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Area forecast discussion
National Weather Service Fort Worth Texas
324 PM CDT Mon may 29 2017

Discussion...
isolated, pulse showers have been occurring south of a Lometa to
Waco to Palestine line this afternoon. Subsidence from an earlier
cluster of storms in the Gulf of Mexico is likely suppressing
additional development this afternoon and evening. This isolated
activity will continue through the early evening hours, and then
relatively quiet conditions are expected overnight. However,
patchy fog may develop along and south of a Goldthwaite to
Waxahachie to Emory line as rich low level moisture remains in
place, and even starts to move back north, combined with clearer
skies and light winds. It's possible isolated areas of near dense
fog may occur where heavier rain has fallen since yesterday
evening.

Better low level moisture will continue to advect north during the
day on Tuesday in response to an upper level trough moving into
the western Continental U.S.. a few isolated showers and possibly a
thunderstorm will be possible as we retain southwest flow aloft
and moisture begins to increase across the region. Due to weak
instability and weak wind shear, any storms that occur are
expected to be pulse-like again and below strong/severe
thresholds. Overall, the majority of the region will be dry
tomorrow. It will be a partly to mostly sunny day with highs in
the 80s. There may some patchy fog again tomorrow night.

Rain chances will increase across our western counties starting
Wednesday with better rain chances spreading across the region
Wednesday night and Thursday. On Wednesday, a negatively tilted
trough will move into West Texas spreading some lift across the
state. Our region will again be humid, unstable and uncapped thus
scattered rain activity is possible and more likely in the
afternoon hours. Widespread severe weather is not expected due a
lack of better forcing and weak wind shear, but isolated strong
storms may be possible with surface based CAPES of 1000-2000 j/kg
in the afternoon hours. Rain chances will continue to increase
Wednesday night as the upper level trough gets closer, and then
more widespread rain is expected on Thursday as the trough crosses
the Southern Plains. The models do have slightly different speeds
of the trough between Wednesday night and Thursday so some
adjustments to the timing of the best pops may be needed over the
next few days. At least a limited severe weather threat may occur
on Thursday, but again, wind shear values will be on the lower end
of the spectrum at 25-30 kts. This usually means that multi-cell
clusters will be more favorable with a threat for severe winds and
hail. With low level winds backed to the southeast, we cannot
completely discount an isolated tornado threat at this time, but
will need to monitor this threat. Also on Thursday, the potential
exists for heavy rain that may result in a flood threat for some
areas.

The upper level trough is actually slow to clear the region and
rain chances will continue on Friday with better chances across
our eastern counties. Another upper level trough enters the
Southern Plains on the heels of the first trough, and rain chances
will increase for next weekend. The models are in decent consensus
now that a front will move through the region with this system
bringing drier conditions for the start of next week. A severe
weather threat cannot be discounted over the weekend.

Jldunn

&&

Aviation...
/issued 131 PM CDT Mon may 29 2017/
18 UTC taf cycle

Concerns---convective potential at Waco this afternoon. MVFR cigs
and vsby possible at Waco during the overnight hours into Tuesday
morning.

For the metroplex taf sites---VFR is expected to continue at the
major airports over the next 24-30 hours. There's a low potential
for some reduced visibility at more rural metroplex taf sites (afw
and gky), but the overall probability is much too low to include
in this set of tafs. Light east winds will likely become light and
variable during the overnight time period with just scattered to at
times broken mid and high level clouds. Southeasterly winds are
expected on Tuesday morning and this flow should allow for a
greater degree of moisture transport. As a result, there's a
chance for some afternoon VFR cumulus, but for simplicity sake, I
have omitted this from the taf.

For the Waco taf site---it's a slightly more challenging aviation
forecast across central Texas as this area still remains entrenched
in better low level moisture. Very brief MVFR cigs were noted over
the past hour or so, but this should diminish soon with the late
may sun and resultant heating and VFR stratocumulus around fl035
is expected to prevail through Sundown. While the dense cirrus
canopy will allow for an influx of daytime heating, mesoscale
subsidence appears to be stifling any attempts at long- lived deep
moist convection. While conditions through the afternoon hours
should become more hospitable for showers, it's unknown as to
whether or not any of this activity can sustain itself to become
robust enough for lightning. As a result, i've cautiously removed
the mention of ts and have opted for an extended period of vcsh.
Should any rain showers activity show signs of becoming more robust, quick
amendments to add in thunderstorms in the vicinity or ts will be needed.

The near surface layer will remain quite moist during the
overnight hours. With decreasing surface wind speeds and the moist
low levels, the stage will be set for some reductions in both
ceilings and visibility. The Fly-in-the-ointment, however, will be
the lingering mid and upper level cloudiness. Current trends
would dictate that thinning of these high level clouds will occur
soon enough such that br develops. Winds just above the surface,
however, may promote some subtle mixing which could simply result
in a thin veil of stratus. Given this uncertainty, I will prevail
MVFR stratus after midnight with just a brief window of 3sm br and
cigs around fl015 near sunrise. Trends in higher resolution model
guidance this evening should help US better gauge this potential.
VFR is expected to return, but at this time, it appears that
it'll be beyond the end of the current taf cycle.

24-Bain



&&

Preliminary point temps/pops...
Dallas-ft. Worth 66 89 71 85 71 / 10 20 20 20 50
Waco 67 86 69 84 69 / 20 20 20 30 50
Paris 63 86 65 84 68 / 10 20 20 20 30
Denton 62 88 67 85 69 / 10 20 20 20 50
McKinney 63 87 67 85 69 / 10 20 20 20 40
Dallas 67 89 71 85 71 / 10 20 20 20 50
Terrell 65 85 67 85 69 / 10 20 20 20 40
Corsicana 68 85 71 84 70 / 20 20 20 20 50
Temple 67 85 69 83 69 / 20 20 20 40 60
Mineral Wells 62 87 66 85 68 / 10 10 10 20 50

&&

Forward watches/warnings/advisories...
none.
&&

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