Flash Flood Warning 18, NWS Greenville-Spartanburg, SC

783 
WGUS72 KGSP 261934
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
334 PM EDT SAT MAY 26 2018

NCC111-262145-
/O.CON.KGSP.FF.W.0018.000000T0000Z-180526T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
McDowell NC-
334 PM EDT SAT MAY 26 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM EDT FOR
CENTRAL MCDOWELL COUNTY...

At 330 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area.  One-and-a-half to two-and-a-half 
inches of rain have fallen since 130 PM EDT. Flash flooding is 
expected to begin shortly.

Some locations that will experience flooding include...
Marion, Old Fort, Pleasant Gardens, Nebo and Lake James. 

Additional rainfall amounts of one to two inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Most flood deaths occur in vehicles. Do not attempt to cross
water-covered roadways, bridges, or low-level crossings. Only a few
inches of rapidly flowing water can carry away your vehicle. It is
not worth the risk. Please TURN AROUND, DON'T DROWN.

The additional heavy rain will increase the risk of landslides,
especially in areas where slides have occurred in the past. Be
especially alert if you are near a stream, especially at the base of
a mountain or in a cove. Watch for loose-moving soil and rocks or a
sudden increase in streamflow. Leave the area quickly if this is
observed. When driving along roads where the terrain is steep or
rocky, watch and listen for falling rocks, mud, trees and other
debris.

When it is safe to do so, please report flood waters or landslides
flowing over roads or threatening property to the National Weather
Service by calling toll free, 1, 800, 2 6 7, 8 1 0 1, by posting on
our Facebook page, or via Twitter using hashtag NWSGSP. Your message
should describe the event and the specific location where it
occurred, including roadways, nearby cross streets, stream names and
other landmarks.

&&

LAT...LON 3578 8195 3567 8194 3560 8221 3570 8221

$$

ARK

273 
WGUS72 KGSP 262056
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
456 PM EDT SAT MAY 26 2018

NCC111-262106-
/O.CAN.KGSP.FF.W.0018.000000T0000Z-180526T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
McDowell NC-
456 PM EDT SAT MAY 26 2018

...THE FLASH FLOOD WARNING FOR CENTRAL MCDOWELL COUNTY IS
CANCELLED...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3578 8195 3567 8194 3560 8221 3570 8221

$$

ARK

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
155 PM EDT Sat May 26 2018

.SYNOPSIS...
Very moist conditions will persist over the region through the
weekend as Alberto develops across the Gulf of Mexico. Tropical
moisture will likely affect our area through much of next week,
bringing the potential for continued heavy rainfall and associated
flooding to the region.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 145 pm: Coverage and intensity of showers and storms continues
to increase this afternoon within modestly unstable/high PWAT
environment. The most concentrated activity is currently located
across the northern mtns and foothills of NC, which is the remnants
of some morning convection that moved across the TN Valley/ southern
Appalachians. Outside of this area, coverage is rather spotty, but
coverage should continue to increase enough to warrant likely pops
across much of the high terrain, with 30-50 pops across the Piedmont
and foothills. It still appears that the atmosphere will become
weakly suppressed across the Piedmont through the afternoon as upper
ridging builds in from the south. Weak downdraft CAPE, high freezing
levels and modest CAPE will limit the severe convective potential,
so heavy/perhaps locally excessive rainfall will continue to be the
main concern, especially if areas that have seen heavy rain over the
past 12-24 hours see a repeat this PM.

850 mb flow will stay mainly southwesterly through the evening
before starting to back to light southeast in southern sections
early Sunday morning. We should see a repeat of this morning, with
very mild minimum temperatures and showers continuing, especially in
and near the mountains, but with enough steering flow to continue to
keep any hydro issues quite isolated. This will continue to saturate
soils, however, and likely set the stage for later hydro issues.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 300 AM EDT Saturday: With sfc high pressure shifting into the
OH Valley and a (slightly weakening) subtropical ridge persisting
with it's westward extension into the Carolinas, focus remains on
Subtropical Storm Alberto and it's affect it'll have on our FA over
the next several days. Unfortunately, discrepancy continues with the
latest 00Z runs of the GFS and ECMWF. The GFS places the center of
Alberto just south of the AL coastline Sunday morning, while the
ECMWF is just about 24 hours slower with the progression, bringing
it just south of the AL coastline Monday morning and not moving
onshore until Monday night. The timing of the heaviest rainfall
across our FA will absolutely rely on the Alberto's progression,
thus do note the general timing mentioned below is not set in stone.

