Scientific Forecaster Discussion

Return to Local Conditions & Forecast
Area forecast discussion 
National Weather Service Fort Worth Texas
339 am CDT Thursday Apr 24 2014

most of the evening convection has exited the County Warning Area into Oklahoma.
Middle-level moisture is not as high as anticipated and thus the
elevated convection that was previously expected for the overnight
hours is less likely. We have seen a couple of weak showers try to
develop but they quickly dissipated due to the moisture problems.
However...steep middle-level lapse rates could lead to a strong
storm if something does fire. Model soundings show further drying
of the middle-levels after 12z and today should be mostly dry across
much of the County Warning Area.

A strong surface low extends from northwest Oklahoma into NE Kansas. This
low should quickly move east...and as it does a cold front will be
able to surge southward on the backside of the low. The front is
expected to reach our northwestern zones around middle-morning and
then should reach the southern County Warning Area border around late-afternoon.
This front will have a little effect on temperatures...with highs
today about 5 degrees cooler than yesterday. High-res model
guidance is showing isolated shower and storm activity along the
front late this afternoon. This has been consistently forecasted
by the guidance...but the front is expected to push farther south
than thought. This should allow for most activity to be south of
the County Warning Area. Nevertheless will hold onto 20 probability of precipitation across the southern
zones for any showers and storms that develop along the front this
afternoon. Cape values will be quite high there is the
potential for any storms that do develop to become severe. This
potential matches well with the 5 percent severe hail/wind
probabilities on the day 1 outlook.

Southerly winds return on Friday in response to the next
approaching system and high temperatures will be back in the
middle to upper 80s across North Texas. This upper low is expected
to be much stronger than the current one. The current forecasted
track is to our north...but there will still be plenty of lift
across the County Warning Area Saturday night through Sunday night. Saturday
should be mostly quiet due to a strong capping inversion that is
expected to be in place. The dryline Saturday afternoon is
forecasted to be about 2 counties west of our western boundary.
Severe storms are expected to develop along the dryline during the
late afternoon hours and storm motions would then take them into
our western counties after 00z. Hail and damaging winds would be
the main threats...but as storms enter our County Warning Area...dewpoints in the
middle-60s and shear profiles would support an isolated tornado
threat. Surface based convection should weaken after 3z as the
boundary layer decouples...but continued lift and elevated
instability will continue the rain chances as elevated showers and
thunderstorms remain possible.

As the upper low nears North Texas Sunday...the dryline will be
able to surge eastward. There remains some discrepancies between
the model guidance on how far east the dryline will go...but the
general consensus is near the I-35 corridor. Storms will be
possible to the east of the dryline...and surface based convection
is expected once the cap erodes in the afternoon. Severe weather
will once again be cape and shear values support
rotating storms. However...poor low-level lapse rates are limiting
higher cape values and veering winds ahead of the dryline should
limit the directional shear. Therefore...hail and damaging winds
will once again be the main threat. Cant rule out isolated
tornadoes...but the best timing would be before 3 PM...before low-
level winds begin to veer and only Uni-directional shear is in place.

The associated cold front is not expected until Tuesday morning as
the upper low stalls to our north as it gets caught in a blocking
pattern. Most medium range guidance keeps the low to our northeast
through Friday. The persistent northerly flow and additional surge
of cooler air will keep temperatures below normal next week.



Preliminary point temps/pops...
Dallas-ft. Worth, Texas 81 59 84 62 84 / 10 0 0 5 0
Waco, Texas 83 54 83 64 83 / 10 5 0 0 0
Paris, Texas 79 54 82 58 82 / 10 5 0 0 0
Denton, Texas 82 49 84 61 84 / 5 0 0 5 5
McKinney, Texas 81 51 83 59 81 / 10 0 0 5 0
Dallas, Texas 82 59 85 62 84 / 10 0 0 5 0
Terrell, Texas 80 54 82 59 84 / 10 0 0 5 0
Corsicana, Texas 81 57 83 61 85 / 10 5 0 0 0
Temple, Texas 85 57 84 64 82 / 10 5 0 0 0
Mineral Wells, Texas 81 53 85 63 86 / 5 0 5 5 10


Forward watches/warnings/advisories...