Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
255 PM EDT Mon Sep 26 2016

.SYNOPSIS...
A cold front will cross our area tonight and be near the Carolina
coast by Tuesday evening.  An upper level low will drop south into
the Ohio Valley by Wednesday and linger over the Central
Appalachians through the end of the week.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 230 PM...convection has fired over the NC mountains as
expected. The environment east of the Blue Ridge is characterized by
a sfc-based CAPE in the 1000-1500 J/kg range, but mid-level lapse
rates are relatively poor, shear is very weak, and dCAPE is minimal.
Will not rule out a few strong storms or an isolated severe storm,
but the risk is fairly low. Slow-moving storms producing excessive
rainfall is probably the bigger concern, as we retain a fairly high
precipitable water near the upper end of climatology. Think
convective coverage will increase into the evening hours east of the
mtns so precip chances continue to ramp up in the fcst...into the
categorical range over parts of the NC mtns and likely over the NC
foothills and wrn Piedmont.

Over the next 24 hours, big-picture-wise a large mid/upper low is
expected to slowly drop down from western Ontario to the upper Great
Lakes, which will bring mid/upper troffing down across the western
Carolinas. This should drive a surface cold front from the TN valley
eastward across the Srn Appalachians tonight and Tuesday morning.
The front will probably get hung up across the mtns thru most of the
day on Tuesday. Weak upper divergence will get strung out across the
region tonight and Tuesday as the right entrance region of the upper
jet moves overhead, but mid-level forcing is not that impressive.
Most of what the front does will be the result of deep convection
firing along and ahead of the feature this afternoon and evening,
and then the weak forcing overnight. The guidance suggests holding
onto a likely precip prob mainly out across the NC foothills and wrn
Piedmont into the overnight hours. Min temps tonight should be mild.
On Tuesday, with the front in our midst, precip chances should ramp
up especially over the eastern zones where a likely was included.
Temps will be at or above normal again.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 245 PM Tuesday: Showers and thunderstorms will be scattered
along and southeast of Interstate 85 Tuesday evening as the front
slowly drops south. This activity will slowly diminish but may
linger into Wednesday morning. Most of Wednesday should be dry as
cooler air moves into the region.

A fairly potent upper level low pressure system will drop southeast
across the Ohio Valley and central Appalachians impacting the area
Wednesday night and Thursday. Several disturbances will swing around
the parent low bringing rainfall to the area. The highest chance of
rain will be in the upslope areas of western North Carolina while
the lowest chance will be in northeast Georgia and upstate South
Carolina where downsloping low level flow will exist. All locations
will be cooler as the impacts of the low translate across the area.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 315 PM EDT Monday...An upper low is expected to be over
Bristol TN Thursday evening then lift north to eastern OH Friday
evening.  The GFS forecast has been accepted as the better
performing operational model. The ECMWF is better today but still
slower in its evolution of the cut off closed low lifting out and
departing New England.  With the lower atmospheric thickness values
associated with this upper low and more cloud cover Thursday night
into Friday, this will keep temperatures several degrees below
normal. Very light rain amounts are possible across the NC Mtns and
north of I-40 Thursday evening then becoming increasingly limited to
the TN border areas until Friday evening when it goes away to the
north of our forecast area.

The closed and cut off upper low will begin to open to the westerly
flow at the north end of the Great Lakes on Saturday. The low will
fill and become absorbed near Montreal Sunday night. We will be at
the southern end of a large area of surface high pressure Sunday
into Monday. The GFS has the high centered over north central Quebec
at 12Z Tuesday ridging down across our area. The orientation of the
low level wind flow with this high may produce upslope wind by
Monday night into Tuesday which may result in light rain in the Lake
Jocassee to Tryon to Lenoir areas.

Temperatures will certainly be several degrees below normal Friday
then slowly rise to near normal as the low moves away from our
region over the weekend. By Monday, temps may even be a little above
normal since the high may not be strong enough and far enough away
to have minimum influence toward wedge conditions.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT: Somewhat convectively inactive to start with as we are
dealing with a lull brought about by convective debris in the wake
of morning convection. Cannot rule out an MVFR-level broken ceiling
but think that VFR will prevail, so this detail will be left out in
favor of including TSRA this evening. The CAM guidance, particularly
the 4km WRF, shows a band of convection moving across metro CLT this
evening, so a TEMPO from 00Z to 04Z was included. After this
activity moves east, we may have to deal with some visibility
restrictions in the pre-dawn hours thru daybreak if we get rainfall
at the site. Have hinted at this with a 6SM vis and scattered low
cloud. The cold front should hang up to the west thru the period,
which will keep wind S to SW, and allow for destabilization with
some heating on Tuesday morning. TSRA may develop again in the late
morning, so have included a PROB30 for that possibility.

