Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Lake Charles la
555 PM CDT Sat Mar 15 2014
00z taf issuance.
large shield of light to moderate rain showers from the I-10 corridor
northward across southeast Texas/c la. Possibility for isolated thunderstorms and rain & MVFR
ceiling/vsby...kept tempo group for aex through 04z. For bpt/lch...will
have intermittent rain showers & MVFR ceiling/visibility through this period. Will
have a period of decreased chances after 04z...but the next
impulse expected to bring rain showers/thunderstorms and rain between 08-14z across the
area...thus placing the appropriate tempo groups for thunderstorms and rain & IFR
vsby/ceilings. By 14-16z...expecting the wind shift...with
lingering -ra. By 18-20z...stronger northwest winds expected and
optimistically going with vcsh.
Previous discussion... /issued 321 PM CDT Sat Mar 15 2014/
middle-afternoon surface analysis shows a cold front stretching from southeastern
Kansas across the OK/Texas panhandles to the desert SW. Water vapor
imagery shows a middle/upper-level cutoff low spinning across western
Texas...with the strongest shortwave rounding it currently moving
into northestern Texas. Regional 88ds show widespread showers and a few
storms covering eastern Texas and crossing the Sabine River at this time...while
farther upstream numerous storms have developed closer to the low
over the cntl Red River valley.
Not many changes to the coming forecast this afternoon as onset of
rain event is currently beginning. Expect showers and additional
storms to continue developing into the evening hours as shortwave
energy continues marching eastward toward the area. Probability of precipitation across the northern
tier of zones were raised to categorical for this evening as best
lift/moisture work their way over these areas. Also threw in
severe wording for tonight across the northern 1/2 of the area as
initial/strongest shortwave GOES slightly negative tilt and is
prognosticated to accompanied by good shear and strong low-level winds.
Primary concern for severe potential continues to be marginal
instability per forecast soundings.
Surface front is expected to ease across the forecast area beginning
tomorrow morning...although sufficient moisture is prognosticated to
linger behind it to maintain chance probability of precipitation for most of the area
through the day and into tomorrow evening when the middle/upper-level
trough finally move into the region. Maintained an isolated thunder
mention for the entire forecast area for tomorrow although the
best shot likely will be closer to the front over the eastern portions
of the area. Rain chances finally come to an end on Monday as the
trough finally pushes through.
A nearly zonal flow is prognosticated through the middle-week while surface high
pressure builds across the area...meaning a dry period into early
Friday. The next shot at rain comes late Friday as the next weak
trough aloft and associated surface front move into the region. The
front is prognosticated to stall across the area while a series of weak
waves pass overhead...thus small probability of precipitation are maintained through next
caution headlines were introduced this afternoon as winds are
forecast to pick up to 15-20 knots this evening with low pressure
deepening over western Texas. However winds are expected to slack off
overnight with the approach of the front. A brief shot of Small Craft Advisory
conditions still look likely beginning after Sundown tomorrow with
the passage of the cold front. Thereafter a mainly light flow is
forecast for the coastal waters.
Preliminary point temps/pops...
klch 63 72 42 57 41 / 60 50 40 20 0
kbpt 63 71 40 58 44 / 60 50 40 20 0
kaex 59 71 38 54 38 / 80 40 30 20 0
klft 64 73 44 56 41 / 70 60 50 30 0
GM...small craft exercise caution until 5 am CDT Sunday for the
following zones: waters from Intracoastal City to Cameron
la from 20 to 60 nm...waters from Cameron la to High Island
Texas from 20 to 60 nm...waters from lower Atchafalaya River
to Intracoastal City la from 20 to 60 nm.