Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 190920
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
420 AM CDT Tue Mar 19 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Tuesday through Wednesday)
Issued at 420 AM CDT Tue Mar 19 2024

The early morning sfc analysis indicates ridging has settled into
SE OK/SW AR, with the center of the ridge expected to drift
farther S into Deep E TX/N LA by daybreak. A mostly clear sky and
light winds have yielded good radiational cooling, with temps
having quickly fallen into the lower/mid 30s across much of the
Freeze Warning area as of 08Z (with the exception of the more
urban areas). This sfc ridge still remains progged to drift
farther S into SE TX/S LA by early afternoon, which will begin a
moderating trend in temperatures commencing today through
Wednesday. While the cirrus shield noted on the morning satellite
imagery over much of W and N TX is currently spilling E towards E
TX, drier air aloft noted on the morning water vapor imagery along
the backside of the longwave trough digging towards the Gulf
Coast should help to erode these cigs, with strong insolation
resulting in a large diurnal swing in temps from this morning`s
lows. Did bump max temps up a degree or so to account for the good
insolation, with temps again falling off quickly this evening
within the dry air mass and light winds. However, min temps
Wednesday morning should run some 10-15 degrees warmer than this
morning, given light SW winds on the backside of the departing sfc
ridge to our SE, and an increase in AC cigs that will shift NE
into the Wrn half of the region late this evening and overnight.
These cigs will be in advance of a weak shortwave trough that will
translate E across NCntrl TX overnight, and across the region
during the day/evening Wednesday. While some sprinkles can`t be
ruled out Wednesday from these cigs, the presence of very dry low
level air should preclude much of this from even reaching the
ground.

Rex blocking over the Wrn CONUS that has been persistent the last
few days remains progged to weaken tonight, with the Cntrl AZ
closed low finally beginning to drift E through NM Wednesday,
before opening up into a trough as it moves through TX Thursday.
Good agreement exists amongst the short term progs that this
trough will remain somewhat amplified as it approaches the region,
in time as low level moisture begins to increase Wednesday across
the Wrn half of the area, which deepens further Wednesday night.
This trough will also tap the subtropical jet to our S and
allowing it to nudge back N, with Pacific moisture aloft deepening
through the day. Large scale forcing is set to increase ahead of
the trough late Wednesday night across Cntrl OK S into Cntrl TX,
with the developing convection beginning to move into SE OK/E TX
just prior to daybreak Thursday. Have maintained mid and high
chance pops late Wednesday night across SE OK/E TX, before the
convection overspreads the remainder of the area Thursday.

15

&&

.LONG TERM...
(Wednesday Night through Tuesday)
Issued at 420 AM CDT Tue Mar 19 2024

The models have trended a bit slower and stronger with this approaching
trough, which should result in more numerous convection over the
region Thursday, where likely pops were expanded over much of the
area. Fortunately, the better instability remains progged to
linger over S TX Thursday, although mid level lapse rates should
be steep enough to support embedded thunder, with the increasing
convection helping to saturate to bndry lyr. The slowing trough
should result in convection persisting longer than earlier
forecast into at least Thursday evening, where pops were increased
to mid and high chance, before diminishing from W to E late. Did
maintain slight chance pops Friday morning across the Ern zones to
account for any lingering isolated -SHRA near the trough center.
What has changed since the morning model runs Monday is that there
is greater consensus that the more amplified troughing solution
will result in sfc low development Thursday night over far SE TX
near or W of Sabine Pass, with this sfc low sliding E across S LA
Friday. Thus, a more Nrthly deep lyr flow would result on the N
and back side of this sfc low, and persist through the day Friday.
Post-frontal cigs in wake of this system will inhibit insolation,
thus resulting in cooler than advertised daytime temps. Have
trimmed back temps areawide Friday, but should this trend
continue, cooler conditions than currently advertised will result.

Should finally see the return of the sun by Saturday, along with
moderating temps back above normal, but the sun will be short-
lived as elevated moisture will quickly spill back E over the area
Sunday, ahead of long wave troughing that will dig through the
Great Basin into the Rockies and Desert SW. Low level moisture
return will commence in earnest Sunday afternoon/night over the
Srn Plains with large scale forcing and associated convection
increasing again ahead of the trough Sunday night. While scattered
convection may affect areas NW of the I-30 corridor late Sunday
night, the bulk of the more widespread convection will affect the
region Monday. Instability return still remains questionable
though, but confidence is high enough for likely pops for much of
the area. It remains to be seen though as to whether there will be
multiple rounds of convection as we move through midweek,
especially as troughing will persist to our W, thus maintaining SW
flow aloft through at least midweek.

15

&&

.AVIATION...
(06Z TAFS)
Issued at 1218 AM CDT Tue Mar 19 2024

For the 19/06Z TAFs, unrestricted VFR conditions will prevail,
with widespread SKC aside from SCT to FEW high cirrus across
portions of east Texas airspace. As high pressure settles in,
winds will become light and variable with some sites nearly calm
by daybreak while areas of frost develop. After 19/12Z winds will
become southerly, transitioning to southwesterly at maximum
sustained speeds of 5 to 10 kts with a few gusts of up to 15 kts
possible.

/26/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  67  44  72  54 /   0   0   0  20
MLU  64  40  71  49 /   0   0   0  10
DEQ  66  39  69  50 /   0   0   0  30
TXK  65  43  69  52 /   0   0   0  30
ELD  64  39  70  49 /   0   0   0  20
TYR  67  47  70  55 /   0   0   0  50
GGG  67  44  70  54 /   0   0   0  40
LFK  67  46  71  55 /   0   0   0  40

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Freeze Warning until 9 AM CDT this morning for ARZ050-051-
     059>061-070>073.

LA...Freeze Warning until 9 AM CDT this morning for LAZ001>006-
     012>014-019>022.

OK...Freeze Warning until 9 AM CDT this morning for OKZ077.

TX...Freeze Warning until 9 AM CDT this morning for TXZ096-097-
     108>112-124>126-138.

&&

$$

SHORT TERM...15
LONG TERM....15
AVIATION...26


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