849 
fxus64 klch 200458 
afdlch 


Area forecast discussion 
National Weather Service Lake Charles la 
1158 PM CDT Friday Mar 19 2010 


Aviation... 
VFR overnight with winds expecting to pickup twrds sunrise. Storms 
late tmrw afternoon. 


&& 


Previous discussion... /issued 722 PM CDT Friday Mar 19 2010/ 


Aviation... 
mostly clear skies tnght with a bit of fog twrds 
sunrise...otherwise VFR weather. 


Previous discussion... /issued 613 PM CDT Friday Mar 19 2010/ 


Update... 
mainly for coastal and marine issues as described below. 


Marine... 
upgraded the gale watch to a Gale Warning (to give 24 hours notice) 
across the 20-60nm zones...as the expected winds still look to be 
sustained over 30 kts...with gusts over 35 kts to possibly 40 kts 
at times off the Texas coast...to shortly before midnight off of the 
SC la coast. Across the coastal waters out 20 nm...expect winds of 
25 kts with gusts to just over 30 kts...expected to stay shy of 
gale force. Across the Inland Lakes and bays...expect winds of 
20-25 kts...with gusts to near 30 kts possible. 


In addition...issued a low water advisory from 7 PM Saturday to 7 PM 
CDT Sunday. The strong offshore winds will result in tides of -2.0 
to -2.5 feet (mean low lower water) around low astronomical tide 
during the early morning hours Sunday and Monday...and only 
rebounding to near zero feet Sunday afternoon. 


Dml 


Previous discussion... /issued 424 PM CDT Friday Mar 19 2010/ 


Synopsis... 
water vapor satellite imagery and upper air analysis shows 
a strong upper trough digging into the western Continental U.S. While shortwave 
ridging was noted over the central/Southern Plains. At the 
surface...ridge axis east of the area...centered over the central Gulf 
Coast states...with gusty srly winds developing over southeast Texas and SW 
la. Low level moisture continuing to increase over the area with 
dewpoints creeping into the lower 50s just west of the area and 
visbl satellite showing cumulus field across much of southeast/eastern Texas. 


Discussion... 
few changes made to the forecast. For tonight...temperatures are not 
expected to be as cool as the past couple of mornings...as the 
modifying Gulf airmass moves over the area. Lows Saturday will be 
near seasonal norms...near 50 north and lower 50s South. 


Spring will officially begin Saturday at 12:32 PM...and it will 
certainly seem like a Spring day with breezy south winds and 
temperatures warming into the lower 70s. However...significant 
changes will be on the way as a potent storm system moves into the 
area. 


A rather strong upper level low will drop into the Southern Plains...moving 
east across Texas. At the surface...a cold front will push rapidly east. 
Decent moisture pooling ahead of the front and convergent lift 
associated with surface front will produce numerous showers and 
thunderstorms...mainly along the boundary. Models seem to 
have a decent handle on the timing of the front...approaching the 
western zones by late afternoon...just east of the Sabine River by early 
evening...and exiting the eastern zones by midnight. A few isolated to 
scattered showers or storms could pop ahead of the system over S 
central la as 40-50 knots low level jet develops Saturday evening. Storm Prediction Center continues 
to delineate a slt risk for portions of the area mainly east of a 
Sabine Pass to Alexandria line...due to the impressive wind 
fields. However...instability remains on the low side as surface 
dewpoints are prognosticated to only reach the upper 50s or near 60. 


Behind the front...strong nwrly winds will develop and much cooler 
air will move into the area...making it feel less like Spring and 
more like fall. With strong cold air advection behind the front...temperatures 
still expected to be about 20 degrees below normal for afternoon highs 
on Sunday...with lows Monday morning in the middle 30s north to near 
40 south. 


Dry weather will prevail into the early part of the week...with 
temperatures gradually moderating back to near normal by 
Wednesday. Next chance for rain will come late Wednesday into 
Thursday as another front approaches the area. Models continue to 
differ on timing of the next system...so few changes to extended 
portion of forecast. 


Marine... 
a light to moderate southerly flow will prevail over the coastal 
waters through Saturday. A potent cold front is forecast to move 
through the Gulf waters Saturday evening...which will result in 
strong northwest winds and rough seas Saturday night into Sunday. 
Small craft advisories will be in effect for the coastal lakes and 
bays and waters within 20 nm beginning Saturday evening. A gale 
watch remains in effect for the outer waters beyond 20 nm as 
frequent gusts to gale force are expected in the wake of this 
front. Strong northwest to west winds will persist through 
Sunday...gradually diminishing by Monday morning. 


&& 


Preliminary point temps/pops... 
klch 52 73 38 56 38 / 10 60 50 10 10 
kbpt 54 72 38 56 38 / 10 80 30 10 10 
kaex 47 71 39 50 35 / 10 60 80 20 10 
klft 50 75 40 53 38 / 10 40 80 10 10 


&& 


Lch watches/warnings/advisories... 
la...none. 
Texas...none. 
GM...Small Craft Advisory from 7 PM Sunday to 10 am CDT Monday for 
the following zones: waters from lower Atchafalaya River to 
Intracoastal City, la extending from 20 nm to 60 nm. 


Gale Warning from 7 PM Saturday to 7 PM CDT Sunday 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 from 7 PM Sunday to 4 am CDT Monday 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. 


Small Craft Advisory from 7 PM Saturday to 7 PM CDT Sunday for 
the following zones: Calcasieu Lake...Sabine Lake... 
Vermilion Bay. 


Small Craft Advisory from 7 PM Saturday to 10 am CDT Monday for 
the following zones: coastal waters from lower Atchafalaya 
River to Intracoastal City, la out 20 nm. 


Small Craft Advisory from 7 PM Saturday to 4 am CDT Monday 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. 


&& 


$$