757 
fxus64 klch 181729 
afdlch 


Area forecast discussion 
National Weather Service Lake Charles la 
1229 PM CDT Thursday Mar 18 2010 


Discussion... 
for the 18/18z taf issuance. 


&& 


Aviation... 
expected some fair weather cumulus to develop this afternoon with 
daytime heating. Cloud based should remain around 5k feet and at 
VFR levels. What clouds that do develop will dissipate after 
sunset with clear skies through the night. 


Rua 


&& 


Previous discussion... /issued 1025 am CDT Thursday Mar 18 2010/ 


Discussion... 
surface high pressure continues to build this morning with mostly 
sunny skies and light northerly winds over the area. Temperatures 
have warmed into the middle and upper 50s as of 10 am...and afternoon 
highs into the upper 60s still looks on target. No update needed 
this morning. 24 


Previous discussion... /issued 507 am CDT Thursday Mar 18 2010/ 


Discussion... 
water vapor satellite imagery this morning showing shortwave trough 
diving south through East Texas/west Louisiana. Upstream...shortwave 
ridge noted translating east through The Four Corners...with several 
swirls evident over the east Pacific/western Canada that will play 
a role in our weather this weekend. At the surface...northwest Gulf 
Coast region falls between high pressure over the central/Southern 
Plains and low pressure off the South Carolina coast. 


A mix of clouds and sun is once again on tap for today as the 
shortwave trough quickly exits to the east...becoming absorbed into 
broader trough that itself will begin to track east out into the 
Atlantic...and the surface ridge over the plains builds southeast into 
the area. Anticipate less cloud cover than yesterday per forecast 
time heights/soundings that show dwindling moisture...but high 
temperatures should remain a little below those realized yesterday 
given the cold air advection that has occurred since...and will continue to occur 
at least through this morning. 


Light and variable winds with a clear sky will prevail tonight with 
the surface high sliding east across the area and the shortwave ridge 
building in overhead. 


Wind will take on a light southerly direction by early Friday as 
the surface high begins to shift east of the area...becoming more 
modest by the afternoon as those aforementioned swirls begin to 
phase over The Rockies and result in deepening low pressure over 
west central Texas. 


The global models are in relatively good agreement with the evolution 
of upper air and surface features for the weekend...though there 
are still some timing/placement issues to contend with. For this 
package...generally split the difference between the faster GFS 
and slower European model (ecmwf)...and showed the front entering East Texas by 
early Saturday afternoon...reaching east and south central 
Louisiana by Saturday evening. Nudged probability of precipitation higher once again as 
confidence increases in rainfall prospects for this event. As for 
severe potential...forecasts of bulk shear/helicity continue to look 
supportive...but if anything...forecasts of moisture/instability have 
trended slightly less so. Storm Prediction Center has carried the slight risk for most 
of the area into the day 3 outlook...and will continue to address 
this potential in the severe weather potential statement. 


Behind the front...strong cold air advection will usher in an 
unseasonably cool air mass...resulting in temperatures generally 10 
degrees below normal Sunday morning through Monday morning. 


The cool air wont last too long...however...as modification is 
expected to occur through the middle of the week in advance of 
another storm system slated to affect the area by middle to late 
week. 


Marine... 
northerly flow will continue today...becoming light and variable 
tonight as surface high pressure builds into the region. As the 
high shifts east of the area after midnight...a light to modest 
southerly flow will develop...which will persist through Saturday. 
A potent cold front is forecast to move through the Gulf waters 
Saturday afternoon and evening...which will result in strong 
northwest winds that will persist into Sunday. Small craft 
advisories will likely be needed for the strong winds/building 
seas behind the front. 


Public/marine...13 


&& 


Preliminary point temps/pops... 
klch 68 48 70 54 71 / 0 0 0 0 40 
kbpt 69 48 72 56 68 / 0 0 0 0 50 
kaex 68 44 71 49 70 / 0 0 0 0 50 
klft 68 45 71 51 72 / 0 0 0 0 30 


&& 


Lch watches/warnings/advisories... 
la...none. 
Texas...none. 
GM...none. 
&& 


$$