Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Lake Charles la
925 am CDT Tuesday Mar 31 2015
Update...the previous forecast remains on target and only a minor
tweak to the current temperatures and sky were needed this morning to
reflect the latest trends. No other changes are needed at this
Previous discussion... /issued 656 am CDT Tuesday Mar 31 2015/
31/12z taf issuance.
near calm winds and abundant low level moisture has resulted in
low clouds at all terminals and areas of fog at southern terminals this
morning. LIFR conditions have prevailed at Ara for much of the
night...with conditions varying between LIFR and MVFR at other
sites. Daytime heating should allow fog/low clouds to mix out by
14-15z with VFR conditions and southwesterly winds around 10 knots from midday
through the afternoon. Winds are expected to diminish again during the
evening with fog redeveloping by 05-07z and continuing through
Wednesday morning. 24
Previous discussion... /issued 403 am CDT Tuesday Mar 31 2015/
main concern in the short term is the fog development. Decent low
level moisture in place with dew points in the upper 50s to lower
60s and air temperatures falling to within a degree of these
readings. This has allowed the formation of low stratus and fog
underneath the nocturnal inversion. Winds above the surface seem
to be strong enough to keep the dense fog patchy in nature with
still widespread visibilities below 2 miles. With the dense fog
being isolated...will hold off on any dense fog advisory. The fog
and low clouds again should burn off fairly quickly after sunrise.
At the surface...high pressure will remain near Florida...keeping
a frontal boundary stalled well north of the forecast area...and
allowing the southerly flow off the Gulf to remain. This will mean
muggy conditions with slightly above seasonal normal temperatures
through the end of the week.
Water vapor imagery shows an upper level low moving into the Baja California
California area. This upper level low will weaken and open into a
wave...and get caught up in the developing zonal flow aloft to
push the feature across late Wednesday into early Thursday. With
feature continuing to show signs of weakening...will hold off on
any chance probability of precipitation until Wednesday afternoon into Wednesday
night...and that will be low end chance probability of precipitation.
An upper level trough moving out of the northern plains on Friday
will dig just enough to the south to help push a cold front into
the forecast area Friday evening...with front pushing offshore
overnight Friday night. Main energy with this feature will stay to
the north. However...there should be enough frontal lift on the
Gulf moisture to produce scattered showers and a few thunderstorms
just ahead and just behind the front.
After some drier air filters in for Saturday afternoon and
evening...another upper level disturbance is expected to move out
of old Mexico and across the lower Mississippi Valley.
Unfortunately this looks to produce clouds and scattered showers
with a few thunderstorms on Easter day. Although main energy
expected to move north of the area...so not expecting much in the
way of hazardous weather during the Holiday.
light southerly winds to continue today into Wednesday as high
pressure remains east of the coastal waters. The southerly winds
are expected to increase some on Wednesday night into
Thursday...as low pressure forms across the Southern Plains.
A cold front is expected to move through the coastal waters on
late Friday night and early Saturday morning. Strong north winds
are expected to develop behind the front through most of Saturday.
Small craft exercise caution to Small Craft Advisory conditions
will be possible during this time frame as sustained north to
northeast winds will be close to 20 knots.
Preliminary point temps/pops...
aex 82 61 81 64 / 10 10 20 30
lch 81 63 81 66 / 10 10 20 30
lft 82 62 81 66 / 10 10 10 30
bpt 81 64 81 67 / 10 10 30 30