652
FXUS64 KHUN 091831
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
131 PM CDT Sun Jun 9 2024

...New NEAR TERM, SHORT TERM...

.NEAR TERM...
(This Evening and Tonight)
Issued at 130 PM CDT Sun Jun 9 2024

A very mesoscale driven forecast this afternoon and evening across
the Tennessee Valley. Ample heating has warmed temperatures into
the mid to upper 80s as of 18z, with SPC mesoanalysis data
showing SBCAPE values between 1500-3000 J/kg (with the highest
values west of I-65). Low level lapse rates are still relatively
modest, but are approaching 7 C/km over much of northwest
Alabama. A couple of outflow boundaries are bisecting the area --
the most prominent one is currently stretching from central
Arkansas, northern Mississippi and just south of the Tennessee
River in northern Alabama. Another boundary stretches from near
Muscle Shoals, AL to Crossville, TN. We will continue to monitor
satellite and radar trends in the near term as they may serve as a
focus convection by late this afternoon and into the evening
hours as synoptic lift from an approaching shortwave increases
forcing and bulk shear values increase to 30-40 kts.

Main uncertainty remains where these boundaries will be located
and when convection gets going. Based on the latest satellite
trends, there is some evidence that these boundaries are drifting
southward and it`s entirely possible that the window for strong to
severe storms may be more limited this far north if storms
initially convect to our south. Still, the presence of the more
northern boundary in particular gives us confidence that
eventually medium (40-60%) chances for showers/storms are
warranted, especially in the 22-04z window as continually hinted
at by the CAMS. We will be primed for damaging winds in clusters
of storms that can organize into line segments during this
window, with marginally severe hail and locally heavy rainfall
secondary threats. This activity will begin to wane and sink south
after Midnight, with PoPs lowering to around 20% by early Monday
morning.

&&

.SHORT TERM...
(Monday through Wednesday)
Issued at 130 PM CDT Sun Jun 9 2024

Rain chances will wane by early Monday morning as cloud cover
gradually diminishes from north to south on Monday. A cooler,
drier air mass will move into the region early next week and we`ll
enjoy high temperatures only in the low to mid 80s for Monday and
Tuesday, with overnight lows in the mid to upper 50s -- all to go
along with sunny conditions each day. Ridging will amplify by
midweek and a gradual warming trend will begin on Wednesday and
carry over into the later part of the week. More on this in the
section below.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 422 AM CDT Sun Jun 9 2024

Although specific details remain unclear at this point, most of
the global models now suggest that that southern stream trough
(discussed above) will travel southeastward into the northern Gulf
of Mexico during the first half of the extended period, before
evolving into nearly stationary cutoff low on Friday/Friday night.
Any northward movement of the low next weekend will likely be
dictated by the strength and orientation of a blocking mid-level
ridge to its north, which will in all likelihood lie across the TN
Valley, providing an extended period of warm and dry conditions
that could potentially extend into the first part of the following
week. That said, we have included a very low (15-20%) POP across
our southeastern counties on Friday and Saturday afternoons, due
to a gradual increase in low-level moisture which will translate
to a notable increase in CAPE given hot daytime temperatures.
Highs will quickly warm into the lower 90s for most valley
locations by Thursday/Friday/Saturday, with lows more gradually
returning to the u60s-l70s by Saturday morning.

&&

.AVIATION...
(18Z TAFS)
Issued at 1132 AM CDT Sun Jun 9 2024

VFR conditions will be the predominant flight category this
afternoon as a front approaches the region from the NW. Model
guidance hints that a cluster/line of storms may develop and push
into the region during a 23-05z timeframe. Have handled this with
a TEMPO group for reduced visibilities and ceilings from TSRA
during this timeframe. AWWs and amendments may also be needed if
this occurs. TSRA chances will wane after Midnight and VFR
conditions will return by Monday morning.

&&

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

$$

NEAR TERM...AMP.24
SHORT TERM....AMP.24
LONG TERM....70
AVIATION...AMP