Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
FXUS64 KLIX 270856
AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
356 AM CDT TUE SEP 27 2016
Upper level analysis shows a low centered over the the Great
Lakes that extends well south and a ridge across the western half
of the country. At the surface, dewpoints reveal that the cold
front is just now moving into the the CWA in southwestern
Mississippi and continues west into central Louisiana. Slight lift
from this boundary will enhance shower and thunderstorm coverage
this afternoon, so have pops up to 30% mainly south of a Houma to
Slidell line as convection will likely not occur until the
boundary is that far south and moving into a region of higher
surface moisture. Temperatures today will fall quite a bit from
yesterday as pressure heights compress and post frontal air mass
begins to move in. Didn`t change fcst temps by much, thus still
expecting mid to upper 80s for max temps.
Models show that the upper low to the north will steadily move south
and slightly east to the Ohio River Valley before tracking back
north towards Canada from Wednesday through the weekend. This
somewhat slow progression will cause the local frontal boundary
to gradually shift slightly further into the Gulf of Mexico each
day. This will result in a dry forecast as continental air mass is
drawn south to the Gulf Coast. This coldest air since May is
expected from midweek onward with Friday looking like the
chilliest of those days as a secondary surge of cooler air moves
in late Thursday. Expect mid 50s to lower 60s Friday morning and
highs barely reaching 80 degrees that afternoon. A gradual
moderation will ensue this weekend as the trough lifts out and
500mb heights begin to increase. Rainfall may not return till
sometime later next week.
Cumulus field to develop again today with cold front in vicinity.
Spotty convective coverage along frontal boundary which will be
slowly moving off the coast today. Main areas that could observe a
shower or ts will be in an arc south of MSY from GPT to HUM during
the afternoon. VFR conditions should hold through tonight as dry air
begins to settle into the area.
.MARINE...Front moving ever so slowly southeast and is located very
close to Lake Pontchartrain this morning. The front will be slow to
move offshore today but will clear the coastal region by this
evening. As dry air begins to move through, unstable conditions
could cause a few gusts to 15 knots. General conditions should
remain under advisory conditions through much of the week. A few
reinforcing surges will move through with the strongest Thursday night
into Friday. This should cause winds and seas to rise to near or
just above advisory conditions.
DSS code: Green.
Decision Support Services (DSS) Code Legend
Green = No weather impacts that require action.
Blue = Long-fused watch, warning, or advisory in effect or
high visibility event.
Yellow = Heightened impacts with short-fused watch, warning
or advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
tropical events; HazMat or other large episodes.
Red = Full engagement for Moderate risk of severe and/or
direct tropical threats; Events of National Significance.
.PRELIMINARY POINT TEMPS/POPS...
MCB 86 62 86 59 / 10 10 0 0
BTR 86 65 86 61 / 10 10 0 0
ASD 88 69 87 61 / 20 10 10 0
MSY 87 72 86 70 / 20 10 10 10
GPT 87 70 87 64 / 30 10 10 0
PQL 88 68 87 62 / 30 10 10 10