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Area forecast discussion...updated 
National Weather Service Fort Worth Texas
622 am CDT Sat Aug 23 2014

/12z tafs/

VFR conditions expected through the period with southerly winds
around 10kts. Some thin high clouds may try to spread into the
region but otherwise skies will remain clear. No significant
aviation concerns expected through the period.



Previous discussion... /issued 346 am CDT Sat Aug 23 2014/
the main upper level features of interest this weekend across the
Continental U.S. Are a subtropical upper level high centered over East Texas
and an unseasonably strong upper level cyclone that is swinging
through the northern rockies. The upper high will ensure dry and
seasonably hot conditions over North Texas today...while the upper
cyclone to our northwest will result in moderate southerly
breezes. Persistence is likely the best guidance for the temperature
forecast in the short term. But as southerly winds diminish a
bit Sunday and Monday...this may result in high temperatures creeping up
a degree or two...while low temperatures cool slightly in non-urban areas.

The upper level high will begin to shift northward by Tuesday
which will allow a TUTT...or tropical upper tropospheric trough to
move into the region from the east. This feature can be seen now
on the water vapor satellite near Cuba...west of the tropical
disturbance near Hispaniola. Model guidance is in good agreement
that the TUTT axis will be immediately followed by a tropical
wave. The tropical wave is identifiable as an inverted trough
axis in the low level wind/height fields. As the TUTT and tropical
wave move into the region from the east on Tuesday and
Wednesday...precipitable water values are forecast to surge from
below 1.5 inches to above 2 inches. Have brought in a slight
chance of afternoon and evening showers/storms to the eastern half
of the area Tuesday...and have spread 20 probability of precipitation over the entire County Warning Area
by Wednesday afternoon. Due to the increased moisture and more
easterly fetch...high temperatures will begin to cool slightly midweek.
If successive model runs continue to show this scenario...probability of precipitation
may need to be increased further.

By middle to late week we will also be watching the evolution of the
longwave trough over the western U.S. As it will influence the
strength and timing of a cold front. The GFS remains the fastest
with moving this trough east and as a result has the cold front
in before all other guidance. The UKMET and Canadian look very
similar to the European model (ecmwf) and therefore have followed their solutions
of a slower front...likely arriving Thursday night. Since plenty
of tropical moisture would be in place ahead of the front...this
is certainly good for rain chances. However due to the timing
uncertainties of the front it is difficult to pinpoint which 12
hour window will be the best for this rain chance. For now have
highlighted Thursday night as the best chance with 30 probability of precipitation...with
20 probability of precipitation Wednesday night...Thursday...and Friday. Again...probability of precipitation on
at least one of these time periods will likely be raised when
better confidence of frontal timing is attained. Temperatures will
cool a few more degrees by Thursday and Friday due to the rain
chances and cold front...but will stay pretty close to normal.



Preliminary point temps/pops...
Dallas-ft. Worth, Texas 101 78 101 78 101 / 0 0 0 0 0
Waco, Texas 101 75 101 74 101 / 0 0 0 0 0
Paris, Texas 98 73 99 73 98 / 0 0 0 0 5
Denton, Texas 101 75 101 74 100 / 0 0 0 0 0
McKinney, Texas 99 75 100 74 100 / 0 0 0 0 0
Dallas, Texas 100 78 101 78 101 / 0 0 0 0 0
Terrell, Texas 100 76 101 75 101 / 0 0 0 0 5
Corsicana, Texas 101 76 101 75 101 / 0 0 0 0 5
Temple, Texas 100 74 100 73 100 / 0 0 0 0 0
Mineral Wells, Texas 101 73 101 73 101 / 0 0 0 0 0


Forward watches/warnings/advisories...



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