Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
704 PM EST Mon Dec 31 2018

.SYNOPSIS...
A continued flow of moist southerly air will result in an
increase in rain chances once again across the region through
Tuesday. After a brief pause in the rain Tuesday night into
Wednesday, another heavy rain event will move into the region
Wednesday night through Friday. Dry weather returns for the weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 645 PM EST Monday: Been watching a band of showers and
storms moving steadily east across N Alabama and middle TN for
several hours. Fortunately, it has also been breaking up, and this
trend will be welcomed as it moves into the wrn part of the NC
mountains. Will continue to monitor its progress and the potential
flood threat. Meanwhile, east of the mountains, the wedge front has
been steadily lifting northward with temperatures rising across
parts of the Upstate and metro CLT. Will make adjustments based
on both developments.

Otherwise...upper ridging continues over the Bahamas, while a
shortwave trough lifting through the Southern Plains continues to
pull Gulf Moisture up into the MS Valley. The attendant surface
low will drag a cold front across the Deep South and approaching
our area tonight. Biggest concern will be precip amounts, even as
the front and convection dissipate through the overnight hours,
but should be enough to drop a quick half inch in extreme western
zones, with upwards of an inch in the higher elevations of the
Smokies/Snowbirds/Nantahalas. Basin-average across the French Broad
Valley (which was the brunt of the more significant flooding last
week) should generally be less than 1/2", but locally the showers
that have passed through today have gone quickly to runoff, so
it's hard to know what kind of response the area waterways will
have with the saturated soil. River forecasts show only a slight
bump in the continued general downward trend of the French Broad
and so hopefully any impacts will be minimal and short-lived. Of
course, this only serves to keep the soil saturated, which will
be a factor in the late-week rainfall.

Very little instability will be attendant with the front as it
approaches our area, with loss of surface heating and quickly
diminishing upper dynamics. However, some elevated instability
might lead to occasional rumbles of thunder in extreme western
zones during the early overnight hours. For anyone planning on New
Years Eve festivities across the mountains, the rain could (pun
intended) put a bit of a damper on the fun. Final concern is the
continued isentropic upglide across the Piedmont contributing to
patches of dense fog. The CLT airport recently went down to 1/8mi,
and a handful of other sites have been sitting between 1/4-1/2mi,
with a large area of the Piedmont below 1mi. The "dense" area is
not widespread enough for a Dense Fog Advisory, but issued an SPS
to account for the patches...these combined with additional drivers
on the road late tonight might make for an unpleasant combination.
Conditions will be monitored closely in case DFA is needed.

The upper wave will quickly fill/damp as it is absorbed by the
longwave trough over the Hudson Bay tonight, and the strongly
occluded surface low will lift toward New England. The trailing cold
front will rapidly begin disintegrating as the Bahamas upper ridge
refuses to budge, and so by daybreak New Years morning there won't
be much left of the front. Overnight lows tonight will be warmer
than seasonal highs. The front will slowly slide south through the
day, pushing the QPF with it, but with CAA basically nonexistent
with the SW flow continuing aloft, afternoon highs New Years Day
will soar to well above-normal levels, approaching 70 in some of
the Piedmont areas.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 150 pm Monday: A much-welcomed lull in the rainy pattern
should be ongoing at the start of the short term, as the leading
edge of quasi-zonally oriented frontal zone sags off the Southeast
coast. This lull should continue through Tues night and into at
least the first half of Wednesday. By Wed afternoon, pops will begin
a gradual increase from the west, as the next round of
frontogenetical forcing increases in response to upper low finally
kicking out over the Southeast/cyclogenesis across the northwest
Gulf/Arklatx area. Pops increase to and remain in the likely range
from late Wed night through Thursday, before peaking at categorical
Thu night/ early Friday with passage of occluding front.

