Wind Advisory 15, NWS Greenville-Spartanburg, SC

617 
WWUS72 KGSP 231803
NPWGSP

URGENT - WEATHER MESSAGE
National Weather Service Greenville-Spartanburg SC
203 PM EDT Thu Apr 23 2020

NCZ051-052-058-059-062>064-240000-
/O.CON.KGSP.WI.Y.0015.000000T0000Z-200424T0000Z/
Swain-Haywood-Graham-Northern Jackson-Macon-Southern Jackson-
Transylvania-
Including the cities of Waynesville, Tuckasegee, Rainbow Springs,
Kyle, and Highlands
203 PM EDT Thu Apr 23 2020

...WIND ADVISORY REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING
ABOVE 3500 FEET...

* WHAT...South winds 20 to 30 mph with gusts up to 55 mph.

* WHERE...Elevations above 3500 feet in Haywood, Swain, Jackson, 
  Macon, Graham, and Transylvania Counties.

* WHEN...Until 8 PM EDT this evening.

* IMPACTS...Gusty winds could blow around unsecured objects. 
  Tree limbs could be blown down and a few power outages may 
  result.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high
profile vehicle. Secure outdoor objects.

&&

$$

499 
WWUS72 KGSP 232357
NPWGSP

URGENT - WEATHER MESSAGE
National Weather Service Greenville-Spartanburg SC
757 PM EDT Thu Apr 23 2020

NCZ051-052-058-059-062>064-240100-
/O.EXP.KGSP.WI.Y.0015.000000T0000Z-200424T0000Z/
Swain-Haywood-Graham-Northern Jackson-Macon-Southern Jackson-
Transylvania-
Including the cities of Waynesville, Tuckasegee, Rainbow Springs,
Kyle, and Highlands
757 PM EDT Thu Apr 23 2020

...WIND ADVISORY WILL EXPIRE AT 8 PM EDT THIS EVENING ABOVE
3500 FEET...

Winds have dropped below criteria, thus the wind advisory will be
allowed to expire.

$$

12

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
255 AM EDT Thu Apr 23 2020

.SYNOPSIS...
An area of low pressure will advance toward the region today and
bring a good amount of rainfall with thunderstorms this afternoon.
Dry high pressure will build back on Friday, before another storm
system moves into the forecast area Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 240 AM EDT Thursday: The convective threat for today now looks
a bit less than previously. Forcing and shear should be oustanding
for the late afternoon and evening hours, but instability north of a
warm front riding into the southern tier of area will be difficult
to pin down. The Day One Convective Outlook follows this trend, with
a Slight risk now confined to locations generally along and
southeast of I-85. However, it's not the time to stand down on the
severe potential too much given that strong forcing that can often
overcome limited instability.

For the details: water vapor imagery reveals a cyclonic system
moving east across southern Missouri early this morning, with a deep
feed of moisture advecting northeast across the Deep South.
Shortwaves ejecting east of the main trough, along with improving
warm advection, are already producing rainfall across our region,
and the coverage of these early showers will increase through
daybreak. The 850 mb jet east of the trough should rise above 50 kt
by mid-morning across the extreme southern Appalachians, and a high
elevation Wind Advisory will be needed there today. Meanwhile,
temperatures are locking in in the 40s and 50s from the rainfall
this morning, which means the airmass has quite a ways to go for
convective destabilization to occur. After a brief mid-morning lull
in the moist upglide, warm advection through the 850 mb level will
become resurgent through the afternoon hours, and coverage will
quickly fill back in. The best low-level jet should then begin to
transit the lower Piedmont circa 21Z. By this time, the surface warm
front should manage to uncover better instability from Elberton to
Greenwood to Chester, and points south. The best upper jet
divergence will cross the region around 00Z, and the evening hours
will likely have the best overlap of deep forcing, a stout low-level
jet, sfc-6 km bulk shear values at 60 kt or better, and an uncovered
warm sector somewhere across the lower Piedmont. This will likely be
the peak period of severe storm threat, with wind and isolated
tornadoes the main concern, but large hail also possible in the warm
sector.

Mid-level dry air may begin to wrap in quickly from the southwest
late in the evening through the overnight. Meanwhile, the upper wave
lifting over the OH Valley will gradually dampen as it passes mainly
north of the region through the central Appalachians overnight. Low-
level moisture and lingering pre-frontal instability should continue
through the overnight hours, but shear will diminish, mid and upper
levels will dry, and low-level flow will veer to reduce the severe
threat. Nevertheless continued showers and isolated thunderstorms
along the passing cold front will be possible through daybreak
Friday.

