Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Fort Worth Texas
659 am CDT Friday Sep 19 2014
Plenty of difficulty to start the day as the moisture remains rich
under 900mb this morning...especially around the dfw metropolitan which
seems to be both on the edge of the high cloud canopy. In addition...
dfw has not seen quite the rains that Waco and central Texas have
the past few days. Throw in the heat island effect and the challenge
will be forecasting any lower stratus. Winds are calm to light
east-southeast everywhere. As for precipitation...925-700mb Theta-E ridge is
just South-West of Waco.
per the current 12z forward u/a run...MVFR ceilings should form and prevail
through late morning. Will advertise brief IFR ceilings/visibilities through
middle morning with clear skies north of the cirrus canopy creating
some lower saturation. VFR conditions return by midday. Will not
mention rain showers or thunderstorms and rain with relatively drier airmass across the
ongoing IFR/LIFR appears likely through 15z-16z...then VFR ceilings
thereafter. Will carry tempo for vlifr conditions with patch fog
through middle morning.
All sites will see east-southeast winds 8-10 kts by this afternoon...becoming
light southeast tonight with a return of MVFR ceilings at all airports by
daybreak Saturday. If heavy rainfall occurs near Waco again today...
similar IFR/LIFR/vlifr conditions and patchy fog may be the case
again early Saturday morning.
Previous discussion... /issued 341 am CDT Friday Sep 19 2014/
the forecast through the weekend will feature continued chances
for showers and thunderstorms in many areas...with slightly above
normal temperatures. The highest rain chances will generally be in
the west and southwest parts of the forecast area where deepest
moisture coincides with weak large scale forcing for ascent.
Widespread heavy rains are not expected...so no headlines or
watches will be issued at this time. However...very high moisture
content and slow movement of convection could lead to isolated
areas of heavy rain into the weekend.
The deep tropical moisture associated with the remnants of Odile
will continue to spread into West Texas today. Some of this
deeper moisture will affect western parts of North Texas later
tonight and Saturday...and a greater coverage of showers and
thunderstorms will warrant some higher chance probability of precipitation in those areas
beginning late tonight. The rain chances on Saturday will range
from around 50 percent in the west near the greatest deep layered
moisture to 20 percent in the east where afternoon thunderstorms
will be possible.
A cold front...associated with a deepening upper trough in the
Great Lakes region...is still forecast to move into the area
Sunday night. Will keep chances for showers in the forecast
through Sunday night as the front moves through...but those
chances appear low given the relatively shallow forcing for
ascent near an expanding upper ridge. The airmass behind the front
will not be substantially cooler...but low level drying and the
resulting cooler nighttime lows will be noticeable.
Dry weather is forecast for Monday through Thursday of next week
as the upper ridge dominates most of the southern half of the
country. A well defined shortwave trough will move from California/Nevada on
Sunday into the northern and Central Plains on Tuesday/Wednesday.
This shortwave may temporarily weaken or suppress the upper
ridge southward...but the effects of the wave will be too far north to
bring any rain chances to North Texas. Temperatures are forecast
to average near normal or perhaps slightly above normal for the
Tuesday through Thursday period.
Preliminary point temps/pops...
Dallas-ft. Worth, Texas 90 73 91 73 92 / 20 10 30 20 20
Waco, Texas 89 72 91 72 92 / 30 20 30 20 20
Paris, Texas 88 69 89 68 90 / 10 10 20 20 20
Denton, Texas 90 71 90 70 92 / 10 10 30 20 20
McKinney, Texas 88 70 89 68 91 / 10 10 20 20 20
Dallas, Texas 89 74 90 73 91 / 20 10 20 20 20
Terrell, Texas 88 71 90 70 91 / 10 10 20 20 20
Corsicana, Texas 89 71 91 71 92 / 20 10 20 20 20
Temple, Texas 88 72 89 71 91 / 40 20 40 20 20
Mineral Wells, Texas 89 71 88 69 90 / 30 30 50 30 20