High Wind Watch 2, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1258 AM EST Sat Feb 23 2019

.SYNOPSIS...
The wet pattern will continue through tonight until a robust cold
front finally moves through the region Sunday morning. The early
part of next week should be dominated by dry high pressure. A cold
front may move through the region from the northwest on Wednesday,
but moisture with this front remains highly uncertain.

&&

.NEAR TERM /THROUGH TODAY/...
As of 1250 AM Sun: Damp and cloudy conditions continue under
CAD set-up across the western Carolinas, thanks to high pressure
centered over New England, and plenty of moisture in place. Through
this afternoon, we are not expecting much change in conditions. As
the sfc high to the north slowly churns eastward, expect the
infiltration of moisture to continue allowing for isolated to
scattered showers, with CAD digging southward across the FA. As
anticipated, a warm front is strengthening overhead, leading
to the development of some showers once again near the NC/SC
border. This front will shift north thru NC over the next few hrs,
as low pressure develops to our west. PoPs have been refined to
better indicate the showers generally moving north to match. Temps
won't change a whole lot thru daybreak, but will slide into the
lower to mid 40s across the entire FA. Today, expect below normal
temperatures to continue, with low to mid 40s across most of the
FA, with the exception of areas along the TN border outside of
the wedge, warming into the mid 50s.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
As of 224 PM EST Friday: The passage of a cold front is our main
concern for the rest of the forecast. Model guidance continues
to indicate the scouring of our cold air damming wedge Saturday
night, but this seems doubtful, at least from the standpoint of
how it would affect our ability to destabilize out ahead of the
approaching strong cold front. At this time of year, it can be
difficult to scour a wedge late at night unless there is a sfc low
moving past to the west. We will probably maintain the low level
isentropic lift and the warm advection at 850 mb right up until the
time the front arrives. Although the wedge boundary will be trying
to lift northward, there is considerable doubt it will make it
north of roughly I-85. Even if the wind comes around to something
with a southerly component, it appears that our chances of seeing
any sort of sfc-based instability is extremely low. For example,
the latest SREF has a less than 2% chance of sb-CAPE reaching 500
J/kg. Will not rule out some elevated thunderstorms over northeast
GA and Upstate SC, but am not planning on any meaningful severe
storm chances. Precip prob will be high thru frontal passage, which
should occur on Sunday morning. Precip chances end over the east
by 18Z Sunday, and we should clear out and see some sun for the
balance of the afternoon. Temps will depend on the frontal passage
and how quickly we clear out, perhaps falling in the afternoon near
the TN border as cold advection arrives, but probably topping out
15-25 degrees warmer than Saturday east of the Blue Ridge.   The
rest of the fcst should be dry. A broad upper trof axis moves past
Sunday night and high pressure builds in from the NW. The sfc high
is expected to move past to our north on Monday and Monday night,
then off the Mid-Atlantic coast on Tuesday. Temps will cool off back
toward normal as the continental air mass moves into the region.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 144 PM EST Friday: Not a lot of certainty with the forecast
from mid-week onward, as there's not much of any signal in the
guidance. The models indicate that we should be under a flat,
non-descript mid/upper flow. The ECMWF has the axis of a very broad
upper trof closer to the east coast and more of a WNW flow, and is
consequently drier than the GFS. That model is flatter and has more
in the way of periodic weak mid/upper forcing. Both suggest the
passage of a weak front Wed/Wed nite, but with little precip. The
fcst will keep low-end precip chances Wed-Thu with temps slightly
above normal and warm enough for just light rain. Fcst confidence
plummets by the end of the week as run-to-run consistency is poor
and consensus is almost non-existent. We carry a chance of precip
based solely on the operational GFS from Thursday night onward,
with near to below normal temps. Expect this part of the fcst to
change, perhaps by a great deal.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Cold-air damming will continue to drive the
pattern thru tonight, meaning IFR to LIFR cigs will persist. The
only possibility of higher cigs appears to be if SHRA cause
brief erosion of the lowest cloud layer via the downward motion
they will induce. An area of SHRA is expected to blossom near
the NC/SC border and gradually advect northward as warm front
atop the CAD airmass effectively shifts in that direction. Thus,
some TEMPOs feature higher cigs, though as has happened at times
last night, MVFR or IFR vsby can be expected with the precip as
well. Off-and-on SHRA and/or DZ will continue into tonight, with
cigs lowering a bit after sunset as wedge becomes more shallow. A
scouring cold front will enter the area early Sunday morning but
the only effect mentionable in this TAF set is a shift to SW winds
at KCLT just before dawn, and developing LLWS concerns; cigs will
linger there until after 12z Sun.

Outlook: Conditions will become much drier yet gusty on Sunday as
a strong cold front crosses the area. VFR conds will return Sun
and remain through the middle of next week.

Confidence Table...

            06-12Z        12-18Z        18-24Z        00-06Z
KCLT       Med   73%     Med   69%     Med   68%     High  84%
KGSP       Med   61%     Med   77%     Med   68%     High  85%
KAVL       High  86%     High  88%     Med   63%     Med   71%
KHKY       Med   67%     Med   78%     Med   66%     High  82%
KGMU       Med   68%     Med   77%     Med   68%     High  86%
KAND       Med   69%     Med   77%     Med   67%     Med   75%

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

www.weather.gov/gsp/aviation

&&

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

&&

SYNOPSIS...SW
NEAR TERM...SGL/Wimberley
SHORT TERM...PM
LONG TERM...PM
AVIATION...Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
958 PM EST Fri Feb 22 2019

NCZ033-048>053-058-059-062>065-501-503-505-507-509-240300-
Avery-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Graham-
Northern Jackson-Macon-Southern Jackson-Transylvania-Henderson-
Caldwell Mountains-Burke Mountains-McDowell Mountains-
Rutherford Mountains-Polk Mountains-
958 PM EST Fri Feb 22 2019

This Hazardous Weather Outlook is for western North Carolina.

.DAY ONE...Tonight.

Minor flooding and elevated stream levels will linger into
Saturday with improvements occurring through the overnight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Moderate to heavy rain will be possible ahead of a cold front on
Saturday night, resulting in a continued threat of minor flooding on
main stem rivers as well as some smaller streams.

In addition, expect very gusty southwest winds Saturday night ahead
of the cold front, and then very gusty northwest winds after the
frontal passage Sunday and Sunday night.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-
506-508-510-SCZ001>014-019-240300-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Alexander-Iredell-
Davie-Catawba-Rowan-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-
Union-Greater Caldwell-Greater Burke-Eastern McDowell-
Greater Rutherford-Eastern Polk-Oconee Mountains-Pickens Mountains-
Greenville Mountains-Greater Oconee-Greater Pickens-
Greater Greenville-Spartanburg-Cherokee-York-Anderson-Abbeville-
Laurens-Chester-Greenwood-
958 PM EST Fri Feb 22 2019

This Hazardous Weather Outlook is for northeast Georgia, piedmont
North Carolina, western North Carolina and upstate South Carolina.

.DAY ONE...Tonight.

Minor flooding and elevated stream levels will linger into
Saturday with improvements occurring through the overnight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Moderate to heavy rain will be possible ahead of a cold front on
Saturday night, resulting in a continued threat of minor flooding on
main stem rivers as well as some smaller streams.

.SPOTTER INFORMATION STATEMENT...

None.