Special Weather Statement, NWS Raleigh, NC

Area Forecast Discussion
National Weather Service Raleigh NC
305 PM EDT THU JUN 30 2016

.SYNOPSIS...
A moist and unstable air mass, combined with a stalled surface
front, will persist across the region through the Fourth of July,
resulting in scattered showers and thunderstorms, primarily during
the afternoon and evening hours.

&&

.NEAR TERM /through tonight/...
As of 305 PM Thursday...

Latest surface map shows a couple of weak frontal zones, one across
the SE CWA (signified by a pressure weakness and wind shift) with
another just to the north and west of the area (denoted by a diffuse
dewpoint discontinuity). Convective initiation is finally underway
over central NC, having been hindered earlier by a weak cap aloft
and lingering CINH, especially over the NW CWA where stubborn
morning stratus limited insolation and subsequent destabilization.
PW progs from this morning were also a bit too ambitious, showing
values rising to 125-150% of normal when in fact the observed PW
(according to blended TPW imagery) is near or just slightly above
normal this afternoon, and this may have also helped to delay
convection. MLCAPE has grown to 1000-1500 J/kg with effective bulk
shear having risen to 30-35 kts, both highest east of Highway 1, and
while mid level lapse rates remain marginal at 5.5 C/km, the low
level lapse rates are 7-8 C/km in the east and rising / spreading
westward with the diminishing stratocu. So we should see convection
growing in spatial extent over the next few hours, focused mainly
across the southern/SE CWA and in the western Piedmont, with upper
divergence in the right exit region of a southwesterly jet extending
from the mid-Atlantic offshore perhaps adding broad forcing for
ascent to augment thermodynamic lift. Will maintain a 30-50%
coverage for now and monitor the evolution of storm coverage. A few
strong to severe storms remain possible, given downdraft CAPE
already at 800-1100 J/kg, with rising CAPE in the -10C to -30C layer
to 200-400 J/kg so far, and we've already seen a splitting supercell
over western SC. Coverage and intensity should gradually decrease
late tonight with reduced deep layer shear and loss of heating,
although scattered showers and isolated storms should persist
overnight given the moist column and persistent elevated
instability. Lows tonight upper 60s to lower 70s. -GIH

&&

.SHORT TERM /Friday and Friday night/...
As of 230 PM Thursday...

The weakening surface frontal zone is likely to be situated just to
our NW Fri, with the column remaining rather moist over the SE CWA.
Strong shortwave energy swinging through the Great Lakes will bring
the axis of the longwave trough eastward through the mid-Atlantic
region and into the Northeast states by Fri evening, with a slightly
lagging surface cold front moving to the Appalachians Fri night. PW
will remain elevated east of Highway 1 but not excessively so, while
western sections will see PW values near or just slightly above
normal. Only eastern sections are apt to see notable mid level DPVA
(and even this will be weak), and the significant height falls and
mid level lapse rates should brush by to our north. These factors
should limit the coverage and strength of convection over the
northwest half of the CWA Fri into Fri evening. Models depict
moderate instability in the east half in the afternoon, reaching
1500-2000 J/kg of MUCAPE, along with marginal but improving deep
layer shear to around 25-30 kts, so a few strong storms are possible
in the Coastal Plain, with sounding analogs suggesting that large
hail and perhaps a weak tornado or two are possible. Thicknesses
will be near normal so expect highs in the upper 80s to lower 90s.
Expect decreasing precip coverage by midnight with little to no
shower chances overnight with the loss of heating and resulting
stabilization and drier mid level air moving in from the west. Lows
68 to 73 under partly cloudy skies. -GIH

&&

.LONG TERM /Saturday through Thursday/...
As of 130 PM Thursday...

A very unsettled pattern for the long term as a cold front will
stall out over North Carolina this weekend and into next week. While
the front may initially make it through the area, it appears it will
creep back to the north for the weekend and keep us in the warmer
airmass. Early in the day Saturday may be fairly dry but by
afternoon the boundary will become active and convection will bring
showers and thunderstorms to the area. Models are in fairly good
agreement about keeping the stalled front in place for several days
as several short wave impulses move along the front, providing extra
forcing, particularly in the afternoons and early evenings when
diurnal heating and instability are maximized. This means that there
will be continued rain chances through the holiday weekend with some
strong to severe storms possible, particularly Sunday and Monday
afternoons when surface based CAPE values begin to approach 1500-
2000 J/kg and bulk shear values rise above 30 kts. In addition PW
values at or above 2 inches for much of the time period and the
possibility of training storms in the stacked westerly flow will
present and increasing heavy rain and flooding threat as time goes
on. At this time WPC is indicating 7 day total precipitation values
of 2-3 inches across the area. That being said, with the
precipitation convective in nature it is important to note that not
everyone will see that much rain, but some could actually see more
if showers and thunderstorms continue to train over a specific
location. Highs during this period mainly in the mid 80s to near 90
degrees, although Sunday could be a couple degrees cooler.

Models diverge on the handling of a low pressure system coming out
of the Mississippi Valley on Monday night into Tuesday but the ECMWF
has been far more consistent on keep the low subdued as it moves
quickly through VA on Tuesday. The GFS is still producing a deep
stronger low that causes a mid level trough to form and thus slows
down the steering flow considerably. Compared to last run, the GFS
is weakening this feature by 5 mb and appears to be backing off this
scenario a little bit. Therefore will continue on with the ECMWF
solution. In either scenario the upshot is the same. Diurnal
thunderstorms continuing through the end of the forecast period.
Temperatures in the upper 80s to low to mid 90s.

