Area forecast discussion
National Weather Service Shreveport la
931 PM CDT Tuesday Jun 18 2013
Discussion...
interesting forecast for the remainder of the night with lots of
ingredients that may result in some thunderstorm redevelopment
overnight.
Regional radar mosaics continue to show a large area of
dissipating showers across our extreme southeast zones at this time. This area
has been steadily shrinking in coverage and intensity over the
last few hours and expect that to continue this evening.
Elsewhere...we are seeing some isolated thunderstorms across the northern
third of NE Texas into SW Arkansas and this activity appears to reside
along the true frontal boundary which is very difficult to find in
the pressure analysis. We are also beginning to see some
redevelopment across deep East Texas to the SW of Lufkin at this time.
Models are too fast in accelerating mesoscale convective vortex across north central Texas
eastward overnight based upon its last location witnessed on visible
satellite this evening. Its moving very slowly to the east
southeast and history suggests we could see redevelopment with
this intense middle level feature through the night. In
addition...the west to east frontal boundary basically extends
from near the Arkansas/la border to just north of the I-20 corridor in
NE Texas. This could very well serve as a focus overnight as well
along with the numerous outflow boundaries that likely reside
across our region from previous convection.
Looking aloft...thetae surfaces at the 850mb and 700mb level show
weak thetae ridges across NE Texas and north la basically just south of
the west to east surface boundary and these could prove to be focus
mechanisms as well.
Given the high precipitable water content as observed on our sounding this
evening...will leave pop forecast as is for the night with the
highest chance probability of precipitation across our extreme southern zones where the
best moisture resides.
Concerning overnight temperatures...02z temperatures are running quite a
bit cooler than this time last night and this is due in part to
all the rain that fell today. Forecast min temperatures overnight seem to
have this well in hand and while current temperatures are near forecast lows
at this time across several locations...do not think these locations will
see too much more of a temperature drop overnight.
What changes were made were fairly cosmetic with sky...dewpoint
and wind grids as well as hourly temperature grids to mimic current
trends. Otherwise...no significant changes to the forecast this
evening.
Update already sent...13.
&&
Aviation...
main band of showers/thunderstorms should exit the area prior to the start of
the 06z taf period. Weak surface cold front was located from near kosa
to keld. Isolated to scattered convection will continue to develop
through the overnight hours as the front slowly drops south. Where
the precipitation is not occurring...MVFR/IFR conditions will likely
develop during the early morning hours. Locations that received
heavy rainfall during the previous day may experience dense fog and
LIFR cigs/vsbys. Slow...but gradual improvement into the VFR is
expected through late Wednesday morning. More scattered showers/thunderstorms will
be possible during peak heating Wednesday along the front and as a
weak upper disturbance associated with convection across the High
Plains moves over the area. However...best chances will likely be
south of I-20. Any convection that does develop should be on a
diminishing trend by 20/02z.
/09/
&&
Preliminary point temps/pops...
shv 69 90 73 93 74 / 30 30 10 20 10
mlu 70 89 70 92 72 / 30 30 10 20 10
deq 64 90 68 92 72 / 10 10 10 20 10
txk 68 90 70 91 73 / 20 20 10 20 10
eld 67 90 69 92 71 / 20 20 10 10 10
tyr 69 91 74 93 74 / 20 30 10 20 10
ggg 69 90 73 93 73 / 20 30 10 20 10
lfk 71 92 73 94 74 / 30 30 10 20 10
&&
Shv watches/warnings/advisories...
Arkansas...none.
La...none.
OK...none.
Texas...none.
&&
$$
13/09
