Text Products for AFD Issued by SHV

Area Forecast Discussion
Issued by NWS Shreveport, LA
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FXUS64 KSHV 201525
AFDSHV

Area Forecast Discussion
National Weather Service Shreveport LA
1025 AM CDT Sat Apr 20 2024

...New UPDATE...

.UPDATE...
Issued at 1016 AM CDT Sat Apr 20 2024

Huge uptick in convection across our northwest half this morning
as isentropic forcing much earlier this morning is now being
supplemented with large scale forcing well in advance of an upper
level trough still upstream of the Texas Hill Country. While low
level instability is of no concern given the relatively cool post
frontal temperatures currently in place, elevated MUCAPE values
between 500-1000 J/KG are combining with 7-7.5 deg/km mid-level
lapse rates and near 40kts of Deep Layer Bulk Shear to produce
organized convection near and northwest of the I-30 Corridor
already this morning with a few severe thunderstorm warnings
becoming necessary for large hail. These storm will remain
elevated today and thus, it appears that large hail will continue
to be the main threats with any severe convection but at least
small hail (pea to dime size) will be common with the stronger
convection for the remainder of the day and into at least the
evening hours.

For the update, expanded categorical pops a little further north
and east through the remainder of the daytime hours to mimic
current trends and latest HRRR data but did keep our southeast
zones in high chance pops only as the more widespread rainfall
will likely not begin impacting these areas until this evening and
overnight.

Did make some temperature changes as our northern and northwest
zones have likely already reached their high temperatures for the
day and the same can be said for areas to the northeast as this
large mass of precipitation moves east through the day.

Updated forecast package already sent...13.

&&

.SHORT TERM...
(Saturday through Sunday)
Issued at 335 AM CDT Sat Apr 20 2024

Very diffuse frontal boundary has cleared our southernmost zones
this morning with spotty post-frontal showers starting to expand
across parts of East Texas and North Louisiana. This trend will
continue to ramp up over the next 24 hours in terms of convective
coverage and intensity as a series of upstream shortwave impulses
translate eastward across Texas into the Lower MS Valley. Although
convection will gradually overspread the entire region later today
and tonight, pockets of heavy rainfall and embedded thunderstorms
are expected to become more focused along and south of the I-30
corridor where 1-2 inches of rainfall will be common along with
localized higher amounts near 3+ inches.

The bulk of this rainfall should occur from this afternoon through
early Sunday morning before the primary trough axis finally pivots
overhead and gradually brings an end to the rainfall. Cloud cover
will eventually follow suit by Sunday afternoon with at least some
sunshine returning late in the day. As a result, afternoon warming
will allow high temperatures to climb into the 60s areawide versus
slightly milder rain-cooled air across the majority of the region
today. The exception will be across our far southern zones closer
to the frontal boundary where cool air advection hasn`t been quite
as pronounced given how diffuse the front has become. Regardless,
we will maintain below average temperatures areawide with morning
lows bottoming out in the 40s near 50 degrees across the region.

/19/

&&

.LONG TERM...
(Sunday Night through Saturday)
Issued at 335 AM CDT Sat Apr 20 2024

Gradual clearing of cloud cover will continue on Sunday night with
even cooler temperatures expected on Monday morning. Lower to mid
40s will be common across the entire region, likely the last time
we`ll see temperatures in this range until sometime later in the
fall season if climo is any indication (our average lows for this
time of year = lower to mid 50s). After the cool start on Monday
morning, it`s all uphill from there as a strong warming trend will
commence and continue through the remainder of next week.

Advancing high pressure will shift east of the area by late Monday
and allow for a return to southerly flow. Looking aloft, weak NW
flow will maintain dry conditions through at least Tuesday before
a shortwave trough well to our north swings south from the central
Canadian provinces into the Upper Midwest and Great Lakes Region.
This trough will help to propel a weak cold front south into our
region by Wednesday and should allow for some isolated convection
across our northern zones from mid to late week. However, this is
a fairly low confidence forecast with some question as to how far
south this front will manage to advance before stalling out and
lifting back northward by the end of the week. This appears to
coincide with a much stronger trough ejecting out of the Rockies
into the Great Plains on Friday into Saturday. Medium-range model
guidance continues to exhibit some timing discrepancies this far
out in time, but early signals indicate this could be a favorable
setup for severe weather. Given the extent of warm air advection
by late week, this potential will be monitored closely over the
coming week.

/19/

&&

.AVIATION...
(12Z TAFS)
Issued at 643 AM CDT Sat Apr 20 2024

For the ArkLaTex terminals, IFR/MVFR with -DZ/BR. We are seeing
an increase in coverage & intensity of convection with some hail
15-21Z as an upper disturbance in N TX now rides over the shallow
cool air. A second disturbance arrives late today/eve with more
convection and then overnight things will calm down with slightly
better vsby/cigs slowly lifting. The NE winds only extend up to
2kft with a super wet SW flow by 3kft and throughout your climb,
due W for FLs 30-50KT from FL200-FL350. FZL is 133 w/ mid level
dry air so no icing issues and prob not much turb with these winds.
/24/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  62  51  67  46 / 100 100  20   0
MLU  62  49  64  43 /  90 100  30   0
DEQ  58  43  66  40 / 100  80   0   0
TXK  59  48  66  43 / 100  90  10   0
ELD  58  46  65  40 / 100 100  20   0
TYR  61  49  65  45 / 100  90  10   0
GGG  61  49  65  44 / 100 100  10   0
LFK  70  51  66  45 / 100 100  20   0

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&

$$

SHORT TERM...19
LONG TERM....19
AVIATION...24
National Weather Service Regional Headquarters
