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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 040740
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
340 AM EDT Sat Apr 04 2020

.SYNOPSIS...
Surface high pressure will settle across the area today. The high
will move offshore late Sunday, which will allow a weak surface
front to move into the area Sunday night before stalling and
eventually washing out early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 340 AM Saturday...

With the low pressure system over the western Atlantic finally
moving out to sea, ridging aloft will be allowed to build east
across the region. Meanwhile downstairs, weak surface high will
settle over the southern Mid-Atlantic States. The associated N-NELY
low-level will advect some slightly cooler air into the area today,
as well as an alto-cumulus cloud layer into NE portions of the
forecast area during the afternoon. Otherwise, expect mostly sunny
conditions again today with afternoon highs a touch cooler than
yesterday; ranging from lower/mid 60s NE to lower 70s SW.

Weak shortwave impulses traversing the SE US will result in
occasionally fair to mostly clear skies overnight. Otherwise, it
will remain dry. Lows in the 40s, to near 50 SW.


&&


.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 340 AM Saturday...

Central NC will remain under the influence of the broad upper ridge
in place across much of the southern CONUS. The area of weak high
pressure centered over the area to start the day will move east and
offshore by the afternoon and evening. This will allow a weak front
to move into northern portions of the area during the early evening,
where it is then forecast to stall out overnight. Despite the fact
that moisture, lift, and instability are all limited, a majority the
deterministic guidance, including the hi-res CAMs, indicate some
isolated shower activity INVOF the northern Piedmont and northern
coastal zones late Sunday afternoon and into Sunday night. Thus, had
added an isolated PoP. Otherwise, with no significant airmass change
on Sunday, temps will comparable to Saturday, though warmer across
the NE zones.
Highs in the upper 60s to lower 70s. Not as cool overnight, with
lows in the lower to mid 50s.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 330 AM Saturday...

Upper level ridging will continue to build east of the Rockies early
next week as an upper-trough inches ashore along the western CONUS
before nearly stalling across the Baja California Coastline through
mid-week. This wave will begin to interact with a developing
northern stream shortwave mid to late week, finally ejecting east as
a developing upper-trough sometime in the Friday - Saturday time
frame.

A backdoor cold front will dip toward but likely remain just north
of the VA/NC border monday night before spreading back north as a
warm front on Tuesday. This in response to surface high pressure
drifting southeast off GA/SC coast, aiding in the re-establishment
of sustained southwesterly flow across the central Carolinas early
Tuesday afternoon. This will result in a gradual warming and
moistening trend through the middle of the work-week with POPs
beginning to increase slightly as a series of weak pacific born mid-
level impulses round the apex of the southern stream ridge. At this
point, a still moisture starved airmass will likely only support
isolated to widely scattered shower coverage, with best distribution
likely occurring both Monday and Tuesday afternoons. Ample capping
should be efficient enough to limit both coverage and shower
intensity for the most part during this time frame.

A drying trend will commence mid to late week as the mid-level ridge
breaks down in response to the approaching trough from the west.
Uncertainty, especially beyond the Thursday period, remains
extremely high at this time thanks to rather large disagreements in
model output solutions in the Day 6/7 period. Most of these
differences stem from how each guidance package handles the Baja
Low. For instance, the GFS never truly cuts the low off from
northern stream influence, helping to encourage the further
interaction with the developing mid-level shortwave ejecting both
features east as a much stronger upper-trough feature. Meanwhile,
ECMWF guidance completely cuts the low off, ejecting the northern
stream jet streak east through the Great Lakes without the cutoff
low over southern CA. This will still result in a cold frontal
passage, but a much weaker and drier one thanks to forcing remaining
further north. With uncertainty remaining so high, have trended POPs
down and elongated their influence mainly through the late Thursday
through Friday time period for now. Either way, a brief wet period
ahead of a likely strong FROPA will occur, followed by a much cooler
and drier airmass which should settle into place as we begin to
progress into next weekend.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
As of 200 AM Saturday...

24 Hour TAF Period: Surface high pressure settling over the area
combined with dry NW flow aloft will result in VFR conditions
through the period(high confidence). Gusts today will be minimal,
with winds generally 5 to 10 mph, becoming E-NELY during the
afternoon and evening.

Outlook: VFR conditions and dry weather are expected through Sunday.
Only slight chances for showers will increase early next week, along
with potentially minimal sub-VFR conditions.

&&

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

&&

$$

SYNOPSIS...CBL
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...JJM
AVIATION...CBL/Badgett