Special Weather Statement, NWS Blacksburg, VA

Area Forecast Discussion
National Weather Service Blacksburg VA
720 PM EDT FRI JUN 24 2016

.SYNOPSIS...
A weak cold front along with an associated area of low pressure
will drift south through the region tonight. The front slides
south of the area by Saturday morning, allowing high pressure to
slowly build in from the north this weekend. Another cold front
will approach from the west on Monday.

See hydrology section below for additional information regarding
ongoing flooding.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 640 PM EDT Friday...

Only very isolated convection has developed across the forecast
area early this evening. We will be quickly losing the heating of
the day for surface based development. However, outflow from any
showers or storms that develop should help maintain additional
convection into the late evening. The focus should gradually shift
southeast along with the progression of the front. Have reduced
precipitation chances to a mix of isolated and low end chance.

As of 222 PM EDT Friday...

Weak surface front continues to sag slowly south toward the northern
portion of the area and should finally drop into North Carolina
overnight as the shortwave trough to the north slides across. This
should keep the threat for bands/clusters of showers/storms going into
this evening with decreasing coverage after loss of heating. Appears
best chances early on across the northwest closer to the boundary where
will have to watch for continued slow moving bands, and then perhaps
out east where latest analysis shows the best convergence/instability
attm. Models tend to focus on deeper convection in the east over the
next few hours and even keep some lingering low level moisture and shra
threat east of the Blue Ridge overnight as the flow turns more
northeast. Thus kept at least chance pops going into the evening with
some low likelys north/northeast, trending down to just isolated
showers east late. Other concern will be with fog/low clouds
given wet ground conditions and some clearing overnight after
scattered showers. Since confidence low given potential for mid
deck to linger only added some patchy fog west and low clouds
east. Low temps similar to last few nights with values mostly in
the 60s.

Surface front and associated weak low pressure will be to the south on
Saturday with weak high pressure slowly building in from north during
the day. However soundings show low level moisture lingering beneath
drying aloft with a faint shortwave sliding southeast across the west
around the upper ridge to the west. This along with weak low level
convergence per the boundary layer flow turning more east to southeast
supports keeping in some low afternoon pops, mainly Blue Ridge,
although some isolated coverage could occur in the southeast
closer to the residual boundary. Should be a bit cooler behind the
front on Saturday given early clouds and more onshore flow with
highs mostly 70s to lower 80s overall.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 200 PM EDT Friday...

Surface high pressure will gradually shift south and wedge in from the
northeast Saturday night into Sunday as upper heights slowly build back
over the region from the southwest. This should tend to shut down most
convection outside of the far southwest Sunday where weak return low
level moisture will exist. Otherwise looking at enough subsidence to go
with mainly clear/sunny north and partly cloudy with only isolated
showers/storms Saturday night/Sunday. Temps mainly seasonal with lows
in the 60s and highs in the 80s.

High will begin to shift east and weaken later Sunday night into Monday
in advance of the next upstream 5h trough that will propel a surface
cold front into the region by late Monday. Models have trended slower
with the progression of the boundary with the ribbon of deeper pre-
frontal moisture staying to the west Sunday night. Thus continued
slight pops only in the far west for now.

Axis of 1-2 inch pwats will slowly advance through the region Monday
afternoon ahead of the front with guidance showing a decent amount of
lift and subsequent instability espcly given the slower movement. Could
again pose a combo limited heavy rain/severe threat if trends continue
so keeping likely pops west Monday, and out east by late in the
day or early evening. Should again be quite warm/humid by Monday
with highs mostly in the sticky 80s to perhaps around 90
southeast.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 1245 PM EDT Friday...

Return to an eastern troughing regime will be underway early next week
as a secondary cold front crosses the region on Tuesday followed by
drier high pressure later Tuesday into Wednesday night. Still should be
enough moisture to spark a few showers and perhaps a storm in the east
Tuesday before stronger downsloping kicks in behind the front making
for a drier Wednesday. Boundary stalls to the south for the end of the
week making for more uncertainty with possible return moisture as added
shortwave energy rotates around the base of the upper trough. As seen
with this last shortwave trough, models were too strong with push of
cooler/drier air, so trending toward a faster return of enough moisture
for showers/storms Thursday afternoon/Friday as a weak wave perhaps
rides along the front to the south. Temps basically close to seasonal
but could be a bit lower from midweek on, and especially at night
when lower dewpoints should allow for more comfortable midweek
lows in the 50s to lower 60s.

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
As of 715 PM EDT Friday...

A surface cold front is still on track to pass through the region
overnight. Isolated to scattered convection is possible in advance
of the front this evening. Most areas will remain VFR through
about 04Z/midnight. In the wake of the front, look for low level
winds to become northeast and bring moisture up against the crest
of the Blue Ridge. IFR/MVFR clouds are expected to develop from
the central portions of the forecast area and eastward. Patchy
IFR/MVFR fog is also expected. Sub-VFR conditions are expected
through the late morning or early afternoon at most locations
central and east before transitioning to VFR. Some patchy light
showers will also be possible from late tonight through morning
hours nearest the Blue Ridge.

