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000
FXUS62 KRAH 160705
AFDRAH

Area Forecast Discussion National Weather Service Raleigh NC 255 AM
EDT Tue Apr 16 2024

.SYNOPSIS...
A backdoor cold front settling across the region will linger today
and then lift north as a warm front tonight and Wednesday. A
weakening cold front will move across the region late Wednesday with
a stronger front expected to move across the area over the weekend.
&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 930 PM Monday...

Chance of showers and isolated thunderstorms far NE through around
midnight.

Severe threat NE is diminishing.

A backdoor cold front was located from central to SE VA this
evening. An outflow boundary was out ahead of the showers/storms
over SE VA moving SE toward areas along and NE of the Roanoke River
in NE NC. However, the latest radar and satellite data indicate a
weakening trend of the convection as it approached NE NC. The latest
severe weather parameters indicted continued CINH over our region
with the only real support for showers/storms near the outflow. We
will maintain the slight to low chance (20-30) near Warrenton and
Roanoke Rapids to Tarboro through around midnight, but expect most
if not all of the convection will die off by then. To the west,
isolated thunderstorms over WVA and SW VA should also die out around
midnight. Otherwise, mostly clear to partly cloudy with lows in the
upper 50s to lower 60s (10-15 degrees above normal).

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
As of 200 PM Monday...

A weak stationary front should remain across the forecast area, with
cooler air generally northeast of the Triangle with warmer air to
the south and west. While the morning should remain dry, an upper
level shortwave is forecast to move across the state Tuesday
afternoon into the evening, which should help trigger another round
of showers and thunderstorms along the front. The GFS/GEFS is
currently the most aggressive with coverage of showers and
thunderstorms, although the HREF/SREF also show a decent amount of
coverage, while the 00Z ECMWF/12Z NAM both show a relatively dry
forecast. Only made minor tweaks to the pops, generally keeping
chance pops north of US-64. With the mid-day update, SPC also added
a marginal (level 1 of 5) severe risk generally north and west of
Raleigh, with steepening low-level lapse rates favoring the
potential for damaging wind gusts. As the front pulls north Tuesday
night, the chance for precipitation will come to an end. With the
front bisecting the forecast area, there should be more of a
gradient in high temperatures for Tuesday - locations near the VA/NC
border will stay around 80 degrees while locations across the south
should rise into the upper 80s once again. Low temperatures should
not have quite as much of a spread, ranging from the mid 50s to the
low 60s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 400 PM Monday...

As a low pressure system moves into Wisconsin and Lake Michigan on
Wednesday and the backdoor front lifts NE and away from our region,
it will turn dry but widespread mid and high clouds should remain.
This will somewhat limit temperatures, but with strong S/SW flow
between this low and a high west of Bermuda, it will still be warmer
than average with Wednesday`s highs in the upper-70s to mid-80s.
S/SW winds may also gust to 20-30 mph in the late morning and
afternoon. As the primary low weakens and moves into Canada, it will
transfer energy to a secondary low that develops over VA and the
Delmarva on Wednesday night. While the best upper forcing will be
well to our NW, an associated weak mid/upper trough will also move
overhead. So there could be enough moisture and forcing to eek out a
few showers (and maybe a storm early) on Wednesday evening and
Wednesday night. This is supported by the ECMWF as well as a
minority of GFS/ECMWF ensemble members. The best chance should be in
northeastern locations, and any amounts will be light (around a
tenth of an inch or less). Lows Wednesday night will be very mild,
in the lower-to-mid-60s.

The primary low will also drag a decaying cold front that moves
through central NC Thursday morning, but it should be a dry passage
and there will be no drop in temperatures behind it. In fact, mostly
sunny skies and shortwave ridging aloft will help bring temperatures
back into the 80s areawide on Thursday, maybe even touching 90 in a
few spots in the far south. Another upper disturbance may bring
another chance of isolated showers and storms on Friday,
particularly if the GFS verifies, but the heavier amounts it shows
in the SE are not supported by its ensembles and appear to be an
outlier. So only have slight to low chance POPs at this time.
Forecast highs on Friday are again in the 80s, but slightly cooler
than Thursday.

A wetter pattern looks to be in store for the weekend. The next
mid/upper low will move east across southern Canada from mid to late
week, which will drag a much stronger cold front that sinks SE and
slowly moves through central NC this weekend, with multiple waves of
low pressure riding along it. Guidance is still in disagreement on
exact timing, with the GFS depicting the frontal passage on Saturday
night while on the ECMWF it isn`t until Sunday/Sunday night. POPs
increase to low chance on Saturday/Saturday night and high chance on
Sunday, when deterministic models and a majority of ensemble members
have precipitation. There could be enough instability for some
storms, particularly in the SE and if the front is slower to move
through as the ECMWF depicts. We should largely dry out by Monday as
high pressure builds in behind the front. The temperature forecast
this weekend is also low confidence and depends on the timing of the
front. The GFS is much cooler than the ECMWF as it drops the front
through the area faster, and the temperature forecast leans towards
their ensemble means which are somewhere in between. Temperatures
will drop significantly when the front does pass through, and by
Monday forecast highs are only in the 60s, which is well below
normal.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 255 AM Tuesday...

24 hour TAF period: VFR conditions are generally expected during the
period although there is a small chance of a few showers or perhaps
a thunderstorm late this afternoon and evening.

A back-door cold front will drop into the region early this morning
and then linger across the area. No precipitation and only a few
clouds are expected this morning with VFR conditions dominating.
Light winds will shift to northeasterly behind the front at 7 to 10
kts with a few stronger gusts. Uncertainty is greater than typical
with the potential for a few showers or even a thunderstorm this
afternoon as an upper level disturbance and the lingering front may
provide a focus for some weak convection. The best chance of
precipitation is from 21 to 03 across the Piedmont. Given the
limited confidence have opted to include just a mention of vicinity
showers and no thunderstorms. The front will lift north tonight and
some low stratus may move into southeastern areas toward daybreak
Wednesday, otherwise a mix of mid and high clouds is expected with
the northeast flow become east and southeast overnight.

Outlook: Generally fair weather and VFR conditions are expected for
Wednesday into Friday with perhaps some early morning stratus
possible. Another cold front will approach the area on Friday and
resulting in a chance of some unsettled weather with showers and
perhaps a thunderstorm. &&

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

&&

$$


SYNOPSIS...Blaes
NEAR TERM...KC
SHORT TERM...Green
LONG TERM...Danco
AVIATION...Blaes