Areal Flood Advisory 13, NWS Fort Worth, TX

Area Forecast Discussion
National Weather Service Fort Worth TX
820 PM CDT Mon May 10 2021

...New Short Term, Aviation...

.SHORT TERM... /NEW/
/Through Tuesday/

Ample MUCAPE and effective shear combined with isentropic upglide
above the frontal inversion to result in numerous thunderstorms
across North Texas this evening. A hail threat will be maintained
with this activity due to steep lapse rates and the ability for
convection to take on an elevated supercellular storm mode.
Convection should be able to continue through the rest of this
evening, but may lessen overnight as the column experiences
convective overturning and undergoes some modest stabilization.

Another round of widespread convection should materialize
sometime tomorrow morning with another strong wave of isentropic
ascent. This should traverse most of the CWA throughout the
course of the day. More marginal lapse rates through the mid
levels and slightly weaker shear are expected to be in place as
this occurs, which should keep the potential for strong/severe
storms lower than this evening's convection. However, some sub-
severe hail will certainly be possible with more robust cells. The
main concern may be from heavy rainfall and flooding with
isolated areas possibly receiving a few inches in a short time
span. This wave should taper off from west to east late tomorrow
afternoon or evening.

Outside of convective chances, other forecast concerns include the
potential for some dense fog tonight, while abnormally cool
conditions persist. The main area for fog potential will be
roughly west of I-35 and south of I-20, and we'll need to keep an
eye on a potential Dense Fog Advisory overnight. Temperatures
will mostly hover in the mid 50s to upper 60s for the next 36
hours beneath overcast skies with some mist/drizzle possible
elsewhere.

-Stalley

&&

.LONG TERM... /Issued 339 PM CDT Mon May 10 2021/
/Tuesday night Through Next Weekend/

Another cold front arrives in late Tuesday afternoon and night
period across the area, as a strong mid level impulse moves
gradually to the south and east of the CWA through Wednesday
morning. This will continue the highest rain chances across
Central and East Texas, while continuing the well below normal and
wet conditions. I did begin to undercut the NBM PoPs gradually
after midnight and through Wednesday, as the CWA begins to
experience gradually increasing mass subsidence aloft. I
maintained lower thunderstorm possibilities versus actual PoPs, as
enough MUCAPE and steep enough lapse rates linger to allow for
some discharge potential above the cool near surface frontal
layer. Though the potential for localized heavy rainfall and an
isolated flood threat continue Tuesday evening, I expect the
heavier convective rainfall to begin shifting toward the Texas
Coast and the Lower Mississippi River Valley as we move into early
Wednesday. Little diurnal range between low and high temperatures
Wednesday are expected to continue as low level cold advection
and expansive cloud cover keep temperatures from responding.
Continuing cloud cover from weak isentropic low level ascent over
the shallow frontal boundary and light northeast winds will likely
keep things cool and moist Wednesday night. Decreasing clouds and
increasing insolation on Thursday should allow for a gradual
modification of the airmass and a warm up back into upper 60s to
mid 70s on Thursday. This will be the transition day and likely
the trickiest day to forecast temperatures, as temperatures could
be warmer, or cooler if cloud cover decreases more or less than
currently depicted in the forecast.

Increasing ridging aloft across the Western U.S. and Rockies will
bring a drier northwest flow regime across North and Central
Texas by Friday. Shortwave ridging then takes hold for much of the
weekend, before breaking down in response to a lead shortwave
transiting the area well in advance of an organizing and
strengthening trough over the Great Basin well to the west. At the
surface, strengthening lee cyclogenesis across the Central High
Plains will bring gusty southerly surface winds and moisture
return back northward across the area moving into next weekend.
This will also bring the humidity back northward, as well as more
seasonable temperatures indicative of mid-May around here. Lows in
the 60s and humid highs in the 80s will make their return.

Though low convective chances increase late Saturday and into
Sunday, it doesn't appear severe weather will be a major issue
due to a strengthening elevated mixed layer/capping inversion
across the area. The more established severe weather threat
appears to be confined across West Texas and the Texas Panhandle
in the vicinity of an established surface dryline, hotter
temperatures likely in the 90s, and strong instability that
correlate with increasingly divergent mid level flow over that
area. Deterministic models want to cut off and deepen the energy
across the Desert Southwest and Northwest Mexico early next week,
while ensembles prefer a deep, but slow-moving open trough that
brings off and on convective chances to the Southern Plains. As is
usually the case with deep, southern latitude systems, finer
details and and potential for more significant weather will likely
iron themselves out with time.

