Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Blacksburg Virginia
215 am EDT Monday Aug 31 2015
a series of weak upper level disturbances will lift north along
the appalachian chain into early Monday...bringing a greater
chance for showers to the region. Upper level high pressure will
then strengthen and keep US in a rather stagnant
pattern...maintaining a chance for afternoon and evening showers
and thunderstorms through the middle of the week.
Near term /through today/...
as of 1003 PM EDT Sunday...
Two areas of showers exist...one over far SW Virginia/NE Tennessee...and the
other over the NC foothills/Piedmont. Mesoanalysis indicated best
deep moisture convergence in the southern Appalachians and near
High-res models and latest NAM show higher probability of precipitation needed for our southern
County Warning Area late tonight. This in association with a shortwave over western
NC. There is yet another upper impulse over central Georgia. These
waves move northeast into central NC and southern Virginia by dawn.
Previous valid discussion...
Clouds tonight will keep temperatures in the middle 60s east of
the Blue Ridge with upper 50s/lower 60s to the west. Highs
tomorrow look to be in the middle 80s east to upper 70s/around 80
Short term /tonight through Wednesday/...
as of 330 PM EDT Sunday...
Expecting 500 mb ridge to build over the eastern United States by
Tuesday night. Models suggest some potential pieces of energy but
these will be weak and do not appear organized enough to provide any
decent lift for the region. Best probability of precipitation will
be on Wednesday when a short wave crosses the Middle Atlantic States.
While there may be weak surface troughs in the area through
Wednesday...overall high pressure remains in place and no change of
airmass is expected. Combination of mav and MOS guidance was
reasonable for highs and lows this time frame.
Monday will see most of this short wave energy pulling off to the
east...leaving US in a moist and weakly forced environment that
should help generate some scattered showers/thunderstorms during
Long term /Wednesday night through Sunday/...
as of 330 PM EDT Sunday...
Models show a high amplitude ridge over the eastern United
States with 500 mb heights around 594 dm over the Ohio Valley by
Sunday. Challenging to track any subtle short waves on the east side
of the ridge that may impact the area. 850 mb temperatures gradually
warm into the +16 to +20 range by Sunday. By Saturday and Sunday
maximum temperatures will be 5 to 10 degrees
Aviation /06z Monday through Friday/...
as of 205 am EDT Monday...
Radar indicates bands of light rain passing north across The
Highlands and foothills of North Carolina...falling out of
ceilings with bases at 6kft and up. Light occasional sprinkles
are being reported elsewhere across the area.
Overnight...expect mainly VFR ceilings to persist...possibly with
high end MVFR along the Blue Ridge toward dawn. Reductions in
visibility will mainly occur in any areas of heavier rain...but
expect they will be few. With cloud cover so widespread...do not
anticipate more than very light mist across the region...holding
visibilities 5sm and up.
Models favoring lowering ceilings across the southeast after dawn
Monday morning as weak wave moves across the North Carolina
Piedmont. Taf forecast for Danville reflects this thinking...but
do not expect any other taf sites will fall be affected. Ceilings
at Danville will improve again during the afternoon...with bases
areawide ranging from 4kft to 6kft. Additional clearing takes
place around sunset.
Extended aviation discussion...
The forecast area will remain in a weakly forced synoptic
environment through midweek...with chances for diurnal convection
mainly from the Blue Ridge west...and some MVFR/IFR fog/stratus
development at night...especially at kbcb and klwb.
as of 700 am EDT Sunday...
The dew point reading at kjfz...Richlands Virginia AWOS...is incorrect.
At this time we do not know when this sensor will be repaired.
short term...air mass
long term...air mass