134 
FXUS62 KGSP 041845
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
245 PM EDT Sun Apr 4 2021

.SYNOPSIS...
High pressure remains in place into the middle of next week leading 
to continued dry conditions, abundant sunshine and gradually warming 
temps. A low pressure system and its associated cold front will 
increase shower and thunderstorm chances middle to late next week.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 140 pm: Upper heights will continue to rise through the 
period, as a ridge builds downstream of a series of short wave 
troughs over western North America. As such, the continued warming 
trend will be the big story of the near term. Although dry surface 
high pressure will become increasingly less influential, dewpoints 
will continue to be slow to increase, and this combined with 
generally favorable radiational cooling conditions at night will 
result in large diurnal temps ranges, with lows expected to average 
right around normal tonight, while Monday's maxes should be a solid 
5 degrees above normal, translating widespread mid-70s across the 
Piedmont and foothills, and lower 70s in the major mountain 
valleys.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 200 PM EDT Sunday: A broad ridge over the Mississippi Valley 
Tuesday with shift east into our area by Wednesday while sharpening 
due to an approach storm system. Deep layer northwest and 
downsloping flow Tuesday combined with mostly sunny skies will 
support continued warming with highs in the 70s to near 80. As the 
axis of the ridge passes over the area Tuesday night into Wednesday, 
winds will back towards the west and eventually southwest supporting 
increased humidity and perhaps cloud cover late in the day. 
Wednesday will probably be the warmest of the next seven days with 
highs in the 70s across the mountains to near 80 east of the 
mountains.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 230 PM EDT Sunday: A strong low pressure system will be 
tracking out of the Central/Southern Plains and into the Midwest 
Wednesday night into Thursday. This will act to suppress the ridge to 
our east allowing for the increase of moisture and cloud cover 
across the region during the medium range. Models are in good 
agreement that the stacked low pressure system will lift north early 
Thursday morning into the weekend. Since this low pressure system is 
expected to track to our northwest and stall across the Great Lakes 
Region into the weekend, this could limit the severe weather 
potential for our CWA; especially since the jet dynamics along with 
higher instability and shear remain to our west across the Deep 
South. A slight chance for rain has been maintained for the far 
western zones starting Wednesday evening. Rain chances will increase 
from west to east throughout the day Thursday. There should be 
enough instability available for thunderstorm development well ahead 
of the FROPA Thursday afternoon into Thursday night. Friday 
thunderstorm chances look to increase again from the afternoon into 
the overnight hours. Both the GFS and ECMWF ensembles have the 
progression of the low pressure system trending slower which could 
lead to the FROPA moving out well ahead of the parent low. This 
could lead to the slowing down or eventual stalling of the FROPA as 
shown by the ECMWF and Canadian over the weekend, potentially 
leading some hydro issues. Meanwhile the GFS tries to push the FROPA 
out of the CWA late Friday into Saturday. Overall confidence remains 
low at this time due this model disagreement. Due to these time 
differences we have decided to keep low end PoPs throughout the end 
of the forecast period.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Continued dry air mass will result in VFR 
conditions persisting through the period, with perhaps some passing 
high clouds from time to time. Winds will generally favor SW at 4-7 
kts or so into this evening...except for NW at around 10 kts at 
KAVL, where some gusts in the 15-20 kts range are also possible. 
Light/vrbl winds develop overnight before SW winds return at around 
5 kts toward the end of the forecast period.  

Outlook: VFR conditions are expected to prevail through the middle 
of next week. Chances for showers, restrictions, and perhaps 
thunderstorms increase Thursday into Friday.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z 
KCLT       High 100%     High 100%     High 100%     High 100%     
KGSP       High 100%     High 100%     High 100%     High 100%     
KAVL       High 100%     High 100%     High 100%     High 100%     
KHKY       High 100%     High 100%     High 100%     High 100%     
KGMU       High 100%     High 100%     High 100%     High 100%     
KAND       High 100%     High 100%     High 100%     High 100%     

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables are available at
the following link:

www.weather.gov/gsp/aviation

&&

.FIRE WEATHER...
Much drier temps is combining with minimal moistening to result in 
very low RH across the area this afternoon, with many locations 
reporting values in the upper teens, esp across Upstate SC and 
northeast GA. A Fire Danger Statement remains in effect for GA zones 
into the evening. The air mass will continue to become gradually 
less dry with time. However, the air mass will also continue to warm 
faster than it dries, so another day with low RH is expected on 
Monday. However, the current expectation is that RH will not quite 
reach the critical 25% value. Thus, no FDS is anticipated for Monday 
at this time.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Fire Danger Statement until 8 PM EDT this evening for GAZ010-
     017-018-026-028-029.
NC...None.
SC...None.

&&

$$
SYNOPSIS...AP
NEAR TERM...JDL
SHORT TERM...Munroe
LONG TERM...AP
AVIATION...JDL
FIRE WEATHER...