Elsewhere: Trends similar to that of KCLT, with timing based on the
4km WRF. The exception is KAVL, where a thunderstorm is already in
the vicinity, so they begin with a TEMPO for TSRA. The models are
hitting on the possibility of MVFR/IFR ceiling and vis across the
mtns Tuesday morning, so this was included at KAVL. As with KCLT,
some fog/low stratus possible early Tuesday morning and introduced
this at KHKY/KAND.

Outlook: Cold front will slowly cross the region through Tuesday.
This should result in better chances for convection. Dry high
pressure builds in behind the front on Wednesday, which should bring
VFR conditions in most places.

Confidence Table...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High  98%     High 100%
KAVL       High 100%     High  96%     High  82%     High  87%
KHKY       Med   66%     High  87%     High  81%     High  88%
KGMU       High 100%     High 100%     High  98%     High 100%
KAND       High 100%     High 100%     High  96%     High  96%

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...DEO
NEAR TERM...PM
SHORT TERM...SW
LONG TERM...DEO
AVIATION...PM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
249 PM EDT MON SEP 26 2016

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-271900-
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-
249 PM EDT MON SEP 26 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA...PIEDMONT
NORTH CAROLINA...WESTERN NORTH CAROLINA AND UPSTATE SOUTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS
THE REGION THIS AFTERNOON AND EVENING AHEAD OF AN APPROACHING
COLD FRONT. THE MAIN THREATS WILL BE TORRENTIAL DOWNPOURS...CLOUD-
TO- GROUND LIGHTNING...AND GUSTY WINDS. LOCALLY HEAVY RAIN WITH
ISOLATED FLASH FLOODING WILL BE POSSIBLE. ALSO...AN ISOLATED
SEVERE STORM OR TWO...PRODUCING DAMAGING WINDS CANNOT BE RULED
OUT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

..TUESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..WEDNESDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..THURSDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..FRIDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SATURDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.
..SUNDAY...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
926 AM EDT MON SEP 26 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     FLASH FLOOD      3 NW CHARLOTTE          35.23N 80.87W
09/26/2016                   MECKLENBURG        NC   OTHER FEDERAL

            STEWART CREEK AT WEST MOREHEAD STREET ROSE ABOVE THE
            FLOOD STAGE OF 14 FEET AT 8 AM THEN CRESTED AT 14.07 FEET
            AT 820 AM. THE CREEK FELL BELOW FLOOD STAGE AT 837 AM AND
            CONTINUING TO FALL.

&&

OUTLAW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1241 PM EDT MON SEP 26 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1100 AM     HEAVY RAIN       5 SE GASTONIA           35.20N 81.11W
09/26/2016  M3.05 INCH       GASTON             NC   COCORAHS

            3.05 INCHES FROM LATE LAST NIGHT THROUGH THIS MORNING AND
            1.34 INCHES IN PAST 4 HOURS.

&&

OUTLAW

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
321 PM EDT MON SEP 26 2016

NCZ033-501-503-261945-
CALDWELL MOUNTAINS NC-AVERY NC-BURKE MOUNTAINS NC-
321 PM EDT MON SEP 26 2016

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
NORTHWESTERN CALDWELL...NORTHWESTERN BURKE AND SOUTHEASTERN AVERY
COUNTIES UNTIL 345 PM EDT...

AT 321 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM WITH
INTENSE LIGHTNING 4 MILES SOUTHEAST OF NEWLAND...OR OVER B.R.
PARKWAY-LINVILLE FALLS TO GRANDFATHER...MOVING NORTHEAST AT 25 MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
NEWLAND...BLOWING ROCK IN CALDWELL COUNTY...CROSSNORE...SUGAR
MOUNTAIN...GRANDFATHER MOUNTAIN...GRANDFATHER MOUNTAIN STATE PARK...
B.R. PARKWAY-LINVILLE FALLS TO GRANDFATHER...UPTON...EDGEMONT AND
JONAS RIDGE.

IN ADDITION TO INTENSE LIGHTNING...PEA SIZE HAIL AND WIND GUSTS UP TO
40 MPH WILL BE POSSIBLE IN THESE AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...TRY TO
GET INDOORS OR INTO A HARD TOPPED VEHICLE. OTHERWISE...STAY AWAY FROM
OPEN AREAS AND ISOLATED HIGH OBJECTS SUCH AS TREES. WHEN INDOORS...
STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING WIRED ELECTRONIC
DEVICES. DO NOT TAKE A SHOWER OR BATH. TRY TO UNPLUG UNNECESSARY
APPLIANCES BEFORE THE STORM APPROACHES.

&&

LAT...LON 3611 8181 3612 8169 3612 8154 3610 8152
      3610 8150 3608 8145 3592 8189 3608 8200
      3614 8182
TIME...MOT...LOC 1921Z 241DEG 20KT 3604 8187

NED