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Area forecast discussion 
National Weather Service Houston/Galveston Texas 
1035 am CST Sat Nov 21 2009 


Discussion... 
surface low located off the SW Louisiana coast at late morning with 
upper low located across southeast Texas. Still have good coverage of light 
rain on radar across the northern 2/3 of the area. Have raised 
probability of precipitation a bit for the afternoon hours accordingly. Precipitation will end 
completely for most areas by middle afternoon if not sooner. Thick blanket 
of low clouds persists across the area. Have increased sky cover 
with eastern areas likely to not see significant clearing until 
early this evening. As a result have lowered maximum temperatures a bit over 
the east. Skies will clear out completely this evening with nice 
weather expected for Sunday. 


Tide levels are dropping quickly with the northerly flow especially 
along the immediate coast. All the sites are reporting levels below 
3 feet with Pleasure Pier down to 1.8 feet and pier 21 down to 2.3 
feet. Currently moving into astronomical low tide so levels should 
continue to drop into this evening. As a result will not issue any 
new cfw highlights for the area. 


35 


&& 


Previous discussion... /issued 625 am CST Sat Nov 21 2009/ 


Update... 
12z aviation update below. 


Aviation... 
satellite shows signs of one more round or two of light rain in 
the near future around the backside of this slowly-exiting upper 
low/wave into the Sabine region through noon. Slow rotation of 
this light rain per radar will keep -ra or -shra around through a 
good majority of the morning...tapering off through the afternoon 
under lifting MVFR broken-overcast decks through sunset. Due to the 
saturated ground...occasional breaks in deck...and lightened winds 
brought on by slightly higher pressures...the formation of early Sat 
evening fog is a mentionable likelihood. Conservative with 
tafs...lowering visbies down into MVFR a few hours past sunset to 
IFR shortly after midnight. Tempo'ed LIFR under mile across 
kcxo/klbx...but believe that if these sites do in fact lower to LIFR 
then there is a high probability of vlifr fog and more area-wide LIFR fog 
issues the next couple of mornings. As of now a heads up that Monday 
morning dense fog looks more likely as low exits far enough ne'ward 
to introduce sky clear and near calm conditions from Sunday evening 
Onward. 31 


Previous discussion... /issued 420 am CST Sat Nov 21 2009/ 


Discussion... 
East Texas middle/upper level low and associated northwest Gulf of Mexico 
surface low will move to the east and northeast today and take all rains 
with it. Will need to carry some probability of precipitation for southeast Texas during the day today 
with rains coming to an end from southwest to northeast as the day progresses. 
Today's high temperatures are based on cloud cover lingering across much 
of the area. Clearing skies sooner than expected could result in warmer 
afternoon highs. Winds along the coast will diminish during the day 
as the storm system moves on out. Surface high pressure building into 
the area brings dry weather with cools night and mild days Saturday night 
through Sunday night. As the high moves east on Monday...warmer south 
to southeast winds return. Moisture levels also begin to increase...and 
this will set the stage for our next chance of rain Monday night and 
Tuesday as the next cold front moves through the area. Chance probability of precipitation will 
be carried with this front...but a slower moving boundary as some models 
are suggesting could result in a better chance of showers and thunderstorms. 
Southeast Texas dries out once this front moves through...and surface 
high pressure building into the area will bring cool nights and mild 
days back to the area from Tuesday night on through the rest of the 
week...including Thanksgiving. Moisture levels don't increase again 
until the weekend...and this could end up bringing the area our next 
chance of rain. 42 


Marine... 
strong easterlies will turn more northerly through the day as the 
low pressure system tracks further away to the northeast...allowing 
for a gradual subsidement of seas and a lowering of high coastal 
water levels. Advisories across the Gulf through the day...scec 
across the local bays. Coastal Flood Warning has been extended 
through noon to account for lagging run-up from this recent swell 
brought on by this persistent strong easterly fetch. Forecast is for 
short period 6 to near 10 foot waves to lower to between 4 to 7 feet 
this evening under relaxing northerlies. As the surface low pulls 
out over the lower Mississippi Valley through the weekend...winds 
across the eastern-most seas will be higher due to a tighter 
backside pressure gradient. North-NE winds and seas will be back to 
Small Craft Advisory levels late Tuesday through Wednesday. A cold 
front and a good shot of cold air behind it will aggressively cross 
the far offshore waters sometime Tuesday night. 31 


&& 


Preliminary point temps/pops... 
College Station (cll) 61 46 70 50 74 / 40 0 0 0 10 
Houston (iah) 60 46 70 49 75 / 40 0 0 0 10 
Galveston (gls) 60 54 68 58 73 / 30 0 0 0 10 


&& 


Hgx watches/warnings/advisories... 
Texas...none. 
GM...small craft should exercise caution until 6 PM CST this evening 
for the following zones: Galveston Bay...Matagorda Bay. 


Small Craft Advisory until 6 PM CST this evening for the 
following zones: waters from Freeport to the Matagorda Ship 
Channel 20 nm to 60 nm...waters from Freeport to the 
Matagorda Ship Channel out 20 nm...waters from High Island 
to Freeport 20 to 60 nm...waters from High Island to 
Freeport out 20 nm. 


Small craft should exercise caution from 6 PM CST this evening 
through this evening for the following zones: waters from 
Freeport to the Matagorda Ship Channel 20 nm to 60 nm... 
waters from Freeport to the Matagorda Ship Channel out 20 
nm...waters from High Island to Freeport 20 to 60 nm... 
waters from High Island to Freeport out 20 nm. 


&& 


$$ 


Discussion...35