269
FXUS62 KRAH 201754
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
152 PM EDT Mon May 20 2024

.SYNOPSIS...
High pressure will remain along the East Coast through Wednesday
before a cold front approaches the region Thursday and brings
unsettled weather into the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 145 PM Monday...

Weak high pressure is currently centered along the coast of New
Jersey. This has allowed the wind to continue out of the northeast,
providing slightly below normal temperatures. A wide area of low
stratus from early this morning has transitioned to diurnal cumulus,
with slightly greater coverage across the eastern half of the
forecast area. These clouds should quickly dissipate around sunset,
leaving clear skies during the evening and into the overnight hours.
Considering there has been minimal change in the air mass, expect
that some cloud cover should regenerate overnight as temperatures
cool off. However, think that the coverage of clouds will be a bit
less than last night, primarily affecting areas along and east of I-
95. There could be some some patchy fog around, but there is not
enough confidence to include this in the forecast. Tonight`s low
should be similar to last night`s values and the coolest out of the
next seven days, in the 50s.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 355 AM Monday...

A weak mid-level trough will move across the cntl Appalachians and
Middle Atlantic through 12Z Wed, while ridging will otherwise extend
across the Southeast. Surface high pressure that will initially
extend along the Middle Atlantic coast will drift offshore and
result in the development of sely/"return" flow Tue afternoon and
mainly calm Tue night. High temperatures should respond and increase
into the lwr-mid 80s, followed by another night of strong
radiational cooling into mostly the mid-upr 50s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 152 PM Monday...

The extended continues to favor increasing chances of showers and
storms as we end the week and go into the weekend. Temperatures will
be on the rise, as will humidity levels Thu-Sat.

Ridging aloft over the region Wed will transition to a WSW flow Thu
into Sat as a trough over the upper Midwest slowly tracks into
eastern Canada by the start of the weekend. Southwesterly surface
flow will return Wed and persist through at least Fri as high
pressure slides offshore. Temperatures Wed into Fri will range from
the upper 80s to low 90s, some 5-10 degrees above normal.

As the aforementioned trough moves east, shortwave energy will start
to spread south from the TN/OH valleys and skirt across NC/VA as
early as Thu evening. We retained the chance of showers/storms
during this period, with highest chances across the north, in closer
proximity to a slowly moving boundary. Instability does not appear
that high but could see a strong storm or two with increasing shear
aloft.

Deterministic and probabilistic data appear in at least moderate
agreement for a late-week convective complex initially forming over
the southern Plains reaching our area late Fri and lingering into
Sat. The GFS/ECMWF/CMC all show this MCS/shortwave moving through
during peak heating Fri. This would potentially be the better chance
of strong to severe storms given 30-40 kts of 0-6 km shear and
upwards of 1500 J/kg of CAPE. The storm chance should linger into
Sat as the system remains overhead. Thus, our highest rain chances
are Fri-Sat. There could be a heavy rain threat as well given PW`s
near the 90th percentile at 1.5 inches.

It would appear models and their ensembles show some degree of drier
westerly flow building back in Sun as the shortwave moves offshore,
but lingering instability should warrant at least a chance of
diurnally driven storms Sun. Another system could approach early
next week, but there is more spread in the guidance at this time
frame such that we kept storm chances mainly during peak heating.
Temperatures should remain in the 80s through the remainder of the
period.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
As of 130 PM Monday...

TAF period: There are some lingering MVFR ceilings in the region,
but expect that all locations should generally have low VFR diurnal
cumulus through the afternoon. Conditions will clear out tonight,
then another round of restrictions are expected late tonight into
Tuesday morning. RWI is favored for restrictions based on
climatology and is the only site with IFR restrictions forecast.
Elsewhere, blended guidance and persistence from observations this
morning, giving a tempo site at other terminals for MVFR fog. Wind
will continue to be out of the northeast through the period,
becoming lighter/calm overnight.

Outlook: Wednesday morning could have yet another round of
restrictions, although most guidance is showing that most
restrictions should be contained to the eastern third of the state,
locally only impacting RWI. Otherwise, the forecast will be dry
through Thursday afternoon, then diurnally driven
showers/thunderstorms are expected into the weekend.

&&

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

&&

$$
SYNOPSIS...Green
NEAR TERM...Green
SHORT TERM...MWS
LONG TERM...Kren
AVIATION...Green