Regarding the heavy rain potential, early activity will have modest
rainfall rates and serve primarily a wetting role. Late day
convective precip rates will pick up along and southeast of the warm
front. This will likely rob some moisture from the more flood prone
areas of the southern mountain escarpment region. Any minor flooding
will likely impact locations where training occurs, and a Flash
Flood Watch is currently not expected.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 100 AM Thursday: An upper level trof will cross the area Fri
morning and keep low-end rain chances across the NC mtns with
residual wrap-arnd shallow moisture associated with an OH Valley sfc
low. By the afternoon...the atmos become becomes drier thru a deep
layer as a s/w ridge axis impinges on the wrn Apps. This will keep a
subs inversion at 5 Kft and allow only fair-wx Cu in the afternoon
across the non/mtns after more widespread morning Stcu. Winds will
remain generally sw/ly outside the mtn valleys where n/ly winds
persist. This flow will help max temps reach the u70s non/mtns and
arnd 70 F across the mtn valleys. Mins will also be held a couple
cats abv normal Fri night as upper clouds increase ahead of an
approaching frontal system. The timing of this cold front and a
possible triple-point low depicted on the NAM/EC is still uncertain
as the latest GFS is much quicker and has less of a chance for stg
convec. However, still think there will be a some chance of
organized stg/svr storms as the GFS seems too fast of an outlier,
thus sbCAPE shud have a chance to increase east of the mtns before
deep shear and pre-frontal convg increase by mid afternoon. Will
continue to monitor the potential convec threat with this system.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 1240 AM Thursday: An exiting ulvl trof will keep -shra
possible mainly across the NC mtns Sun thru Sun night, with dry
conds elsewhere and max temps right arnd normal. A modified cP
airmass will continue to mix into the area Mon and lower td/s into
the m30s, which will make for low afternoon RH values and perhaps
create fire-wx concerns across NE GA. Winds look to weaken thru the
BL thru the day, which will deter fire-wx issues elsewhere. Winds will
generally shift sw/ly on Tue and modify td/s up a bit, yet no good
chance of afternoon -shra/tstms as a subs inversion remains in place
arnd 6 Kft. Nice temps will be in store both Mon and Tue with highs
in the lower to mid 70s. By Tue night, an ulvl ridge axis shifts
east and heights become difl as a stg upper low develops and swings
across the Glakes. This system will push a cold front across the
FA sometime Wed. The timing is uncertain at this point, which will
make a big difference wrt to the amt of destabilization available
for either general or stg tstms. Will continue to monitor this
potential hazard. Otherwise, Wed looks like another warm pleasant day
with highs in the mid to upper 70s with low relative humidity. Good
rad cooling conds Sun night may create frost issues across the NC
mtns, otherwise min temps will be held a little abv normal thru the
period.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
At KCLT and Elsewhere: Blossoming rainfall and lowering VFR cigs
will impact all of the TAF sites through the early morning hours.
Anticipate a rapid fall into MVFR cigs/vsby through the later
morning hours once the column moistens up, with IFR at times under
the best showers. Once the showers begin at any site, they should be
fairly persistent through the period, but improving instability
later in the day will require a PROB30 for thunderstorms mainly
after 20-21Z, and a touch later at KCLT, with a VRB 30kt gust
mention. Will also feature LLWS for KAVL and KCLT later today for
both high elevation impacts, and shallowing of the surface stable
layer. Winds will become mainly SE to S and gusty at times through
the day before turning more SSW then SW tonight as the cold front
approaches from the west. There should be quite a bit of variability
in both visibility and ceilings in the better showers and storms,
but with IFR to MVFR expected on average for the bulk of the day and
evening hours.

Outlook: After a dry Friday, another storm system may bring flight
restrictions, rainfall, and thunderstorms back on Saturday. Dry
conditions return the latter half of the weekend into early next
week.

Confidence Table...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       High  97%     High  81%     Med   79%     High  88%
KGSP       High  90%     High  90%     High  89%     High  92%
KAVL       High  86%     High  86%     High  80%     High  96%
KHKY       High  87%     Med   79%     High  94%     High  96%
KGMU       High  88%     High  87%     High  89%     High  93%
KAND       High  86%     Med   68%     High  94%     High  89%

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

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory above 3500 feet from 8 AM this morning to 8 PM
     EDT this evening for NCZ051-052-058-059-062>064.
SC...None.

&&

SYNOPSIS...SBK
NEAR TERM...HG
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...HG

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
829 PM EDT Wed Apr 22 2020

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-240030-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-
Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-
Rowan-Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union NC-
Caldwell Mountains-Greater Caldwell-Burke Mountains-Greater Burke-
McDowell Mountains-Eastern McDowell-Rutherford Mountains-
Greater Rutherford-Polk Mountains-Eastern Polk-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Greater Greenville-Spartanburg-Cherokee-York-
Anderson-Abbeville-Laurens-Union SC-Chester-Greenwood-
829 PM EDT Wed Apr 22 2020

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

.DAY ONE...Tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

A storm system will bring showers and thunderstorms to the area on
Thursday. Some storms could be strong to severe, with the primary
threats being large hail and damaging winds. Isolated tornadoes will
also be possible. Additionally, periods of moderate to heavy rainfall
could cause isolated flooding conditions by Thursday evening
continuing into Thursday night.

.SPOTTER INFORMATION STATEMENT...

None.

12