LIX issues Area Forecast Discussion (AFD) at Feb 13, 11:52 AM CST ...New AVIATION...
137
FXUS64 KLIX 131752
AFDLIX
Area Forecast Discussion
National Weather Service New Orleans LA
1152 AM CST Thu Feb 13 2025
...New AVIATION...
.UPDATE...
Issued at 1009 AM CST Thu Feb 13 2025
Performed a morning short-term update to bring in latest
guidance with obs/trends. The front is through here and all
rain/storms are long gone. What's left is lingering clouds across
the area. The 12Z KLIX RAOB from this morning illustrates these
multiple layers of clouds well, with low-level stratocumulus
streets sandwiched between the (very low) LCL and base of a
strong subsidence inversion at 925mb, next mid-level layer above
this at 800-850mb and some cirrus advecting across the area, as
well. These clouds will slowly deteriorate for a few locations
per satellite trends and HRRR forecast soundings illustrating
progressive LCL/subsidence base drying meaning periods of sunshine
could break out for many locations later today, however, could be
slower for northern/western and coastal SE LA areas where more
persistent CAA and thicker cloud base resides. Because of this,
did decide to nudge highs slightly lower for all areas (towards
the 25th percentile) as CAA will remain strong given northeasterly
breezy winds, but was more aggressive for lowering highs for
northern, western and coastal SE LA locations where the chance
for sunshine will be less. So far, hourly trends agree with this
decision so will keep an eye on it and should it get off track
will adjust.
Otherwise, like just mentioned it'll become breezy later today as
we progressively mix out adiabatically in the PBL coupled with
persistent CAA, then should see a slow clearing pattern into
tonight becoming chilly for most areas. Will dive deeper in the
afternoon package. KLG
&&
.SHORT TERM...
(Today through Friday Night)
Issued at 343 AM CST Thu Feb 13 2025
A cold front continues to move east early this morning and should
be south and east of our region by around sunrise or so. Behind
the front, CAA has already started with temperatures and dewpoints
dropping into the 40s over the western portions of the CWFA. The
CAA regime will continue through the day so max temperatures today
will stay well below where we have been over the last several
days. In fact, temperatures may be around or just a few degrees
below average for mid February, with mild afternoon conditions and
crisp mornings. Going into Friday temperatures will still be
around average, however, as a surface high pressure begins to move
east over the Great Lakes to the Mid Atlantic, surface flow will
transition to southerly quickly increasing the low level moisture
and initiating a warming trend. Within the newly established WAA
regime on Friday, a few low topped brief showers may be possible
embedded within the warm surface return flow. (Frye)
&&
.LONG TERM...
(Saturday through Wednesday)
Issued at 343 AM CST Thu Feb 13 2025
A broad scale upper trough will reside over the high plains as
the long term period begins. A rather robust H5 short wave looks
to spread eastward across the Red River Valley during the day
Saturday. This will help push a cold front southeast toward our
region from the midsouth. At the surface, strong WAA is taking
shape with dewpoints rising to near 70 in many cases. Ahead of the
front, instability will be increasing with CAPE values ranging
from 1000-2000 J/kg. Bulk shear will also be increasing,
especially late afternoon and during the evening with a 50kt LLJ
developing over the region. With SRH values approaching 200 m2s2,
give or take...there will be the potential for severe
thunderstorms. There are some limitations and uncertainties still
to work through, such as warm sector shower/convective activity,
which could limit instability. However, if this fails to develop,
there could be a window for a couple of rounds of severe
thunderstorms...one in the later afternoon/evening and one
overnight with the passage of the front. First round would be in
the form of supercells (with a severe hail/tornado potential) as
there will be some directional shear component and the best CAPE.
That said, looking for a trigger, the best forcing and heightfalls
will be delayed or remain just to our north over the mid south
region. So, going into the overnight...overall more shear, but
less CAPE, especially with any rainfall over the earlier uncapped
warm sector. Still, bulk shear values signal the potential for
damaging wind gusts and mesovorts in bowing segments.
By Sunday, the front clears the region and a strong CAA regime
sets up across the region with much below average temperatures on
the way. By Monday morning, temperatures drop to the 30s for most
and even upper 20s across southwest Mississippi. To start the
workweek, a dry northwest flow will be over our region as the
upper level trough continues to spread downstream. This pattern
helping usher in the colder and drier airmass will not hang
around too long before it evolves into a more zonal pattern, which
should be one key to a warm up (albeit modest and brief).
Followed by a return flow developing by Tuesday morning as a
strong surface high pressure moves to our east.
By the end of the forecast period the previous surface front lifts
northward and positions over the central Gulf. A strong H5 impulse
amplifies over the central US pushing another cold front
southward. A triple point low develops over the northwest Gulf.
This is where our next rain and storm chances reside with a
stronger QPF signal within the area of isentropic upglide north of
the warm front over our region through Wednesday afternoon. It is
to be noted this is Day 7 and both the GFS and ECM have this
feature, just vary temporally and spatially. (Frye)
&&
.AVIATION...
(18Z TAFS)
Issued at 1148 AM CST Thu Feb 13 2025
Main impacts across area terminals this afternoon will continue to
be mainly BKN (to intermittent OVC) low CIGs following a recent
FROPA for most central/western terminals. CIGs are expected to
generally remain around 1.5 to 2kft this afternoon, but should see
gradual clearing with time going into tonight, improving flight
categories. Otherwise, additional impacts include breezy N to NNE
winds today upwards of 10-15kts with gusts of around 20-25kts,
especially KNEW. Winds will lighten some tonight but still remain
in the 06-10kt range, with primarily VFR but can't rule out
intermittent low clouds at times especially into the early
overnight hours.
&&
.MARINE...
Issued at 343 AM CST Thu Feb 13 2025
Hazardous marine conditions are ongoing across the local waters.
There may be some slight improvement later this morning, but this
will only last a brief time before winds and seas increase back to
SCA thresholds this afternoon. Expanded the SCA through Friday
evening, however, another expansion may become necessary as winds
build ahead of the next cold front due into the region late
Saturday or early Sunday. Behind the front, SCA winds are
anticipated through at least early Monday morning before winds and
seas improve briefly as high pressure spreads over the local
waters. (Frye)
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 55 38 64 55 / 0 0 20 20
BTR 60 43 66 59 / 0 0 20 20
ASD 65 42 67 59 / 0 0 10 20
MSY 63 48 67 62 / 0 0 10 20
GPT 64 41 66 58 / 0 0 10 20
PQL 68 42 69 59 / 10 0 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Small Craft Advisory until 6 PM CST Friday for GMZ530-532-534-
536-538-550-552-555-557-570-572-575-577.
MS...None.
GM...Small Craft Advisory until 6 PM CST Friday for GMZ532-534-536-
538-550-552-555-557-570-572-575-577.
&&
$$
UPDATE...KLG
SHORT TERM...RDF
LONG TERM....RDF
AVIATION...KLG
MARINE...RDF
Source: LIX issues Area Forecast Discussion (AFD) at Feb 13, 11:52 AM CST ...New AVIATION... (https://mesonet.agron.iastate.edu/p.php?pid=202502131752-KLIX-FXUS64-AFDLIX)
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