329 
fxus64 klch 240203 
afdlch 


Area forecast discussion 
National Weather Service Lake Charles la 
903 PM CDT Wednesday Jul 23 2008 


Synopsis... 
tropical cyclone Dolly still pushing slowly westward across lower 
south Texas north of Brownsville. Large cyclonic flow around the 
system is producing a deep southeast flow over the forecast area. 
The latest upper air sounding from klch shows the result of this 
flow with a very moist tropical-like airmass in place as 
precipitable water value near 2.25 inches. 


Radar shows some shower activity hanging on around lower southeast 
Texas and lower southwest Louisiana where msas analysis still has 
some decent surface moisture convergence. 


Over the coastal waters...large swath of Small Craft Advisory 
winds...along with residual swells from Dolly still affecting the 
region. The east-southeast fetch having its effect of water piling 
along the coast. Tides around 1 1/2 feet above predicted levels 
during high tide time. This morning the actual tide reached 3.6 
feet MLLW at the Calcasieu Pass gauge and again up to 3.4 feet 
this evening. Reports of water up to Highway 82 in Cameron 
Parish...but no major problems. 


&& 


Update... 
as is typical in these tropical like airmasses...shower activity 
beginning to decrease during the evening hours...especially over 
land. Would expected nocturnal activity to re-develop later on 
tonight over the coastal waters...with trajectories taking some of 
the showers onshore the coastal areas before diminishing as they 
reach I-10. Have adjusted probability of precipitation accordingly with best chance over 
lower southeast Texas and extreme lower southwest Louisiana...with 
just a slight chance north of I-10. 


Will extend coastal flood advisory for one more high tide 
cycle...which will be around 6 to 7 am...as storm tide 
program...which has been doing a decent job with this 
event...shows actual tide levels between 3 and 3.3 feet MLLW at 
the next high tide. 


&& 


Rua 




&& 


Previous discussion... /issued 354 PM CDT Wednesday Jul 23 2008/ 


Discussion... 
Dolly is now ashore...with the eye over Port Mansfield this hour. 
The outer rainbands from Dolly are affecting our region at the 
moment. Expect ongoing convection for the evening hours...tapering 
off after midnight...but still keeping the chances better than 
normal. Low temperatures tonight will be quite warm...ranging in the middle 
70s...to upper 70s for SW la/southeast Texas...as the gradient wind likely 
stays up near 10 miles per hour overnight. Coastal tides have been running 
about 1.5 feet above normal. With the high tide still yet to come 
this evening between 7-8 PM...the coastal flood advisory will remain 
in effect for total tide values reaching 3-3.5 feet...and will 
diminish after midnight. 


For Thursday...best chances for rain showers/thunderstorms and rain remains over southeast Texas/SW 
La...Due to the remaining moisture axis from Dolly. This will 
gradually move west with the remnants...with probability of precipitation going down to 
20% or less by late evening. 


For Friday through next Monday...hot and dry with only 20% chance 
of late afternoon rain showers/thunderstorms and rain at best. You guessed it...a large upper 
ridge Will Park over the Southern Plains during this period essentially 
putting a warm dry lid on most cumulus development...with only the 
most robust updrafts making it to thunderstorms and rain stage. Temperatures will be quite 
hot during this period...with middle 90s across southeast Texas/S la...upper 
90s to possibly reaching 100 further inland on sun. 


By Tuesday...a weak upper low over the eastern Gulf will likely drift 
west...slinging increased moisture from east to west across la 
into southeast Texas...thus raising probability of precipitation a bit during this period. 


Dml 


Aviation... 
scattered rain showers/thunderstorms and rain continue to develop across the area this afternoon 
.With activity expected to decrease in coverage later this evening. 
Heaviest convective activity has lifted north of klch and kbpt...with 
light rain under VFR ceilings prevailing through the rest of the afternoon 
and possibly into early evening. Additional activity may affect this 
area toward morning...especially kbpt...but will not include in taf 
atmosphere. Rain showers/thunderstorms and rain will affect klft and kara over the next 1 to 2 hours...with 
VFR expected thereafter. Vcsh/thunderstorms in the vicinity kaex into early evening. IFR conditions 
possible in stronger shra/tsra...with wind gusts up to 30kt. 


SC 


Marine... 
numerous shra/tsra...along with east-southeast winds 20-25g30 seas 6-9 feet 
continue at buoy 42035...which is and is a good estimate for the 
remainder of the marine zones east to Intracoastal City this evening. 
Further east to the Atchafalaya River...southeast winds 15-20 kts and 
seas 5-7 feet will continue this evening...subsiding by midnight. 
The Small Craft Advisory remains for all of the 20-60nm zones after midnight through 
Thursday afternoon for residual swells of 7 feet...otherwise winds will 
be below criteria by the afternoon hours. 


&& 


Preliminary point temps/pops... 
klch 76 90 76 93 75 / 50 50 20 20 10 
kbpt 77 89 76 94 75 / 50 50 20 20 10 
kaex 75 94 73 97 73 / 40 40 20 20 10 
klft 74 92 75 95 76 / 40 40 20 20 10 


&& 


Lch watches/warnings/advisories... 
la...coastal flood advisory until 8 am CDT Thursday for the following 
zones: Cameron...Iberia...St. Mary...Vermilion. 


Texas...coastal flood advisory until 8 am CDT Thursday for the following 
zones: Jefferson. 


GM...Small Craft Advisory until 4 PM CDT Thursday for the following 
zones: waters from Cameron, la to High Island, Texas extending 
from 20 nm to 60 nm...waters from Intracoastal City, la to 
Cameron, la extending from 20 nm to 60 nm...waters from 
lower Atchafalaya River to Intracoastal City, la extending 
from 20 nm to 60 nm. 


Small Craft Advisory until 5 am CDT Thursday for the following 
zones: coastal waters from Cameron, la to High Island, Texas 
out 20 nm...coastal waters from Intracoastal City to 
Cameron, la out 20 nm...coastal waters from lower 
Atchafalaya River to Intracoastal City, la out 20 nm. 


&& 


$$ 

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