Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 270556

National Weather Service Raleigh NC
156 AM EDT Tue Jul 27 2021

A surface trough will will waver across the region through


As of 950 PM Monday...

Thunderstorms still appear likely through midnight to the northeast
of Raleigh, moving in from southern Virginia. However, the severe
thunderstorm watch issued earlier for the NW Piedmont was cancelled
at 7pm, the slight risk of severe weather has been removed by the
Storm Prediction Center, and the threat for any severe weather or
flooding seems likely to be over. Some gusty winds will still be
possible with the remaining thunderstorms. A slight chance of
showers remains after midnight, but nothing organized is expected.
Some areas of fog will be possible, particularly where heavier
rainfall occurred earlier (Stanly, Franklin, Nash, and Halifax
counties). Conditions will remain quite muggy overnight, with lows
dropping into the low to mid 70s.


As of 230 PM Monday...

Another low-amplitude shortwave trough will traverse the
mid-Atlantic region late Tuesday. Meanwhile, the surface boundary
will remain draped across the area.

This boundary will likely provide the primary focus for convection
amidst a very moist and unstable regime. Models shift the highest
+2.0" PWATS across south/southeastern portions of the forecast area,
and this is where the model consensus keep the highest PoPs. Shear
is not as strong as today, so any severe threat should be
unorganized, in a generally pulse severe regime.

Highs in the upper 80s to lower 90s with heat indices in upper 90s
to near 100 across the southern zones.

Convection should abate from loss of heating Tuesday evening with
mostly dry conditions Tuesday night. Lows in the upper 60s north to
lower/mid 70s south.


As of 355 PM Monday...

The surface boundary will drop south of central NC on Wednesday,
with the Piedmont trough remaining over the area. As the mid/upper
trough moves east and offshore, dry NW flow aloft will result in
decreased convection chances on Wednesday. However, both the GFS and
ECMWF show enough lingering moisture for slight to low chance POPs
across the area outside of the northern Piedmont. The best chance
for any showers and storms is in the far south and east. Increasing
thicknesses will bring temperatures a few degrees higher than
Mon/Tue, with highs in the lower-to-mid-90s.

With the shortwave trough moving completely out of the area, and the
strong mid/upper ridge over the Plains extending farther east,
height rises aloft and subsidence will result in hot and dry
conditions on Thursday. Forecast highs are in the mid-to-upper-90s,
with maximum heat indices in the upper-90s to lower-100s.

A cold front will approach from the north on Friday, bringing a
better chance of showers and storms once again. Convection chances
will be partly dependent on the timing of the front, with the GFS
bringing it through during peak heating compared to the ECMWF which
holds it off until Friday night. Even still the GFS and its
ensembles have trended drier closer to the ECMWF, so continue low
chance POPs at this time. Temperatures will also be dependent on
frontal timing, but highs could reach the upper-90s in the south
once again.

As the cold front stalls south of the area, Saturday will be drier,
but with a broad mid/upper trough over the Eastern US, isolated
showers and storms still cannot be ruled out with the best chance in
the south. Sunday and Monday have low chance POPs as a shortwave
rotates around the base of the trough, and another cold front then
approaches the region. Forecast highs from the weekend into Monday
are seasonable, in the upper-80s to lower-90s.


As of 155 AM Tuesday...

An outflow boundary from rain-cooled air, and associated lift, has
resulted in the development and maintenance of small cluster of
showers/storms from near HRJ to JNX to GWW this morning; and some of
these may affect RWI and FAY before dissipating in the next few
hours. That rain-cooled and associated high relative humidity air
will otherwise support areas of IFR-MVFR ceilings until diurnal
heating causes the moist layer to lift and scatter by 14-15Z.
Additional scattered showers and storms are expected to develop this
afternoon primarily across the srn half of NC, including FAY, RWI,
and RDU.

Outlook:  Early-morning sub-VFR fog and low clouds will remain
possible through Fri morning at all sites. While isolated showers
and storms may develop each afternoon, they should be few in number.
A better chance of showers and storms will arrive Fri afternoon with
the arrival of a cold front. Drier VFR conditions are expected to
return Sat as this front settles to our S.




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