Special Weather Statement, NWS Raleigh, NC

Area Forecast Discussion
National Weather Service Raleigh NC
200 PM EDT Wed Jul 5 2017

.SYNOPSIS...
An upper level low will track slowly east across the Mississippi
river valley tonight and gradually approach the Appalachians from
the west late Thursday into Thursday night.

&&

.NEAR TERM /Through Tonight/...
As of 135 PM EDT Wednesday...

Rich moisture, moderate diurnal destabilization, favorable low-level
convergence and weak DPVA attendant the deamplifying shortwave invof
the NC/VA border will continue to support development of convection
in the N Piedmont/NE Coastal Plain this afternoon and early evening.
Confidence of convection decreases south of Triangle region where
forcing will be weaker and predominately confined to shallow
convergence within a broad surface low over central NC. Convection
allowing models suggest that convection developing in the N
Piedmont/NE Coastal Plain early this afternoon will gradually
propagate S/SW via outflow into the Sandhills by 00Z this evening.
With steep low-level lapse rates and moderate DCAPE (~1000 J/kg)
expected south of the Triangle this afternoon, the aforementioned
scenario appears very reasonable. Regardless, expect activity to
wane by or shortly after midnight in association with nocturnal
cooling and subsidence in the wake of the deamplifying shortwave as
it progresses east of central NC.

Weak shear will persist south of the Triangle, however, more
substantial low/deep-layer shear will be possible in the far N
Piedmont/NE Coastal Plain this afternoon as mid-level flow
accelerates in advance of the deamplifying shortwave and surface
winds back invof the effective front. To the south, steep low-level
lapse rates, moderate DCAPE, high PWAT and ~25 kt H7 flow suggest a
greater potential for severe convective downbursts (in comparison to
previous days). Locally heavy rainfall /isolated flash flooding/
will remain possible, primarily in urban and other flood prone areas
along/north of Hwy 64.

&&

.SHORT TERM /Thursday and Thursday Night/...
As of 135 PM EDT Wednesday...

An upper level low over the central MS river valley will deamplify
and track slowly east into western TN/KY during the day Thu and the
western slopes of the Appalachians by 12Z Fri. The MSLP gradient
will begin to tighten over the Carolinas as the aforementioned wave
approaches the mountains from the west, with unidirectional WSW/SW
flow throughout the column. With small amplitude waves in SW flow
aloft expected to remain well N/NW of central NC and very little in
the way of low-level convergence, expect dry conditions to prevail
over the majority of central NC. Isolated convection cannot be ruled
out invof the seabreeze in the far SE Coastal Plain Thu afternoon,
nor can it be ruled out in the W/NW Piedmont where isolated mountain
convection may drift downstream via 20-30 knot mid-level flow. With
such weak forcing, convection will be diurnal in nature and should
quickly wane after sunset. Expect highs 90 to 95 with lows Thu night
several degrees warmer than previous nights, in the mid 70s, due to
a strengthening MSLP gradient and persistent southwesterly breeze.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 200 PM Wednesday...

The general upper air pattern for this part of the forecast will be
characterized by high pressure over the four corners region of the
U.S. with a trough over the east coast. A series of disturbances
will pass over the region during this time, resulting in some
unsettled weather. The usual diurnal timing of convection, best
chances in the afternoon and evening with a lull overnight, will
prevail.

A shortwave will move over Central NC on Friday, with best chances
for convection will be ahead of the surface boundary associated with
the upper wave as it progresses through the area from the northwest.
More of the same can be expected on Saturday and Saturday night
ahead of an approaching cold front, though the poor diurnal timing
may limit the chances of convection. High in the upper 80s to mid
90s Friday and Saturday, lows in the low to mid 70s Friday nights.

The aforementioned cold front will surge southward into Central NC
Sunday. Latest medium range models bring the front all the way
through Central NC, which would keep the majority of the region dry,
however if it does stall over the area Sunday night into Monday,
convection would be possible in the southeast. As for temperatures,
Lows decrease a bit for Saturday and Sunday nights, mid 60s to low
70s, upper 60s to low 70s Monday and Tuesday nights. Expect highs
Sunday through Tuesday in the mid to upper 80s, upper 80s to around
90 degrees on Wednesday. Chances for precipitation will increase
again for the middle of the week, but there is too much uncertainty
to get into specifics at this time.

&&

.AVIATION /18Z Wednesday through Monday/...
As of 135 PM EDT Wednesday...

