River Flood Warning 3, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
302 PM EST Wed Feb 5 2020

.SYNOPSIS...
Mild and unsettled weather will be seen out ahead of an approaching
cold front which will cross the forecast area by Thursday night.
With abundant moisture ahead of the front, the potential for heavy
rainfall is high. Drier and cooler air will return to the region on
Friday.

&&

.NEAR TERM /THROUGH THURSDAY/...
Ongoing precip is waning across the non/mtns as a lull in activity
begins. Not expecting much additional precip this afternoon over
this area as the next round of more widespread rain moves in from
the nrn GOM this evening. Across the mtns, the better precip has
remained confined to the spine area where generally less than an
inch of rain has fallen over the past 6 hrs. Not expecting any
sigfnt issue with hydro this afternoon and evening...but as a warm
front aligns across the wrn zones this evening...precip rates will
increase greatly as upper level support increases deep layered
omega.

Right now...thinking the mtns will receive arnd 2-4 inches with the
sw/rn facing upslope regions getting up to 5+ inches over the next
30 hrs. This will create flooding issues along streams as well as
main-stem rivers like the French Broad. Also...a landslide threat
continues to look probable in areas that receive the higher end
rainfall....generally across wrn portions of Graham and Macon
counties as well as the srn facing slopes of the Balsams into the
Smokies. Another area of potential landslides will be across the srn
Blue Ridge in srn Transylvania county.

The heavier rain axis will transition more to the non/mtns by late
morning Thu as a cold front begins to sweep across the FA west to
east. Flooding issues along the I-85 corridor are possible as the
rainfall rates will be mod/high in an increasingly convective
environment thru the afternoon. Along with flooding concerns...the
frontal band will likely induce a squall line traversing the entire
FA btw 15z-00z. The better, yet meager, instability will be across
the Upstate and across the I-77 corridor. But as was seen a couple
weeks ago...high amts of instability are not needed in a strongly
forced environment to produced severe thunderstorms. With an
attendant llvl jet progged to reach 50-60 kts the convective line
will remain rather organized and produce stg/svr outflows esp
outside the mtns. Also...line breaks are probable and with
increasing helicity...a few tornadoes are also possible mainly along
and south of I-85. The system mostly moves east of the FA aft 00z
Fri...with lingering gusty showers lingering into the short range
period.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 255 PM EST Wednesday: The center of deepening sfc low pressure
will cross the Central Appalachians to the northern Mid-Atlantic
Thursday night, pushing the trailing cold front east of the forecast
area. Precip should start to taper off/shift east Thursday evening,
with lingering showers along the TN border due to increasing
westerly upslope flow. Any ongoing flooding should be transitioning
to more run-off/mainstem river issues after 00z Friday, but the
Flash Flood Watch will go to midnight, due to uncertainty on the
exact timing of precip tapering off. The upslope showers should
transition from rain to snow, as CAA brings down snow levels.
However, it will take some time, and by the time conditions become
ideal for NW flow snow shower activity, moisture will begin to dry
out. Still expect 1-2" of snow above 3500 ft along the TN border,
with possibly higher amounts above 5000 ft. Not expecting any need
for a winter weather advisory. Temps will drop into the 30s in the
mountains, and mainly mid 40s across the piedmont by daybreak Friday.

As cold air slips in behind the departing low, temps will remain
chilly thru the day Friday. Breezy westerly winds will make it feel
even cooler, but at least the skies should clear out east of the TN
border counties. Highs mainly in the 30s to lower 40s in the
mountains and upper 40s to lower 50s in the piedmont.

Friday night thru Saturday night...the 12z suite of model guidance
is in good agreement on a vigorous shortwave streaming through the
mean longwave trough across the eastern CONUS and across the
forecast area. The exact timing of the quick shot of dPVA and
associated precip is trending toward the daylight hours Saturday,
shifting east by Saturday evening. This is important for the lower
valleys and even the piedmont, as thicknesses are so cold, that an
early morning onset could result in precip starting out as snow. But
as it stands, it looks like just elevations above about 3000 ft will
have any snow accum, with the rest of the area just seeing light
rain. QPF with this system is also trending lower, so snow accums
look to be in the 1-2" range. Temps will continue to be at or
slightly below normal.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 120 PM EST Wednesday: Starting at 12Z Sunday with thickness
heights rising as the 500mb trough moves out over the Atlantic.
Surface high pressure over the East Coast will keep our area dry on
Sunday and into Monday as it moves over the Atlantic.  The next
front is forecast to drift SE from the Ohio River and become
stationary across Tennessee by late Monday.  The front is forecast
to lay out through mid week from Louisiana to eastern PA. Low
pressures will ride NE along this front keeping rain in our
forecast for days.  A trough will dig across the West and creating a
bigger low around eastern Texas Tuesday night. This low moves NE
Wednesday increasing rain over our mountains.  By 12Z Thursday, the
ECMWF has the low over western PA and the more progressive GFS has
this low beyond Maine by 12Z Thursday. The result will be the most
rain over the mountains and somewhat less out over the piedmont
through this forecast period.  Some thunder across the GA and SC
piedmont late Tuesday and across a larger area late Wednesday.
Expect temperatures to be just above normal Monday then well above
normal through mid week in the warm sector.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
At KCLT AND elsewhere...A pessimistic TAF for all sites. A moist
large-scale frontal system will advance on the area and create high
amts of precipitation along with lowering CIGs and VSBY thru the
period. Expect IFR and lower CIGS to begin the period all sites and
remain into the afternoon with possibly some improvement to low MVFR
by the later afternoon as the BL warms and mixes decks a little
higher. However...all sites will drop back to IFR or lower this
evening and remain low thru the period. VSBYs will also be lowered
to 1 SM or lower in the higher rainfall producing cells. A strong
low-level jet develops aft daybreak outside the mtns and LLWS is
likely by mid-late morning. Also...a convective band will cross the
area and bring tstms to all non/mtn sites by the latter part of the
period with stg VRB outflow winds possible.