&&

.AVIATION /12Z Thursday through Monday/...
As of 1255 PM Thursday...

MVFR to IFR cigs persist at INT/GSO, with VFR conditions elsewhere.
INT/GSO will see a transition to MVFR at both sites by 19z, and VFR
cigs are expected there by 21z. Otherwise, VFR conditions will hold
through the evening, although the development of scattered storms
this afternoon lasting through the evening could bring a period of
MVFR or IFR conditions lasting a couple of hours. A frontal zone
currently stretching SW to NE across NC will waver a bit back and
forth today before shifting just NW of the area tonight, ensuring a
warm and moist air mass over central NC which will facilitate
scattered showers and storms. FAY/INT/GSO should be the first to be
affected by storms during the mid and late afternoon, followed by
RDU/RWI into the evening. Strong gusty and erratic winds can be
expected in and near storms, with a period of MVFR or IFR
conditions. Numerous mid and high clouds leftover from storm
clusters are anticipated later tonight, with a chance of MVFR cigs
and MVFR vsbys in fog late tonight (08z-13z) at all locations.

Looking beyond 18z Fri, VFR conditions will rule much of the time,
however there will be a daily risk of scattered storms across all of
central NC, focused from mid afternoon until around midnight, as
another front approaches from the northwest and stalls out just to
our northwest. Sub-VFR conditions will be possible in and near any
such storms. Rain chances will be greater toward the end of the
period (Mon through Tue) as an upper level disturbance approaches
from the west. Late-night/early-morning IFR/LIFR stratus and fog
are possible both mornings as well. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

SYNOPSIS...JB
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Ellis
AVIATION...Hartfield

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE RALEIGH NC
333 PM EDT THU JUN 30 2016

NCZ008>011-025>028-041>043-077-078-088-089-011100-
GRANVILLE-VANCE-WARREN-HALIFAX-DURHAM-FRANKLIN-NASH-EDGECOMBE-WAKE-
JOHNSTON-WILSON-HARNETT-WAYNE-CUMBERLAND-SAMPSON-
333 PM EDT THU JUN 30 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

AN ISOLATED STRONG TO SEVERE STORM IS POSSIBLE THROUGH THIS
EVENING. STRONG WIND GUSTS AND SOME HAIL ARE POSSIBLE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A FEW STRONG TO SEVERE STORMS ARE POSSIBLE FRIDAY AFTERNOON AND
EVENING... WITH A PRIMARY THREAT OF LARGE HAIL. STRONG TO SEVERE
STORMS ARE POSSIBLE AGAIN ON MONDAY... AND THESE STORMS WILL BE
CAPABLE OF PRODUCING DAMAGING WIND GUSTS... LARGE HAIL... AND
LOCALLY HEAVY DOWNPOURS... ESPECIALLY DURING THE AFTERNOON AND
EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

NCZ007-021>024-038>040-073>076-083>086-011100-
PERSON-FORSYTH-GUILFORD-ALAMANCE-ORANGE-DAVIDSON-RANDOLPH-CHATHAM-
STANLY-MONTGOMERY-MOORE-LEE-ANSON-RICHMOND-SCOTLAND-HOKE-
333 PM EDT THU JUN 30 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A FEW SEVERE STORMS ARE POSSIBLE LATE THIS AFTERNOON THROUGH THIS
EVENING. DAMAGING WIND GUSTS OVER 60 MPH AND LARGE HAIL OVER ONE
INCH IN DIAMETER MAY OCCUR.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

STRONG TO SEVERE STORMS ARE POSSIBLE ON MONDAY. THESE STORMS MAY BE
CAPABLE OF PRODUCING DAMAGING WIND GUSTS... LARGE HAIL... AND
LOCALLY HEAVY DOWNPOURS... ESPECIALLY DURING THE AFTERNOON AND
EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
619 PM EDT THU JUN 30 2016

NCZ086-302300-
HOKE NC-
619 PM EDT THU JUN 30 2016

...A STRONG THUNDERSTORM WILL AFFECT PORTIONS OF HOKE COUNTY UNTIL
700 PM EDT...

AT 619 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR RAEFORD...MOVING NORTHEAST AT 5 MPH.

WIND GUSTS AS HIGH AS 50 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
RAEFORD...ANTIOCH...ROCKFISH...SILVER CITY AND BOWMORE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEEK SHELTER IN A NEARBY BUILDING OR VEHICLE. WIND GUSTS AS HIGH AS
50 MPH ARE CAPABLE OF KNOCKING DOWN SMALL OR WEAKENED TREES AND
BLOWING AROUND TRASH CANS...POTTED PLANTS...LAWN FURNITURE AND OTHER
LIGHT OUTDOOR OBJECTS.

&&

LAT...LON 3489 7935 3492 7935 3493 7936 3494 7935
      3495 7936 3496 7936 3500 7941 3519 7925
      3496 7903 3488 7918 3487 7928
TIME...MOT...LOC 2219Z 231DEG 5KT 3496 7931

VINCENT