Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 061444

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
944 AM EST Sat Mar 6 2021

Dry Canadian high pressure will become reinforced today as low
pressure moves southeast across the Gulf of Mexico. The dry high
pressure will persist into at least early next week before moving
off the southeast coast.


As of 940 AM EST Saturday: Despite some echoes on radar, not seeing
any precip reaching the ground. That said, can`t rule out a few
sprinkles dropping out of the lower cloud deck along and near the
Upper Savannah River valley. Lower clouds diminishing across NC
already and will clear through early afternoon over the Upstate and
NE GA. Highs look on track. Dew points are all over the place this
morning. Expect drying to develop with good mixing and weak
downslope flow this afternoon. With the cooler highs expected, RH
values may not drop as much over NE GA as they did yesterday, but
will be very dry elsewhere.

Otherwise, shortwave traversing the Deep South is being absorbed
into the longwave system with the parent low off in NE Canada.
Surface high pressure centered over the western Great Lakes under
the confluent flow upstream of the trough is ridging toward the
Southern Plains, with a finger of a ridge stretching into the
Carolinas. Best moisture associated with this shortwave is to our
south, with cloud levels dropping through the late overnight hours
across the area but especially the Upper Savannah Valley and
Upstate. However, continued very, very dry at the surface, so
despite some weak radar returns across the TN Valley and N GA, very
little if anything reaching the ground. Have continued trend of
sprinkles wording in the grids in mainly SW zones, but that said,
some WPC superensemble members are wanting to spit out some very
light snow along the NC/GA/SC line. Profiles are certainly cold
enough aloft, but with the very dry layer at the surface, most
likely anything would evaporate/sublimate. Have no plans to add any
flurries to the grids, but will monitor obs across N GA as the
shortwave dives around.

The shortwave will push out of the area during the day today, though
with troughiness remaining in place and enough moisture to keep some
cloud cover across the area. Guidance has trended cooler with
afternoon highs today as a result. Still expect very dry air with
strong mixing again today, but slightly better than yesterday. With
that and the cooler temperatures, expect that NE GA will not reach
fire danger criteria, so no plans to issue an SPS at this time.
Should still see some <20% RH in NC, but winds remain too light for
any concerns for products.


As of 235 am Saturday: Upper heights will rise across the region
during the short term, as a deep trough progresses away from the
East Coast, and a low amplitude ridge builds west of the
Appalachians. This pattern will more or less anchor very dry low
level high pressure across the region through the period, with
continued fire weather concerns/low afternoon RH being the only item
of concern. For more info...see the Fire Wx discussion below.
Otherwise, temps will warm through the period under increasing
thickness values, with one more day of below-normal temps expected
Sunday before above-climo conditions expected to return for Monday.


As of 255 am Saturday: As a major storm system takes shape across
the southwest Conus, low amplitude ridging will develop near the
Southeast coast early in the medium range, and generally persist
through the period. Dry low level ridging will lose its grip on the
area...albeit very gradually, as the low levels won`t truly begin
moistening to a significant degree until toward the end of the
period. The main story will be the continued warming trend, as temps
are expected to be above normal through the period, possibly well
above normal by the end of the week. Global models are somewhat at
odds regarding the evolution of a frontal zone associated with late
week northern stream height falls, with the ECMWF and Canadian
solutions bringing the front and attendant light precip into the
forecast area Friday, while the GFS holds the boundary well north
and west of the area. We are featuring only the slightest of precip
chances across western and northern zones on Friday.


At KCLT and elsewhere: VFR through the period at the TAF sites,
with upper clouds continuing this morning and low VFR overspreading
especially the Upstate. Cannot rule out some brief sprinkles with
the lower cloud deck, but confidence remains too low to include at
any of the TAFs. Winds starting off on the N side at TAF time, but
exact location of ridge axis may allow Upstate TAFs to veer around
to SE before going SW, whereas NC TAFs will vary between NE and NW
but generally stay on the N side (NNW at KAVL). Cannot rule out very
brief backing at KCLT to WSW around 00z tonight, but this would be
temporary so will not be carried in the TAF. Clouds will clear out
later today.

Outlook: Dry high pressure will remain in control well into next
week with VFR conditions prevailing.

Confidence Table...

            00-06Z        06-12Z        12-18Z        18-00Z
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:


Another dry day in store today across the area. However, critical
RH values of less than 25% are expected to impact areas generally
east of U.S. 25. As such, it doesn`t appear that Fire Danger
Statement criteria will be met across northeast Georgia. While very
low RH is expected this afternoon across the western Carolinas,
especially across the NC foothills, where minimum values of 15-20%
are expected, winds will remain below FDS criteria. Thus, no special
products will be issued for today, but critical RH will continue to
headlined in the planning forecast.

Minimum RH should dip to the 15-25% range across the entire forecast
area Sunday afternoon. Elevated mountain winds...generally 10-20 mph
with higher gusts could warrant at least a Fire Danger Statement
across the mountains Sunday afternoon, while another Fire Danger
Statement appears likely for northeast GA (where only one of wind/RH
criteria are required along with dry fuels). Dewpoints will begin
creeping up on developing S/SW flow Monday, but min RH is still
expected in the 20-25% range.




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