On a consensus basis, guidance does not really offer much in the way
of an additional heavy rainfall threat until the occluding front
passes late Thu night/Friday. (The operational GFS being the lone
holdout, as it does produce a solid .5-.75 inch across our western
areas Thu morning.) As such, the most likely time for additional
hydro issues during mid/late week would appear to be with the
potential for at least localized flash flooding early Friday,
followed by possible redevelopment of main stem river issues later
Friday into the weekend. The good news is precip is expected to end
somewhat quickly from the west throughout Friday, setting the stage
for a mostly dry extended.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
As of 145 PM EST Monday: Extended range model guidance remains in
decent agreement with respect to the encroachment of dry slot atop
the region Friday night, eventually limiting any lingering shower
chances to just the mountains which are in proximity to the wrap-
around moisture and track of the upper low.

Progressive drying is progged to continue on Saturday as deep low
pressure tracks into the NE CONUS. Pressure gradient in the wake of
departing low may result in breezy conditions during the day but it
will remain mild with afternoon max temperatures a couple of
categories above the early January climo.

Quiet wx is on tap for the latter half of the weekend beneath broad
cyclonic flow aloft and a weakened sfc pressure gradient. Little in
the way on sensible wx for Monday as well, perhaps just an influx of
cloudiness spreading downstream of developing plains system. Maximum
temperatures both Sunday and Monday may be 8-10 deg F above normal.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: A grim aviation fcst for the overnight hours
with widespread IFR to VLIFR conditions continuing at several TAF
sites. Conditions at KCLT may improve a bit this evening ahead of
a cold front, with wind becoming gusty late this evening. Precip
chances increase with the frontal band moving in from the west after
04Z. Confidence fairly low after that. Guidance suggests keeping
an IFR ceiling well into Tuesday morning and that was generally
followed, but have shown improvement at 14Z as wind comes around
to SW. Conditions should start improving to MVFR with the wind
shift to NW at all sites through the afternoon hours.

Outlook: Dry conditions late Tuesday into Wednesday will be short-
lived, as unsettled weather and possible flight restrictions return,
continuing through the end of the work week.

Confidence Table...

            00-06Z        06-12Z        12-18Z        18-00Z
KCLT       High  82%     Med   73%     High  83%     High  93%
KGSP       Med   69%     High  86%     High  80%     High  99%
KAVL       High  92%     High  85%     High  94%     High 100%
KHKY       Med   70%     High  90%     High  82%     High 100%
KGMU       Med   72%     High  86%     Med   75%     High  99%
KAND       Med   74%     High  86%     High  80%     High  99%

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...CSH
NEAR TERM...PM/TDP
SHORT TERM...JDL
LONG TERM...CSH
AVIATION...PM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1224 PM EST Mon Dec 31 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-011730-
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-
1224 PM EST Mon Dec 31 2018

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

.DAY ONE...This afternoon and tonight.

A period of moderate to heavy rain is possible late tonight. River,
stream and reservoir levels are already running quite high, and with
the ground saturated, even modest amounts of rainfall could cause
localized flooding.

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

The rain occurring early in the week will keep soils saturated prior
to yet another widespread rainfall event, which is likely to arrive
Wednesday. Periodic heavy rain may occur until that event tapers off
Friday. Flooding may redevelop or worsen during the late-week period
as a result.

.SPOTTER INFORMATION STATEMENT...

None.

Lane

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
821 PM EST MON DEC 31 2018

NCZ059-062>064-010145-
Transylvania NC-Southern Jackson NC-Northern Jackson NC-Macon NC-
821 PM EST MON DEC 31 2018

...A STRONG THUNDERSTORM WILL IMPACT MACON...SOUTHWESTERN
TRANSYLVANIA AND JACKSON COUNTIES UNTIL 845 PM EST...

At 820 PM EST, Doppler radar was tracking a strong thunderstorm 7
miles southwest of Franklin, moving northeast at 50 mph.

Locations to be impacted include...
Franklin, Cullowhee, Highlands, Balsam, Rosman, Webster, Cashiers,
Lake Toxaway, Lake Glenville and Gorges State Park.

Wind gusts up to 50 mph will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions may
cause scattered trees and power lines to fall. Seek shelter inside
an interior room.

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3543 8308 3542 8305 3540 8304 3538 8301
      3508 8277 3509 8279 3506 8287 3500 8320
      3499 8348 3500 8352 3502 8352 3504 8356
      3507 8357 3511 8362 3512 8362
TIME...MOT...LOC 0120Z 242DEG 61KT 3508 8343

ARK