Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Lake Charles la
1021 am CST sun Dec 28 2014
minor tweaking of the temperature/dew point/wind/pop grids for the
remainder of today. Temperatures will be in the 40s across much of
the region by this afternoon...except for lower Acadiana where it
will be in the 50s.
Previous discussion... /issued 542 am CST sun Dec 28 2014/
28/12z taf issuance.
southwesterly flow aloft continues to bring moisture over the colder low
level airmass...resulting in overrunning clouds and rain.
Currently...the main swath of rain has shifted north of the taf sites
with the exception of a smaller band streaming NE across the
Acadiana area. IFR ceilings to prevail today...with -ra increasing as
an upper trough moves east. Intermittent periods of heavier rain showers are
expected...accompanied by LIFR ceilings and MVFR visibilities. Rain will
taper off from west to east during the evening with LIFR ceilings and areas of
fog reducing visibilities to MVFR overnight. Northerly winds around 10 knots will
decrease to 5 knots during the evening. 24
Previous discussion... /issued 356 am CST sun Dec 28 2014/
cold front has moved off into the coastal waters and will exit the
entire forecast area by sunrise. With that...the end of any
surface based convection...heavy rainfall and sea fog has ended.
The extremely high precipitable water values of 1.9 inches...more than twice the
Standard deviation...on the 28/00z upper air sounding at
klch...has been replaced by precipitable waters according to GPS-met data of
between 1.4 and 1.6 inches...and these values should continue to
decrease to between 1.25 and 1.4 inches by afternoon.
The upper level trough is still located out over West Texas and
northern old Mexico...and will continue to move eastward and
through the forecast area tonight. Until the trough moves
through...decent isentropic lift will continue to produce over-
running rains...mainly light to occasionally moderate. Rainfall
amounts for the remainder of today into early tonight will average
from 1/3 to 3/4 of an inch. With the clouds...rain and cooler air
mass...will be a rather raw Sunday...probably good one to stay
inside and fix some Gumbo and read a book...or watch football or a
movie on the TV.
Once the upper level trough passes...the main weather player will
be a large Canadian high pressure system that will move down from
the prairies along the eastern rockies and settle over the Southern
Plains by middle week. This will keep the forecast area on the cool
side...even if some sunshine does appear...although some upper
level cloudiness will likely still add a filter to full sunshine.
By the end of the week...the surface high moves off to the
east...and a cut off low over the southwest U.S. Will move slowly
toward the forecast area. Disturbances moving out in the southwest
flow from it...along with increasing middle and upper level moisture
will provide a slight chance of light rain late on new years evening
night...with a gradual increase in mainly light over-riding type
rain during New Years Day.
Some stronger showers and storms will be possible by Friday into
early Saturday as return off the Gulf brings a warmer and more
humid air mass for the upper level disturbance to work with as it pushes
a surface cold front into the forecast area.
cold front has pushed through all but the outer waters between
Intracoastal City and the lower Atchafalaya River...and the front
should exit this area by sunrise...dispersing any sea fog that
remains. Moderate northwest and north winds will prevail behind
this front for the remainder of the day. Highest winds will be
over the western portions and will keep small craft exercise
caution until afternoon. The offshore winds will continue through
middle week as a strong Canadian high pressure system slides on down
into the region. The north winds will increase Tuesday night into
Wednesday...as the coastal waters begin to feel the affects of the
high...with the possibility of Small Craft Advisory conditions
during that time. Winds will turn out of the southeast by the end
of the week...as low pressure develops over The Rockies.
Preliminary point temps/pops...
klch 53 43 58 43 58 / 90 50 10 0 0
kbpt 51 42 58 43 58 / 90 30 10 0 0
kaex 49 41 54 40 55 / 90 50 10 10 0
klft 57 45 59 44 58 / 70 50 10 10 0
GM...small craft exercise caution until 3 PM CST this afternoon 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...
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.
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