Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Remove Highlighting --
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FXUS61 KRNK 280534
Area Forecast Discussion
National Weather Service Blacksburg VA
134 AM EDT SAT MAY 28 2016
High pressure will remain off the Mid Atlantic coast during
tonight into Saturday. Meanwhile, Tropical Depression #2 should
move northwest toward the South Carolina coast by Sunday, and it
could linger over the Carolinas through early next week.
.NEAR TERM /THROUGH TODAY/...
As of 945 PM EDT Friday...
Showers and thunderstorms are currently fading over the Mid
Atlantic, and this activity should dissipate by midnight. With
recent rainfall and clearing skies, patchy valley fog is likely
to develop by Saturday morning. Low temperatures were dropped a
couple degrees in this update to reflect the latest observational
trends, so the overall range will be from the mid 50s in the
mountains to the mid 60s in the Piedmont.
For Saturday, our attention turns to Tropical Depression #2.
Models are in agreement on moving this system northwest from the
Bahamas toward the South Carolina coast later this weekend. NHC
expects the depression to likely strengthen into what would
become Tropical Storm Bonnie. In advance of this tropical system,
there will be subsidence overhead to keep most of Virginia and
North Carolina dry. However, heating may provide enough
instability to spark isolated afternoon showers and thunderstorms
in southeast West Virginia, far western Virginia, and the
northwest North Carolina mountains. High temperatures on Saturday
afternoon will range from the mid 70s in the mountains to the mid
80s in the Piedmont.
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
As of 320 PM EDT Friday...
The ridge along the Mid Atlantic coast will start shifting east
Saturday night as a tropical depression/tropical storm makes
landfall on the South Carolina coast. Rain showers should track
into or develop across the southeast part of the Piedmont Saturday
evening, but expect the rain overnight into early Sunday to focus
more toward the core of the tropical system. Pops and QPF were
increased for Saturday night, especially with upslope flow along
the southern Blue Ridge mountains. Low temperatures on Saturday
night will only drop into the upper 50s in the west to the mid 60s
in the east.
Sunday will be very unsettled with periods of rain across the
forecast area. The rain will be heavy at times. Played the
highest pops along the southern Blue Ridge with the upslope
enhancement. PWATS climb upwards into the 1.5 to 2.0 inch range,
and an area of deep tropical moisture appears evident on most
models from the tropical low northward across the Piedmont. The
amount of thunderstorms is in question as instability is minimal
given extensive cloud cover and a saturated atmosphere. High
temperatures were lowered on Sunday to around 70 degrees in the
mountains to the upper 70s in the Piedmont. Showers and a few
thunderstorms continue Sunday night with the best chances along
the Blue Ridge mountains. Low temperatures Sunday night will vary
from the mid 50s in the mountains to the mid 60s in the Piedmont.
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 230 PM EDT Friday...
Model guidance varies on the position and timing, but each offer a
solution for an area of low pressure along the east coast Monday
morning somewhere between South Carolina and North Carolina.
Moisture on the western flank of this system is progged to
influence our region to various degrees through Tuesday. The GFS
and Canadian solutions are slow to eject the system northeast from
the the SC/NC border. The GFS offers a solution that ejects a
piece of the low northeast Monday but with the main system
remaining anchored near SC/NC. The European and NAM solutions
eject the low a little more quickly towards the northeast. In
different ways, both of these scenarios yield similar forecast
solutions for the region. If the slower solution pans out, it will
mean the bulk of the moisture will remain south of the forecast
area, and the region will experience subsidence on the north side
of the system. If the quicker solution pans out, any precipitation
the area receives will be on the backside of the system and skirting
the eastern portion of the region. Our forecast will reflect the
best chances of precipitation across the southeastern portion of
the area Monday into Tuesday with limited or no precipitation
across the far northwest.
Tuesday night into Wednesday night, the low will continue to make
slow progression to the northeast. The biggest difference will be
with the European solution that started its progression just
slightly sooner. At the same time, an upper trough will be
approaching from the west. The uncertainty in the departure track
of the low, plus increasing dynamics from the approaching
trough, and a boundary layer rich with moisture, will allow for
isolated to scattered showers and storms across the forecast area.
Chances gradually increase Thursday into Friday for one of two
reasons. If the GFS solutions come to pass, the upper trough will
deepen, close off, and stall across the center of the country.
This would allow for plenty of moisture to stream north from the
Gulf of Mexico into the region. Pieces of energy ejecting eastward
from the main low will act as trigger mechanisms for daily
convection. If the European solution is correct, precipitation
chances will also increase as the upper trough remains
progressive and moves eastward along with its associated cold
front into and through the region.
Temperatures during this portion of the forecast will average above
normal with upper 70s to around 80 for highs across the mountains
and low to mid 80s across the Piedmont. Lows in the upper 50s to
around 60 will be common across the mountains with low to mid 60s
across the Piedmont.
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --As of 130 AM EDT Friday...
Fog may become an issue once again early this morning but moreso
at LWB than either sites. Will introduce a tempo group for mvfr
fog at LYH/DAN given higher dewpoints. BCB at times may drop to
ifr toward 09-12z.
Any fog will dissipate quickly Saturday morning. VFR ceilings and
visibilities are expected through the day. There is a small chance
of showers and thunderstorms again in the afternoon northwest of
KLWB and KBLF. Models have been consistent in showing a band of
drying and subsidence between showers and thunderstorms on the
western side of the Appalachians and the leading edge of deeper
moisture in advance on the tropical system approaching South
The forecast will hinge heavily on the track of the tropical
system, which will bring increased moisture and shower chances to
the area that could linger well into next week. This will result
in widespread showers by Sunday and periods of MVFR to IFR cigs as
well as a greater potential for late night/early morning fog.
Confidence in the evolution of the forecast past Monday is low,
but the pattern appears to remain wet for the Mid Atlantic.
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