River Flood Advisory 17, NWS Greenville-Spartanburg, SC

970 
WGUS82 KGSP 180943
FLSGSP

Flood Advisory
National Weather Service Greenville-Spartanburg SC
543 AM EDT Wed Aug 18 2021

...The Flood Advisory was replaced with a River Flood Warning for 
the following rivers in North Carolina...

  French Broad River At Asheville affecting Buncombe County.

NCC021-181045-
/O.CAN.KGSP.FL.Y.0017.000000T0000Z-210818T0943Z/
/AVLN7.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.NO/
543 AM EDT Wed Aug 18 2021

...The Flood Advisory for the French Broad River At Asheville has 
been replaced...

The Flood Advisory is replaced by a river flood warning for
  the French Broad River At Asheville.
* At 4:45 AM EDT Wednesday the stage was 10.9 feet and falling.
* Minor Flood Stage is 9.5 feet.
* Forecast...The river will slowly fall through Wednesday.


&&

LAT...LON 3550 8262 3560 8261 3569 8265 3570 8257
      3558 8255 3550 8254

$$

JMP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
325 AM EDT Tue Aug 17 2021

.SYNOPSIS...
The remnants of tropical cyclone Fred will generate heavy rainfall
across the forecast area today and into tonight. Expect cooler than
normal temperatures today with a warming trend through the end of
the week. Abundant moisture will continue across the region through
much of the week leading to periods of heavy rainfall and isolated
strong thunderstorms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 325 am EDT: The forecast remains on track with the center
of T.S. Fred moving northward over southeast AL and southwest GA
at this early hour. Seeing plenty of light returns on the radar,
indicating ongoing light rain/sprinkles. Meanwhile, scattered
showers were developing over the wrn Piedmont and Upstate, which
really could happen at any time at any location in this very moist
S/SE upslope regime. A larger area of shower activity...not quite a
band...was poised to start moving northward into the lower Piedmont
through the remainder of the pre-dawn hours.

No important mid-course corrections are suggested by any of the
recent guidance. The bulk of what will remain of Fred should move
north/northeast across the srn Appalachians late today and early
tonight. There remains some annoying spread in the QPF from the
model guidance, with the GFS still sticking to its low amounts, so
we continue to discount that solution. The QPF guidance from HPC was
generally accepted, which concentrates the highest amounts in the
S/SE upslope areas of southern NC and near the Escarpment. Without
any sort of sfc boundary around, the main focus will be closer to
the Escarpment, and thus our QPF has gone up a bit in the upslope
areas, but down across the wrn Piedmont. Of note is the somewhat
rare High Risk in the Excessive Rain Outlook in the headwaters of
the French Broad River. This makes sense because of the very high
rainfall in that location early Monday. Based on the new QPF, we
are comfortable with keeping the extent of the Flash Flood Watch
right where it is, with no expansion eastward at this time. That
doesn't mean that areas to the east are completely out of the woods
on this one. There remains a small possibility of a band training
over the Charlotte metro area, for example, so we should not let
our guard down. The general 4-6" of rainfall in the next 24 hours
along/near the Blue Ridge Escarpment raises the threat of landslides
and slope failures, so we will continue to highlight that in our
Flash Flood Watch. The end time of the Watch still looks good as
model guidance has sped up the transit and departure of the system.

The other main threat will be for tornadoes this afternoon and
evening along and east of the Escarpment. The new Day 1 Slight Risk
looks good. Timing looks favorable/ideal across a large part of the
fcst area with the main system lifting northward late in the day. A
favorable overlap of low level shear of 35-50kt in the right half
of the system with a tongue of 1500-2000 J/kg of sfc-based CAPE
lifting into northeast GA and the Upstate from 18Z onward suggest
a good potential for rotating updrafts. The 00Z HREF shows that to
such an extent that a Tornado Watch is anticipated at some point
later today for a large chunk of the area, so be on the lookout
for that. The threat should diminish by mid-evening as the shear
lifts northward and we lose the buoyancy in the environment.

We will monitor the development of sfc winds later today, and
could issue a Wind Advisory for parts of the area based on the
idea that trees would be blown down from 30-35 mph gusts because
of saturated soils.

