Area Forecast Discussion
Issued by NWS Greer, SC

Home | 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
FXUS62 KGSP 241035

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
635 AM EDT TUE MAY 24 2016

High pressure will prevail over the Southeast most of this week. A
moist southerly flow will develop by tomorrow, which will lead to
warmer temperatures and mainly afternoon chances of showers and
thunderstorms each day through Friday.


As of 635 AM, mid clouds moving east of the area as cirrus moves in
from the west. Fog has been patchy and light this morning and will
dissipate quickly. Upper ridging builds into the area today and
tonight as surface high pressure moves east across the area. This
results in a weak, but increasing southwesterly flow. Expect some
ridge top cumulus to develop during the afternoon, with mostly sunny
skies elsewhere. With thicknesses rising, highs today will top out
near or a little above normal. Any ridge top cumulus will dissipate
with loss of heating this evening. However, expect an increase in
clouds across the mountains overnight as a weak short wave moves
through the ridge and into the area. Forecast remains dry, with lows
dropping to near or a couple of degrees above normal. Patchy fog
will again be possible, but chance of widespread or dense fog is low.


As of 315 AM Tue: High pressure over the South Atlantic coast
will bring south to southwest return flow into the area Wed and
Thu. Diurnal instability will trend upward from day to day, driving
diurnal showers and thunderstorms. Subsidence will keep the Piedmont
sufficiently stable Wed, so PoPs are confined to the mountains then;
they expand to about the I-85 corridor Thu. Minimal shear implies
mainly disorganized pulse storms can be expected with localized
downbursts being the main threat besides lightning. Temps will
rise about a category above climo each day.


As of 300 AM Tue: The late week pattern will be dominated by a
broad upper ridge centered over the mid-Atlantic coast and sfc high
pressure. This by itself would result in rather run-of-the-mill
weather for late May, in which PoPs would be tied to diurnal
instability and temps at or a little above climo. However, the
proverbial fly in the ointment is what appears to be increasing
consensus for a tropical low to move into the Carolinas over
the weekend. Spread on the track thereof is still pretty wide
overall, but the 00z GFS and EC both show landfall near the Grand
Strand. They differ on its position thereafter. Winds do not appear
to be of concern on land at this point, but the nature of moisture
flux varies across the guidance spectrum, so it is difficult to
say whether PoPs would be greatly increased or decreased by the
presence of the system. It is difficult to make a model blend (for
grid production purposes) that does not reflect any influence from
it, though confidence on its track remains moderate at best. My
preferred choice of action at this point is to reflect PoPs only
slightly above climo, with mainly diurnal trends, but elevated
sky cover and slightly cooler temps Sun-Mon.


At KCLT and elsewhere: SCT mid clouds will move east of the area
early this morning with cirrus moving in through the rest of the
period. Light NW or W wind becomes SW as mixing develops by noon.
Winds become light and variable or calm this evening. Patchy fog
cannot be ruled out overnight, but chance of restrictions is low.

Outlook: Mainly VFR conditions will prevail through the week, but
patchy morning fog chance continues at KAVL. Scattered afternoon
SHRA/TSRA may return Wednesday, with daily coverage increasing
Thursday and Friday.

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  83%     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 schedule TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:




SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...RWH is the U.S. government's official web portal to all federal, state and local government web resources and services.