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Area forecast discussion 
National Weather Service New Orleans la
333 am CDT Thursday Aug 21 2014

Short term...convection quickly dissipated in the evening with clouds
thinning out through the night. Much like last night temperatures cooled
quickly with much of the area in the middle to upper 70s by 7z with the
exception of coastal areas which are still in the lower 80s.

Forecast remains unchanged through the end of the work week and weekend
with hot and mostly dry conditions expected to continue. Strong middle
level ridge will dominate the region through the weekend becoming
centered over the lower MS valley. This will suppress convection over
the northern half of the County Warning Area but along the coastal areas seabreeze
interactions will most likely lead to isolated and possibly scattered
storms. As for temperatures afternoon highs should generally warm up a
few degrees higher than what we saw yesterday. By this weekend we
could see numerous locations in the upper 90s and possibly approach
100 degrees in southwestern MS. H925 temperatures will jump to 28 and possibly
29c by sun and this mixed down to the surface could push temperatures twrds
the century mark in isolated locations. As for heat issues...the heat
index doesnt get out of hand as slightly drier air will be in
place over the region. Afternoon heat indices look to maximum out around
106 degrees. Combine that with morning lows likely in the lower
to middle 70s over much of the area north of I-10 and in the upper
70s south most locations should be able to recover from the heat.
Again the exception could be the north.O. Metropolitan where lows could hover
around 80 so we will need to watch this area. /Cab/

Long term...medium range models are in good agreement with the middle
level pattern to start the week but by Tuesday night/Wednesday they differ
significantly with respect to the pattern. The ridge will continue
to dominate the region Monday and into Tuesday but with the center of the
ridge shifting further north on Monday there is a chance that we
could get into the erlys with a weak wave pushing into the region
late Monday. This would provide slightly better rain chances
beginning Monday night.

Tuesday night and through the end of the forecast period the models begin to
diverge with the European model (ecmwf) strengthening the ridge and retrograding it
back to the middle MS valley and Central Plains. The GFS on The Hand is
driving a strong short wave into the Central Plains early Wednesday. The main
protagonist is strong Pacific northwest energy diving south-southeast Monday. The European model (ecmwf) drives
it further to the south and by Tuesday morning closes off a low over northern
California with the ridge rebuilding over the MS valley. The GFS
doesnt dive the energy as far south and instead brings a strong
short wave into plains Tuesday night/Wednesday with the ridge becoming pinched over
the applachians while losing some of its influence over the County Warning Area. The
European model (ecmwf) solution would suggest continued warm temperatures and rather low end
probability of precipitation...15-20%. The GFS solution would lead to near normal temperatures and probability of precipitation
closer to 30-40%. With the models really struggling we will continue
to use a blend of the models for Wednesday and Thursday but show a gradual
increase in probability of precipitation across the region.

As for your tropical update...the models are really struggling with
the wave east of the Windward Islands. The 7z tropical weather
outlook from NHC is still calling for a 70% chance of development
in the next 5 days but it has shifted east and the models are now
suggesting that what...if anything develops may stay well east of
the area and in the Atlantic. With no system having even developed
yet there is still too much uncertainty to accurately tell where
an evenutal tropical cyclone would go...lets at least see if it
develops first. As always its approaching the peak of hurricane
season an with our area along the Gulf Coast we should always
continue to follow the latest in the tropics. /Cab/


Aviation...expect VFR conditions to prevail throughout the morning
and afternoon hours outside of any afternoon convection. Have not
included any mention of thunderstorms in tafs...but will have to
monitor the situation throughout the day. Otherwise...expect light
southwest winds generally less than 10 knots and partly cloudy skies
with cloud bases around 4kft during the day.


Marine... a ridge of high pressure will remain centered over the
coastal waters through the weekend. Winds will be somewhat light and
variable as seabreeze and landbreeze interactions dominate the
nearshore waters. Nocturnal winds along coastline should be stronger
meanwhile...winds further offshore will be consistent from the south and
southwest at 5 to 10 knots where the seabreeze is less dominant. By
early week...winds will shift to the east and will increase to the
10 to 15 knot range. Seas will generally range from 1 to 2 feet
through the weekend. As the easterly flow takes hold next week waves
should climb to the 3 to 5 foot range by Tuesday.


Decision support...
Activities...slurry support.

Decision support services (dss) code legend
green = no weather impacts that require action
blue = long fused watch/warning/advisory in effect or high
visibility event
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 95 74 93 74 / 20 10 20 10
btr 95 76 95 76 / 20 10 20 10
asd 94 76 94 76 / 10 10 20 10
msy 93 78 94 78 / 20 10 20 10
gpt 94 77 95 76 / 20 10 20 10
pql 94 75 95 74 / 20 10 20 10


Lix watches/warnings/advisories...


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