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

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FXUS64 KFWD 241751 AAC

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1251 PM CDT Sat Jun 24 2017

Earlier widespread showers and thunderstorms continue to diminish
in extent and intensity early this afternoon as somewhat drier air
tries to work into the region from the north. While VFR conditions
currently prevail at the Metroplex airports, there are signs of
lower clouds waiting in the wings to the north, and some
occasional dips to MVFR are possible through the mid-afternoon
hours along with occasional spits of rain. The wind field is quite
chaotic at this hour, with winds effectively light and variable.
Anticipate these will gradually turn to favor an east-northeast to
northeasterly direction this afternoon. Waco should experience
similar trends, with cig reductions perhaps into the low-MVFR
category through the afternoon.

Additional MVFR stratus should develop overnight as the shallow
frontal inversion re-saturates again. Subtle isentropic ascent
will continue atop the cool airmass, and this may be enough to
spark off renewed showers, although confidence in placing this
activity is quite low at this time. Slightly better chances exist
across Waco which will remain closer to better surface convergence
overnight, which warrants a mention of VCSH after 25/08z. Given
decreasing instability aloft, thunder chances appear low overnight
and into Sunday.



.UPDATE... /Issued 1142 AM CDT Sat Jun 24 2017/
After quite the soggy morning with widespread showers and
thunderstorms, things are finally starting to settle down across
the region late this morning. Satellite trends reveal that cloud
tops continue to rapidly warm as the incipient thunderstorms have
decayed, leaving behind a widespread swath of light to
occasionally moderate showers. We`re only seeing very occasional
lightning strikes at this time, so have limited thunder wording to
"isolated" in the updated forecast. In terms of PoPs, have
confined the highest chances to our south and western counties,
and trend them downwards through the rest of the afternoon. Given
how expansive the convective debris cloudiness is, it appears the
atmosphere will remain quite worked over--at least across the
northern portions of the CWA--limiting potential afternoon re-
development here. Across our Central Texas counties, enhanced
convergence near a stalling front may help focus additional
shower/thunderstorm development later this afternoon.

Given the widespread cloud cover, knocked a few degrees off our
high temperatures today, except across the northeastern counties
where a bit more filtered sunshine may allow temperatures to rise
into the middle 80s. This is certainly a welcome change from the
oppressive heat on Friday.

Weak isentropic ascent overnight and into Sunday atop the shallow
and cool airmass may be enough to allow some spotty
showers/storms to re-develop. As a result, we`ll maintain low PoPs
through this portion of the forecast.



.DISCUSSION... /Issued 422 AM CDT Sat Jun 24 2017/
After the hottest day of the year, a cold front moved into North
Texas. Late Friday evening, thunderstorms developed along the
slowly advancing boundary, expanding in areal coverage during the
early morning hours. The activity is now largely outflow driven,
peeling up the rich nocturnal air mass across Central and East
Texas. With ample instability in the mid-levels, downstream
parcels should allow the complex to maintain its intensity past
daybreak. This will likely be inadequate for severe winds, but
a few gusts may still reach or exceed 40 mph. With extraordinary
precipitation efficiency, the primary concern will be flooding
issues that result from heavy rainfall.

Winds have returned to the south the wake of the storms, evidence
that the front is still lagging behind. It may show little
inclination to move south until the next round of precipitation
arrives later this morning. Moisture convergence along the 850mb
front resulted in widespread thunderstorm development around
midnight from the Texas Panhandle into western Oklahoma. While
elevated, these cells have managed to maintain their discrete
nature, lengthening the duration of individual updrafts. Within a
northwest-southeast oriented axis of elevated instability, these
updrafts have proven capable of half-inch hail. The northwest flow
from 500mb up to the top of the troposphere is helping to guide
this activity into the richer moisture to the southeast. This
multi-cell complex will be entering an area that was overturned
just a few hours earlier, and it will become increasingly
separated from the 850mb front. While this will result in a
gradual decrease in intensity during the daylight hours this
morning, reducing the hail threat within North Texas, the complex
will still be capable of additional heavy rainfall. Flooding will
continue to be a concern this morning, particularly where these
downpours coincide with significant rainfall earlier this morning.

The complex will dissipate around midday, and any redevelopment
this afternoon would likely be confined to Central and East Texas
where outflow/frontal forcing may linger. The longer the morning
complex survives, the less likely there will be any additional
activity late in the day. For much of the region, this afternoon
will be unseasonably cool with a northerly breeze. While
postfrontal dew points may remain in the 60s, lingering cloud
cover and wet ground should keep temperatures well below normal.
Even if the mercury reaches the low 80s in the Dallas/Fort Worth
Metroplex, it will be the coolest daytime temperatures this late
in June since rainy 2004. For some locations, today`s high
temperatures will be more than 20 degrees cooler than Friday`s.

The widespread convection will maintain a weakness in the mid-
level flow that could allow for renewed daytime shower and
thunderstorm development Sunday and Monday, particularly with
adequate sunshine. The better chances will be across the west and
south. Thereafter, ridging aloft may nose enough into the region
to limit activity during much of the upcoming workweek. However,
the northwest Gulf will remain in a col between the western ridge
and a dirtier ridge over Florida and the Greater Antilles. As a
result, inclement weather may dominate the Texas Coast. During the
afternoon hours, the northwest extent of this activity may be
within our southeast zones.

Late in the week, the tail end of a trough axis, associated with
a polar low tracking through the Canadian Prairies, may swing past
our meridian. Although its lift may remain to our north, its
passage could allow another summertime cold front to approach next
weekend. While this may imply that the summer heat will be kept at
bay, subtropical ridging and above normal temperatures look like
they will prevail during the first week of July.



Dallas-Ft. Worth    81  70  84  69  88 /  90  20  20  10  10
Waco                82  72  85  69  88 /  80  30  30  20  20
Paris               85  67  85  65  87 /  60  20  10  10  10
Denton              81  68  84  67  87 /  80  20  20  10  10
McKinney            82  67  85  67  87 /  70  20  20  10  10
Dallas              82  71  85  70  88 /  90  20  20  10  10
Terrell             82  69  85  68  88 /  80  20  20  10  10
Corsicana           83  71  85  69  87 /  80  20  30  20  20
Temple              83  71  85  69  87 /  80  30  30  30  30
Mineral Wells       79  68  83  67  86 /  80  20  30  20  20




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