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000
FXUS62 KRAH 210031
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
831 PM EDT Sat Apr 20 2024

.SYNOPSIS...
In the wake of the slow moving cold front, high pressure will build
into the area tonight through Tuesday. Meanwhile, as the front
settles south into South Carolina and Georgia, a developing wave of
low pressure along the front will bring wet and cool conditions to
central NC late tonight and Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 335 PM Saturday...

A Marginal/Level 1 Severe Risk has been introduced across
southern portions of the forecast area. Destablization and low-lapse
rates are more robust due to the slow movement of the cold front.
Strong effective shear of 40-50 kts will support the potential for
supercells with damaging winds and hail the primary threat from
these. The risk will be greatest through 9pm.


Tonight: The aforementioned cold front will continue to shift slowly
south through SC and into GA as high pressure builds east into NC.
Meanwhile, a low-amplitude shortwave over the Southern Plains will
eject eject in advance of a more vigorous shortwave trough diving
SEwd into the Central Plains. A ribbon of shortwave impulses will
begin to interact with the front to our south and will result in the
onset of isentropic lift and moisture advection into the area after
midnight. Clouds will fill back in Saturday night, with stratiform
rain spreading in/developing, mainly across southern portions of the
area during the predawn hours. Significantly cooler with lows
ranging from mid/upper 40s north to lower/mid 50s south.

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 200 PM Saturday...

A southern stream low pressure system that is expected to move out
of the southern Gulf states late Saturday night then up and along
the SE coast through Sunday night. Rain chances are expected to
begin early Sunday morning across the  southern and western Piedmont
regions, and progress northeast across the region during the day.
Pops during the afternoon across mainly the southern two thirds of
the CWA will range from 75-85% as the center of the low is just off
the NC coast. As it ejects to the NE late afternoon and evening,
PoPs will diminish from NW to SE late evening and into the overnight
hours. QPF amounts will range from less than quarter inch in the NW
to around 0.75” across the Sandhills and southern Coastal Plains.
Sunday is expected to be just rain, with all the instability
offshore and closer to the center of the low, no thunder is put in
the forecast.

Dew points will be starting off low, mainly in the 40s, across the
region. Paired with morning temperatures in the low 50s along the
northern Piedmont this will result in a very chilly rainy day where
the rain will help keep temperatures around 50 degrees (in the
north).  Elsewhere, temperatures are a little uncertain as they will
depend majorly on the timing of the rain and how early it will
arrive. If morning heating could sneak in before the rain comes, we
expect a major temperature spread across the region. For now have
timed out temperatures to timing of the incoming of rain, which
gives the southeastern portions of the CWA a few hours of
availability to heat early morning thus, highs for Sunday will be
non-diurnal and expected to occur in the morning. As the precip
moves into the region the cooling process will begin and temps are
expected to fall through the day (especially in the SE where the
morning temperature starts in the upper 50s but afternoon
temperatures will be in the low 50s).

Precipitation will completely move out of the area just after
midnight with high pressure quickly building in from the west. Skies
will be mostly clear by morning with morning lows Monday in the low
40s north, to upper 40s south.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 210 PM Saturday...

Although some showers could persist along the immediate North
Carolina coastline Monday morning, it appears that all of the rain
should have moved east of the forecast area. Skies will be clearing
through the day, but a persistent northerly wind will keep
temperatures below normal, although warmer than Sunday - widespread
mid 60s. The warming trend will continue through the rest of the
forecast, with highs in the 70s (and lower 80s across the south on
Saturday).

In the previous forecast package, the primary concern for the second
half of the week was whether a cold front was going to stall in the
vicinity of the Carolinas and allow for diurnal showers or whether
it would push south and allow for a dry forecast. The most recent
model guidance seems to suggest that there is minimal potential for
showers on Wednesday (with nearly all precipitation remaining to the
north), but that the cold front should push through the region. The
better chance of showers in the extended forecast should be Saturday
near the warm front of a second system moving into the Plains.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 830 PM Saturday...

VFR ceilings will develop/become increasingly-widespread Sunday
morning, as a couple of mid/upr-level disturbances approach and
interact with a frontal zone that will settle off the coast of the
Carolinas late tonight and Sunday. Ceilings will gradually lower to
IFR-MVFR and be accompanied by rain on Sunday, with flight
conditions lowest and rain relatively heaviest at RDU/FAY/RWI. A
period of nely gustiness may also result Sunday morning, especially
at RWI and RDU, as an area of surface low pressure develops/
strengthens along the aforementioned, offshore front.

Outlook: Light rain and flight restrictions will end from southwest
to northeast Sunday evening. High pressure through early next week,
then the passage of a moisture-starved cold front Wednesday
afternoon-evening, will favor VFR conditions through most of the
next week.

&&

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

&&

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