Noticeable mid-level dry air in place which allowed for a brief lull
in shower/thunderstorm activity coming into the short term forecast
period will (per the GFS) quickly be dismissed into Sunday afternoon
as a surge of deep tropical moisture makes it's way northward
through portions of the Southeast and into the FA (not until Monday
morning per the ECMWF), re-saturating the atmospheric column. As has
been discussed the past few days, model guidance continues to
support PWATs ranging between 1.5 to 2.0 inches late Sunday into
Monday (again, depending on which model you reference), which is 2+
standard deviations above climo. With the tropical airmass in place
as Alberto meanders across MS/AL through Monday night/early Tuesday,
and weak instability becomes available, expect isolated to scattered
showers and thunderstorms to become widespread in nature beginning
Sunday evening. The potential for heavy rainfall and localized flash
flooding remains the primary threat attm with the rainfall
rates of most interest (through both the short term and medium
range forecast period). Taking into account the recent rainfall
over the past week which caused flooding/landslide issues, this
will be especially a concern for areas across the NC mountains
and the Escarpment, overnight Sunday into Monday per the GFS (or
moreso Monday, based on ECMWF). To give an idea of the rainfall
we've seen across the NC mountains this past week, for the
month of May, the all-time monthly total precipitation record
for Asheville which was 9.18 inches (set in 2009) has already
been broken - with 9.69 inches already recorded for May 2018,
and we still a few days to go yet in the month. Even so, with
rainfall being the primary concern, will note that while winds
attm look to be minimal, any brief gusts in thunderstorms along
with the already saturated soils - it won't take much to bring
down weak trees. While not issued with this update, a flash
flood watch remains a possibility. High temperatures will remain
just below normal, with overnight lows hovering around normal.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 315 AM EDT Saturday: Given both the temporal and spatial
discrepancy of Alberto between the 00Z runs of the GFS and ECMWF, a
general consensus will be used for this forecast period. With
Alberto gradually weakening as it moves up through the TN valley
around midweek, latest guidance continues to suggest the opening of
it's associated 500 mb low as it eventually merges with the upper
trough in place across the upper midwest into the latter part of the
week. With the persistent SSW flow/moisture supply, heavy
downpours/localized flooding will remain a concern, especially
across the upslope areas, as long as showers and thunderstorms
continue to develop and move across the FA. Even as the remnant sfc
low tracks west of the FA, from the TN Valley to the OH Valley and
then into the northeast into the weekend, guidance continues to
depict an upper longwave trough north of the area with weak
disturbances traveling within the feature and nearing the FA. Thus
keeping an overall unsettled weather pattern through the end of
the week, with coverage gradually transitioning from widespread
to isolated/scattered in nature by Friday. High temperatures
will continue to teeter around normal, climbing to above normal
at the end of the week, with overnight lows remaining fairly
mild.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Significant convective coverage is currently
confined to the mountains and portions of the foothills. Tempos for
TSRA are warranted at KHKY and KAVL through 22/23Z, with VCTS and/or
prob30s warranted through the evening. Activity is currently more
spotty across the rest of the area, but at least VCSH/VCTS are
warranted at KCLT and the Upstate SC terminals, with a tempo still
carried at KCLT from 19-23Z. Convection should gradually diminish
through the evening. Otherwise, another round of low stratus and/or
fog is forecast to develop toward daybreak, then quickly improve
within a couple of hours after sunrise. Sunday afternoon convective
chances appear lower than in recent days, although at least isolated
coverage can still be expected.

Outlook: Tropical moisture will increase by Sunday night into
Memorial Day, increasing the frequency and intensity of SHRA and
associated restrictions through much of next week. Morning
stratus/fog are possible each day, especially following any heavy
rainfall the previous day.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High  86%     High 100%     Med   74%     Med   76%
KGSP       High  99%     High 100%     High  81%     Med   79%
KAVL       High 100%     High  99%     Med   60%     Med   74%
KHKY       High  88%     High 100%     Med   72%     High  80%
KGMU       High 100%     High 100%     High  89%     High  81%
KAND       High 100%     High 100%     High  90%     High  80%

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...HG
NEAR TERM...HG/JDL
SHORT TERM...SGL
LONG TERM...SGL
AVIATION...JDL

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
352 AM EDT Sat May 26 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-270800-
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-
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-Chester-Greenwood-
352 AM EDT Sat May 26 2018

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

.DAY ONE...Today and Tonight.

With plenty of moisture in place, localized flooding is possible
from any heavy downpours associated with scattered showers and
thunderstorms.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

..Sunday...Heavy rain with flooding possible.
..Monday...Heavy rain with flooding possible.
..Tuesday...Heavy rain with flooding possible.
..Wednesday...Heavy rain with flooding possible.
..Thursday...Heavy rain with flooding possible.
..Friday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Skywarn spotters are requested to forward any reports of flash
flooding to our office.

SGL