Area Forecast Discussion Issued by NWS Shreveport, LA
000
FXUS64 KSHV 181438
AFDSHV
Area Forecast Discussion
National Weather Service Shreveport LA
938 AM CDT Mon Mar 18 2024
...New UPDATE...
.UPDATE...
Issued at 934 AM CDT Mon Mar 18 2024
Surface high pressure continues to build across the region this
morning allowing for temperature and dew point values to drop
areawide. Aloft, northwest flow will maintain mostly sunny skies
across much of the region with a few high clouds persisting across
portions of deep east Texas and north Louisiana. Otherwise,
afternoon high temperatures will range from the 50s north of
Interstate 30 to the lower 60s elsewhere. Current forecast is on
track, no update needed at this time. /05/
&&
.SHORT TERM...
(Monday through Tuesday Night)
Issued at 424 AM CDT Mon Mar 18 2024
The morning sfc analysis indicates the leading edge of the cooler
and much drier air has spilled S into Deep E TX and the Srn
sections of NCntrl LA, as depicted by the sharp separation of sfc
theta-e over these areas. However, the morning satellite imagery
depicts a considerable low AC shield persists along and behind
this air mass over all of E TX/N LA/SW AR/extreme SE OK, ahead of
the base of the digging longwave trough that extends from Nrn OK
into the Ozarks and the Mid MS Valley. As this trough continues to
dig SE this morning, much drier air should result in these cigs
diminishing from NW to SE later this morning through the early
afternoon hours, allowing for the welcome return of the sun
following the last few days of wet and stormy conditions that had
prevailed over the area. Cold advection which still lags the cold
front to the N of our region, will eventually spill S and take
root after daybreak this morning, before becoming neutral by
midday once deeper mixing is realized. However, below normal temps
are expected this afternoon as readings only top out in the
mid/upper 50s north to lower/mid 60s S, some 10-15 degrees below
normal.
Gusty N winds later this morning into the afternoon which eventually
decouple by/shortly after sunset, once Canadian sfc ridging now
over the Cntrl Plains slides SE into the region this evening.
Thus, good radiational cooling will set up later this
evening/overnight, resulting in widespread frosty conditions
areawide. In fact, the 00Z guidance has trended colder than
yesterday with min temps tonight given the extent of the drier air
spilling S, with near to sub-freezing temps expected beyond the
existing Freeze Watch area, into much of NE TX/NW and NCntrl LA.
Thus, have upgraded the Watch to a Freeze Warning while expanding
the Warning to cover areas mainly N of the I-20 corridor of E
TX/NW LA, and E of the I-49 corridor in Ncntrl LA. Since the
growing season is underway and this expected freeze has surpassed
the average last freeze of the late winter/early spring season,
precautions should be taken areawide to protect tender vegetation
that could be harmed by these cold temps.
The sfc ridge remains progged to slowly drift S into S LA Tuesday
afternoon, before emerging out over the Nrn Gulf Tuesday night.
Thus, temps will begin a gradual moderating trend Tuesday (but
still remain below normal), with insolation possibly hindered by
an increasing cirrus shield that will spread across E TX/N LA from
the W. This will also translate to milder conditions Tuesday
night, especially as AC cigs develop/spread NE into E TX/Wrn LA
just ahead of a weak mid level shortwave that will eject NE across
Cntrl TX. Despite some weak forcing aloft that is shown amongst
the short term progs, the very dry low level air mass remaining in
place should preclude any measurable rain from occurring, although
a few sprinkles can not be ruled out.
Thank you WFO`s FWD, LZK, and LCH for coordination this morning.
15
&&
.LONG TERM...
(Wednesday through Monday)
Issued at 424 AM CDT Mon Mar 18 2024
The rex block pattern in place over the Wrn CONUS this morning
looks to persist through much of Tuesday, before the Srn AZ closed
low finally begins to drift E and gradually open up into a trough
Wednesday as it enters the TX Panhandle Wednesday afternoon. Low
level moisture advection should finally commence Wednesday within
the SW low level flow on the backside of the sfc ridging once it
shifts SE into the Gulf States/Nrn Gulf. Additional elevated
moisture should also increase from the W ahead of the ejecting SW
U.S. low, which will set the stage for the potential for scattered
to numerous convection as it begins to develop/spread into SE OK/E
TX late Wednesday night, and across the remainder of the region
Thursday ahead of the approaching trough. Better agreement exists
amongst the GFS/ECMWF with a stronger amplitude of the trough,
which would suggest more numerous convection over more of the
region Thursday. Fortunately, the better instability looks to
remain SSW of the region into SE TX and along the S LA coast,
although lapse rates aloft should be sufficient for embedded
thunder until the trough departs the area to the E Thursday night.
Have expanded likely pops over all but the Ern zones Thursday,
where high chance pops exist, before reducing pops to chance
Thursday night.
Very little air mass change is expected in wake of this trough by
week`s end, with seasonal temps returning as we round out the end
of the work week. A warming trend will resume next weekend though
given increased insolation, but dry conditions should continue
through Sunday as we await the next upper level pattern change to
start the final full week of March. While details vary amongst the
various long range progs, the general consensus suggests that a
longwave trough will begin to carve across the Wrn CONUS by Sunday
night/Monday, with a long duration of active SW flow aloft yielding
to periods of convection over the region for much of next week.
15
&&
.AVIATION...
(12Z TAFS)
Issued at 620 AM CDT Mon Mar 18 2024
For the 18/12Z TAFs, lingering MVFR to lower VFR cloud decks across
southern ArkLaTex airspace will depart to the south within the next
several hours, followed by unrestricted VFR abounding from 18/18Z
onward. SKC will be punctuated only by returning BKN to SCT high
clouds across east Texas late in the forecast period. Northeasterly
winds will become northwesterly through the day at speeds of 10 to
15 kts with gusts of 15 to 25 kts possible.
/26/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 63 34 66 44 / 0 0 0 0
MLU 61 32 63 40 / 0 0 0 0
DEQ 56 28 65 39 / 0 0 0 0
TXK 59 31 65 43 / 0 0 0 0
ELD 59 29 63 39 / 0 0 0 0
TYR 61 34 66 47 / 0 0 0 0
GGG 61 33 65 44 / 0 0 0 0
LFK 64 35 67 45 / 0 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Freeze Warning from midnight tonight to 9 AM CDT Tuesday for
ARZ050-051-059>061-070>073.
LA...Freeze Warning from midnight tonight to 9 AM CDT Tuesday for
LAZ001>006-012>014-019>022.
OK...Freeze Warning from midnight tonight to 9 AM CDT Tuesday for
OKZ077.
TX...Freeze Warning from midnight tonight to 9 AM CDT Tuesday for
TXZ096-097-108>112-124>126-138.
&&
$$
SHORT TERM...05
LONG TERM....15
AVIATION...26