Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 032344
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
744 PM EDT Fri Apr 3 2020

.SYNOPSIS...
High pressure slowly builds into the region through Saturday, then
shifts to our east on Sunday. A weak cold front will push in from
the northwest by Sunday evening, stalling over the area Monday,
before lifting back north as a warm front on Tuesday. A stronger
cold front will cross the region on Wednesday.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 725 pm Friday: The current forecast remains on track, with mid
and upper clouds encroaching on the southern Appalachians in the WNW
mid/upper flow east of a flattening short wave ridge. The ridge axis
will likely move across the across the Appalachians by the end of
the period late Saturday. Some intermittently broken clouds may
accompany weak vorticity lobes moving across the southern mountains
overnight into Saturday morning, but the moisture should gradually
thin and dissipate through Saturday. With the pesky clouds marring
the radiation across the region overnight, min temps have been
raised a degree or so in southwest sections where the clouds should
be thicker through daybreak. Otherwise, slackening winds and a dry
boundary layer will allow tonight`s min temps to cool to just a
couple of degrees above climo, albeit moderated a bit by the
increasing clouds. Tomorrow`s maxes should again be a solid 5
degrees warmer than normal. Dewpoints creeping into the 30s are
expected to result in slowly improving RH profiles Saturday. See the
Fire Wx discussion below for details.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 215 PM EDT Friday: The short term will be dominated by a
broad 500 mb ridge that will build somewhat across the eastern 2/3rd
of the CONUS. At the sfc, a dying cold front will approach the
Southern Appalachians from the Ohio Valley Sunday aftn, with the
latest guidance not too impressed with QPF response. There may be
just enough moisture to support isolated to widely scattered showers
in the mountains. If you throw out the GFS, the Piedmont looks dry.
The front stalls out across NC in an east-west orientation, as a
modest high pressure center enters the Northeast. The front actually
gets a little stronger on Monday thanks to some frontogenesis, and
should trigger scattered showers across the NC zones, with isolated
coverage to the south. Sbcape of 500+ J/kg may be enough for some
tstms, but given lack of strong forcing, the severe threat should
remain low despite 35-40 kt of 0-6 km bulk shear. Temps will
continue a warming trend with the building upper ridge. Highs about
5-10 deg above normal, lows 10-15 deg above normal.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 245 PM EDT Friday: a couple of impulses diving out of southern
Canada will work to flatten the eastern CONUS upper ridge Tuesday
thru Wednesday, with the second wave becoming a large vortex over
the Great Lakes by Thursday. Meanwhile, a large closed low over
California will slowly wobble east Wednesday thru Thursday. The
medium range guidance are completely all over the place with when
this low gets picked up by the northern stream and ejects east of
the Rockies. The GFS is the usual fast guidance opening it up by 12z
Friday, while the Canadian holds on to it thru the weekend. The
first wave that will drop into the Great Lakes will push a cold
front across the forecast area Wednesday. But behind that,
confidence in the forecast really goes down. I expect temps to trend
cooler, back to near normal by next Friday. Precip will be mainly
confined to the mountains, highest on Tuesday and Wednesday (mainly
chc mountains and slgt chc east), then slgt chc or less Thursday and
Friday.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and Elsewhere: VFR conditions will persist through the
period as a ridge axis steadily moves east from the MS River Valley
to the Appalachians. Mid/high clouds may stream into the area from
time to time in the WNW flow aloft, but with cigs mainly at or above
10 kft. Light NW winds this evening will turn light NE overnight all
but KAVL. Some southerly return flow should set up across the
Upstate TAF sites through the day on Saturday, with KCLT finally
toggling ESE toward Saturday evening.

Outlook: Expect VFR conditions to persist into early next week.
Flight restrictions may return on Tuesday as moisture increases
ahead of a weak front.

Confidence Table...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High 100%

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

&&

.FIRE WEATHER...
A Fire Danger Statement will remain in effect for Upstate SC through
Saturday. The South Carolina Forestry Commission has opted to issue
a "Red Flag Fire Alert" for the entire state. We usually let that
speak for itself, but since the FDS has already been issued, we`ll
let it ride out to avoid confusion. Weaker winds as well as
increasing dewpoints (yielding min RH in the 25-35% range) are
expected Saturday, thus no additional products are expected at this
time for GA or NC.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Fire Danger Statement until 8 PM EDT this evening for GAZ010-
     017-018-026-028-029.
NC...Fire Danger Statement until 8 PM EDT this evening for
     NCZ035>037-056-057-068>072-082-501>510.
SC...Fire Danger Statement until 8 PM EDT this evening for
     SCZ001>014-019.
     Fire Danger Statement from Saturday afternoon through Saturday
     evening for SCZ001>014-019.

&&

$$
SYNOPSIS...ARK
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...HG
FIRE WEATHER...JDL/HG


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