Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 271028
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
630 AM Sat EDT May 27 2017

.SYNOPSIS...
A surface trough will be located over the Piedmont this afternoon
through Sunday. An upper level disturbance will cross the region
this afternoon and early evening, followed by another disturbance
Sunday afternoon.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 244 AM EDT Saturday...

There is a slight risk of severe thunderstorms this afternoon and
evening.

Westerly flow in the mid levels will be increasing to 40-45kt this
afternoon from the mid-Mississippi valley east across NC/VA. At the
surface, low level moisture will be on the increase with surface dew
points forecast to reach into the lower to mid 60s this afternoon.
With ample sunshine expected, strong heating will result with
temperatures to reach the 80s by noon, and the upper 80s by peak
heating. Resulting MLCapes on the order of 2000+ J/KG will result.
Any approaching, hard to time disturbance in the increasing
westerlies will combine with the aforementioned parameters to
support the development of scattered thunderstorms this afternoon,
mainly over the western and northern Piedmont into the northern
Coastal Plain. Considering the expected favorable elevated mixed
layer (EML) and the degree of instability expected, some of the
thunderstorms will become strong with at least isolated severe
storms expected. The main hazards are expected to be large hail and
damaging wind gusts.

Just about all the convection allowing models depict scattered
thunderstorms this afternoon, with the main area of concern over
areas from the Triad to the Triangle, with lesser chance of severe
storms from the Sandhills to the Southern Coastal Plain, which is
expected to be displaced from the higher severe weather parameters.

A few of the storms may linger into the evening, otherwise a lull in
the convection is expected tonight. However, areas to our west will
have to be watched in the fast flow aloft as storms upstream may be
able to make it east of the Mountains due to the lingering
instability and strong steering flow. Lows tonight in the mid 60s to
near 70 (where it does not rain).

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 244 AM Saturday...

Isolated severe storms possible Sunday afternoon and evening.

While the main focus for severe convection may be more over
Tennessee/Kentucky, a few storms or even short lines of storms may
cross the Mountains and develop SE of the Blue Ridge, into the
Piedmont during the afternoon and evening. The development to the SE
should be encouraged by strong afternoon heating and resultant
instability again along and east of the Blue Ridge, with a forecast
maximum of instability over central NC. Dew points in the mid to
upper 60s along with temperatures forecast to reach the mid to upper
80s, will result strong instability over the NC/VA Piedmont east
through the Coastal Plain. This will be a favorable environment for
strong to locally severe storms again Sunday.

Convection is expected to weaken and decrease Sunday night as the
region gets convectively overturned and/or nighttime stabilization
develops. Lows generally in the 65-70 range again expected.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 350 AM Saturday...

A deep mid/upper level trough is again expected to develop across
the eastern half of the country next week, with the deep mid/upper
low expected to slowly wobble eastward across south central Canada
to southeast Canada. This will drive another cold front into central
NC on Monday. Afternoon low level thickness values support high
temps above normal for Monday, generally ranging from the mid to
upper 80s NW to the lower to mid 90s SE. A cold front driven by an
embedded s/w in the cyclonic flow around the deep mid/upper low,
will be the focus for strong to severe storms Monday
afternoon/evening. With MLCAPE values of expected to range from 1500
to 2500 J/kg and deep layer shear on the order of 40 to 50 kts,
expect we will have the potential for supercells with the main
threat of damaging winds and large hail. Thus, SPC has most of our
area in a slight risk for severe storms Monday.

The surface front will settle southeastward and stall and weaken
across eastern portions of NC Monday night into Tuesday. Lingering
mostly diurnal chances/slight chances for showers and storms will be
possible from mid to late week as quick moving  low amplitude (hard
to time) disturbances move through the l/w trough. Temps will
generally be near to slightly above normal during this time frame,
with highs generally in the 80s, lows in the 60s.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
As of 630 AM Saturday...

A disturbance aloft will bring a chance of thunderstorms to most
areas this afternoon into the early evening. Otherwise, VFR
conditions are expected through 12z/Sunday.

Outlook: A series of upper level disturbances along the frontal zone
will nudge the front south into the area Sunday. There be a chance
of mainly late day storms on Sunday, and again on Monday through
Wednesday as a cold front slowly approaches from the west and
potentially stalls over the area.

&&

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

&&

$$

SYNOPSIS...Badgett
NEAR TERM...Badgett
SHORT TERM...Badgett
LONG TERM...BSD
AVIATION...Badgett



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