Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 161133
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
633 AM EST Thu Feb 16 2017
High pressure crosses the Gulf today as the upper trough moves east
over the Atlantic. Expect a broad upper ridge to dominate the
weather for much of our nation this weekend and early next week
resulting in a warming trend. A weak low pressure crosses the deep
southeast this weekend. The next weather maker is not expected until
mid to late week.
.NEAR TERM /THROUGH TONIGHT/...
As of 630 AM: Heights slowly rise through the period as an upper
trough moves east of the area. A series of weak short waves will
cross the area in the NW flow aloft. This will bring varying amounts
of cirrus and possibly mid clouds over the area. Cannot rule out
thick mountain wave cirrus from time to time which could limit
heating or retard cooling. At the surface, the pressure gradient
across the area slowly relaxes as high pressure builds in from the
west. Before that happens, very gusty NW winds will continue across
the higher elevations with low end gusts developing in the more
sheltered valleys and outside of the mountains as mixing develops
this morning. Winds diminish across the area late this afternoon or
early this evening and turn westerly outside of the mountains as a
weak lee trough develops. Highs will be a couple of degrees above
normal unless the thick mountain wave cirrus develops dropping temps
a few degrees. Lows will be near normal but could be a couple of
degrees warmer if mountain wave cirrus lingers.
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 200 AM EST Thursday: A sharp upper ridge axis will cross the
CWFA on Friday, followed by a fast-moving southern stream trough on
Saturday. At the surface, a weak area of high pressure will linger
across the Carolinas, while a very weak low tries to develop and
track just off the northern Gulf Coast. Low level flow will back
from NW to SW Friday night thru Saturday. However, little moisture
will be able to advect this far north, with models suggesting that
convection will be mostly confined to the Gulf Coast. So PoPs will
briefly ramp up to the chance range on Saturday, highest in the west
where upslope lift may help. QPF will be light. The bigger story
will be temps warming back up to well above normal both Friday and
Saturday. Highs will be 10-15 degrees above normal and lows about
5-10 degrees above normal.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 130 AM EST Thursday: On Sunday, the weak low will be moving
east of our area as it will produce very little weather anyway.
Thickness values will be increasing going into the early part of the
week with an upper ridge axis crossing the Mississippi Valley
heading east. Temperatures will be around 15 degrees above normal
through the medium range as we expect very little weather. No more
than slight to low chance POPs are forecast which is expected in the
current Day 7. The ECMWF has modified since yesterday as yesterdays
model had a southern low over Texas early week then completely
fading out as it reached Florida just after mid week. The GFS and
ECMWF are now in remarkable agreement with the low near the LA coast
at 12Z Wed. The models diverge a bit Wed night into Thursday which
is the end of the current forecast. The GFS promotes a more defined
area of precip over our region while the EC dives the low farther
south over Florida with very little precip over our area. Again with
this medium range the temperatures are way too warm to have wintry
precip. Min Temps will be just a few degrees below normal Max Temps.
Some light low level upslope flow is expected to start Monday night
through Wed in varying degrees from south to SE against the south
to SE facing mountains.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Drier air will remain over the area through
the next 24 hours, resulting in VFR conditions through the period
with increasing cirrus and possibly mid clouds. Wind speeds will
increase this morning as mixing begins with steady gusts at KAVL and
off and on low end gusts elsewhere. Direction will remain NNW at
KAVL with WNW elsewhere. Winds diminish this evening and turn WSW
with a lee trough developing, direction remains NNW at KAVL.
Outlook: Conditions remain dry through the end of the work week. The
next chance of restrictions looks to be on Saturday as an upper
disturbance approaches the area from the west.
11-17Z 17-23Z 23-05Z 05-06Z
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 and ensemble forecasts
are available at the following link:
Very gusty winds continue through the day across the higher
elevations with gusts developing this morning in the more sheltered
valleys and outside of the mountains as mixing begins. RH values
will fall to 25 percent or less across all but the northern NC
Mountains this afternoon. Fuel moisture values are starting off high
from the rain on Wednesday morning. However, they will likely dry
quickly with the winds and falling RH values. Therefore,
coordination may be needed with area land managers for the potential
issuance of a fire danger statement for this afternoon.