National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS62 KRAH 201811
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
210 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 /TODAY THROUGH TONIGHT/...
As of 950 AM Saturday...

A slow moving cold front, which is progressing south at a slower
clip than models suggested and that currently extends just north of
HWY 64, will settle south throughout the day. Moisture pooling along
the front has led to the development of widespread fog and low
clouds. As such, the widespread cloudiness across the area should
decrease from north to south through the late morning to afternoon,
giving way to mostly sunny skies across the north, with a mixture of
sun and clouds across the southern counties. Highs are expected to
range from lower/mid 70s north to lower/mid 80s.

Convection has moved offshore but some isolated showers and storms
could re-develop across the southern counties later this afternoon
once we reach convective temps in the lower 80s, where weak to
moderate buoyancy with MLCAPE values of 500 to 1500 J/KG is
expected. Deep layer shear of 35-45 kts is more than sufficient to
support an isolated damaging wind gust.

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 /18Z SATURDAY THROUGH THURSDAY/...
As of 150 PM Saturday...

24 hour TAF period: Lingering sub-VFR ceilings at KRWI and KFAY will
will gradually lift to VFR through 20z, owing to sfc heating and as
the surface front drops slowly south across eastern and southern
portions of the forecast. Additionally, scattered showers and storms
are expected to develop across southern NC, INVOF KFAY between
20 to 02z. Otherwise, underneath multi-cloud layers, VFR conditions
are expected to hold largely through 12z Sunday, followed by a
lowering of ceilings to MVFR and IFR as rain spreads in from the
south. Winds at all TAF sites will become N-NELY behind the front
with some intermittent gustiness of 15-20 kts possible Sunday.

Outlook: Light rain and associated sub-VFR restrictions will scatter
out from NW to SE Sunday night as a wave of low pressure to our
south track out into the Atlantic. A moisture starved cold front
will cross the area late Wednesday. Precip will be limited along the
front as are the chances for any related sub-VFR restrictions.
Otherwise, VFR conditions are expected Tuesday through Thursday.




&&

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

&&

$$

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