National Weather Service Raw Text Product

209 
FXUS64 KLCH 100942
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
342 AM CST Mon Dec 10 2018

.DISCUSSION...

Short Term...Today and Tuesday...

A broad 1028 hPa high pressure area will build southeastward into
the Lower Mississippi River Valley today and be centered over the
CWA on Tuesday. This will result in dry conditions and clear 
skies today and Tuesday. 850 hPa temperatures of -1 to -2 sigma 
will contribute to below normal temperatures despite abundant 
sunshine both today and tomorrow. The combination of clear skies 
and near calm winds tonight will be favorable for radiational 
cooling and freezing temperatures for areas along and north of 
Interstate 10. The entire area has already seen a freeze this 
season and northeast portions of the CWA look to bottom out 
several degrees above 25 so no Hard Freeze products appear to be 
needed at this time.

Long Term...Wednesday through Sunday…

By Wednesday, the surface high pressure will shift to the east of
the CWA and allow for return flow to develop ahead of a shortwave
trough digging into the Southern Plains. There is some 
uncertainty regarding the amplitude and timing of this shortwave 
trough based on ensemble and deterministic model guidance. 
However, the shortwave trough is expected to support cyclogenesis 
and the development of a surface low in the Southern Plains 
Wednesday into Thursday. The surface cold front associated with 
this low is expected to approach the CWA late Wednesday and move 
across the region during the day on Thursday. The return flow 
ahead of the surface cyclone should result in enough Gulf moisture
being advected into the region to support at least some surface 
based instability to support thunderstorms. Model guidance 
currently is indicating the potential for 500-1000 J/kg SBCAPE, 
which in conjunction with 30+ knots of 0-6 km shear could support 
some organized convection. However, based on the uncertainty in 
the development of the shortwave trough, surface cyclone, and 
surface based instability, it is too early to highlight any 
hazards other than lightning with thunderstorms that do develop.

The surface cyclone is expected to be fairly progressive and the
majority of the precipitation should end across the region by
Thursday evening. However, similar to the system that move through
the area this past Saturday, some light drizzle wrapping around
the back edge of the low could linger across the region on Friday.

Beyond Friday, the upper level height field over the CONUS will
consist of a very broad trough with embedded shortwaves
progressing through it. Model guidance is depicting a wide variety
of solutions for the timing and amplitude of the individual
shortwaves. Therefore, the forecast for the end of the long term
period remains relatively close to Superblend output with low
precipitation chances and near normal temperatures.

&&

.MARINE...

High pressure will build over the region today and be centered
north of the region on Tuesday which will allow for offshore winds
to decrease. Onshore flow will develop on Wednesday as the high
pressure shifts eastward. A storm system will move across the
Lower Mississippi Valley late Wednesday into Thursday and this
will result in widespread showers and thunderstorms over the
coastal waters. Strong offshore flow will develop behind this
system and Small Craft Advisories will likely be needed for
Thursday into Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  52  27  57  36 /   0   0   0   0 
LCH  56  34  57  43 /   0   0   0   0 
LFT  53  33  56  40 /   0   0   0   0 
BPT  55  35  58  47 /   0   0   0   0 

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Exercise Caution until 6 AM CST early this morning 
     for GMZ450-452-455-470-472-475.

&&

$$

PUBLIC...26