882
FXUS62 KRAH 301758
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
158 PM EDT Thu May 30 2024

.SYNOPSIS...
A vigorous mid and upper-level disturbance will pivot across and
offshore the southern Middle Atlantic through early Friday. Canadian
high pressure will otherwise extend across the region through early
Saturday, then drift off the coast of the Carolinas by Saturday
night.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1055 AM Thursday...

The morning forecast update was sent with no notable change from the
previous forecast of a seasonably mild and low humidity day, with a
a slight-low chance of a shower over the nrn-cntl Coastal Plain this
evening-early tonight.

.PREV DISCUSSION... /ISSUED 240 AM EDT Thu May 30 2024/

Located on the backside of the Eastern US trough, a shortwave over
the Great Lakes this morning, will amplify as it digs southeastward
through the Mid-Atlantic region late this afternoon and evening, and
then coastal/eastern NC tonight and early Friday morning before
moving offshore.

Deep W-NWLY flow will continue to promote a dry airmass across the
region, with PWATS of 0.6-0.7" registering in the lowest 10th
percentile of the climatological data set. Similarly, BL dewpoints
are expected to advect and mix out into the mid to upper 40s across
much of the area. Instability will be greatly lacking across the
area as afternoon temps warm into the mid/upper 70s north to lower
80s south, which is slightly below normal for this time of year.

Despite the dry air in place, coastal plain counties
will have a chance of seeing a few showers during the late evening
and overnight hours as the upper PV anomaly and associated elevated
lapse rates  ascends upon eastern NC. Elsewhere, dry conditions
should persist as Canadian high pressure builds south into the area.
Lows tonight in the lower to middle 50s, with a few upper 40s
possible in the typically cooler northern Piedmont locations.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 240 AM Thursday...

Any ongoing shallow convection to start the day should be east of
the forecast area with synoptic scale subsidence overspreading the
area from the west as the upper trough moves offshore.

The weather headlines will be the cool, below normal temperatures
and ultra comfortable humidity as Canadian high pressure settles
over much of the Eastern Seaboard. Highs are expected to range from
lower/mid 70s north to upper 70s/near 80 south, which will feel
cooler thanks to 30 and 40 degree reading dewpoints. Anyone with
outdoor plans Friday evening may want to bring along a light sweater
or jacket as temps should drop off quickly into the upper 50s/lower
60s, with overnight temps expected to bottom out in the mid to upper
40s north to lower 50s elsewhere.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 200 AM Thursday...

A series of northern stream lows will track eastward through Canada
through the middle of next week, with a number of s/w disturbances
rotating about the lows potentially impacting the weather across the
mid-Atlantic and Carolinas. The sub-tropical ridge will progress
slowly eastward through the area Sat/Sat night as a s/w trough move
eastward through the MS Valley. This s/w will then continue
generally eastward across the Appalachians and through the mid-
Atlantic Sun/Mon, however the timing and track differ between the
medium-range guidance. Another s/w will follow behind it but,
similar to the first s/w, the model differences continue wrt timing
and track. A northern stream s/w ejecting eastward from a low over
western Canada will deepen as it moves along the US/Canada border
Tue/Wed, closing off over then tracking eastward through the Great
Lakes Wed/Wed night. At the surface, cool high pressure move slowly
esewd through the Carolinas Sat/Sat night. The high will move ese to
off the Carolina/Southeast US coast on Sun, where it should sit
through Mon then slowly drift eastward Tue/Wed. A warm front should
lift through the area Sun night/Mon, with southerly return flow once
again advecting warm, moist air into the area through early next
week. Surface flow should become increasingly swly as the high
shifts further offshore, with more of a Gulf influence by mid-week.
A bit of a low confidence precipitation forecast from Sun through
Wed given the uncertainty wrt the shortwaves. For now, expect
largely dry weather through Sun, with chances for precipitation
returning for Sun night through Wed. Temperatures should be near to
slightly below normal through Sun, then return to near/above normal
and moderate through mid next week.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 155 PM Thursday...

Canadian high pressure will build from the Great Lakes swd and
across the Carolinas, with associated influence for light nly
surface winds and VFR conditions through Friday. There will,
however, be a slight chance of a shower near and northeast of RWI
early tonight, accompanying the passage of a vigorous mid/upr-level
disturbance.

Outlook: Return flow warmth and moisture, combined with a lee trough
or weak surface front, will result in a chance of mainly diurnal
showers/storms Sunday through the middle of next week.

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...CBL
LONG TERM...KC
AVIATION...MWS