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

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915
FXUS64 KLIX 240458
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1158 PM CDT Sun Jul 23 2017

.UPDATE...
Updated for 06z Aviation discussion.

&&

.AVIATION...
Radar indicated a few showers developing over central Louisiana to
the west/northwest of KHZR, and satellite indicated some at least
partially convective clouds developing over portions of southeast
Louisiana. This may be the trends some of the synoptic and
mesoscale convective allowing models are indicating for overnight.
Use previous forecast with some modifications for latest radar
and model trends to put various VCTS, PROB30 and TEMPO TSRA groups
through the afternoon Monday. Otherwise, VFR conditions will
prevail away from under the SHRA/TSRA. 22/TD

&&

.PREV DISCUSSION... /issued 846 PM CDT Sun Jul 23 2017/

SOUNDING DISCUSSION...
There were not any problems with the upper air release this
evening. The 00Z sounding indicated an unstable and very moist
profile. The precipitable water value was 2.19 inches. The profile
was quite moist throughout the lower and mid levels. Westerly
flow prevailed up to 500 mb, light and variable winds were noted
above that level up to near 300 mb, then northerly winds were
observed from 300 to 200 mb with mostly easterly flow above that
level. 11

PREV DISCUSSION... /issued 356 PM CDT Sun Jul 23 2017/

DISCUSSION...
Showers and thunderstorms continue across the forecast area this
afternoon and they should last into the evening hours. The
strongest convection is moving across the northshore this
afternoon. Locally heavy rain will be this biggest threat this
evening. The good thing is that the convection is moving and is
not stationary like it was yesterday. A strong short wave moving
out of Minnesota will cause the upper trough currently over the
northern half of the country to sharpen and dig southeast helping
to develop a weak sfc trough near the area just to the northeast.
This should be enough to kick off some storms for Monday. Some of
the thunderstorms associated with the trough could become strong
or even severe but most of this activity is expected to stay just
northeast of the area. Expect some chance of showers and storms
for Tuesday and Wednesday mainly in the eastern portions of the
forecast area. Thursday expect only a slight chance of afternoon
showers, but the next organized chance of rain could come in the
form of a cold front that is depicted in the guidance for next
weekend. Both the GFS and the EMCWF show this front moving into
the Deep South by Friday night and sticking around for most of the
weekend before clearing the area Sunday afternoon. Will have to
watch this develop over the week and make adjustments as needed.
Otherwise expect temperatures to be around average for this time
of year. 13/MH

AVIATION...
Main issue has been convection but this should continue
to slack off as we head into the evening. Most terminals will drop
into MVFR as showers move over but could see tempo IFR with any
stronger storm. Once convection dissipates terminals should remain
in vfr status through the evening. After 6z we may begin to see low
clouds develop leading to a few terminals dropping into MVFR status.
There may also be tempo MVFR vsbys during the early morning hrs at
MCB. /CAB/

MARINE...
High pressure will build in from the south across the northern
Gulf while a weak trough develops near the area early in the work
week. This will lead to a slightly tighter gradient and higher
winds out of the southwest. Winds may become more westerly by mid
late next week. Showers and thunderstorms will once again be more
prevalent during the early morning hours and of course winds and
seas will be higher near storms.

DECISION SUPPORT...
DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.

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  72  89  73  90 /  40  60  30  50
BTR  75  91  75  93 /  30  60  20  20
ASD  77  92  76  93 /  30  60  30  40
MSY  76  92  77  93 /  30  60  20  20
GPT  77  90  77  91 /  30  60  30  50
PQL  75  91  75  91 /  40  60  40  60

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$



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