GSP's take on Friday
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 130 PM EST Tuesday: A positively-tiled upper trough will
dig across the western CONUS during the beginning portions of the
forecast period, while an attendant frontal boundary stretches from
the Southern Plains, through the ArkLaTex region, and into the
OH Valley and northeastern CONUS. As the pattern evolves through
the period, expect the frontal boundary to sag into the Southeast
Wednesday night into Thursday as the parent low lifts into the
northeastern CONUS. With a surface high shifting offshore and
the flow aloft gaining a southwesterly component, deep moisture
advection and low-level convergence will lead to a swath of precip
to push into the CFWA during the alluded timeframe. With a 40-50 kt
LLJ and scattered upper forcing to go along with high PWAT values
(1.00"-1.50+"), expect precip rates to be enhanced, which ultimately
may lead to a low-end hydro threat. Model guidance continue to
show the alluded frontal boundary stalling over the CFWA Thursday,
which may lead to an extended period of precip. As a result, likely
to categorical PoPs will remain in the forecast on Thursday. While
the frontal boundary remains stalled over the region, the positively
tilted trough will strengthen into a vertically stacked low over
the Four Corners region and shift to the Southern Plains Thursday
night. The surface low riding underneath will undergo cyclogenesis
and rapidly strengthen as it rides along the stalled boundary and
lifts in the mid-MS Valley. The stalled boundary over our CFWA will
activate into a warm front in response and lift well north of the
CFWA by Friday morning. This will set the area under a stout warm
sector regime, ahead the approaching frontal system.
Underneath the aforementioned warm sector, an environment favorable
for severe weather will be in store. The cold front attached
to the surface cyclone will be strongly forced as it encroaches
the CFWA by Friday afternoon. Model guidance continue to support
500-1000 J/kg of SBCAPE across the area as the front enters the
CFWA. Great deep layer shear and unidirectional hodographs support
the development of a squall line as the main frontal zone swings
through the CFWA. Mini-supercells could form out ahead of the
front as well. In this case, all three severe hazards will be
possible with damaging straight-line winds and a few embedded
tornadoes being the main focus. With the forward progression of
this system being relatively quick, any hydro threat will be low
and localized. One caveat being thrown into this forecast is the
timing between global models and the pesky NAM. Global models
are still in great consensus and that the main frontal band will
push through the area during peak heating. On the other hand,
the NAM is slower in the front`s progression and appears to push
the front across the CFWA just after peak heating, which could
limit the overall severe threat as a result. This will be a trend
to watch out for, especially once the hi-res models start to get
a handle on this setup on Wednesday. We urge everyone to continue
monitoring the forecast leading up to Thursday and Friday as it will
change between now and then, but the run-to-run consensus between
all operational models and ensembles makes it hard to believe that
there won`t be at least a low-end severe threat across the western
Carolinas and northeast Georgia. Temperatures through the period
will be well-above normal.