Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Remove Highlighting --
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FXUS61 KRNK 281758
Area Forecast Discussion
National Weather Service Blacksburg VA
158 PM EDT Fri Apr 28 2017
High pressure will build off the southeast Atlantic coast and
begin a trend for warmer and more humid conditions through the
upcoming weekend. A strong cold front will move through the area
Monday with showers and thunderstorms, followed by some cooler,
but near seasonal temperatures through the first part of next
.NEAR TERM /THROUGH TONIGHT/...
As of 1015 AM EDT Friday...
Fog/stratus continues to slowly burn off this morning, and
expect it will be gone everywhere during the next hour or two.
Otherwise, it looks like a quiet day with warm and humid
conditions. Will be monitoring new data, especially meso models,
for convective trends early tonight but high confidence in dry
conditions through sunset this evening.
High pressure is forecast to build over the southeast CONUS
today...rising heights and thicknesses resulting in warming
temperatures with afternoon highs 10 to 15 degrees above normal.
Dewpoints in the 50s will help maintain mild conditions during
the overnight with lows tonight only dipping into the 55 to 65
degree range...quite comfortable for April.
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
As of 400 AM EDT Friday...
During this portion of the forecast, surface high pressure will be
anchored east of the coast of the Carolinas. As each day passes, a
strong cold front and its parent closed upper low, will approach the
region from the west, with the front arriving on Monday. The parent
low at that time will be crossing the Great Lake region.
The result for our forecast region will be increasing southerly
winds as the pressure gradient tightens between the approaching
front, and the nearly stationary offshore surface high. These
stronger winds will advect both increasing moisture and warmer air
aloft into the region.
On Saturday, we are still expecting record, or near record, high
temperatures across the region thanks to the increasing warm air
advection. Please reference the CLIMATE section of this discussion
for details. Isolated showers or thunderstorms will be possible by
mid-day and continue into the afternoon, especially along and west
of the crest of the Blue Ridge.
Saturday night into Sunday, the warm air advection will continue.
However, moisture will still be on the increase in the from of
increased cloud cover. Sunday is expected to be cooler than Saturday
thanks to these clouds, along with isolated showers and storms
across the mountains.
Sunday night into Monday, low level winds increase significantly
ahead of the approaching cold front. By Monday morning, guidance
ranges from having anywhere between a 35 to 50 kt 850mb southerly
wind overhead. Anticipate a gustier day, along with increased low
level shear. Cloud cover will continue to be abundant with
increasing chances of showers and storms through the day. The
increased shear will lend itself towards an increased chance of
On Monday night, the front passes quickly to our east. Expect
decreasing cloud cover, and drier and cooler air to progress into
Temperatures during this portion of the forecast will be above
average during, with each day`s average slightly cooler than the
prior day. On Monday, record warmth is expected with a mix of the
mid to upper 80s across the region. By Monday, highs in the upper
60s to lower 70s over the mountains with mid to upper 70s over the
Piedmont. Low temperatures Saturday night and Sunday night will be
fairly uniform with readings in the low to mid 60s. Monday night
behind the front, low to mid 50s are forecast.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 400 AM EDT Friday...
A general area of troughiness remains across the East Coast of the
U.S. while high pressure at the surface builds into the area.
Primarily dry and slightly above normal temperatures are expected
Tuesday and Wednesday. By Thursday, a shortwave trough progressing
through the broader trough pattern, will move into and through the
Lower Mississippi then Tennessee Valleys. The result will be
increasing clouds, better chances of showers and storms, and cooler
temperatures on Thursday for the region.
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --As of 745 AM EDT Friday...
Generally expecting VFR conditions through the TAF period with
some MVFR possible overnight with fog/stratus development at
KBCB and KLWB. There is some uncertainty as to the chances for
showers/thunderstorms tonight mainly along and north of the
Interstate 64 corridor as convection develops upstream and
slides along a warm front. The majority of guidance is keeping
the frontal boundary and associated convection to our north, but
some meso guidance has the convection clipping the northern
portion of the area. Believe the most likely scenario is for the
warm front and convection to remain to our north, but an
outflow boundary from this convection will sink into the region
and may trigger a showers or thunderstorm in a small time
window around Midnight. Will use VCTS at KLWB to cover this with
no mention of showers/thunder elsewhere. Conditions tomorrow
will be quite unstable in the hot and humid airmass but there is
significant capping aloft. In the absence of synoptic forcing
to break the cap, will have to rely on orographic
effects/differential heating to enhance convergence and do not
expect this to be overly effective. So aside from an isolated
shower/storm late in the day mainly in the mountains, expecting
a dry day and will keep mention of precipitation out of the TAFs
for the latter portion of the valid period. Winds will
generally be light
Extended Aviation Discussion...
High pressure should build off the Southeast coast during this
weekend. Other than the potential for MVFR/IFR morning fog at
the usual river valley locations, VFR conditions should prevail
Saturday and Sunday. As a low pressure system approaches from
the west late Sunday and Sunday night, the potential for
afternoon showers and thunderstorms will increase. The cold
front associated with this system should reach the Appalachian
Mountains by Monday and depart offshore by Tuesday morning. As
such, expect the best chance of MVFR conditions during the
-- End Changed Discussion --
Potential for high temperature records to be broken Saturday,
Roanoke 89/1915 89
Lynchburg 88/1974 90
Danville 91/1981 89
Bluefield 83/1996 86
Blacksburg 83/1974 86