Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX

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445
FXUS64 KFWD 271513
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1013 AM CDT FRI MAY 27 2016

.AVIATION...
Have attempted to narrow down the timing of shra/tsra cessation
at the metroplex TAF sites this morning. The back edge to the
precipitation shield continues to steadily advance northeastward
out of Comanche and Erath counties. Based on radar and satellite
trends, have ended VCTS at KFTW and KAFW at 17Z, and then at
KDFW/KGKY/KDAL at 18Z. Clouds should then scatter out this
afternoon.

At the Waco TAF site, think precipitation and cloud cover will
hold a bit tougher, and shower chances should continue into this
afternoon.

Finally, have removed the mention of thunder this afternoon at all
the TAF sites based on latest indications that the atmosphere will
remain heavily worked over and subsident in the wake of the
morning convection.

Carlaw

.../PREVIOUS AVIATION DISCUSSION/...
/ISSUED 641 AM CDT FRI MAY 27 2016/
Showers and thunderstorms continue to move across the area this
morning affecting all North and Central TX area TAF sites. This
activity should continue slowly pushing east, but stratiform
precipitation impacting vsbys in the wake of the main line with
occasional lightning strikes will continue through 15Z at the
metroplex airports. Waco will see heavier rainfall through the
next few hours with lightning a continued threat through midday.
South winds should resume and increase in speed as a departing
wake low moves out of the area which is currently wreaking havoc
on wind speeds and directions area-wide.

As this system moves off to the east early this afternoon, skies
should become broken or scattered with any ceilings improving to
VFR later today. Daytime heating and an upper-level disturbance
will result in one final opportunity for thunderstorms this
afternoon before activity ceases by late evening. Coverage of any
thunderstorms this afternoon is expected to be limited and have
only included a few hours of VCTS with low confidence that TAF
sites will be impacted at all. MVFR cigs are likely once again
Saturday morning, just after midnight at Waco and closer to 10Z at
the Metroplex sites.

-Stalley



&&

.UPDATE...
Quick update this morning to account for temperatures affected by
convection and to adjust PoP trends through midday. Activity is
still expected to shift eastward through the morning and into the
early afternoon and continue to decrease slightly in intensity as
evidenced by the warmer cloud tops over the past hour. Additional
heavy rain may continue to cause flooding across our Central TX
counties through the next 6 hours.

3 features will influence any possible redevelopment through the
afternoon hours today: A surface dryline (which some guidance
aggressively brings towards the I-35 corridor by mid afternoon),
a shortwave trough located to our northwest, and a residual MCV
associated with the 2nd round of activity overnight/this morning.
Redevelopment of isolated strong to severe storms remains possible
this afternoon, especially where any clearing occurs through
midday. Should any storms manage to develop late this afternoon,
they will be capable of becoming strong to severe with a damaging
wind, hail, and low tornado threat. Coverage of storms will be
limited and there is a small chance that northing is able to
redevelop at all due to subsidence from the morning activity, but
trends will need to be monitored through the afternoon hours for
this potential.

-Stalley

&&

.PREV DISCUSSION... /ISSUED 327 AM CDT FRI MAY 27 2016/
Our first wave of showers and thunderstorms has moved east of the
I-35 corridor early this morning. This activity continues to
weaken as it outruns the stronger upper forcing and its low-level
moisture intake becomes interrupted by the thunderstorms located
further to the south near the I-10 corridor. A wake low from this
MCS has begun to produce wind gusts of 30 to 40 mph in areas
behind the precipitation shield, and would expect this trend to
continue through the next couple hours.

The next wave of convection has taken shape to our west and has
already moved into our western counties from Jacksboro to Cisco
as of 3am. These storms are being fueled by the low-level jet and
associated intense moisture transport underneath a plume of steep
lapse rates aloft. Much like the first wave, this second MCS will
have essentially unlimited moisture to feed on as it moves
eastward and affects a large portion of North and Central Texas
this morning.

