DFW FORECAST DISCUSSION
000
FXUS64 KFWD 160436
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1136 PM CDT Sat Jun 15 2019


.AVIATION...
Timing thunderstorms will continue to be the primary challenge
with this TAF package. A complex of storms is finally starting to
organize across the Big Country at 04Z. These storms will continue
to move east through the night, reaching the Metroplex TAF sites
around 09Z. Waco may see a few storms in the vicinity a few hours
after sunrise, but most activity should remain to the north.
Storms should exit to the east shortly after sunrise Sunday with
the passing of a shortwave trough. Much of Sunday should be storm
free, however, a second round of storms will likely develop early
Sunday evening when another shortwave and a cold front enter the
region.

A 40 knot low level jet will bring stratus northward overnight
with MVFR ceilings expected in Waco around 09Z and slightly later
across the Metroplex TAF sites. However, thunderstorms could
briefly alter ceiling trends. VFR conditions are expected Sunday
afternoon and evening.

A breezy south wind will continue between 12 and 16 knots along
with some gusts to 26 knots. The wind gusts in and around
thunderstorms will likely be a bit stronger.

79

&&


.SHORT TERM... /Issued 328 PM CDT Sat Jun 15 2019/
/Tonight through Sunday/

This afternoon`s satellite imagery reveals a shortwave trough over
New Mexico moving east towards the Texas Panhandle. Thunderstorms
should develop quickly this afternoon across west-central Texas in
the vicinity of a dryline as forcing associated with the shortwave
arrives. Scattered storms will spread east along with the
disturbance, eventually congealing into an MCS while approaching
North Texas this evening. The latest timing brings activity into
the northwest zones around 10 PM, then into the I-35 corridor
(mainly along and north of I-20) around midnight. There is a
possibility of storms weakening the farther east they travel, but
with good instability in place and continued lift from the
shortwave, a damaging wind threat will likely exist late into the
night. Storms will spread east of I-35 overnight and will have
begun to spread south of I-20 where a warm, moist tropical airmass
will exist. Activity will continue propagating southeast before
exiting the area Sunday morning.

Additional thunderstorms are likely later in the day Sunday,
though the timing is a lot less certain. Several models are keying
in on redevelopment shortly after sunrise somewhere along the Red
River associated with a secondary vort max swinging around the
back edge of the main shortwave. If so, activity would propagate
southeast across the region during the morning, exiting to the
southeast early Sunday afternoon. It is possible, however, that
conditions will have become too stable for morning development
following the overnight convection. In this case, despite the
forcing associated with the secondary impulse, we would need to
wait for several hours of surface heating and destabilization, and
additional storms would hold off until afternoon (and would be
more isolated in nature). Either way, more showers and storms may
already be developing just northwest of the area by late
afternoon as the next disturbance approaches from the west,
continuing what is likely to be several days of unsettled
weather.

30

&&

.LONG TERM... /Issued 328 PM CDT Sat Jun 15 2019/
/Sunday Night Onward/

Active weather should persist Sunday night and into Monday, with a
continued risk for occasional strong or severe storms lasting into
the week. This type of activity cannot be easily "timed" or
"placed" as it is driven by small-scale features dependent on
preceding convection, so the main message here is to keep an eye
on weather if you have outdoor plans and be prepared for perhaps
rapidly changing forecasts in the coming days.

Through the extended, the environment will remain characterized
by strong to extreme instability owing to ample low-level moisture
content and warm daytime temperatures coupled with incredibly
steep mid-level lapse rates. As is typical heading into the
summer months, westerly flow aloft and attendant deep-layer shear
will remain rather weak, occasionally strengthened by low-
amplitude shortwave disturbances. This high CAPE low shear
environment will be the story of the extended forecast,
contributing to periodic thunderstorm chances over the next
several days. At the beginning of the extended period Sunday
evening, convection may already be ongoing across portions of the
forecast area as previously discussed. Despite some convective
overturning and stabilization from storms earlier in the day, a
quick recovery with persistent south flow should allow for new
development to occur, likely northwest of the CWA late Sunday
afternoon and evening. This activity would likely form into a
complex or two which should dive southeastward into North Texas
later Sunday evening and overnight. A strong/severe storm risk in
the form of wind/hail will accompany this activity simply due to
the nature of the instability present. The weak shear may limit
individual storm intensity/longevity while favoring primarily a
multicellular storm mode. There will also be a continued risk for
flash flooding, as some areas will likely have received multiple
rounds of rainfall through Sunday night. All of these storms
should continue to shift southeastward through Monday morning.

After perhaps a bit of a lull during the first part of Monday,
renewed development is expected throughout the day. Several
mesoscale boundaries should exist from previous convection, along
with perhaps a reinforced effective frontal zone that may be
driven southward into North Texas from Oklahoma. This will set the
stage for widely scattered convection occurring, especially
during the peak heating hours Monday afternoon and through Monday
evening.

The Tuesday/Wednesday time period should see slightly lower
convective chances with an attendant warm-up due to less
storm/cloud coverage during the afternoon hours. Storms will
likely be confined to typical summertime diurnally-driven
convection in the afternoon and evening hours each day. Coverage
should be more limited due to the presence of some weak upper
ridging and slow height rises. Isolated storms will still pose a
marginal severe risk for hail and downburst winds with strong
instability remaining in place. Heat index values will be in the
upper 90s to near 100 on Tuesday, but may creep into the 100-105
range on Wednesday depending on the amount of cloud cover or
afternoon convection. Meanwhile, coarser guidance has been rather
persistent regarding the potential for a thunderstorm complex to
develop across the TX Panhandle and western Oklahoma on Wednesday
night which would have a tendency to dive southeastward into North
Texas within increasingly northwesterly flow aloft. Despite what
will likely be a smaller-scale process, model run-to-run
consistency lends credence to this possibility, and PoPs have been
configured as such for the time being.

The warm and humid conditions will prevail through the end of the
week with continued convective chances primarily during the peak
heating hours each day. Highs will remain in the mid to upper 90s
with heat index values in the neighborhood of 100F.

-Stalley

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    73  88  72  88  72 /  50  30  60  50  40
Waco                75  91  73  90  73 /  40  30  60  50  20
Paris               72  85  69  81  69 /  50  40  70  70  50
Denton              72  88  71  87  71 /  50  30  60  50  40
McKinney            73  88  71  85  71 /  50  30  60  60  40
Dallas              74  90  72  88  73 /  50  30  60  50  40
Terrell             74  88  72  89  72 /  50  30  60  60  40
Corsicana           73  87  72  85  72 /  40  30  60  60  30
Temple              74  90  73  91  73 /  30  30  50  50  20
Mineral Wells       71  88  69  89  70 /  50  30  60  40  30

&&

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

$$

79

NWS FWD Office Area Forecast Discussion