842 
FXUS64 KLCH 062218
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
418 PM CST Wed Mar 6 2019

.DISCUSSION...

Short Term [Today and Thursday]

This afternoon's surface analysis indicates a 1032 hPa high
pressure extends across the Lower Mississippi River Valley. Clear
skies combined with daytime mixing and insolation have allow for
temperatures to climb into the mid to upper 50s across most of the
region this afternoon. 

The surface high pressure will move eastward during tonight into
Thursday and result in becoming more southeasterly. These
southeasterly winds will contribute to increasing moisture and
cloud cover during the overnight hours. Therefore, temperatures
are not expected to fall to 32 or below as in the past two nights.
Overnight lows should range from the mid 40s along the coast to
the mid 30s across northeastern portions of the CWA.

Despite cloud cover tomorrow, temperatures are expected to
continue to warm as southeasterly winds contributes to warm air 
advection across the area. Daytime temperatures should climb into
the 60s across the entire area. In addition, moisture is expected
to increase which will result in a chance for showers, mainly 
across southeast Texas in the afternoon into the evening.

Long Term [Friday through Tuesday]

A short wave trough will dig into the central Plains on Friday
into Saturday which will help support cyclogenesis. This will 
result in strong low level height and surface pressure gradients 
across the region which will result in a strong kinematic wind 
field over the Lower Mississippi River Valley. Model guidance is 
indicating 0-6 km wind shear will be in excess of 45 knots. 
Meanwhile, effective helicity is forecast to be in excess of 250 
m2/s2. These strong wind fields will result in the potential for 
organized convection and severe weather during the day on 
Saturday.

The main question mark with regards to severe weather on Saturday
will be the amount of instability that can develop ahead of the 
surface front. Steepening 700 hPa - 500 hPa lapse rates and
dewpoints into the mid 60s will be supportive of a conditionally
unstable environment developing. On the other hand, isentropic 
ascent will result in widespread cloud cover which will limit 
heating and destabilization. Despite the cloud cover, model
guidance is still indicating the potential for MLCAPE of 1000-1500
J/kg which in conjunction with the aforementioned wind fields will
certainly support at least the potential for severe convection
across the area on Saturday.

Based on this conditional threat, the Storm Prediction Center 
currently has the entire area highlighted in a Slight Risk of 
severe weather. However, the highest likelihood for severe 
weather occurring appears to be concentrated in the northern 
portions of the CWA into central Louisiana during the mid to late
afternoon of Saturday. Continue to monitor the forecast over the
next few days for updates on this potential severe threat.

Beyond Sunday, a more amplified height pattern is forecast to
develop across the CONUS into early next week. Two troughs are
forecast to be centered over the East Coast and West Coast with a
ridge axis centered just east of the Lower Mississippi River
Valley. This will help induce return flow across the region during
the early part of next week. As a result of this return flow,
temperatures are expected to be above normal with chances of
showers and thunderstorms on Monday and Tuesday.

&&

.MARINE...

Onshore flow will redevelop as high pressure moves east of the
area. An increasing pressure gradient will result in these onshore
winds increasing to 10 to 15 knots and remaining elevated through
Saturday. These winds will become stronger Saturday ahead of a 
front pushing into the region and Small Craft Exercise Caution or
Advisory products may be needed. Elevated rain and thunderstorm 
chances will accompany the front as it moves through the coastal 
waters Saturday. Easterly flow is expected to redevelop in the
wake of this system and continue into early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  38  62  58  72 /   0   0  30  40 
LCH  43  67  62  72 /   0  20  20  40 
LFT  42  65  59  74 /   0   0  10  30 
BPT  47  70  64  73 /   0  30  30  30 

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&

$$

PUBLIC...26