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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 160708
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
305 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 /THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 310 AM Tuesday...

Upper pattern through the extended: Weak mid-level ridging will move
over the southeast Thursday into Friday promoting nwly flow aloft
over central NC.  A series of short-wave perturbations will
periodically pass over central NC Friday through Sunday, followed by
a potentially more vigorous short-wave Monday into Tuesday.

Thursday:  A brief period of drying is expected as flow turns nwly
aloft on Thursday.  Downslope warming will promote another day of
above normal highs in the mid to upper 80s. Decent mixing will
promote wly gusts of up to 20 mph at times Thursday afternoon.

Friday through Sunday: Flow aloft will generally remain wly Friday
through Sunday. However, ensembles are hinting at a few passing
short-waves potentially moving over our area in this time period.
These features could trigger scattered showers and thunderstorms
Friday and Saturday afternoon/evening. Forcing for ascent does like
pretty muted as guidance maximizes mid-level height falls well to
our north. This may limit coverage both afternoons, but scattered
showers and storms appear plausible.

Flow aloft turns a bit more swly Sunday and Monday increasing low-
level moisture advection into the southeast. However, guidance is in
a bit of disagreement wrt to rain and thunderstorm chances in this
period. The GEFS/GFS shunt instability and heavier rain to our
south. Conversely, the Euro/EPS/GEPS are more convectively active
over central NC. For now, maintained high chance to low likely POPs
favoring our southern zones Sunday through Monday.

Temperatures Saturday through Monday will largely depend whether CAD
will set up or not (the raw 18Z GFS has highs in the upper 40s in
the Triad Monday afternoon). For now will favor a blend of cooler
and warmer solutions Sunday and Monday with highs in the mid 60s.
-- End Changed Discussion --


&&

.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...Luchetti
AVIATION...Blaes