05/

&&

.AVIATION... /NEW/
/00z TAFs/

A few more hours of TSRA impacts are possible at DFW area airports
before convection tapers off somewhat later this evening.
Afterwards, predominantly IFR or even LIFR conditions should exist
into tomorrow morning at all TAF sites. Another round of TSRA is
expected sometime tomorrow morning with additional TSRA expected at
all TAF sites. Right now, the most likely window for this would
be about 15z to 19z, but this timing could change by a couple
hours in either direction depending on trends. Activity should
taper off from west to east in the afternoon or evening.
Otherwise, some visibility reductions are possible throughout the
period, particularly at Waco tomorrow morning when some borderline
dense fog is possible. Poor flying conditions with IFR/LIFR cigs
should persist into tomorrow night.

-Stalley

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    56  64  57  67  55 /  80  90  60  20  10
Waco                60  68  58  66  56 /  50  90  70  40  20
Paris               54  59  54  65  51 /  70  90  60  20  10
Denton              54  61  54  65  52 /  70  90  50  20  10
McKinney            55  60  55  66  53 /  80  90  50  20  10
Dallas              58  64  58  67  56 /  90  90  60  20  10
Terrell             56  63  55  66  52 /  90  90  60  20  10
Corsicana           59  68  58  67  55 /  70  90  70  30  20
Temple              59  71  60  67  56 /  40  80  70  40  20
Mineral Wells       54  62  53  64  51 /  50  90  40  30  10

&&

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

Hazardous Weather Outlook
National Weather Service Fort Worth TX
550 PM CDT Mon May 10 2021

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-111215-
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-
550 PM CDT Mon May 10 2021

This Hazardous Weather Outlook is for North and Central Texas.

.DAY ONE...Tonight.
Thunderstorm chances will continue through tonight. A few strong to
severe storms containing hail are possible, especially in North Texas
this evening. Gusty storm outflow winds can't be ruled out across
eastern Central Texas if storms develop near a stalled front. In
addition, brief heavy rainfall may also result in minor flooding.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.
Thunderstorm chances will continue through Wednesday. While the
overall severe weather threat will be low, localized heavy rainfall
may lead to isolated instances of flash flooding across eastern
Central Texas late Tuesday into Tuesday night. Mainstem rivers across
this area may also experience enough run off for the potential for
minor flooding in nearby farmland.

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

Special Weather Statement
National Weather Service Fort Worth TX
950 PM CDT Mon May 10 2021

TXZ104-105-119-120-110315-
Hunt TX-Collin TX-Rockwall TX-Dallas TX-
950 PM CDT Mon May 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN ROCKWALL...NORTHWESTERN
HUNT...SOUTHEASTERN COLLIN AND NORTHEASTERN DALLAS COUNTIES UNTIL
1015 PM CDT...

At 949 PM CDT, Doppler radar was tracking a strong thunderstorm over
Garland, moving northeast at 50 mph. Another strong thunderstorm was
located between Farmersville and Nevada and will move northeast at
50 mph.

Nickel size hail will be possible with these storms.

 Locations impacted include...
Dallas, Plano, Garland, Mesquite, Richardson, Allen, Rowlett, Wylie,
Rockwall, Greenville, Sachse, Murphy, Royse City, Fairview,
Princeton, Fate, Lucas, Parker, Farmersville and Lowry Crossing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so closely monitor for additional
information or possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Fort Worth.

&&

LAT...LON 3281 9667 3296 9679 3324 9649 3340 9592
      3310 9603
TIME...MOT...LOC 0249Z 237DEG 45KT 3293 9664

Bain

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Special Weather Statement
National Weather Service Fort Worth TX
1011 PM CDT Mon May 10 2021

TXZ094-095-110400-
Lamar TX-Fannin TX-
1011 PM CDT Mon May 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN LAMAR AND EAST CENTRAL
FANNIN COUNTIES UNTIL 1100 PM CDT...

At 1010 PM CDT, Doppler radar was tracking a strong thunderstorm over
Dodd City, or 8 miles east of Bonham, moving northeast at 50 mph.

Nickel size hail will be possible with this storm.

 Locations impacted include...
Paris, Honey Grove, Dodd City, Windom and Toco.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so closely monitor for additional
information or possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Fort Worth.

&&

LAT...LON 3388 9554 3389 9551 3388 9551 3389 9546
      3387 9545 3387 9539 3370 9549 3348 9605
      3359 9615 3386 9587 3384 9584 3384 9582
      3386 9581 3384 9577 3386 9575 3389 9575
      3388 9570 3391 9567 3392 9563 3391 9555
TIME...MOT...LOC 0310Z 237DEG 42KT 3358 9603

Bain

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FORT WORTH TX
1016 PM CDT MON MAY 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1010 PM     HAIL             LAVON                   33.03N 96.43W
05/10/2021  E1.25 INCH       COLLIN             TX   EMERGENCY MNGR

            QUARTER TO HALF DOLLAR SIZE HAIL IN LAVON.

&&

MSS

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