420
FXUS62 KRAH 041901
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
300 PM EDT Tue Jun 4 2024

.SYNOPSIS...
A series of mid-level disturbances will move east and interact with
an unseasonably moist airmass over NC through Thursday. A pre-
frontal trough and cold front will move across the area Thursday
evening through early Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 300 PM EDT Tuesday...

A shortwave trough centered over the western NC this afternoon is
expected to continue eastward through the afternoon and evening. As
surface high pressure off the Mid-Atlantic coast continue to pump
warm moist air into the region showers and storms will continue to
develop over the next few hours. Expect storms to be pulse-type
especially over the NW Piedmont region as the shortwave trough moves
closer to the region. A second round is possible later tonight as an
approaching MCV from the SW could re-develops closer to the region.
While coverage is isolated this afternoon and evening, PoP chances
slowly reduce, not completely diminish overnight into early
Wednesday. WPC has maintained a marginal ERO for excessive rainfall
across the much of the area with the greatest threat for flash
flooding in urban/flood-prone areas. Lows overnight will range from
mid to upper 60s.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 225 PM Tuesday...

Upstream MCVs will continue to influence central NC`s sensible
weather during this period as Bermuda high pressure remains in
control.

The first MCV, currently over central TN, will likely traverse
central NC during the 1st half of the diurnal cycle. Isolated to
widely scattered weak convection is possible as this feature moves
through the area during what is otherwise poor diurnal timing.

In the wake of the lead MCV, possible remnants of another MCV
associated with the linear cluster over NE TX and lower MS Valley,
could potentially move through the area during peak afternoon
heating, with re-development of showers and storms from west to east
across the area during the afternoon and evening. Deep layer shear
increases slightly, but is still weak, and should mitigate the
severe threat. Mean storm motion should also be higher than recent
days, but given moist PWATs of 1.9-2.0", some localized flash
flooding remains possible. Isolated to widely scattered
showers/storms could linger overnight, especially with renewed lift
from an elongated shortwave trough extending south from the mid-
latitude cyclone over southern Ontario.

Highs into the mid 80s to around 90 F, with some lower 80s possible
over the NW Piedmont where the second round of convection could pop
off earlier. Lows in the mid 60s to lower 70s with areas of stratus
expected.


&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 330 AM Tuesday...

By Thursday morning, an upper low will be over southwestern Ontario
with a surface low a bit farther to the northeast. The surface cold
front should extend southeast across the Great Lakes into
Pennsylvania, then arc back to the southwest along the I-85/95
corridor. While some minimal changes were made to the area of likely
shower coverage on Thursday, likely pops generally remain to the
southeast of US-1. MUCAPE should be on the order of 1000-2000 J/kg,
while effective bulk shear remains at or below 30 kt. Thursday also
appears to be the warmest day out of the next seven, with west-
southwesterly flow providing warm advection allowing highs to max
out between the mid 80s and lower 90s.

Although slight chance pops will continue from US-1 to the east
Thursday evening, have continued the inherited dry forecast for
Friday as the GEFS has finally come in line with other models
showing all precipitation to the east of the region. Friday appears
to be the day that noticeably drier air will arrive, with dewpoints
dropping into the 50s (and upper 40s in the Triad). The dry forecast
continues through Saturday into Sunday. Unfortunately, different
runs of the GFS/ECMWF and their respective ensembles continue to
flip-flop as to when the next front will approach the southeastern
United States, so this part of the forecast has below normal
confidence. For now, have slight chance pops Sunday night and chance
pops everywhere Monday. The Thursday/Friday front won`t bring much
change in high temperatures, with highs remaining in the 80s through
the weekend. However, there will be some relief each night, with
overnight lows in the lower 60s instead of the upper 60s.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 205 PM Tuesday...

Isolated showers and storms are beginning to develop across portions
of the CWA, but ceilings are generally around 3k-4k ft over the
Triad and 4k-7k elsewhere. Mostly VFR conditions are expected this
afternoon and evening with the exception of periods when storms move
over/near the terminals causing reduced vsby and ceilings. As the
mid level disturbance moves across the region tonight and early
morning, this could result in some flight restrictions early
Wednesday morning ahead of the cold front.

Outlook: Showers ans storms associated with a cold front that is
expected to come through the region late Wednesday /Thursday will
result in flight restrictions of MVFR or lower in some areas. VFR
conditions are expected to return Friday through the weekend before
another disturbance moves into the region early next week.

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...CA
SHORT TERM...CBL
LONG TERM...Green
AVIATION...CA