Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 200646
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
240 AM EDT Tue Jun 20 2017

.SYNOPSIS...
A cold front will track east across the mountains this evening, then
stall over the Carolinas tonight. The front will gradually dissipate
over the region on Tuesday.

&&

.NEAR TERM /Today and Tonight/...
As of 1010 PM Monday...

A lead cold front, and relatively deep convergence axis that extends
through around 850 mb per proximity RAOB and regional VWP data, is
roughly aligned with the wsw to ene-oriented band of training
convection now over the nrn NC Piedmont. Low level moisture
transport, analyzed to be strongest from the nrn NC Piedmont to the
nrn Middle Atlantic coast per RAP/SPC-mesoanalysis 850 moisture
transport data, is forecast to lift newd with a llj now traversing
those areas through 06Z. Low level shear resulting from the presence
of the llj --characterized by 0-1 km bulk shear values of 25-35 kt
and effective SRH around 200 m2/s2-- will remain supportive of
transient supercell/bowing structures along the convective line.
However, the associated risk of severe wind gusts will likely remain
limited due to the presence of weak mid level lapse rates of around
5.5 C/km or less and associated generally weak MLCape of aob 1500
J/KG - and associated limited updraft strength/depth. As such, heavy
rain and a risk of flash flooding will instead pose the primary
hazard overnight.

&&

.SHORT TERM /Tuesday and Tuesday night/...
As of 200 PM Monday...

The cold front progressing into the region late this evening is
expected to stall over central NC tonight and persist during the day
Tue, amidst broad cyclonic flow aloft and rich moisture (PWAT
~2.00"). With the above in mind, expect numerous showers/storms in
vicinity of the stalled front Tue/Tue night, primarily east of Hwy 1
and south of Hwy 64. Little potential for convection is expected
north of the front in the far N/NW Piedmont near the VA border where
a drier airmass (PWAT ~1.50" and dewpoints in the lower 60s) is
progged to be in place during the day Tue. However, even in the
northern Piedmont, isold to sct convection will be possible AOA ~00Z
as the front washes out and moisture returns N/NW toward the
Appalachians. With cloud cover and convection, expect highs in the
lower 80s across most of central NC. Lows Tue night should range
from the mid 60s far N/NW to lower 70s far S/SE. -Vincent

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
As of 147 AM EDT Tuesday...

The chance of showers and thunderstorms will increase again Thursday
as deep subtropical moisture surges northward again around the
Bermuda surface high pressure. The influx of deep subtropical
moisture will be aided by the remnants of the tropical disturbance
that is forecast to get pulled NW into the western Gulf Coast states
Thursday. A broad southerly flow from a wide open Gulf of Mexico
will lead to PW`s increasing again to 2+ inches by Thursday and
Friday, into the weekend and early next week.

Convection should be largely diurnally driven, with likely POP
during the afternoon and evening, then high chance POP`s overnight
Thursday into Monday. Rainfall may be enhanced by a cold front that
is expected to slowly move SE into the region Sunday into Monday.
QPF of 2-4 inches is expected late week into the weekend into
Monday. With the recent heavy rain over portions of the Triad,
Triangle, and the Piedmont in general, a flooding threat may
develop.

Temperatures should be above normal given the very high dew points
in the 70s, keeping nightly lows 70+ and possible 75 in the SE.
Highs should be in the mid 80s NW ranging to lower 90s SE each day,
with some cooling aided by the expected heavy rain and cloudiness
early next week.

&&

.AVIATION /06Z Tuesday through Saturday/...
As of 240 AM Tuesday...

A large area of convection extending from near Roanoke Rapids
southwest through the Triangle to near Charlotte NC is associated
with an approaching cold front. The showers and storms will slowly
shift southeast through daybreak with reduced cigs and vsbys and an
embedded thunderstorm or two. Expect cigs to fall into the MVFR and
possibly IFR range by daybreak in most location with most of the
convection dissipated by this time. Conditions will improve after
sunrise with VFR conditions expected behind the front in the Triad
today at the KINT and KGSO terminals. Near and southeast of the
front, after a periof of VFR conditions this morning, scattered
convection is expected to redevelop this around midday and this
afternoon with the greatest coverage across the Sandhills and
southern Coastal Plain near the KFAY terminal. Another round of low
stratus is likely to develop late tonight.

Looking beyond the 24 hour TAF period...a typical summertime regime
is expected with perhaps greater than climatological coverage during
the period. This pattern will feature scattered diurnal afternoon
and evening convection with periods of early morning stratus. During
the period it appears convective coverage will be more limited on
Wednesday into Thursday and increase into the weekend. -Blaes
&&

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

&&

$$

SYNOPSIS...Vincent
NEAR TERM...MWS
SHORT TERM...Vincent
LONG TERM...Badgett
AVIATION...Blaes


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