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NWS Area Weather Forecast Discussion
County Warning Area [CWA]: RNK
Regional NWS Weather Office: Blacksburg, VA

000
FXUS61 KRNK 282335
AFDRNK

Area Forecast Discussion
National Weather Service Blacksburg VA
735 PM EDT Fri Apr 28 2017

.SYNOPSIS...
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
week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 7:30 PM EDT Friday...

Forecast looks to remain on track. Thunder in western Greenbrier
later tonight looks even less favorable than earlier anticipated
as showers currently pushing toward the region are having
trouble clearing the terrain. Made slight adjustments up for
overnight lows as temps are not falling as fast as previously
forecast and newer guidance is trending warmer.

As of 215 PM EDT Friday...

Satellite imagery showing a Cu field mainly east of the
mountains with some cirrus over the top, but the radar is quiet
and expect it to remain that way into tonight. 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 some low chance POPs extreme north for a 3 to 4 hour
period around Midnight to cover this and keep an eye on trends
to see if fine tuning is needed.

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
some slight/low chance POPs for a shower/storm late in the day
mainly in the mountains, expecting a dry day.

Temperatures will be quite summer-like with lows tonight in the
mid/upper 60s east to upper 50s/around 60 west. Highs on
Saturday will be near 90 east to mid/upper 80s west. Since this
our first taste of real warmth, make sure air conditioning units
are clear of debris before turning them on, and be sure to take
frequent hydration breaks when outdoors on Saturday.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 215 PM EDT Friday...

Large upper ridge off the southeast coast through Sunday night. Low
pressure tracks across Missouri on Sunday with a warm front
extending into Pennsylvania and a cold front over the central and
southern Mississippi Valley. This puts the Mid Atlantic region well
into the warm sector. No organized lift or forcing so will keep
probability of precipitation low through Sunday night.

Models still showing some differences with the timing of the cold
front on Monday. Will keep the highest probability of precipitation
on Monday along with a mention in the Hazardous Weather Outlooks of
strong to severe thunderstorms threat due to a 50-60 knot low level
jet.

Minimum temperatures will be mild on Sunday night with increasing
moisture and mixing from a south wind ahead of the front. Have
stayed just above MAV guidance for lows Sunday night. Front will not
be reaching the foothills and piedmont until Monday afternoon and
evening. This should give enough time, depending on the cloud cover
from upstream, for heating ahead of the front. Raised maximum
temperatures east of the Blue Ridge on Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 215 PM EDT Friday...

Upper low moves through the Great Lakes on Monday night and high
amplitude eastern trough in reinforced Tuesday through Thursday.
00Z ECMWF closes off a low over the Gulf Coast states by Friday
morning, while the GFS is much deeper in the northern stream.

Surface boundary becomes east-west oriented on Tuesday and
Wednesday. Weak waves of low pressure will track east along the
front. will carry a dry forecast Tuesday through Wednesday with near
normal temperatures.

The 00Z ECMWF brings one of these waves and the associated
probability of precipitation into the Mid Atlantic region on
Wednesday night and Thursday. WPC leaned toward the ensembles in
this time frame, tracking a low from the Tennessee Valley Thursday
through the Mid Atlantic states on Friday. This pattern favors below
normal temperatures for both of those day.

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
As of 215 PM EDT Friday...

Generally expecting VFR conditions through the TAF period with
some MVFR possible overnight with fog/stratus development at
KBCB and KLWB. Thunder overnight at KLWB is still possible, but
will likely pass far enough to the north as current METSAT and
radar indicate the bulk of the convection lies north of the warm
front through IN/OH. Unstable conditions will exist tomorrow as
temperatures and dew points will be more reminiscent of summer
rather than of April, however a strong cap should suppress most
convective development. If there will be any thunder it will
likely be very isolated and terrain induced, therefore would
only be in the higher elevation. Due to the isolated nature of
this convection, has for the time being not been mentioned in
the TAFs. Winds will be generally light and southerly during the
TAF period.

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
frontal passage.

&&

.CLIMATE...
Potential for high temperature records to be broken Saturday,
April 29.

 Current record/yearForecast
Roanoke89/191589
Lynchburg88/197489
Danville91/198189
Bluefield83/199685
Blacksburg83/197485

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

$$
SYNOPSIS...MBS
NEAR TERM...JR/MBS
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...JR/MBS
CLIMATE...JR

Forecast Discussion from: NOAA-NWS Script developed by: El Dorado Weather