Through 18Z Thursday: Convection will continue to develop across
northern areas as an upper level disturbance and attendant low
pressure system track east along or near the NC/VA border.
Confidence is lower with regard to whether or not convection will
affect areas south of the Triangle.  Low ceilings and fog will be
possible once again at the end of the TAF period, primarily at
northern terminals (INT/GSO/RDU/RWI) where rainfall is most likely
this afternoon and evening. Any low clouds will dissipate by 14Z
Thursday followed by VFR conditions.

Looking Ahead: VFR conditions will prevail through 12Z Fri.
Southwest winds will increase to 10-15 knots with gusts up to 20
knots Thu afternoon, decreasing to 7-12 knots Thu night. Southwest
winds will increase to around 15 knots with gusts up to 25 knots
during the day Friday as the MSLP gradient tightens in assoc/w a
compact low pressure expected to track east along or just south of
the Mason-Dixon line. Convection will be possible at all terminals
Fri aft/eve. The strongest storms will be capable of producing
surface winds gusts AOA 50 knots. Diurnal convection and early
morning low ceilings will remain possible through Monday.

&&

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

&&

SYNOPSIS...Vincent
NEAR TERM...Vincent/Franklin
SHORT TERM...Vincent/Franklin
LONG TERM...KC
AVIATION...Vincent/Franklin

Hazardous Weather Outlook
National Weather Service Raleigh NC
548 AM EDT Wed Jul 5 2017

NCZ021>025-038>043-073>078-083>086-088-089-061000-
Forsyth-Guilford-Alamance-Orange-Durham-Davidson-Randolph-Chatham-
Wake-Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson-
Richmond-Scotland-Hoke-Cumberland-Sampson-
548 AM EDT Wed Jul 5 2017

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Today and Tonight.

Scattered showers and thunderstorms may produce locally heavy
rainfall this afternoon and evening. Isolated flash flooding will be
possible, primarily north of Highway 64 in urban areas and other
flood prone locations. Additionally, a few storms could become
severe, with a primary threat of damaging winds.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Isolated severe thunderstorms and locally heavy rainfall will be
possible Friday afternoon and evening as an upper level disturbance
and attendant low pressure system track east across the Mid-Atlantic.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

NCZ007>011-026>028-061000-
Person-Granville-Vance-Warren-Halifax-Franklin-Nash-Edgecombe-
548 AM EDT Wed Jul 5 2017

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Today and Tonight.

Numerous showers and thunderstorms are expected to develop this
afternoon as an upper level disturbance and associated low pressure
system track east in vicinity of the Virginia border. A few storms
could become severe, with a primary threat of damaging winds. A
brief, isolated tornado cannot be entirely ruled out. Locally heavy
rainfall and isolated flash flooding will also be possible,
primarily in urban areas and other flood prone locations.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Isolated severe thunderstorms and locally heavy rainfall will be
possible Friday afternoon and evening as an upper level disturbance
and attendant low pressure system track east across the Mid-Atlantic.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Vincent

Special Weather Statement
National Weather Service Raleigh NC
433 PM EDT WED JUL 5 2017

NCZ011-052130-
Halifax NC-
433 PM EDT WED JUL 5 2017

...a strong thunderstorm will affect portions of central Halifax
County Until 530 PM EDT...

At 432 PM EDT, Doppler radar was tracking a strong thunderstorm near
Halifax, moving east at 5 mph.

Wind gusts up to 50 mph will be possible with this storm.

Heavy rain and minor flooding and deadly cloud to ground lightning
will also be possible with this storm.

Locations impacted include...
Halifax, Enfield, Weldon, Tillery and South Weldon.

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.

Locally heavy rain will quickly reduce visibility and result in
ponding of water on roadways, standing water in low lying areas, and
minor flooding of creeks, streams, and areas of poor drainage.
Drivers are urged to slow down and use extra caution to avoid
hydroplaning, especially in urban areas where prolonged heavy rain
can quickly lead to flooding.

Cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3642 7759 3642 7756 3640 7754 3637 7755
      3634 7759 3632 7757 3630 7754 3631 7750
      3632 7747 3632 7744 3629 7741 3626 7741
      3625 7738 3621 7739 3614 7737 3619 7772
      3628 7778 3640 7779 3643 7759
TIME...MOT...LOC 2032Z 264DEG 6KT 3630 7764

77