Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Fort Worth Texas
1144 PM CDT Sat Sep 20 2014
For the 06z tafs...no significant changes were made from the 00z
tafs...therefore the previous discussion is attached below.
Confidence in thunderstorms affecting dfw area tafs behind the
front remain low...so left the forecast dry for now.
../previous aviation discussion/...
/issued 624 PM CDT Sat Sep 20 2014/
For the 00z tafs...the timing of a weak cold front across the area
tomorrow is the primary forecast concern.
VFR conditions are expected to hold through the valid forecast
period. In the short term...east to southeasterly flow has brought
significantly drier air to the Interstate 35 corridor from the
east. Dew points at all area taf sites were mixing out into the
upper 50s and dfw area amdar soundings indicated no energy for
buoyant convection in the atmosphere with this drier air now in
place. Dry air will not just keep area airports dry ahead of the
front...but will also keep low stratus away from the area tonight
through early tomorrow morning.
Regarding the front tomorrow...winds are expected to become light
and variable well ahead of the front after midnight tonight across
the region. Winds are expected to become light and northeasterly
by late tomorrow morning. The true front is not expected to arrive
in the dfw area until 00z...but north flow should already be in
place before this arrives. Winds will pick up a bit behind the
front and shift around to due north. Some models are hinting at
scattered thunderstorms developing behind the cold front tomorrow
evening just north of the dfw area. Will wait and see if this
signal holds in future model runs before placing any mention of
thunder in the dfw area tafs. If storms occur behind the
front...they look most likely to affect the dfw area around 03z
forecast is in good shape this evening and will only update to
remove the mention of showers for the remainder of the evening.
Substantially drier air has moved in across the region and think
that most of the additional precipitation will be confined to the
western part of the state. No other changes planned at this time.
Previous discussion... /issued 253 PM CDT Sat Sep 20 2014/
visible satellite shows a large hole in the afternoon cumulus
field across the eastern zones which is evidence of the drier air
that is moving into the County Warning Area from the east. As this dry air
continues to advect eastward...chances for any light showers will
also end for most of the area. However will keep a slight chance
of showers in the far western zones into the overnight hours where
enough moisture and weak lift from the remnants of Odile may
reside for some activity. Otherwise clearing skies are expected
tonight and winds will become nearly calm across the most of North
Texas. This will enhance radiational cooling and low temperatures should
cool into the middle 60s to low 70s.
A cold front is currently located across northern Kansas and is
heading southward. This front should cross the Red River Sunday
evening...but ahead of it a hot day is expected in North Texas
with temperatures reaching the 90s with lots of sunshine.
Moisture ahead of the front will be very limited and little to no
surface instability is forecast across North Texas when the front
moves in Sunday night and Monday morning. Also because wind fields
are so light ahead of the front...low level convergence will be
limited. Still will show a slight chance of showers/storms late
Sunday afternoon and evening over the northern zones as some
convection should fire in Oklahoma and move southward. This
convection will dissipate when it encounters increasing stability
over North Texas. The front will not move through the southern
zones until Monday afternoon...and will keep a slight chance of
rain in the forecast across the southern parts of the area for
anything that may pop up with the aid of afternoon heating.
Cold advection will be weak behind the front as the core of the
cool airmass will stay over the eastern part of the Continental U.S. As the
surface high tracks into the Ohio River valley. Although not much
cool air will arrive with this front...the air will be drier. This
dry air will promote good radiational cooling and allow overnight
lows to drop into the 60s area wide...with some pockets of upper
50s. High temperatures will stay mild...either near or slightly above
normal in the middle to upper 80s. Generally clear skies will
prevail...daytime humidity will be low...and winds will be light
from Tuesday into Friday...so it will feel fairly pleasant next
Extended models continue to show the storm track with the upper
level westerlies remaining well north of the region due to a
stationary upper level low off of the western coast of Canada. In
addition...easterly flow will prevail in the lower levels which
will tend to keep Gulf moisture south of the region. Thus the
forecast continues to look dry into next weekend despite the
GFS/European model (ecmwf) forecasting a weak upper low to develop over the
plains by next weekend.
Preliminary point temps/pops...
Dallas-ft. Worth, Texas 72 93 70 87 66 / 5 5 10 10 5
Waco, Texas 69 93 70 90 66 / 10 5 5 20 5
Paris, Texas 68 89 64 81 59 / 5 20 20 5 5
Denton, Texas 67 91 67 86 61 / 5 10 20 5 5
McKinney, Texas 66 92 66 86 59 / 5 10 20 5 5
Dallas, Texas 72 93 70 87 66 / 5 5 10 10 5
Terrell, Texas 69 94 69 87 62 / 5 5 10 10 5
Corsicana, Texas 69 94 71 89 64 / 5 5 10 10 5
Temple, Texas 69 93 70 91 66 / 10 5 5 20 5
Mineral Wells, Texas 69 91 68 86 64 / 10 5 10 10 5