Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KRNK 280431
Area Forecast Discussion
National Weather Service Blacksburg VA
1131 PM EST Sun Nov 27 2016
High pressure across the region tonight shifts east and offshore
by Monday. A weakening cold front will push a band of showers east
into the area later Monday night and Tuesday. Another wave of
low pressure will develop along the front across the southeast
states by midweek bringing another surge of rainfall to the area
Wednesday into Wednesday night.
.NEAR TERM /THROUGH MONDAY/...
As of 815 PM EST Sunday...
Very dry air remains across the region tonight with dewpoints
stuck in the 20s and evening soundings showing PWATS of below two
tenths of an inch under a very dry column aloft. This would again
support colder lows espcly in the valleys given such dry ground
pending just how fast high clouds seen advecting in from the west
associated with a weak upper disturbance thicken up. Latest model
cloud fields do show a decent canopy by late tonight espcly west as
high level moisture works through the mid level ridging but expect
somewhat overdone given dry air. Therefore opening up the range of
lows to more 20s valleys/outlying areas to closer to 40 along the
higher ridges where will get into a bit more return southwest flow
under deepening warm advection aloft after midnight. Otherwise
beefed up cloud cover some to reflect more of an increasing high
cloud flavor overnight with perhaps the far west becoming mostly
cloudy under thinning high clouds over the next few hours.
Previous discussion as of 230 PM EST Sunday...
High pressure will linger over the coastal piedmont of Virginia and
North Carolina into Monday morning, then move offshore during the
afternoon. While this ridge is in the vicinity, overnight
temperatures will cool off into the 20s across mountain valleys and
rural areas east of the Blue Ridge. Warm air advecting in aloft
will keep ridgetops mild with lows in the lower 30s.
High clouds will enter after midnight and become thicker through the
day Monday. These clouds will insulate the area and keep
temperatures from warming to normal values Monday afternoon. If the
atmosphere saturates quickly, a few light showers may move over the
North Carolina Highlands by late afternoon.
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 310 pm EST Sunday...
Not too much change with this forecast period. Exceptions are
limited if any thunder threat Tuesday and QPF totals from both
events sliding down some, but still overall looks like at least an
inch to 2 inches most locations.
The rain showers start to shift rapidly up the Blue Ridge and either
side into early Tuesday morning and most locations will see rain
Tuesday as a strong southwest low level jet sends a plume of
moisture from south to north. Winds will also be increasing
especially in the higher ridges of WV to NC. The pattern is conducive
for wind advisory level winds at least near Burkes Garden to Mt.
Rogers and the ridges along the TN/NC border. Coverage should be
isolated enough and will hold off on advisory headlines for winds
since its mainly Monday evening. Will continue to mention in the
As the low level just pushes into the mid-Atlantic Tuesday morning
the winds should start to wind down, though still seeing enough
gradient to keep some gusts to 30 mph across the higher ridges into
the afternoon while valleys and piedmont will see 10-15 mph with
gusts to 20 mph.
Expect a potential for a line of heavier showers Tuesday sliding
across then looks like a lull in the rain Tuesday evening before
next wave and associated front track to the Central Appalachians
Wednesday. This next batch seems to have better upper support with
150 kt jet moving across the MS valley into the Great Lakes putting
us in the right entrance region Wednesday. Instability still looks
best south and east of us Wednesday afternoon so mainly seeing
showers, though there could be some thunderstorms southeast of
Will see cooler air work in late Wednesday night with drying taking
place. Models differ on how fast moisture moves out so will lean
toward slower per collaboration with surrounding offices.
As far as temps, still looks mild Tuesday and Wednesday, despite the
showers with mainly 60s.
Lows will be above normal during the period with 40s Monday night,
upper 40s mountains to mid 50s piedmont Tuesday night, and lower 40s
mountains to upper 40s piedmont Wednesday night.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 115 pm EST Sunday...
Bulk of the showers will be lifting out as we head through Thursday
as upper low weakens across the Great Lakes and cold front moves to
the coast. Colder air pours in for Friday-Saturday as northwest flow
sets up. Appears enough moisture to have slight chance of snow or
rain showers Thu night into Friday night for western Greenbrier.
Shortwave ridging sets up by Saturday-Sunday and another wave shows
up in the area Sunday-Sunday night with small chance of rain/snow
Highs Thursday close to normal will drop to 5 to 8 degrees below
normal Friday-Sunday with highs in the 40s west to lower 50s east.
Low temperatures should be at or slightly below normal through the
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --As of 1130 PM EST Sunday...
VFR conditions including light winds to prevail under high
pressure overnight with a thickening canopy of high clouds
continuing to increase from the west through dawn Monday.
Moisture should continue to slowly increase on Monday as the
surface high exits offshore allowing the flow to veer more south
and southwest by the afternoon. Expect this to moisten things
enough to allow the development of some cumulus /strato-cu Monday
afternoon with this cloud field beneath sheared mid/high clouds
arriving from the west. Some potential for spots near the Blue
Ridge to lower to near high end MVFR levels by late Monday but
iffy given dry air in place. Otherwise keeping it VFR for now with
any lower canopy mainly above 4k feet under lowering mid deck
above. Winds should also bump up a bit with speeds increasing to
8-15 kts, with a few gusts to 20-25 kts possible on the ridges as
the low level jet picks up under increasing warm advection aloft.
Flying conditions will deteriorate Monday night as moisture
deepens ahead of a band of showers that should arrive from the
west around midnight and continue into early Tuesday morning.
Expect this combined with upslope flow along the Blue Ridge to
result in conditions lowering to MVFR across most sites during the
evening, and possible IFR in low cigs and restricted vsbys in
rain/fog espcly mountains after midnight into the early morning
hours of Tuesday. Since appears most of the rainfall will be just
south and west of the TAF sites Monday evening, will only include
a shower mention in the far western locations for now ending
In addition, strong southeast winds with gusts to 30-40+ kts may
occur around KBLF Monday night as well as some of the higher
ridges along the western slopes through dawn on Tuesday before
Extended aviation discussion...
Initial wave of rainfall will exit later Tuesday with leftover
sub-VFR conditions in place before a more significant batch of
rain arrives later Tuesday night and continues into Wednesday
evening. This likely to keep widespread sub-VFR ceilings and
visibilities in place until a cold front passes through the region
early Thursday. Drier air behind the front should result in a
return to VFR east of the mountains while upslope sub- VFR cigs
likely linger across the southeast West Va locations, where rain
or snow showers appear possible. Broad northwest flow looks to
keep this scenario in place on Friday as well with upslope driven
sub-VFR cigs western mountains and mainly VFR to the east.
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-- Changed Discussion --As of 800 PM EST Sunday...
Humidity slowly recovering across the valleys and east of the Blue
Ridge but remains very dry on the ridges where values remain below
30 percent early tonight. However winds are quite light most
spots so expect moisture to continue to edge up espcly valleys as
temps cool, while may take most of the night for the ridges to
recover above 50-60 percent per latest arid evening soundings.
Better push of moisture advection to take shape Monday with the low
level southerly jet pushing into the area by Monday night. This
should help lift dewpoints up enough to alleviate the ongoing low
humidity although some of the ridges may still stay below 30
percent until later Monday afternoon. Winds will pick up after
dark Monday night and gusts to 40 mph or more over the higher
ridges of southern WV to NW NC are likely. At the same time RH
will be rising into the 40s and 50s as rain starts to initiate
over the mountains Monday night.
Still looking for two good rain events, though amounts are
trending lower, but still in the 1-2 inch range Tuesday-Wednesday.
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