Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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FXUS64 KLIX 190831 CCA

National Weather Service New Orleans LA
331 AM CDT Sat Aug 19 2017

A more typical wet mid August pattern will persist through at least
this weekend and possibly into next week. An upper level trough
currently extends from the Great Lakes to the southeastern United
States. Strong daytime heating and decreased subsidence will allow
for afternoon thunderstorms to develop. MAV and ECMWF guidance
came in with pops ranging from 40 to 60%. The HRRR also shows good
coverage of storms from noon through the early evening hours.
Taking a look at model soundings, dry air will be in place aloft
with increased mid level moisture and an inverted-V profile in the
lower levels. This overall profile has been known to be conducive
for wet microbursts. Will be putting a mention of this potential
in the HWO and possibly social media posts today.

From a temperature standpoint, daytime highs should be similar to
yesterday, 90 to 95, but daily mixing has brought dewpoints down
into the mid to lower 70s in the afternoon hours. Thus shouldn`t see
heat indicies much higher than 105.

A TUTT low, currently seen on WV moving west across the Florida
Straits, will be tracking west across the GOM Sunday. This feature
in combination with daytime heating will enhance convection and
allow for scattered showers and thunderstorms to develop. The GFS
has backed off pops quite a bit Sunday, while the ECMWF holds on the
more numerous convection. Have sided more so on the wetter side as
has been the general pattern all summer to date.

An upper ridge will try to build in from the east during the first
half of next week while the TUTT low slowly progresses into the
northwestern Gulf. Moisture drawn onshore will keep rain chances
higher through Tuesday. Moving into mid week, models indicate a
broad long wave trough will send a frontal boundary towards the
region. This will keep the CWA in an enhanced pop development


.AVIATION...TSRA development will mostly begin after sunrise
today. With any development near any particular terminal, there will
be a higher probability of downburst wind speeds reaching severe
criteria causing dangerous low level shear. Ceilings generally SCT-
BKN at 030 to 040 through the day. VFR conditions expected outside
convective locations.


.MARINE...No changes as high pressure remains the dominant
factor over the northern gulf. Diurnal fluctuations will remain the
main driver of winds. Most nights, look for a weak enhanced jet over
the waters east of the MS delta where winds could bump up to 10-15
knots at times. Seas will remain in the 2-3 ft range or less.


DSS code: Yellow.
Deployed: NOHSEP.
Activation: None.
Activities: DSS support for NOHSEP; Monitoring Convective trends
            River Flooding; and Heat Advisory.

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.


MCB  92  74  92  74 /  50  10  30  10
BTR  93  74  93  76 /  50  10  30  10
ASD  94  75  93  76 /  50  10  40  10
MSY  93  77  93  78 /  50  10  30  10
GPT  92  76  92  78 /  40  10  30  10
PQL  95  74  93  77 /  30  20  30  10



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