Can anyone pull the latest GSP discussion? Thank you
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FXUS62 KGSP 021848
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
248 PM EDT Sat Apr 2 2022
.SYNOPSIS...
Dry weather continues through Monday although a weak system may
bring a few sprinkles to the area this evening. Mild high pressure
brings warmer temperatures to start the week. Then, a wet storm
system is expected to arrive Tuesday, with unsettled weather
continuing through the middle of the week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 145 PM: Low pressure near Chicago is associated with a sharp
shortwave aloft, which is phased with a weaker wave now over western
KY/TN. Patchy alto/cirrus clouds extend from the Great Lakes to Gulf
Coast as a result of these features. The more southerly wave will
pass the CWA this evening, and as a result a period of cloudiness
is expected. Kept the sprinkle mention added by previous shift,
with ASOS sites reporting spotty trace RA upstream. Max temps
look to be impacted a little bit, and revised aftn temps have been
brought down a tad. RH at obs sites is mostly presently above 25%
and is expected to stay there; land management agencies indicated
fuel moisture readings still appeared high enough for enhanced
fire danger this afternoon.
The passage of the shortwave and sfc low to our north will bring
a relatively weak cold front across the area overnight, with winds
shifting as soon as late evening in the mountains and by daybreak in
the lower Piedmont. Min temps end up around normal. While a few CAMs
spit out light QPF in the NW Flow areas in the wee hours Sunday,
moisture profiles are so shallow that we will mention only a brief
period of sprinkles (possibly flurries in very high elevations).
Skies will be virtually clear at daybreak across the Piedmont,
and clear during the morning in the mountains. Downsloping should
have a big impact on Sunday temps, allowing upper 60s and lower 70s
in the Piedmont. Temps are expected to rise a few degrees above
raw model values, so coaxed winds/gusts toward the high end of
guidance. Please see Fire Wx section below for notes on fire danger.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 130 PM EDT Saturday: Quasi-zonal flow aloft will push
across the CFWA Sunday night into Monday as a surface high riding
underneath slides across the Mid-Atlantic and Carolinas. Mostly
clear skies and light winds will set up decent radiational cooling
conditions Sunday night. Thus, patchy frost will likely develop
across the I-40 corridor. Low RH values may develop Monday afternoon
and elevate fire weather concerns, especially across the NC zones
where wind gusts will be higher. The surface high pushes offshore
Monday afternoon into Monday night, which in turn, allows for
a return flow to enter the CFWA. Moisture and cloud cover will
increase as a result as deep layer southwesterly flow sets up shop
across the southeastern CONUS Monday night and Tuesday, ahead of
an upper level trough to the west. Max temperatures will be at or
slightly above normal for Monday as WAA begins to filter into the
CFWA. Low temperatures Monday night will run slightly above normal
due to increasing cloud coverage.
Southern stream shortwave is shown ejecting across the Southern
Plains Monday night into Tuesday with a low pressure system
developing underneath. Stout 40-50 kt S-SW LLJ will impinge on
the CFWA just ahead of the system as it marches across the Lower
MS Valley and Deep South. PWAT values will surge above 1.00"
across the higher elevations and around 1.50" or higher east of
the mountains by Tuesday as the LLJ pulls in deep moisture from
the Gulf and Atlantic. The timing is still in question as the GFS
is slightly more progressive than other operational model runs as
precip begins in the southwestern zones by mid-morning Tuesday,
while the ECMWF and CMC wait until Tuesday afternoon. The system
will be fast-moving, but strong isentropic lift and upper divergence
to go along with a completely saturated vertical profile from the
top-down will pose the risk for very heavy rainfall rates in a
short period of time. In this case, a hydro threat for flash flood
could develop Tuesday afternoon/evening, especially in the favorable
upslope locations along the southern Blue Ridge Escarpment and in
the far southern zones, where the core of the low pressure system
will cross and destabilization is strongest. QPF amounts at this
time will range from >0.5"-2.0" for most locations with locally
higher amounts in the favorable aforementioned regions. Instability
will be marginal at best Tuesday afternoon, but a few hundred J/kg
of SBCAPE may develop in the southern tier, which could produce
a couple of strong storms in this area, but any severe threat is
low at this time. The low pressure system is expected to lift out
of the CFWA by Tuesday night and provide a lull in precip before
the next system impacts the area during the middle part of next
week. High temperatures on Tuesday will be at or slightly above
normal due to strong WAA.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 215 PM EDT Saturday: Deep stacked low will drop into the
north-central CONUS Wednesday as the initial shortwave lifts
offshore. Ongoing deep layer southwesterly flow and WAA regime will
be in store, which will help uptick temperatures into the 70s for
most locations with low 80s becoming a possibility south and east
of the I-85 corridor Wednesday. Model guidance continue to hint at
good SBCAPE values to develop Wednesday afternoon in response, but
global models and even the GEFS continue to slow down the timing
of a cold front that`s associated the the stacked low. As of now,
the cold front`s arrival is expected to be overnight Wednesday,
which would lower any severe threat. With good deep layer shear and
some form of surface instability Wednesday night, expect there to
be a linear segment of convection along the cold front as it pushes
into the CFWA. A lot of uncertainties, but this could produce at
least a low-end severe threat for portions of the CFWA. The threat
could increase if the cold front arrives during peak heating,
but not looking likely at this time. Expect the fropa to occur
some time Thursday morning as a post frontal regime settles in
behind the from later Thursday into the first part of Friday.
The stacked low is expected to move into the Great Lakes region
and stretch across the eastern CONUS Thursday through much of
next weekend. This will lower thicknesses drastically under broad
cyclonic flow aloft. Model guidance continue to produce NW flow
precip across the mountains, with the possibility of some showers
breaking containment east of the mountains later Friday. 850mb
temperatures dip below freezing by Friday as stout CAA filters
into the region and will remain sub-freezing through the end of the
forecast period, especially across the higher elevations. The GFS
and ECMWF keep NW flow precip, especially along the TN border in the
forecast from Thursday night through at least Saturday. Snow will
likely fall in elevations above 3500` during this time frame with
some form of accumulating snow becoming a favorable trend along
the TN border and in the Smokies, but amounts are uncertain at
this point in time. Temperatures will start out well above normal
Wednesday before lowering each day through the end of the medium
range and becoming below normal by Friday into next weekend across
the CFWA.
&&
