approaches from the west.
The contribution of unseasonably rich boundary layer moisture may
be partially offset by rain-cooled air, particularly if the
surface layer doesn't get a chance to recharge during the daylight
hours. Nonetheless, lift and steadily steepening lapse rates aloft
may still be sufficient for updrafts supportive of hail (with
accompanying downburst winds) even if boundary layer parcels are
inadequate.

There may be a break between Friday morning's initial activity
and renewed development along an advancing front. This would
enhance the chances for strong/severe cells within a larger but
less coherent quasi-linear complex. However, the density of
competing updrafts may work against this, keeping the severe
potential marginal at best. In any event, heavy rainfall may pose
a flooding threat with remarkable precipitation efficiency.
Precipitable water values may approach 2 inches on Friday,
unprecedented for this late in the calendar year. Despite rather
progressive storm motion, the likelihood of multiple cells
impacting individual locations, some of which received significant
rainfall in the past week, flooding concerns could arise. Event
totals may reach/exceed 3 to 4 inches in areas that are both west
of I-35 and north of I-20. As we further assess the most likely
area to be impacted, a Flood Watch may be needed with subsequent
forecast packages.

As the surface boundary and its accompanying convective complex
continue pushing east Friday night, the focus will shift into East
Texas. With the upper low ejecting toward the Missouri Valley this
weekend, the front will gradually lose its momentum. This will
keep the mT air mass within our eastern zones, maintaining rain
chances. But for the bulk of North and Central Texas, the frontal
passage will usher in cooler, drier, and sunnier weather for
Saturday and Sunday. A warming trend may push temperatures into
the 80s on Tuesday before the next front and rain chances arrive
during the middle of next week.

25

&&

.AVIATION... /NEW/
/18Z TAFs/

MVFR cigs will continue through this evening over the D10
terminals with a potential brief period of VFR at KACT later this
afternoon. IFR cigs nudged into the far southern portions of the
D10 airspace, but never made it to the terminals (KGKY being the
only exception). It remains unlikely that IFR cigs will make it
to the other terminals this afternoon, but expect cigs to drop to
IFR status late tonight, generally after ~06Z at KACT and ~08Z at
D10. Isolated to scattered showers with embedded lightning
strikes will remain possible along the I-35 corridor for a couple
more hours this afternoon, but trends generally point to most of
this activity remaining west and southwest of the TAF sites
through the evening and overnight. Shower and thunderstorm chances
will return to the terminals during the day Friday.

A northeast wind at around 10 kts will gradually shift more
easterly through the afternoon.

Langfeld

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    72  67  70  56  69 /  40  40  80  80  20
Waco                76  67  75  55  71 /  50  40  80  80  20
Paris               75  60  69  58  70 /   0  20  70  90  40
Denton              71  63  70  51  70 /  30  50  90  80  20
McKinney            73  63  70  55  71 /  20  30  80  80  20
Dallas              73  65  73  55  71 /  30  30  80  80  20
Terrell             73  64  73  57  71 /  30  30  80  90  30
Corsicana           75  68  76  60  72 /  40  30  80  80  30
Temple              78  66  78  55  73 /  60  50  70  70  20
Mineral Wells       69  63  71  49  71 /  50  70  80  60  10

&&

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

Hazardous Weather Outlook
National Weather Service Fort Worth TX
337 AM CST Thu Nov 7 2024

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-080945-
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-
337 AM CST Thu Nov 7 2024

This Hazardous Weather Outlook is for North and Central Texas.

.DAY ONE...Today and Tonight.
Patchy fog will impact some locations this morning. Some of the fog
will be dense, with visibility of 1/4 mile or less.

There is a chance of thunderstorms today and tonight, mainly along
and west of the I-35 corridor. The strongest storms could contain
hail and gusty winds.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.
More widespread thunderstorms are expected Friday and Friday night.
Some of the storms could produce hail and gusty winds, but the
primary concern will be heavy rainfall that could reaggravate
flooding issues.

Thunderstorm chances will linger across East Texas this weekend.

The next round of storms will arrive during the middle of next week.

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service Fort Worth TX
1230 PM CST Thu Nov 7 2024

TXZ100-071900-
Young TX-
1230 PM CST Thu Nov 7 2024

...A strong thunderstorm will impact portions of southeastern Young
County through 100 PM CST...

At 1229 PM CST, Doppler radar was tracking a strong thunderstorm 9
miles southwest of Graham, moving northeast at 25 mph.

HAZARD...Nickel size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to outdoor objects is possible.

This strong thunderstorm will be near...
  Graham around 1240 PM CST.
  Lake Graham around 1245 PM CST.

Other locations impacted by this storm include South Bend and
Eliasville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3320 9872 3320 9842 3296 9855 3296 9882
TIME...MOT...LOC 1829Z 212DEG 20KT 3300 9870

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...<30 MPH

Dunn