Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Lake Charles la
1103 PM CDT Friday Jul 11 2014
for the 06z taf package.
inland convection has come to an end...with just some high cirrus
over central/south central Louisiana. No major changes from
previous forecast...with VFR expected to prevail and tempo MVFR
toward morning based on latest guidance/persistence. Isolated to
perhaps scattered convection expected again tomorrow
afternoon...but held out of forecast given temporal/spatial
Previous discussion... /issued 641 PM CDT Friday Jul 11 2014/
for the 00z taf package.
VFR at all terminals for the time being...though currently
tracking a westward moving outflow boundary crossing the
Atchafalaya River. Timed the boundary into the klft/kara area to
around 0030 give or take...so inserted a 2 hour tempo for the wind
shift and -tsra to start the forecast period. Will continue to monitor
radar trends for a possible aww for kara should the need
arise...and for affects further downstream later this evening. VFR
should otherwise prevail...though based on a blend of latest
guidance and persistence...did insert tempo MVFR kaex-klch-kbpt
for a few hours in the morning. Will take a look at this potential for
the Acadiana terminals with the 06z issuance.
Previous discussion... /issued 616 PM CDT Friday Jul 11 2014/
mesoscale convective system over MS/southeast la this afternoon sending a rather large outflow
boundary SW towards c and SC la...with additional rain showers/thunderstorms and rain
forming along the outflow boundary as it marches SW. Latest hrrr
showing this trend with additional rain showers/thunderstorms and rain developing as the
boundary moves SW the next 3 hours...dying off after sunset.
Thus...increased probability of precipitation over this region for this. Updates already out.
Previous discussion... /issued 237 PM CDT Friday Jul 11 2014/
weak high pressure aloft capping almost all northern areas of our
County Warning Area this afternoon... while further to the
south...the feebly seabreeze and weak winds aloft putting a lid on
activity at the moment. High pressure aloft certainly not helping
here as well. Will carry low probability of precipitation tonight areawide with only token 20
percent in the Lafayette and Beaumont areas.
Looking ahead through the weekend...see hot days and warm nights
ahead for the region as high pressure aloft generally keeps a lid on
any widespread development. As is the case in the Summer
time...expect sea breeze activity to be the main kicker for middle
morning and afternoon convection.
Beginning next week...will be watching an unusual intense cyclone
dropping southward out of mid-Canada. Not unheard of to get a cool
front into Louisiana in the Summer. However...it is not a common
Summer topic we usually discuss. Therefore...let US discuss this
like rational humans that we are (knowing full well we are jumping
for Joy to get any heat relief).
As the intense cyclone deepens across the Great Lakes...upper level
troughing begins to deepen across the eastern United States. We begin
to actually see a good northerly flow aloft which will also reflect a
cool front driving southward into northern Louisiana late on
Tuesday. The front will probably hang up there...however due to the
upper level northerly flow...most likely will see weak northerly
winds begin to show up at the surface across our area by Tuesday
night into early Wednesday. The cool front will drive southward into
our area Wednesday and reach the coast by Thursday morning.
The good news is that we plan on carry at least chance probability of precipitation next
Tuesday through Friday as all the ingredients begin to come together
for rains. These probability of precipitation will be adjusted upward I would imagine as we
get closer to this coming rain event. The timing is currently the
only hangup for giving increased resolution to what areas will
likely see the best chances.
One thing we can say with much certainty...a change to a wetter
pattern and somewhat cooler temperatures just from the cloud cover
will begin next week as winds shift northerly to boot. Normally a
northerly wind in Summer spells hot hot temperatures. However...with
the cloud cover and rain...we should actually cool a few degrees on
the highs Wednesday through next Friday. Please...do not take the
winter jackets out...it will not be that kind of cold. Laughing out
Marine...weak high pressure will continue to hold over the Gulf
waters maintaining light winds and lows seas. Isolated shower and
thunderstorm activity can be expected mostly at night carry over in
the morning hours before dissipating.
Preliminary point temps/pops...
klch 76 94 75 93 / 20 30 10 20
kbpt 76 95 76 94 / 20 30 10 20
kaex 75 95 75 95 / 20 20 10 20
klft 76 93 76 93 / 30 30 10 30