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Area forecast discussion...updated 
National Weather Service Fort Worth Texas
1011 PM CDT Wednesday Sep 17 2014

Update...
convective activity continues across the southern counties of the
County Warning Area this evening and slow moving storms are producing heavy
rainfall. Localized areas of nuisance flooding or potentially
localized flash flooding may occur over the next few hours. The
activity is expected to weaken overnight in the absence of decent
lift and a weak low level jet. Adjusted probability of precipitation and temperatures overnight to
account for the latest trends.

More precipitation is expected to develop on Thursday and chances
for a heavy rain/flash flood potential appear to be increasing for
our southern and possibly southwestern areas. Today/S earlier
model runs indicated a rich moisture axis providing a focus for
convective development some where across our southern counties.
The boundary could be noted in the forecasted Theta-E fields and the
850-700 mb wind fields. Although the models varied on the location
of the this axis...they all had an axis of higher quantitative precipitation forecast amounts
developing some where in the central Texas area...generally around
and/or south of the Waco area. With high precipitable waters still in place
across the region...this raises some concern for a flash flood
threat across our southern counties on Thursday. Our neighbors to
the south already have flash/flood watches in place. We would
like to see the full 00z model suite before making any final
determinations of the need for and location of a watch. The 00z
NAM has now shifted the axis of precipitation across our southwest
and the 12z European model (ecmwf) appears to also support this. The most likely
time frame for heavy precipitation to occur is late Thursday morning
through the evening hours and we feel we have some time to see how
the overnight convection trends and also analyze the full 00z
model suite before making any final decisions on a Flash/Flood
Watch for tomorrow.

82/jld

&&

Aviation...
/issued 618 PM CDT Wednesday Sep 17 2014/
the current weather pattern is comprised of an upper trough over
the southeast Continental U.S. And an upper ridge over the central and
southwest. This typically yields hot and mundane weather across North
Texas in the Summer. However...the remnants of tropical cyclone
Odile have worked their way northeast and east from the eastern
Pacific into the southwestern part of the country. This has
essentially weakened the ridge and brought above-normal amounts
of middle and upper level moisture from the southwestern states
eastward across north and central Texas within a series of subtle
shortwaves.

For aviation concerns...this means periods of scattered mainly
afternoon showers and thunderstorms for the next few days.
Currently...showers and storms in the metroplex are being enhanced
by outflow boundaries from previous storms. The possibility for a
short-lived thunderstorm will exist at the metroplex taf sites for
another hour or so...then things should wind down with the loss of
surface heating. Activity is beginning later in the Waco
area...but moisture and instability will be sufficient for
thunderstorm development near kact during the next couple of
hours...especially if any mesoscale boundaries work their way
south.

Conditions should quiet down after 03z with VFR expected for the
rest of the forecast. Due to the high amounts of moisture
currently in place...we may add vcsh at all locations for the
overnight and early morning period. There will be a chance of
thunder again Thursday afternoon...but the latest model data keeps
activity farther southwest and away from North Texas taf sites.

30



&&




Previous discussion... /issued 355 PM CDT Wednesday Sep 17 2014/
scattered showers and thunderstorms have developed across the
region this afternoon ahead of a weak upper level shortwave. This
activity will tend to move east and southeast...and the most of
the activity is expected to shift to the south of I-20 later this
evening. Locally heavy rain and cloud to ground lightning will
accompany some of these storms. A few gusty winds may occur with
the storms before sunset.

We will remain in a moist atmosphere into the weekend as
southerly low level winds prevail while upper level moisture
continues to spread east across Texas. With weak disturbances
moving across the region...we will continue to see scattered
showers and thunderstorms. Some locally heavy rain will accompany
some of the storms late tonight through Thursday. At this
time...expect the more widespread heavy rain to be to the south of
the forecast area...thus will not be issuing a Flash Flood Watch
for our part of central Texas at this time. Rain chances should
shift more to the western part of the forecast area late Friday
into Friday night...but as the upper level remnants of Odile move
into the Central Plains...rain chances will return across all of
North Texas Saturday. As the Odile remnants move east...expect a
cold front to move down into late Sunday into early Monday. Rain
chances should come to an end across all but the southern zones
after Sunday night...with lingering chances into Monday south of a
Lampasas to Athens line. Rain chances will return by Wednesday as
another shortwave moves out into the plains.

58




&&



Preliminary point temps/pops...
Dallas-ft. Worth, Texas 74 89 73 90 73 / 20 40 20 20 10
Waco, Texas 72 86 71 89 70 / 60 70 20 30 10
Paris, Texas 71 88 68 89 69 / 20 30 10 10 10
Denton, Texas 72 89 70 90 70 / 20 30 20 20 10
McKinney, Texas 72 89 69 90 69 / 20 30 20 10 10
Dallas, Texas 76 89 73 90 73 / 20 40 20 20 10
Terrell, Texas 74 87 70 89 70 / 20 40 20 10 10
Corsicana, Texas 73 86 70 89 70 / 30 50 20 20 10
Temple, Texas 69 86 71 89 70 / 60 80 20 40 20
Mineral Wells, Texas 72 87 69 88 69 / 30 50 20 30 20

&&

Forward watches/warnings/advisories...
none.

&&

$$

30/82

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