Despite previous convection, a favorable environment for
convection remains in place across the region with MUCAPE of
2000-3000 J/kg still in place. A capping inversion is in place
and this system is primarily elevated, but getting a good handle
on the strength of the cap has been a challenge. Some areas may
manage to see strong wind gusts from embedded bowing segments this
morning if any of the more intense winds are able to make it down
to the surface. DYX radar was showing some 40 to 50 kt winds in
the lowest 2500 ft as the line passed through the RDA location,
but reported gusts at the surface have been considerably less.
Otherwise, some small hail will will be possible with the most
intense updrafts. Overall, the severe threat with this morning`s
MCS seems quite low at this time. This system should affect the
I-35 corridor for the morning commute, between 5 and 8am, and will
impact our eastern areas through mid-morning.

Flooding continues to be the primary concern this morning as the
aforementioned moisture transport has resulted in PW values of
1.6-1.9in across the area which are around +2SD above normal. All
thunderstorms will continue to be efficient rainfall producers and
flash flooding is likely wherever cell training occurs. Do not
plan to expand the Flash Flood Watch at this time with the highest
flood threat still expected to be primarily across Central TX,
although isolated flooding issues are possible outside of the
Watch today.

After our morning MCS rolls through some clearing may occur by
late morning or early afternoon. With the main trough axis still
positioned to our west, there should still be some large-scale
ascent over our region. The dynamic lift from the approaching
shortwave will probably need to contend with residual subsidence
from our morning complex, which may act to inhibit the amount of
lift in our area later today. In the wake of this morning`s MCS,
skies may go broken to scattered or even mostly sunny in a few
spots by late morning or early afternoon. Would expect daytime
heating to be sufficient to allow the atmosphere to recover and
become increasingly unstable again by early this afternoon.
Redevelopment of isolated to scattered thunderstorms will be
possible essentially area-wide, especially during peak heating
today. If they are able to develop, buoyancy and shear will be
sufficient for some strong to severe storms which would pose a
wind, hail, and tornado threat. The shortwave should depart the
area this evening and any remaining activity should taper off from
west to east by tonight.

While large-scale subsidence due to upper ridging should dominate
the region on Saturday, ample instability from continued gulf
moisture transport combined with daytime heating with clearing
skies will still be of concern. Coarser models have been depicting
a weakness aloft across southern/Central TX on Saturday afternoon
which may allow some storms to develop across parts of our Central
TX counties at a minimum. Have maintained low PoPs with very
little coverage expected from any activity on Saturday. Slight
chances for thunderstorms will continue on Sunday as weak ridging
aloft is replaced by broad troughiness over the western CONUS, but
this should not be enough to completely ruin any outdoor holiday
weekend plans.

Greater rain chances return to the forecast on Monday, Memorial
Day, as a deeper trough nears the area and an upper jet noses into
the region. Some guidance has been persistently developing an MCS
in the TX Panhandle on Sunday evening and rolling it through our
area Sunday night and Monday morning. This seems like a reasonable
solution, but we`ll have to see how the hi-res guidance handles
the evolution once this is within the forecast time range.

A slow-evolving weather pattern for the rest of next week means
that there will be chances for showers and storms every single day
with a cloudy and rainy start to the month of June. Extended
guidance continues to show a weak front entering TX around midweek
and then stalling this feature through Central TX. This would only
act to increase our rain chances through the end of the week
should this solution materialize. It is still far into the
forecast to assess severe weather potential, but limited shear may
act to preclude a widespread severe weather threat, especially
towards the end of the week.

-Stalley



&&


.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    83  72  88  71  85 /  70  30  20  20  20
Waco                85  74  88  70  85 /  80  30  20  30  20
Paris               79  70  86  69  85 /  70  40  30  10  20
Denton              82  68  87  68  84 /  60  30  20  20  20
McKinney            80  70  87  69  85 /  80  30  20  20  20
Dallas              83  74  89  71  87 /  80  30  20  20  20
Terrell             81  72  88  71  85 /  80  30  20  20  20
Corsicana           83  73  88  71  85 /  80  30  30  20  20
Temple              85  73  87  70  83 /  70  30  30  30  20
Mineral Wells       85  66  88  69  84 /  50  20  10  20  20

&&

.FWD Watches/Warnings/Advisories...
Flash Flood Watch until 6 PM CDT this evening for TXZ135-142>148-
156>162-174-175.

&&

$$



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