319
FXUS64 KLIX 100015
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
615 PM CST Sat Nov 9 2024

...New UPDATE...

.UPDATE...
Issued at 606 PM CST Sat Nov 9 2024

Main change made this evening was to account for rainfall south if
I-12. Latest trends on radar shows scattered to numerous showers
tracking inland from the Gulf. Previous forecast POPs were way to
low for the New Orleans metro and surrounding areas. So bumped
those up quite a bit for the tonight period. Intensity should be
limited though, so kept QPF well under an inch vs the much higher
QPF potential for areas northwest of Baton Rouge. Those parishes
and counties in the watch are still right on the edge of flooding
rains. The rainfall activity has been slowly spreading
southeastward and will be monitoring closely over the next several
hours for the potential of flash flooding. It should be noted that
WV imagery does show fairly potent mid level dry air pushing
eastward across southern LA. This could help limit heavier rain
from spreading too far south tonight.

&&

.SHORT TERM...
(This evening through Sunday night)
Issued at 305 PM CST Sat Nov 9 2024

Tropical Storm Rafael, now with its center exposed, continues to
weaken over the central Gulf of Mexico and will come to almost a
complete halt, at least briefly, over the next 12-24 hours. A deep
upper low was over Nebraska this afternoon, and was pulling
moisture from Rafael northward across Louisiana ahead of a frontal
boundary along the Texas border. Precipitable water values near
climatological maxima for mid-November of 2.1 inches or higher,
per LCH sounding, have aided in the production of heavy rainfall
across western Louisiana with ground truth reports of 2 to 4
inches or more have been noted since 6 AM CST. Meanwhile, the
morning soundings at LIX and JAN showed drier air between 700 and
900 mb, with precipitable water values closer to 1.6 inches.

The shortwave moving through the upper trough will lift to the
northeast overnight with probably a 6 hour period of heavy
rainfall potential for the extreme northwest portion of the CWA.
There`s likely to be a fairly sharp cutoff between excessive
rainfall and comparatively light totals. While the main threat
area is likely to be just west of our area in the LCH CWA, it`s
entirely too close to call as whether any heavy rain occurs within
our CWA. Have opted to issue a Flood Watch for Excessive Rainfall
for a couple southwest Mississippi counties and adjacent southeast
Louisiana parishes overnight through midday Sunday. At this point,
the threat appears to be lower for the Baton Rouge and McComb
areas, but the threat there is non-zero. Certainly can`t rule out
2 to 4 inch totals with spot amounts much higher wherever the
heaviest band sets up.

Low level moisture will remain across the area through Sunday
night, but forcing diminishes Sunday morning. Mostly cloudy skies
with scattered showers are likely to be the end result for the
afternoon and overnight hours as drier air only slowly filters in
from the west. Temperatures tonight and Sunday will continue to be
near record warmth, but overnight lows Sunday night may finally
return to the 60s, instead of breaking records.

With wind fields subsiding over the next 24 hours, and
astronomical tide ranges diminishing, the threat for minor coastal
flooding should gradually subside as well. Will leave current
advisories in place, but do not anticipate additional issuances.

&&

.LONG TERM...
(Monday through Friday night)
Issued at 305 PM CST Sat Nov 9 2024

Rafael finally gets out of the way on Monday with ridging building
over the northern Gulf of Mexico with zonal flow to the north of
that. An active northern stream will move s strong shortwave
across the center of the country Tuesday and Wednesday, likely
pushing a cold front through the area Wednesday night. Latest
model guidance arriving in the last hour or so is coming in
wetter than the nearly dry forecast we`ve had riding, so it is
entirely possible that in the next forecast package or two, rain
chances will need to be increased significantly. Other than that
frontal passage, the forecast is likely to be dry going into the
weekend.

Monday high temperatures will be only slightly cooler than the
last few days, but humidity values should be somewhat lower. For
mid and late week, the operational GFS and ECMWF solutions have
essentially swapped positions, with the ECMWF solution now being
the cooler of the two, with readings closer to normal. There`s
quite a spread in low temperatures within the respective ensembles
for Wednesday night through Friday night, so forecast confidence
leaves a little to be desired. A little better agreement on high
temperatures with most of the area probably in the 70s.

&&

.AVIATION...
(18Z TAFS)
Issued at 1219 PM CST Sat Nov 9 2024

Ceilings have generally improved to MVFR or VFR this afternoon as
temperatures have warmed. Can`t rule out a few showers, but any
impactful precipitation likely to hold off until well after
sunset. Main threat of TSRA would be for KBTR during the overnight
hours with potential for IFR or lower ceilings and visibilities.
All terminals could see some flight restrictions in rain Sunday
morning. While MVFR conditions are likely at that time, IFR is
certainly a possibility. Gusty winds to 25 knots are likely this
afternoon at KMSY/KNEW/KHUM, but we should see those subside
somewhat after sunset.

&&

.MARINE...
Issued at 305 PM CST Sat Nov 9 2024

As Rafael gradually winds down over the next 36 hours or so, wind
fields should similarly weaken. However, it will take some
additional time for seas to subside. We will keep the Small Craft
Advisory in place through mid-morning Sunday, but may need an
extension of the advisory for seas in the outer waters. Beyond
that point, should be a bit quieter few days until after the cold
front passage toward the middle or end of the workweek.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  69  78  64  77 /  70  70  50  30
BTR  74  83  67  82 /  60  60  30  20
ASD  73  81  67  80 /  50  60  40  30
MSY  75  82  70  79 /  50  60  40  30
GPT  73  80  67  79 /  30  50  40  30
PQL  73  83  67  84 /  30  50  30  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch through Sunday morning for LAZ034>036.

     Coastal Flood Advisory until 10 AM CST Sunday for LAZ057-058-060-
     066>070-076>078-080-082-084-086-087.

     Coastal Flood Advisory from 9 PM Sunday to 9 AM CST Monday for
     LAZ066>070-076-078.

GM...Small Craft Advisory until 10 AM CST Sunday for GMZ550-552-555-
     557-570-572-575-577.

MS...Flood Watch through Sunday morning for MSZ068-069.

     Coastal Flood Advisory until 10 AM CST Sunday for MSZ086>088.

     Coastal Flood Advisory from 9 PM Sunday to 9 AM CST Monday for
     MSZ086.

GM...Small Craft Advisory until 10 AM CST Sunday for GMZ552-555-557-
     570-572-575-577.

&&

$$

SHORT TERM...RW
LONG TERM....RW
AVIATION...RW
MARINE...RW