451
FXUS62 KRAH 311859
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
259 PM EDT Fri May 31 2024

.SYNOPSIS...
Canadian high pressure will build across and offshore the Middle and
South Atlantic through Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 235 PM Friday...

A longwave ridge now centered from the TN Valley to Hudson Bay will
progress east and extend from the Carolinas to QC by 12Z Sat.
Accompanying strong height rises, maximized in excess of 150 meters
at 300 mb over the lwr Great Lakes in 12Z RAOB data, will spread
sewd and across the srn Middle Atlantic. While associated mid/upr-
level subsidence will result over cntl NC, extrapolation of visible
satellite data trends indicate a cirrus/cirrostratus canopy may
persist at least through this evening across the srn NC Piedmont and
Sandhills.

At the surface, the center of ~1026 mb Canadian high pressure over
ern OH/wrn PA will follow the aforementioned height rises aloft and
across the srn Middle Atlantic and become situated squarely over NC
tonight.

The presence and influence of the Canadian high, and calm tonight,
will yield unseasonably cool low temperatures in the middle 40s to
lwr 50s (~10-15 F below average).

&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
As of 255 PM Friday...

A longwave mid/upr-level ridge will progress across and offshore the
srn Middle Atlantic, downstream of a shortwave perturbation, and
slightly preceding MCVs/convectively-generated vorticity axis, that
will pivot newd from the mid-South to the cntl Appalachians and srn
Middle Atlantic. Associated lift will result in the ewd progression
and lowering of high through mid-level ceilings over cntl NC Sat
night, including down to 10-12 thousand ft AGL over the wrn NC
Piedmont by 12Z Sun.

At the surface, Canadian-sourced high pressure will drift off the
coast of the Carolinas and into the wrn Atlantic, with associated
light sly flow that will develop and result across cntl NC.
Modification of the high, and the development of the "return", sly
flow, will favor warming of high temperatures into mostly the low-
mid 80s, but with continued low humidity in the 20th-30th
percentile. Low temperatures will also be less cool but still
slightly below average, mostly in the mid 50s to around 60 F,
mildest where clouds will thicken and lower first over the nw NC
Piedmont.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
As of 231 PM Friday...

A series of short wave troughs are forecast by models to move across
our region through much of the period.  Meanwhile at the surface,
high pressure will be centered to our east offshore of Cape Fear at
the start of the period and will generally remain to our east during
the period, with sw low level flow persisting over the Carolinas and
promoting gradual WAA and increasing PWAT through the week.   The
Piedmont trough will develop each day, with the next substantial sfc
front approaching and moving through late Thursday when a deeper
upper trough begins to develop over the Great Lakes region.

The sensible weather as a result of the above pattern will feature
gradually increasing temps and humidity each day as sw low level
flow persists.  Sunday will be the last of the near-normal temp days
for the period, with highs in the mid 80s, but then highs a few deg
either side of 90 will be possible each day the rest of the week.
Most of our CWA should remain dry on Sunday, with the exception of
our western Piedmont zones where a few isold showers/tstms are
possible.   Then for the remainder of the week, well have mainly
diurnal aoa-climo PoPs Monday through Wednesday, then the highest
PoPs late Thursday in response to the approaching front.  The front
should be to our east by Friday morning, with dry weather for the
rest of Friday.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As of 210 PM Friday...

Canadian high pressure will build across and offshore NC and favor
VFR conditions through Saturday.

Outlook: Return flow moisture, combined with a lee trough and weak
surface front, will result in a chance of mainly diurnal
showers/storms, and also a small chance of pre-dawn, patchy sub-VFR
restrictions, Sunday through the middle of next week.

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...np
AVIATION...MWS