Special Weather Statement, NWS New Orleans, LA

AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
308 AM CDT Tue Mar 16 2021

.SHORT TERM (Today through Thursday)...
A broad upper level ridge is currently draped across much of the
Gulf of Mexico, and northern Caribbean with a trough axis rotating
towards the Great Lakes. There is a weak shear zone between those
features where moisture appears to be pooling. That region roughly
extends south into the CWA. This area, generally along and north of
the I-12/10 corridors in LA will be the focus for rainfall today.
Radar currently shows scattered showers streaking northeastward over
SELA. Medium range and meso models indicate that these on/off
showers (with thunderstorms later today) will continue in those same
areas. There should be some northward shifting as the day
progresses. Looking at model soundings, there may be enough
instability for a few strong storms in southwest Mississippi and
adjacent LA parishes during the afternoon hours. Training could also
lead to isolated areas of a few inches as we saw yesterday across
the city of New Orleans. Rain chances are in the 60-80%+ range for
areas along and north of I-12.

An upper level low racing across the Desert Southwest today will
track through the Texas Panhandle and northern Oklahoma Wednesday. A
deepening surface low (upper 990s) will be moving right long that
same path with an appendant cold front extending to the Gulf of
Mexico. During the day on Wednesday, models suggest convection will
initiate around noon INVOF the CWA with a focus again along the I-12
corridor as the 700mb cap is eroded. At that same time, GFS and NAM
BUFR model soundings suggest a high CAPE and low shear environment.
CAPE values from 1500-2500 J/KG with 0-6km shear of 50kts definitely
brings the potential up for severe thunderstorms. Helicity looks
slightly better with these most recent model runs compared to 24 hrs
ago. Nothing crazy but 150-250m2/s2 type values which is plenty
sufficient locally. WBZ of around 10kft at that time means large
hail will certainly be possible. Would say that all modes of severe
weather are possible. Overall, still in high agreement with SPC's
Slight Risk with maybe thinking SW MS could be in the Enhanced Risk.

Not sure how much severe will carry over into the evening along the
front as it moves through as it appears that instability drops off
rapidly as 00Z approaches. The quick moving front will then clear
out the rain overnight with rain finished by sunrise Thursday.

The forecast after Wednesday night is relatively quiet. All of the
main impacts will occur between now and Wednesday evening and then
we will cool down and dry out. All of the operational models,
ensembles, and the NBM are in overall general agreement with this.
Due to this, confidence is high in the extended forecast with
slightly below normal high temps Thursday and a dry forecast.

MEFFER
&&

.LONG TERM (Friday through early next week)...
No major changes in the extended as it should still remain quiet. It
will begin cool and then begin to moderate Sunday and into next
week. Most of the extended will remain dry but there is a very small
chance of light showers Friday night through Saturday night. No
deviations from the NBM guidance outside of Saturday morning. That
night appears to be a decent cold air drainage night in the typical
areas so we did drop a few locations by a few degrees.

NW flow will already be in place Friday and should remain that way
through Saturday night. Still looks like a s/w will drop down in the
NW flow late Friday night and through Saturday. Again there is a
small chance that it could squeeze out enough moisture to get a few
showers to develop but overall likely just an increase in clouds.

It still looks like a ridge will build in on Sunday and this will
help to moderate the temps but the ridging is much weaker than what
was shown 24 hours ago. Even though the ridge slides over the area
it appears to be suppressed south and not as strong. Weather still
looks quiet as we head into next week but there could be another
rather strong system working across the southwest CONUS and towards
the Southern Plains.

/CAB/
&&

.AVIATION...
Mixed bag of CIGS through tonight from IFR to VFR. Some sh/ts will
also have an equal opportunity of affecting any terminal through
tonight causing IFR and some LIFR conditions.

&&

.MARINE...
A cold front is expected to impact the northern gulf waters
Wednesday night with sh/ts and shifting winds from southerly to west
and NW by Thursday morning. Wind speeds could be around 20kt late
Thursday but will ease to around 10-15kt by Saturday then shift to
NE and east by Sunday and rise to 20-25kt with some rain through the
first part of next week. Winds will shift to SE Tuesday and ease to
10-15kt ahead of the next cold front that will likely stall by mid
week inland.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  79  66  79  50 /  80  20 100  70
BTR  82  68  82  52 /  70  20 100  50
ASD  82  67  81  54 /  40  20 100  80
MSY  82  69  82  58 /  30  10  90  70
GPT  77  66  77  57 /  30  20  90  90
PQL  79  65  77  57 /  30  10  90  80

&&

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

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>