Area forecast discussion
National Weather Service Fort Worth Texas
327 PM CDT Thursday may 23 2013
Discussion...
latest surface analysis shows the boundary from the morning storm
complex in Oklahoma is currently draped near the I-20 corridor
northwest to near Childress. This boundary can easily be seen on
visible satellite with clearing subsident air to the north of the
boundary. To the south...low clouds remain in place with surface
dewpoints in the upper 60s and lower 70s. A 20z forward radiosonde observation does show
an uncapped airmass with plenty of instability. With this
environment and the boundary in place...cant rule out a
thunderstorm this afternoon. However...the limiting factor is
there is little to no convergence along the boundary to really
help initiate upward motions of the parcels. Will throw in a
mention of isolated T with a 10 pop before 00z for areas near the
boundary. If a storm does go...it would likely become severe with
a very unstable airmass and 0-6 shear near 40 kts.
The high moisture south of the boundary is being advected to the
northwest with middle 60 dewpoints all the way to Childress where the
first supercell thunderstorm has developed within upslope flow. A
shortwave can be seen on water vapor moving into New Mexico...and
as this upper support encompasses more of the region...additional
thunderstorms are expected across the Panhandle and West Texas.
These storms are likely to be severe given high cape and strong
shear. The storm movement today will likely be slow...and
primarily to the south/southeast...which should keep much of these
storms away from our western zones until late tonight. If this
were to occur...most storms would by then be much weaker with the
loss of surface heating and an increasing nocturnal capping
inversion. Our best shot of precipitation would likely be from any
complex of storms that could develop in Oklahoma...similar to what
occurred last night. The ttu WRF does develop a complex in western
Oklahoma after 06z and sends it south into the northwestern zones
near daybreak tomorrow.
Tomorrow afternoon...models are consistent in developing a weak
middle level low over West Texas in response to todays activity via
latent heat release processes from the thunderstorms. This low will
slowly meander east by tomorrow afternoon and should provide enough
upper support for isolated to scattered convection. Went with a 20
pop across all of North Texas for tomorrow and 30 pop for the
western zones...where the best lift should be located. Middle-level
flow tomorrow will be 5 to 15 knots which leads to only 10 to 20
knots of shear. Cape values will likely be near 2000 j/kg so think
severe chances will be minimal but cant rule out a marginally severe
hail storm before the updraft dies. What is most likely to occur is
multicell clusters with the potential for heavy rainfall given slow
movements. Will keep low probability of precipitation in the western zones tomorrow
night...as storms there are more likely to be still ongoing after
00z. Will continue the 20 pop for all counties Saturday as weak low
could still be meandering around the area...but with little upper
support or a surface focus for convection Sunday and beyond...kept
the rest of the forecast dry. This lift for storms Friday and even
Saturday is dependent on there being a lot of activity from this
afternoon and evenings storms...so the forecast could change.
Temperatures over the next few days will remain in the upper 80s to
near 90s degrees for most of the area with lows mainly in the upper
60s. A stronger trough is expected to move through the SW Continental U.S.
Around middle-week and then eject into the plains sometime late next
week. Given the uncertainties regarding the timing of the best
lift...will keep the forecast dry at the end of the period...but
later shifts will likely need to add probability of precipitation...once higher confidence
can be gained regarding the timing.
Hampshire
&&
Preliminary point temps/pops...
Dallas-ft. Worth, Texas 72 89 69 87 69 / 20 20 10 20 20
Waco, Texas 70 89 69 87 68 / 10 20 10 20 10
Paris, Texas 65 82 62 85 66 / 20 20 10 20 20
Denton, Texas 68 88 67 88 69 / 20 20 10 20 20
McKinney, Texas 67 87 66 87 68 / 20 20 10 20 20
Dallas, Texas 73 90 71 88 70 / 20 20 10 20 20
Terrell, Texas 70 88 67 87 68 / 20 20 10 20 10
Corsicana, Texas 71 89 68 87 68 / 10 20 10 20 10
Temple, Texas 69 88 68 86 66 / 10 20 10 20 10
Mineral Wells, Texas 69 88 66 86 66 / 30 30 20 20 20
&&
Forward watches/warnings/advisories...
none.
&&
$$
85/85
