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

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FXUS64 KFWD 250154
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
854 PM CDT SAT SEP 24 2016

.UPDATE...
No major changes in the forecast this evening, as most everything
is on track. Satellite data continues to show cloud top cooling
with the cluster of storms over the Metroplex, but at least these
storms are moving at a decent clip to the north. As these storms
have lingered, they will at least move through any one spot within
an hour or less.

Attention then turns to the northwest, where the showers and
thunderstorms continue from central Oklahoma down to the Permian
Basin. As expected, the low level winds have increased, with the
VAD wind profile showing 30 knots of wind between one thousand
and four thousand feet. This will help keep the storms going to
the northwest, but will also keep the forward progress of the
storms in check for a while. Still anticipating the line to creep
to the east, making its way into our western counties between 11
PM and 3 AM, and into the I-35 corridor after 3 AM.

Fox

&&

.AVIATION...
/ISSUED 649 PM CDT SAT SEP 24 2016/
/00Z TAFS/

Most of the precipitation around the Metroplex has diminished
early this evening with the exception of a few showers moving into
Ellis County. These will continue north over the next hour but we
should continue to see a downward trend in intensity as we lose
daytime heating. Farther south...a cluster of thunderstorms is
approaching the Waco area. The bulk of the precipitation looks
like it will pass just east of the airport but will include a
tempo for 3SM +TSRA through 8pm. In addition...a fairly robust
outflow boundary will also overspread the area so winds will
become gusty over the next hour. Similar to the activity to the
north...we should see a decrease in intensity through 8pm.

Farther to the west...the line of convection from the Big Bend
region northward into Oklahoma is tied to the large upper trough
and cold front moving into the Great Plains. This area of
convection should slowly move east but appears unlikely that it
will make a significant eastward push overnight. The high
resolution guidance continues to suggest that some outflow air
will move east and support new development possibly as far east
as the Metroplex by early Sunday morning. While it`s uncertain
how far east any outflow boundary would push...think the lack of
significant dry air down low should keep the boundary from racing
eastward. This means that most of the showers and thunderstorms
overnight should remain to the west of the major airports. Will
keep the VCTS going through the morning hours as it is likely that
convection will continue its slow eastward progress with new
development during the day Sunday. Ahead of any showers/storms
late tonight...MVFR cigs are again likely to develop and spread
north.

Convective chances on Sunday will be a little better than today
areawide. Will continue with the VCSH during the late morning
hours and VCTS from mid afternoon into the evening. The actual
cold front is expected to be in the area by mid afternoon with
winds becoming north around 21Z. Scattered showers/storms will
continue behind the cold front into Sunday night.

Dunn


&&



.PREV DISCUSSION... /ISSUED 344 PM CDT SAT SEP 24 2016/
A large upper level trough to our west continues to slowly ease
east this afternoon. Although it won`t make it across the Southern
Plains, the impacts from this system on North and Central Texas
will include increasing rain chances, a front, and cooler weather.

This afternoon, showers and thunderstorms have been ongoing from
Northwest Oklahoma to West Texas ahead of the upper level trough.
With the influence of the upper level ridge having been weakened
across North and Central Texas and southerly winds continuing to
provide rich moisture into the region, isolated to scattered
showers and thunderstorms have been developing and moving north
across our area. Lightning and gusty winds to 30 mph have been the
main threats with this activity. We do not anticipate severe
storms through this evening, but an isolated strong storm could
produce winds closer to 50 mph before sunset.

The overnight period is when we expect rain chances will increase
for roughly the northwestern half of the region. A weak shortwave
currently crossing into Texas near the Big Bend area is expected
to continue moving north-northeast this evening, aiding in
additional lift across our western counties. The low level winds
in the 925-850 mb layer are also expected to increase to near 30
kts, providing additional support for convective development this
evening. The area of showers and storms to our west is expected to
move east, reaching our western counties this evening. The models
are quite variable in when the rain will really increase near our
western border, but most of the guidance is indicating between
9-11 pm CDT. By sunrise, the low level winds decrease in speed,
and the shortwave will be lifting northwest of the region. We
should see a weakening of the overall showers/storms and likely a
reduction in coverage through the morning hours. For the overnight
period, will keep the highest PoPs west of a Gainesville to Fort
Worth to Goldthwaite line with PoPs steadily dropping off further
east. Due to potential training of storms, it`s possible some
localized flooding may occur during the overnight period. An
isolated instance of flash flooding is not completely out of the
question depending on rain rates and if training occurs over a
certain area, but flash flood guidance is fairly high in our
western counties, as it is for most of North and Central Texas.
Will encourage the next shift to keep an eye on radar trends and
assess the potential for any Watches overnight and into Sunday.

The most significant changes to expected rain/storm trends comes
Sunday-Monday. An upper level low is forecast to cut-off within
the base of the trough over northern Mexico on Sunday and then
retrograde. In the wake of the departing shortwave in the morning,
and with the best dynamics located well to our west near this
cut-off low, we could end up in a lull in activity late Sunday
morning and into the early afternoon hours until the cold front
arrives later in the afternoon or evening hours. Isolated to
scattered shower and thunderstorm activity ahead of the front is
still expected as heating occurs with rich moisture still in place
and a lack of subsidence over the area. Also, any boundaries that
may be left over from the overnight and morning convection may
become a source for lift. Even in an unstable and uncapped
atmosphere, shear values and lapse rates tomorrow are weak, thus
we do not expect severe storms.

As the front moves in, it should become a focus for additional
shower and storm development. The highest chances for rain will
still be across mainly the western half of the region where we
will keep high PoPs but understand that this is not an indication
it will rain most of the day. We will keep high PoPs overnight as
the front moves through with again the highest rainfall totals
mainly west of Interstate 35. Showers and storms may also occur
behind the surface front as the H850 front lags behind. Lightning
and heavy rainfall will be the main hazards through the overnight
period but rainfall totals are not high enough to warrant a
Flood/Flash Flood Watch at this time. However, minor flooding will
be possible. Rainfall totals through the event are expected to be
less than an inch to the east of Interstate 35, where several locations
may not see rain at all, to 1-3 inches along and west of
Interstate 35. The highest rainfall totals of 2-3 inches are
expected west of Highway 281.

The cold front is expected to push through our southern counties
by early Monday morning. It will continue to push deep into the
Gulf of Mexico early next week with dry air filtering into the
region starting Monday. Some lingering rain may occur on Monday as
the H850 front also slowly moves south, but any leftover rain is
expected to end Monday night. The Gulf of Mexico will remain cut
off from moisture return next week with north and east surface
winds prevailing across the region through the end of the week.
Even as an upper level ridge builds back into the Southern Plains,
temperatures will be very pleasant next week with highs in the 70s
and 80s and lows in the 50s and 60s.

JLDunn



&&


.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    77  85  64  76  62 /  50  60  70  30  10
Waco                77  88  66  77  60 /  40  60  70  30  20
Paris               72  88  65  78  59 /  20  30  40  30  10
Denton              73  84  62  73  57 /  60  60  60  30  10
McKinney            73  87  64  77  58 /  40  60  50  30  10
Dallas              77  86  65  77  63 /  40  60  60  30  10
Terrell             73  89  67  80  61 /  30  50  60  30  10
Corsicana           75  89  67  80  61 /  30  50  70  30  20
Temple              75  87  65  76  61 /  30  60  70  30  20
Mineral Wells       73  81  61  70  55 /  70  70  70  30  10

&&

.FWD Watches/Warnings/Advisories...
None.
&&

$$

91/14


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