Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KRNK 241751
Area Forecast Discussion
National Weather Service Blacksburg VA
151 PM EDT Fri Mar 24 2017
High pressure off the coast will establish a warmer and more moist
southerly flow across the Appalachians and central mid Atlantic region
into the weekend. A slow moving cold front will enter from the west on
Sunday with a chance for showers and possibly a thunderstorm. Our
weather then looks to remain unsettled through next week as a series of
disturbances move across the central and southern part of the country,
keeping a chance for showers and thunderstorms in our forecast through
.NEAR TERM /THROUGH TONIGHT/...
As of 100 PM EDT Friday...
The wedge has eroded over parts of SE WV this morning. A warm
front in northwesterly flow continues to track across the Mid
Atlantic region. With all this taking place, an isolated shower
or two may track across western Greenbrier this afternoon.
As of 345 AM EDT Friday...
It`s looking like a quiet end to the workweek as an upper level ridge
is the dominant weather feature over the Appalachians, though there
will be a fair amount of cloud cover around. At the surface, high
pressure along the middle Atlantic coast will continue to push offshore
today. Satellite imagery shows some lower clouds extending back from
the NC mountains toward the Gulf coast, guidance supports return flow
around the high drawing these clouds up into the region this afternoon
along and east of the Blue Ridge into Southside. Additionally, a short
wave will swing through the Ohio valley along a warm front on the rim
of the upper ridge. This is generating some shower/storms well off to
our northwest, but expect some showers to brush by to our north today
with lower clouds extending southward into the region. Quiet weather
then continues tonight as the ridge axis crosses the region and high
pressure at the surface remains parked off the mid Atlantic coast.
With a deepening southerly flow, temperatures will moderate
considerably from readings yesterday with highs about 10 degrees warmer
which will be above normal for late March.
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
As of 400 AM EDT Friday...
A very active, highly kinematic, westerly flow will be in place
across the U.S. with the Pacific wide open. A parade of
vigorous upper-level low pressure areas will march from west to
east across the U.S. through the period. At least four such
significant systems are noted during the 7-day period beginning
Saturday will bring one last day of dry weather to the area as
an upper ridge briefly moves across the area and temporarily
blocks the upstream system in the central U.S. A warm front will
continue to lift northward through the northern portions of the
Mid-Atlantic into NY and New England. The surface high that has
been providing us with the cool weather the last few days will
move to our southeast. The region will be solidly in the warm
sector with southerly to southwesterly surface flow. 850mb temps
will soar into the double digits allowing surface temps to warm
well into the 60s west to the 70s Piedmont. These readings are
about 10-15 degrees above normal for late March.
By Sunday, the first of the Pacific system will arrive. Models
are in general agreement on the details. Timing is faster than
has been indicated in recent days with this system now arriving
in the western part of the CWA Sunday morning and then into the
Piedmont by Sunday afternoon. The faster arrival of these system
also heralds better dynamics as well. Models are in pretty good
agreement on a near solid line of showers and thunderstorms
translating from the TN valley into western VA. The risk of
severe weather with this system appears low as instability is
meager at best with capes below 500 J/kg. Have included a slight
chance of thunder western areas, but left as showers east of
the Blue Ridge at this time. Rainfall amounts are expected to
range from 1/2 to 3/4 inch west of the Blue Ridge to 1/4 to 1/2
inch east of the Blue Ridge. Temperatures will remain warm
Sunday, but the clouds and precipitation will keep readings on
the order of 5-7 degrees cooler than Saturday. The clouds,
southerly flow, and warm, Gulf air in place will keep overnight
minimums very balmy, well into the 50s most areas.
On Monday, the first upper low will lift northward toward the
Great Lakes and weaken as yet another upper-low follows quickly
on its heels moving out of the Central Plains. This system
promises to be somewhat more progressive and transition into an
open wave as it moves into the eastern U.S Tuesday. This leaves
the CWA in an unseasonably warm, humid air mass Monday between
systems with little in the way of dynamics or forcing, yet with
lots of clouds and high RH. Any breaks in the sun could trigger
isolated pop up showers and thus have left in chance pops west
to slight chance pops east with no thunder. Temperatures will be
warm Monday with lows in the 50s and highs mostly in the 70s,
except 60s western mountains.
.LONG TERM /TUESDAY THROUGH THURSDAY/...
-- Changed Discussion --As of 142 PM EDT Friday...
Active pattern this period.
Upper-level low pressure system will arrive in our region early
Tuesday. Dynamics are marginally favorable for thunderstorms, but if
line of convection moves in sooner, lack of thermodynamics will
limit thunder threat.
High temperatures are expected to be in the 60s to lower 70s.
Wednesday should be dry with upper ridge building again.
Thursday, still dry as upper low slowly edges eastward over the
southern plains keeping us under warm ridge, although could start
see mid/upper level moisture working in from the southwest. High
pressure nosing in from the northeast may keep it cooler, so kept
highs in the 60s.
Friday, the upper low pushes northeast toward the midwest with
strong high situated over the mid atlantic coast. Will start seeing
warm advection precip arriving late Thursday night with front not
moving into the area until later Friday. By then dynamics weaken
over the north.
-- End Changed Discussion --
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 140 PM EDT Friday...
High pressure along the Mid-Atlantic coast will continue to
push offshore today allowing winds to come around to the south
and southwest. A barrier jet is situated over the piedmont (LYH-
DAN) this afternoon and will result in breezy and gusty winds
(15-20G25kt) into this evening. Extensive mid and high clouds
this morning are becoming scattered as temperatures warm and
The southerly winds will allow low level moisture to increase
resulting in increased potential for MVFR ceilings
overnight/early Saturday along and south of the VA/NC border.
Otherwise, ceilings should remain VFR for most areas through the
TAF period. Some patchy valley fog is possible overnight but
confidence is low.
Extended Aviation Discussion...
Moisture continues to increase over the weekend ahead of an
upper-level low pressure area moving northeast from the southern
plains. Precipitation is not expected until Sunday when sub-VFR
conditions become more of a possibility. Otherwise looking at
overall VFR to start the weekend with most lower cigs remaining
west of the area until later Sunday at this point. Periods of
unsettled weather will continue into the first half of next week
as a series of upper-level lows track from west to east across