The trend toward a faster system has resulted in a quicker lowering
of precip probs late tonight and early Wednesday.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 210 AM EDT Tuesday...The remnants of TC Fred continue to push
up the spine of the Apps Wed. A trailing wake trof will persist
however, and provide a focusing zone for afternoon precip. Deep
convec chances look low as soundings show dense drying air aloft and
warming temps arnd h7. Have capped general thunder chances at 30-35%
for the afternoon with the best chances occurring across the nrn
zones. Winds will begin to weaken across the mtn tops with only
low-end gusts likely by the end of the day. The atmos moistens
up a little Thu as a cold front and energized upper trof
approach the mtns. With lowering h5 heights, mlvl LRs will
increase leading to a better chance of afternoon thunder. Expect
general thunder across the non/mtns, but a few stronger or
loosely organized cells are possible across the higher terrain
as bulk shear increases to arnd 30 kts. Max temps will return to
normal levels in persistent sw/ly to w/ly aided by llvl
downslope flow. Mins will remain elevated a couple degrees abv
normal thru the period.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 250 AM EDT Tuesday...A broad ulvl trof will persist across the
region thru Sat as a reinforcing shot of vort energy traverse a wrn
ridge and crosses the area by Sat night. The surface pattern will
feature hipres to the south and llvl winds will align w/ly Fri,
which will inhibit the convec potential somewhat, but overall weak
forcing and destabilization will likely overcome the sbCIN and allow
for sct pulse-type tstms Fri afternoon. On Sat, the upper energy and
good moisture transport from the wrn GOM will combine and increase
PWATS back to near 2.0 inches. With the upper trof hanging out and
nw/ly mech lift, there could be a few deep cells producing high
precip rates and possible flooding issues across the higher terrain.
A strong ulvl high develops across the Southern Plains Sun and the
FA will come under the influence of increased subs and weak shear.
Still, anticipate climo PoPs and afternoon tstms to develop typical
of late Aug both Sun and Mon afternoons. Max and temps will remain
right around normal levels thru the period.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Aviation weather looks grim over the next
18 hours or so as Fred or its remnants approach early this morning
and track over the srn Appalachians later today. We are locked
in to a S/SE upslope flow of deep tropical moisture, which will
allow for ceiling to fall down to IFR/LIFR at all sites through
the morning hours, while more intermittent shower activity spreads
up from the south/southeast ahead of the storm. A shower or storm
could develop at any time at any location in this regime. That
makes TAFs necessarily pessimistic, with prevailing MVFR vis and
IFR ceiling for most of the day, altho there will be some MVFR
or better holes from time to time. As the main system moves past
late in the day, wind should become gusty from the SE. This will
probably lead to a low level wind shear at least at KAVL. Once
the center passes this evening, very slow improvement should begin
with drier air wrapping in from the SW. Guidance keeps prevailing
IFR restrictions at this time, and this was generally accepted.

Outlook: A gradual downward trend in diurnal convection is expected
Wednesday in the wake of Fred's remnant, then continuing during
the latter half of the week. Widespread low stratus and areas of
fog are expected each morning through at least late-week.

Confidence Table...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       High  81%     High  84%     High  87%     Med   75%
KGSP       High  80%     Med   77%     Med   72%     Med   77%
KAVL       High  89%     High  92%     High  92%     High  91%
KHKY       Med   77%     High  83%     Med   68%     High  89%
KGMU       Med   74%     High  85%     High  80%     Med   75%
KAND       High  89%     High  80%     High  89%     High  86%

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...Flash Flood Watch through Wednesday morning for GAZ010-017-018-
     026-028-029.
NC...Flash Flood Watch through Wednesday morning for NCZ033-048>053-
     058-059-062>065-501>510.
SC...Flash Flood Watch through Wednesday morning for SCZ001>007-
     010>012-019.

&&

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

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
857 PM EDT Mon Aug 16 2021

GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062>065-501>510-
SCZ001>007-010>012-019-180100-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Madison-Yancey-
Mitchell-Swain-Haywood-Buncombe-Graham-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-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-Anderson-Abbeville-Laurens-Greenwood-
857 PM EDT Mon Aug 16 2021

...FLASH FLOOD WATCH IN EFFECT FROM MIDNIGHT EDT TONIGHT THROUGH
WEDNESDAY MORNING...

This Hazardous Weather Outlook is for northeast Georgia, western
North Carolina, and most of Upstate South Carolina.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Flash Flood Watch.

Isolated to scattered to thunderstorms may develop through the
nighttime hours. Occasional cloud-to-ground lightning strikes and
heavy rainfall will be the primary threats.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Flash Flood Watch.

Isolated tornadoes are possible across the western Carolinas and
northeast Georgia Tuesday afternoon and evening.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

NCZ035>037-056-057-068>072-082-SCZ008-009-013-014-180100-
Alexander-Iredell-Davie-Catawba-Rowan-Cleveland-Lincoln-Gaston-
Mecklenburg-Cabarrus-Union NC-Cherokee-York-Union SC-Chester-
857 PM EDT Mon Aug 16 2021

This Hazardous Weather Outlook is for piedmont North Carolina and
upstate South Carolina.

.DAY ONE...Tonight.

Isolated to scattered thunderstorms will be possible across the
western Carolinas through the nighttime hours. Cloud-to-ground
lightning strikes and locally heavy rainfall will be the primary
threats. Isolated flooding will be possible in any areas repeatedly
affected by showers and thunderstorms.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Deep tropical moisture associated with the remnants of tropical
storm Fred will interact with an old front and the mountains to
produce periodic heavy rainfall through the middle part of the week.
The flood threat will steadily increase as showers and thunderstorms
wet the soil. At this time, the greatest potential for excessive
rain appears to be Tuesday and Tuesday night as a remnant
circulation from Fred moves northward along the mountains. This
could result in a flash flooding threat, especially in areas that
receive multiple rounds of heavy rainfall.

Isolated tornadoes are possible across the western Carolinas Tuesday
afternoon and Tuesday evening.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

HG