Extended discussion... As of 1233 PM EDT Friday...

High pressure will try to build from the northeast on Saturday,
but there should be enough instability over the mountains for
isolated afternoon showers and thunderstorms during the weekend.
Coverage of these storms should increase by Monday before becoming
more isolated on Tuesday with the passage of another cold front.
Expect a return to more widespread VFR behind the front on
Wednesday. Overall, expect periods of IFR/MVFR within the showers
and thunderstorms and also during potential early morning fog due
to wet soil conditions.

&&

.HYDROLOGY...
As of 311 PM EDT Friday...

Extensive flood damage has occurred especially from Greenbrier
county in West Virginia through Alleghany county in Virginia, and
some roads remain impassable. River levels have crested along the
Greenbrier at Alderson and continue to fall. Water levels should
also continue to recede at Buchanan on the James River into
tonight with gradual rises downstream to near action stage in
spots. These hydro issues will persist into tonight so please see
the latest river flood warnings (WBCFLWRNK) and statements
(WBCFLSRNK) for updates.

&&

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

&&

SYNOPSIS...JH/RCS
NEAR TERM...DS/JH
SHORT TERM...JH
LONG TERM...JH
AVIATION...DS/JH/RCS
HYDROLOGY...JH

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BLACKSBURG VA
346 PM EDT FRI JUN 24 2016

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>044-507-508-252000-
ASHE-ALLEGHANY NC-SURRY-STOKES-ROCKINGHAM-CASWELL-WATAUGA-WILKES-
YADKIN-TAZEWELL-SMYTH-BLAND-GILES-WYTHE-PULASKI-MONTGOMERY-GRAYSON-
CARROLL-FLOYD-CRAIG-ALLEGHANY VA-BATH-ROANOKE-BOTETOURT-ROCKBRIDGE-
PATRICK-FRANKLIN-BEDFORD-AMHERST-HENRY-PITTSYLVANIA-CAMPBELL-
APPOMATTOX-BUCKINGHAM-HALIFAX-CHARLOTTE-MERCER-SUMMERS-MONROE-
EASTERN GREENBRIER-WESTERN GREENBRIER-
346 PM EDT FRI JUN 24 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH
CAROLINA...NORTHWEST NORTH CAROLINA...CENTRAL VIRGINIA...SOUTH
CENTRAL VIRGINIA...SOUTHWEST VIRGINIA...WEST CENTRAL VIRGINIA AND
SOUTHEAST WEST VIRGINIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED STRONG TO SEVERE THUNDERSTORMS COULD OCCUR INTO THIS
EVENING WITH DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
408 PM EDT FRI JUN 24 2016

WVZ507-242100-
EASTERN GREENBRIER-
408 PM EDT FRI JUN 24 2016

...SCATTERED LIGHT TO MODERATE SHOWERS WILL MOVE THROUGH THE AREA...

THROUGH 500 PM EDT...SCATTERED LIGHT TO MODERATE SHOWERS WILL
PROGRESS ACROSS MAINLY THE SOUTHEASTERN PART OF GREENBRIER COUNTY.
MOST OF THE SHOWERS WILL PRODUCE LESS THAN ONE TENTH OF AN INCH...
WITH SOME ISOLATED LOCATIONS EXPERIENCING ONE THIRD OF AN INCH. NONE
OF THIS RAIN ACTIVITY IS EXPECTED TO WORSEN THE FLOOD SITUATION. A
FLOOD WARNING CONTINUES UNTIL 630 PM EDT.

LAT...LON 3776 8026 3774 8026 3772 8025 3768 8033
      3769 8035 3770 8034 3771 8035 3769 8036
      3769 8038 3771 8038 3770 8039 3772 8039
      3769 8046 3770 8047 3769 8052 3772 8062
      3774 8066 3788 8044
TIME...MOT...LOC 2005Z 332DEG 8KT 3783 8043 3772 8061

DS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
823 PM EDT FRI JUN 24 2016

VAZ024-250115-
ROCKBRIDGE-
823 PM EDT FRI JUN 24 2016

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN ROCKBRIDGE COUNTY...

AT 823 PM EDT...A STRONG THUNDERSTORM WAS 8 MILES NORTH OF
BROWNSBURG...MOVING SOUTH AT 25 MPH.

PEA SIZE HAIL IS POSSIBLE WITH THIS STORM...ALONG WITH FREQUENT
CLOUD-TO-GROUND LIGHTNING.

LOCATIONS IMPACTED INCLUDE...
ROCKBRIDGE BATHS...
FAIRFIELD...
VESUVIUS...
AND BROWNSBURG.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

LAT...LON 3793 7920 3789 7915 3785 7914 3785 7915
      3782 7916 3781 7941 3805 7943
TIME...MOT...LOC 0023Z 348DEG 22KT 3805 7928

RAB