485
FXUS64 KHUN 260544
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1244 AM CDT Sun May 26 2024

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 841 PM CDT Sat May 25 2024

Outflow boundaries lifting northeastward have been the driving
force behind the sporadic showers and thunderstorms, and the start
of the increase in cloud cover this evening. Additional cloud
cover will stream in tonight ahead of the Southern Plains system.
With light winds in place, low stratus is possible. The convection
with this approaching system will reach the region Sunday morning
and is expected to generally remain north of the forecast area.
Cannot rule out an isolated shower/storm or two, especially in the
southern middle TN counties though. Adjusted POPs to accommodate
boundary driven convection and hourly temps, otherwise the
forecast was on track for tonight.

&&

.SHORT TERM...
(Sunday through Tuesday)
Issued at 235 PM CDT Sat May 25 2024

Before any mention of severe weather, we must discuss the high
temperatures on Sunday! We have a very high chance of seeing our
first 90 degree day at several locations. This has been well
represented in nearly all of the HIRES models. Unfortunately this
will only aid in destabilizing the boundary layer throughout the
day tomorrow and prime the environment for overnight storms.
After very sunny peak heating hours, CAMS indicate 1500-2000+ J/KG
of CAPE lingering into the overnight hours for storms to take
advantage of.

Our severe threat comes from a surface low pressure system passing
just to the NW of us. A broken line of storms will move through
the area ahead of an attached cold front Sunday night into Monday
morning, bringing all modes of severe weather and warranting a
slight risk (2/5) from SPC. As we entered into CAM coverage this
morning, models have been very consistent with harsh environmental
parameters being present Sunday night. The aformentioned CAPE
will support strong updrafts with 50-60+ KTS of bulk shear
favoring organized convection and yielding a low but non zero
tornado threat. Steep lapse rates from 7-8 C/KM will support a
hail threat and the orientation of the line will be very favorable
for damaging winds, which will likely prevail as our primary
threat. While CAMS have been consistent in showing the line and
favorable parameters, they have yet to align on timing. What
appears clear right now is that the HIRES models favor a earlier
arrival of the line and a faster departure as compared to
previously used global models. Current models have the line
entering NW AL Sunday night as early as 8 pm but as late as
midnight. Current exit times look to be around mid morning on
Monday.

Timing is one of two aspects we will continue to refine in
subsequent forecasts. The second aspect is the potential for
scattered storm development ahead of the line. Models have not
necessarily picked up on this yet but the environment Sunday
afternoon and evening will be supportive of all modes of severe
weather should anything develop ahead of the line.

After the line exits our area, clear and dry conditions will
develop in its wake throughout the day on Monday. These conditions
will prevail for the remainder of the short term as high pressure
will begin to build in from the NW. Highs will be slightly cooler
than Sunday only reaching the mid to high 80s Monday and Tuesday.

&&

.LONG TERM...
(Tuesday night through Friday)
Issued at 359 AM CDT Sat May 25 2024

Sfc high pressure allows for dry weather to settle over the
region through the mid week. Upper level shortwaves will allow a
very low chance of showers (10% or less) during this time,
however, confidence is low in this occurring. High temperatures
during this period are forecast to be in the 80s with overnight
lows in the 50s/60s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1244 AM CDT Sun May 26 2024

VFR conditions continue through the morning hours at both KMSL and
KHSV. Around 14-15Z, MVFR conditions are likely as low cloud cover
moves in. In addition to this, gusty SW winds up to around 15-20
kts are forecast through the afternoon into the evening hours.
During the evening hours, a PROB30 group has been introduced for
potential thunderstorm development causing lowered visibilities
and cloud cover. Just past the TAF period, there is a potential
for LLWS to impact both terminals and it will likely need to be
added in the next update.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

$$

NEAR TERM...JMS
SHORT TERM....RAD
LONG TERM....HC
AVIATION...HC