Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New Orleans la
340 PM CDT Sat Jul 12 2014
surface high pressure remains centered over the southeast Continental U.S.. a
cold front extends from central Canada through the Great Lakes
region and into the plains states.
Locally...much less thunderstorm activity on radar compared to
same time yesterday...but starting to see some more showers pop up
over last hour or so. Temperatures generally sitting in the lower
90s away from storms. In rain cooled areas...temperatures being reported
as low as the upper 70s.
high pressure will remain in place centered over the southeast
Continental U.S. For the next few days. Generally on shore flow will continue
to bring warm and moist air into the area from the Gulf of Mexico.
Typical afternoon showers and thunderstorms can be expected each
day with isolated to scattered coverage for the next few days.
Afternoon temperatures will be near or slightly above normal...
topping out in the low to middle 90s most places. Heat index values
look to peak near or just over 100 degrees for the next couple
A strong upper low will drop southward toward the Great Lakes
region on Monday. The associated trough axis will dig into the
middle Mississippi Valley...pushing a strong cold front southward.
This front will bring unseasonably cool air into the middle part
of the country for middle week. By the time the front makes it this
far south...it won't have quite as strong a gradient across it as
the upper low begins to lift northeastward and the front loses its
forward push. Model guidance is in fairly good agreement that the
front will make it into but not through the local area...and it is
expected to stall somewhere around the Interstate corridor. Should
mention that if there is enough thunderstorm development along the
front...outflow from the thunderstorms could help push the front a
bit farther south than currently forecast. This is something that
will need to be watched as the front approaches.
For areas behind the front...temperatures should drop a few
degrees...but it doesn/T look like there will be a significant
cool down at this point. Am carrying high temperatures in the middle
to upper 80s instead of lower 90s for Wednesday and Thursday.
Again...if the front moves a bit farther south than currently
forecast...afternoon highs may need to be adjusted downward a
couple more degrees. For areas ahead of the cold front...a few
degrees of cooling can be attributed to increased cloud cover in
the vicinity of the front.
Concerning rain chances...looks like the best chances of rain will
come on Tuesday as the front moves into the area...and am carrying
high end chance probability of precipitation for that period. May need to adjust upward to
likely or categorical as the situation becomes a bit clearer
concerning how far south the front will move and when it will
arrive. As previously mentioned...the front will be losing much of
its forcing by the time it arrives...so widespread severe weather
does not look like a significant threat at this time. However...
there is definitely some potential for a few storms to become
strong or severe.
The stalled frontal boundary will gradually wash out through the
end of the week...but will continue to provide a focus for
scattered showers and thunderstorms each day. Am generally
carrying solid chance probability of precipitation for the Wednesday through Friday
period. Again...severe weather does not look like a significant
threat...but a couple storms could become strong/severe each
convection coverage considerably less this afternoon than Friday but
still can expect temporary MVFR ceilings and visible in isolated convection
through 01z. Short lived MVFR visible restrictions possible in fog haze
around between 09-13z. Otherwise VFR conditions prevailing.
high pressure along the Gulf Coast will maintain light winds and low
seas through Sunday. A cold front will approach the coast Tuesday
and into Wednesday...but at this time it does not look like the
front will make it into the coastal waters. There is some
uncertainty...however...as outflow from pre-frontal convection
could provide enough forcing to push the front farther south than
currently forecast. Will need to watch this as the front
approaches. With winds forecast to remain generally near or below
10 knots through most of the period...expect seas to remain at or
below 2 feet.
Decision support services (dss) code legend
green = no weather impacts that require action
blue = long fused watch/warning/advisory in effect or high
yellow = heightened impacts with short fused
watch/warning/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 to high risk severe
and/or direct tropical threats; events of National
Preliminary point temps/pops...
mcb 72 93 72 92 / 20 30 20 40
btr 74 95 73 94 / 20 30 20 40
asd 73 93 73 93 / 20 30 20 40
msy 76 91 76 91 / 20 40 20 40
gpt 77 90 75 91 / 20 30 20 50
pql 71 91 72 92 / 20 30 20 50
rest of discussion...95/dm