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000
FXUS62 KGSP 150632
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
232 AM EDT Mon Apr 15 2024

.SYNOPSIS...
Dry high pressure will linger to our south into the first half
of the week giving our region above normal temperatures and more
humidity than we`ve felt lately. Small chances of showers and storms
do return to some areas of the mountains today as a result. A front
will approach our area from the west through the middle of the week,
and could bring more showers and thunderstorms by Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 200 AM: Skies are clear across the CWA, with midlevel
clouds having advected out with the departing shortwave. Over the
course of the day today, the upper trough over the NE CONUS will
move offshore and the ridge to our west will become the dominant
feature for our weather. A light southwesterly return flow will
result in still higher dewpoints. As partial thicknesses continue
to rebound temperatures will also trend warmer, well into the 80s,
within a few degrees of record highs. With the influence of the
ridge diminishing, these conditions appear to mix out the subsidence
inversion, such that a respectable amount of SBCAPE is generated by
many of the models. We are for want of a trigger mechanism. Embedded
shortwave will pass thru the middle OH Valley into Virginia today,
but heights remain on an upward trend owing to the migration of
the ridge. Nonetheless, the GFS/ECMWF/GDPS develop spotty QPF
response over our mountains. Based on CAM output, this looks
to be especially isolated and worthy only of a brief isolated
shower/t-stm mention near the Blue Ridge Escarpment. Soundings
are very dry aloft and updrafts may not amount to much especially
given minimal trigger. Any such storms should diminish diurnally;
some CAM runs hint at semi-organized convection moving off the
frontal zone in the OH Valley and propagating southward into our
northern CWA. The chance of that appears no greater than before;
we had previously carried a small PoP in our north as a nod to that
possibility. In light of recent model runs have moved the overnight
PoP to late evening in our northern mountains. Partial convective
debris clouds do stand a good chance of reaching the CWA, so a
partly to mostly cloudy night is expected in the I-40 corridor. Mins
tonight again 10 or more degrees above normal with light winds.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
As of 2:25 PM EDT Sunday: The short-term fcst picks up at 00z on
Tuesday with upper ridging in place over the Southeast and upper
trofing centered well to our north over New England and a closed
upper low moving over the SW CONUS. Over the next couple of days,
the upper low will lift northeast towards the Great Lakes and act
to flatten the upper ridge over our area. By the end of the period
late Wednesday, the upper low is expected to be centered over the
western Great Lakes and starting to get absorbed by another broad
upper trof amplifying over southern Canada. At the sfc, what is left
of a diffuse frontal bndy/lee trof will linger over our area as the
period begins late Monday. This could result in some lingering
showers and even a few thunderstorms over our northern zones into
early Tuesday. Over the next couple of days, a robust low pressure
system will lift out of the Great Plains and move a cold front to
our doorstep towards the end of the period late Wed. Over the past
couple of days, most of the model guidance has been trending slower
wrt the progression of the low and its associated frontal bndy. At
present, it`s looking like the front won`t move thru our area until
just beyond the short-term period, on Thursday. Regardless, we can
expect warm, predominately SWLY low-level flow across our area thru
the period as we remain under the western fringe of the Bermuda High.
Temperatures will remain well-above normal for mid-April thru the
period.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 2:05 PM EDT Sunday: The extended forecast picks up at 00z on
Thursday with a closed upper low opening back up and moving up and
over the Great Lakes. Over the next 24 hrs or so, what`s left of the
low will get absorbed by a reinforcing upper trof/closed low that
moves southeast out of central Canada. This system will continue to
translate southeast into next weekend and act to flatten/suppress
the upper ridging over our region. At the sfc, a robust low pressure
system will be lifting over the western Great Lakes and moving a
fairly dry cold front to our fcst area as the period begins late
Wednesday/early Thursday. The progression of this frontal system
has been trending slower over the past couple of days with most of
the current guidance moving it thru our fcst area on Thursday. In
its wake, the sfc pattern remains progressive, however model solu-
tions diverge wrt exactly where and when the next low will develop.
It`s looking more likely that we will see brief drying on Friday
and another low developing just to our NW over the weekend along
a moist frontal boundary. Regardless, there is good consensus that
by the end of the period early next week, broad Canadian high pre-
ssure will spread over our area from the NW and bring dry wx to the
region. Temperatures will start out well-above climatology and likely
cool to near-normal, if not below, by the end of the period.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: VFR, with SW winds thru the period at
all sites except KAVL, where initially NW winds are likely to
go light/VRB as SW flow regime strengthens during the day, and
eventually should go SW by late afternoon. Some low-end gusts
likely less than 20 kt are possible at all sites during the
afternoon. A diurnal cu field should develop in the afternoon
over the mountains and foothills, with bases comfortably VFR. A
stray SHRA or TSRA is possible near KAVL and KHKY but chance too
low to mention. Some convection developing along frontal boundary
across KY/VA may propagate south into the northern NC mountains
this evening to very early Tue morning, but resultant chance of
SHRA/TSRA is even lower at the terminals. Midlevel clouds and/or
cirrus debris likely will spill over the NC sites overnight however.

Outlook: Isolated SHRA/TSRA are not out of the question Tue and
Wed afternoons near KAVL and KHKY. Otherwise VFR generally will
persist through midweek under high pressure regime.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...Wimberley
NEAR TERM...Wimberley
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...Wimberley