-- Discussion containing changed information from previous version are highlighted. --
778
FXUS62 KRAH 190117
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
915 PM EDT Wed Sep 18 2024

.SYNOPSIS...
A weak area of low pressure off the Mid-Atlantic coast will lift
northeast through Thursday and be replaced by high pressure that
will gradually build into central North Carolina through the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
As of 915 PM Wednesday...

The bulk of convective activity so far this evening has largely been
associated with the the dampening upper wave/low moving east along
the NC/SC line. In comparison, convection associated with the weak
front draped across the far northern counties has been more sparse.
Only time will tell if this trend will persist, but hi-res model
guidance indicates that both these features will support a
continued chance of isolated to widely scattered activity well into
the overnight hours.

Low overcast will overspread the area from north to south through
the overnight hours. Some patchy fog may be possible, but guidance
has lowered probabilities of fog in favor of mostly stratus.
Overnight lows will settle in the mid/upper 60s for most areas.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 305 PM Wednesday...

Aloft, the trough situated over the East Coast should slowly slide
eastward through Thu night, but remain along/just off the East Coast
by Fri morn as high pressure builds over the Plains and MS Valley.
At the surface, a low will meander off the northern mid-Atlantic/New
England Coast Thu/Thu night, while high pressure over the ern Great
Lakes ridges swd along the Appalachians. Meanwhile, the low that has
lingered over the northeast NC coast should shift esewd but linger
just off the central NC coast Thu before moving further southeast
over the Atlantic. Expect generally nly/nely flow across central NC
through Thu night. Some showers may linger into Thu morning over the
Piedmont. There could be a brief lull in activity before additional
scattered showers and isolated storms develop Thu aft, mainly along
lingering surface boundaries. Skies may remain mostly cloudy through
Thu morn and into the aft, which could further limit daytime
heating. Highs should top out in the mid 70s to low 80s, but could
be a couple/few degrees higher if cloud cover decreases earlier that
forecast. While the weather should dry out, there should be
lingering partly to mostly cloudy skies Thu night, with lows
expected to range from upper 50s north to mid 60s south.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 245 PM Wednesday...

Overall, the surface pattern for the extended forecast period should
be relatively quiet. At the beginning of the period, high pressure
will be over eastern Canada with a ridge extending to the southeast
across the Carolinas. This will change little through the period
until a cold front approaches the Appalachian Mountains on
Wednesday. However, at mid/upper levels, there will be occasional
ripples of energy moving across the western half of North Carolina.
Friday through Tuesday all show minimal precipitation clipping the
Triad in the ECMWF and GFS ensembles, yet with the exception of
Monday, the deterministic models don`t show any precipitation during
that time period. Having inherited a dry forecast and seeing little
conclusive evidence in the models, am inclined to keep the forecast
dry. However, Will go ahead and put in slight chance pops to the
forecast for Wednesday afternoon across northwestern counties for
the new day 7 forecast with the approaching front. Normal
temperatures for late September are around 80 and 60 - forecast
values are slightly above average for Friday through Sunday, then
near average for Monday through Wednesday.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 750 PM Wednesday...

VFR conditions are largely expected to start the TAF period. The one
exception will be at FAY, where isolated storms have developed
within 5 miles of the terminal. These storms are expected to weaken
over the next few hours, but included a TEMPO for IFR conditions in
the immediate near-term. A trend from VFR to IFR and then LIFR is
expected to commence with the passage of a surface boundary draped
along the NC/VA border. These conditions are expected to develop
across the northern terminals (GSO/INT/RDU/RWI) between 03 and 06z
and between 08-11z at FAY. These IFR/LIFR conditions are largely
favored to be driven by low ceilings. However, some recent guidance
suggests patchy fog possible at FAY, perhaps due to storms
saturating the low-levels prior to the boundary passage. Confidence
on this is low but included a TEMPO for these LIFR conditions. There
could be some isolated storms early Thu near RDU/RWI, with
confidence highest at RDU. Aviation conditions should lift to MVFR
around 15-18z and gradually become VFR by the late afternoon. The
surface boundary will linger over the area Thu and will favor widely
isolated storms, most favored at FAY/RWI and perhaps RDU.

Outlook: Areas of overnight and early morning stratus will remain
possible Fri and Sat mornings. Aviation conditions should largely
trend VFR Sun and Mon.

&&

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

&&

$$

SYNOPSIS...Swiggett
NEAR TERM...CBL/Swiggett
SHORT TERM...KC
LONG TERM...Green
AVIATION...Kren