Outlook: Extended periods of MVFR or IFR conditions are likely
into Thursday night as the cold front moves slowly across the
region. Conditions should improve on Friday.

Confidence Table...

            20-02Z        02-08Z        08-14Z        14-18Z
KCLT       High  92%     High  90%     High  86%     Med   76%
KGSP       High  90%     Med   68%     Med   72%     High  84%
KAVL       High  84%     High  85%     High  82%     High  82%
KHKY       High  90%     Med   62%     Med   79%     Med   70%
KGMU       High  92%     Med   64%     Med   73%     High  85%
KAND       High  89%     Low   52%     High  84%     Med   78%

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 Thursday evening for GAZ010-017.
     Flash Flood Watch from Thursday morning through Thursday
     evening for GAZ018-026-028-029.
NC...Flash Flood Watch through Thursday evening for NCZ033-048>053-
     058-059-062>065-501-503-505-507-509.
     Flash Flood Watch from Thursday morning through Thursday
     evening for NCZ035>037-056-057-068>072-082-502-504-506-
     508-510.
SC...Flash Flood Watch from Thursday morning through Thursday
     evening for SCZ001>014-019.

&&

SYNOPSIS...CSH/DEO
NEAR TERM...SBK
SHORT TERM...ARK
LONG TERM...DEO
AVIATION...SBK

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
342 PM EST Wed Feb 5 2020

GAZ018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-506-508-
510-SCZ001>014-019-062045-
Stephens-Franklin-Hart-Elbert-Alexander-Iredell-Davie-Catawba-Rowan-
Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union NC-
Greater Caldwell-Greater Burke-Eastern McDowell-Greater Rutherford-
Eastern Polk-Oconee Mountains-Pickens Mountains-Greenville Mountains-
Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg-
Cherokee-York-Anderson-Abbeville-Laurens-Union SC-Chester-Greenwood-
342 PM EST Wed Feb 5 2020

...FLASH FLOOD WATCH IN EFFECT FROM THURSDAY MORNING THROUGH
THURSDAY EVENING...

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

.DAY ONE...This afternoon and tonight.

Hazardous weather is not expected at this time.

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

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

   Flash Flood Watch.

A strong cold front will move slowly across the region on Thursday.
In addition to the heavy rain, isolated to scattered thunderstorms
are expected as the cold front crosses the region Thursday and
Thursday evening. Some of the thunderstorms could be strong to severe
with damaging wind gusts. A brief, isolated tornado will be possible
mainly along and south and east of Interstate 85.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to forward any reports of large hail,
damaging winds, tornadoes, or flash flooding to our office.

GAZ010-017-NCZ033-048>053-058-059-062>065-501-503-505-507-509-062045-
Rabun-Habersham-Avery-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-
Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Caldwell Mountains-Burke Mountains-McDowell Mountains-
Rutherford Mountains-Polk Mountains-
342 PM EST Wed Feb 5 2020

...FLASH FLOOD WATCH IN EFFECT THROUGH THURSDAY EVENING...

This Hazardous Weather Outlook is for northeast Georgia and western
North Carolina.

.DAY ONE...This afternoon and 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.

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

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

   Flash Flood Watch.

A slow-moving cold front will bring deep moisture across the western
Carolinas and northeast Georgia through Thursday. Periods of heavy
rain are expected tonight and continuing Thursday afternoon, with
the heaviest rain expected late tonight through Thursday morning.
Embedded thunderstorms may also bring the threat of cloud-to-ground
lightning and gusty winds.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to forward any reports of large hail,
damaging winds, tornadoes, or flash flooding to our office.

ARK