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

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FXUS64 KLIX 231850 AAA
AFDLIX

Area Forecast Discussion...UPDATED
National Weather Service New Orleans LA
1250 PM CST Fri Feb 23 2018

.AVIATION...
Complex situation with unstable airmass in place presenting a
large area of low clouds and showers in response to a MCV feature
that moved out of the gulf this morning. Widespread MVFR ceilings
lowering to IFR in rainfall. These conditions should hold through
this evening but lower to more widespread IFR ceilings generally
after about 07Z. Variable conditions expected for better part of
the morning Saturday.

&&

.SOUNDING DISCUSSION...
Special 18Z balloon release to assess the current convective
trends locally and to assist in warm sector pre-conditioning for
weather anticipated for Saturday and Sunday in the Gulf States.
Very unstable sounding sampled just east of the convection with
precipitable water values off the chain at 1.61" for mid-February.
This is the normal value for June. Low based LCL/LFC around 2kft
with EL around 38kft. Not the deepest convection by far, but
efficient rainfall potential, as evidenced by street flooding in
parts of New Orleans metro this morning from a brief shower. Wind
profile shows some modest turning from SE through SW 10-50kt, the
lower portion only ranging 10-30kt. Dry air above a saturated
layer aloft conducive for wet microburst potential in downdrafts,
probably closer to 45-50 mph. CHAP run on 12Z sounding had a Ricks
Index of 138 which did yield a 13% chance of severe for gust
potential 45kt, waterspouts likely and pea sized hail. The 18Z
CHAP run softened to a RI 58, PoP 38% non-severe for gust
potential now 12kt, no hail, no tor. Precip potential indicated
3.02"-4.49" and recent along-flow alignment of convective axes
does cause concern of brief echo training in this efficient air
mass next few hours.

&&

.DECISION SUPPORT...
DSS code: Yellow.
Deployed: None.
Activation: None.
Activities: Radar support for convection in area.

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  82  69  83  63 /  70  40  50  80
BTR  84  69  84  64 /  80  20  30  70
ASD  84  69  84  69 /  60  40  30  40
MSY  82  70  84  68 /  60  30  20  40
GPT  79  68  79  68 /  50  50  20  40
PQL  80  67  81  68 /  50  40  20  40

&&

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

$$

24/RR


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