778
FXUS62 KRAH 221736
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
135 PM EDT Wed May 22 2024

.SYNOPSIS...
High pressure over the western Atlantic will extend across the
Southeast through tonight. Disturbances in westerly flow aloft will
interact with an underlying surface trough as they track from the
lower MS Valley to the srn Middle Atlantic Thursday through the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 900 AM Tuesday...

No major changes with this mornings forecast update. Made minor
adjustments to some temperatures and dew points for today, but
otherwise forecast is on track. Mostly cloud free skies today with
high temperatures in the mid to upper 80s.

As of 345 AM Wednesday... A sub-tropical mid-level ridge will extend
from the Gulf of Mexico newd and across the Southeast and Carolinas,
while low amplitude, wswly flow, and embedded convectively-amplified
disturbances, will exist on its northwest periphery from the srn
Plains to the cntl Appalachians and nrn Middle Atlantic.

At the surface,  ~1017 mb high pressure centered just off the Middle
Atlantic coast swwd and along the coast of the Carolinas will
remain, while an Appalachian-lee trough --and axis of weak to
moderate instability-- will develop this afternoon across the srn
Middle Atlantic Foothills/wrn Piedmont.

Sensible weather associated with the pattern described above will
feature warm(er) and dry conditions throughout cntl NC, though with
an isolated shower or storm that may initiate on the surface trough,
then subsequent outflow, and drift toward the far nw Piedmont before
dissipating with nightfall. High temperatures should be a few
degrees higher than those of Tue and generally in the mid-upr 80s,
followed by milder lows mostly in the lwr-mid 60s.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 135 PM Wednesday...

By Thur morning, the ridge axis, both sfc and aloft, will be to our
east.  Meanwhile, a couple short wave troughs will be centered well
to our N and NW, one just north of the Great Lakes and another over
the northern Rockies. SW flow between those features will gradually
increase over our area as this pattern slowly shifts east. Within
that SW flow will be several low-amplitude waves and likely to be
several MCVs from earlier convection, which models suggest will
support a round of showers and thunderstorms crossing our CWA during
the late afternoon and evening hours Thursday.

With the ridge to our east, southerly flow will result in a warmer-
than-average airmass over our region.  High temps Thursday will be a
bit warmer than today...highs from the mid 80`s NW to around 90 east
and southeast.  Given this warm airmass and dwpts in the mid 60s,
there will be plenty of instability for thunderstorm activity. That,
along with increase mid-level flow and resulting shear will support
a risk for isold severe thunderstorms with damaging winds and hail
the main threats.  The latest round of CAMs generally are fairly
close regarding timing... with a line or several clusters of
thunderstorms moving e/se across our CWA from about 21Z through 03Z
tomorrow.  After the storms move east, quiet weather expected the
rest of the night. Low temperatures will be in the 60s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 251 AM Wednesday...

Broad troughing across the eastern US will maintain a steady flow of
rich swly moisture transport across central NC through the extended.
Embedded short-wave/MCV features will move over our area triggering
periods of showers and storms each successive day.

At the sfc, an offshore high will pump continuous swly flow across
central NC allowing unstable conditions to flourish each day. Further
upstream, a front will stall west of the Appalachians. As the
aforementioned short-wave energy moves through aloft, expect periods
of showers and storms to develop each day.  Ensembles suggest
periods of stronger shear may be possible Friday (across the south),
Sunday, and again on Monday. As such, the kinematics may be strong
enough to support a few stronger storms these days. The CSU ML model
suggests low-end probabilities for severe weather across our area
each of these days as well. However, we are still a few days out and
details should become more clear as we approach the weekend.  For
now, maintain chance POPs through this period.

With no discernible change in airmass expected, temperatures will
remain above normal in the mid to upper 80s each day of the
extended.

&&

.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
As of 135 PM Wednesday...

High pressure over the region will continue to favor VFR conditions
through the 18z TAF period. Along with VFR conditions expected for
much of the period, light S and SW winds around 5-10 knots are
expected and some some fair weather cumulus clouds. By Thursday
afternoon and early evening, increasing cloud coverage will approach
ahead of an approaching frontal boundary.

Outlook: A chance of SUB VFR conditions are possible with
showers/storms moving through the area through the weekend, mainly
during the afternoon-evening.

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...CA/MWS
SHORT TERM...MWS
LONG TERM...NP
AVIATION...CA