Area Forecast Discussion
Issued by NWS Greer, SC

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KGSP 241011
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
611 AM EDT Sun Sep 24 2017

.SYNOPSIS...
Broad, dry high pressure will persist across the region through the
middle of next week. Tropical Cyclone Maria is expected to remain
off the East Coast through mid-week. A cold front will sweep across
the region on Thursday, bringing drier and much cooler air to the
area for week`s end.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 600 AM EDT...No sigfnt changes needed to the fcst grids. Mtn
valley fg and low cigs will reamain steady state before burining off
rather quickly aft 13z.

A dry pattern will become even drier today as high pressure
continues to ridge in from the north. This high will be stacked thru
a deep layer while a strong h5 high centers across the ern Glakes.
Model soundings are showing limited moisture to work with as well as
deep layered sbCIN...thus supporting only fair-wx Cu and perhaps
some Ci moving in from TC Maria as she advances north. PoPs have
been left nil for the entire FA as weak e/ly mech lift over the
higher terrain will not have enuf moisture to overcome a strong subs
inversion.

Max temps will again reach a few degree warmer than climo...and with
a normal diurnal drop-off min temps will also be held a few degrees
above normal. Some low-end gusts as possible in good momentum
transfer especially across the ern zones...but overall winds will
remain below 10 kts or so. Dewpoints will mix out into the L60s
non/mtns as well...making for a very nice day on tap all locales.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 330 AM Sunday: The dry and unseasonably warm weather will
persist through early week, as mean, high amplitude upper ridging
persists over the area. A combination of surface high pressure
centered over the northeast Conus and Tropical Cyclone Maria moving
N/NW toward the NC coast will support a sharp surface ridge over the
area, with N->N/NE surface winds, which could become somewhat breezy
by the end of the period. Although moisture may increase to some
extent within the circulation around Maria, especially over the
Piedmont, showers would be very unlikely considering the official
forecast track during the late short term, which would suggest a
subsident regime over our area. Pops will therefore be kept below
slight chance through the period, while temps will remain a solid
5-ish degrees above climo.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 340 AM Sunday: It still appears that a pattern change is in
the offing by the end of the week, as a series of potent short wave
troughs traversing the northeast quadrant of the Conus act to break
down the upper ridge. An attendant frontal boundary is expected to
cross the forecast area during the Thu/Thu night time frame.
Persistent, mostly dry N/NE flow in advance of the frontal zone will
yield very limited moisture, and fropa will most likely be of the
dry variety. Only token slight chance pops will be carried across
portions of the high terrain during the aforementioned time. The
front will sweep Tropical Cyclone Maria away from the East Coast,
before any impacts of note would occur across our area. The primary
impact of the front will be to give the area the first taste of
fall, as temps are forecast to be at least 5 degrees below normal
and dewpoints considerably drier by Day 7.

Global model guidance is depicting some degree of cyclogenesis
along the remnant baroclinic zone in the vicinity of the Southeast
coast next weekend (although timing/location/intensity of the
cyclogenesis remains highly uncertain), so small pops are carried by
the end of Saturday, mainly across the southeast third of the
CWA.

&&

.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
At KCLT and Elsewhere: No flight restrictions all sites except KAVL
this morning. Recent precip and lingering mtn valley moisture will
allow for LIFR cigs and vsby before daybreak which will dissipate
thru 14z. Stacked high pressure will preclude any convec concerns
with sbCIN remaining high thru a deep layer per the latest model
soundings. Cu will be hard to form within drying LCLs. Winds will
remain aligned generally in a ne/ly direction with some low-end
gusts possible this afternoon, generally across the ern zones
including KCLT.

Outlook: Dry conditions expected for the first half of the week.
Under mostly clear skies and calm conditions, fog and/or low stratus
are likely in the mtn valleys each of the next few mornings.

Confidence Table...

            10-16Z        16-22Z        22-04Z        04-06Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High  80%     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 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...JDL
NEAR TERM...SBK
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...SBK


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.