Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 130914
AFDRAH

AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
413 AM EST Wed Nov 13 2019

.SYNOPSIS...
Cold high pressure will extend into the region from the northeast
overnight through Wednesday night. Low pressure will form over the
Gulf of Mexico early Thursday, then track northeast across Florida
and along the Southeast coast through Saturday.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
As of 225 AM Wednesday...

Expect a cold but quiet day, the last one before wet weather
returns. The latest surface analysis shows the incoming frigid
surface high centered over extreme W KY, on pace to drift across to
WV by daybreak before tracking NE to the New England coast through
tonight while extending down into central NC. We may see a few high
thin clouds cross the area W-E early-mid afternoon associated with a
band of higher PW, but otherwise sunshine should be abundant. Based
on the character of the incoming air mass with decent CAA, as well
as projected thicknesses nearly 80 m below normal, temps will be
much below normal today, with highs of 40-45. Forecast profiles
suggest that the low levels will remain sufficiently mixed to
support continued periodic gusts over the E and S portions of the
forecast area (where the MSLP gradient remains tight) into the
daylight hours, although these should diminish through the morning.
By tonight, the mid level flow will continue to back, drawing in
moisture aloft from the eastward-drifting upper low over N Mexico.
This long-fetch SW mid level flow into the Carolinas will lead to
increasing and thickening high clouds overnight. And as the low
level anticyclone shifts over the region and offshore, the ensuing
flow from the ESE will help pull Atlantic low level moisture into SE
CWA, such that patchy low stratus may work into our SE including FAY
and GSB toward morning. With any winds diminishing this evening
under fair skies, temps should fall off quickly, although they
should level off late as clouds increase. Expect chilly lows from
around 20 N to the mid-upper 20s SE, very close to record lows but
likely falling just short. -GIH

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 320 AM Wednesday...

The arctic surface high will continue to pull NE off the coast of
the Canadian Maritimes and away from NC, although it is likely to
deposit a residual stable pool over the Piedmont Thu morning.
Surface pressures will continue to fall near the Southeast coast as
inverted troughing develops and strengthens through Thu night,
evolving into a full-fledged synoptic front extending along the
Southeast coast and across N FL into the Gulf. In the mid levels,
the low over NE Mexico will continue to open up and lift NE over the
Gulf Coast as northern stream energy dives over WY/CO Thu morning
dives SE and absorbs the Gulf Coast energy, culminating in a large
and deepening low over the lower Miss Valley by Fri morning. Mid
level DPVA out ahead of the Gulf wave will help induce surface low
development along the baroclinic zone, and while the latest model
runs differ in placement of this cyclogenesis, it appears most
likely to occur over the far NE Gulf late Thu or Thu evening, with
the low tracking NE along the front through Thu night with
strengthening onshore-directed moist low level Atlantic flow into
NC. Moisture and forcing for ascent will both be strengthening and
deepening Thu afternoon and especially Thu night, with the latter
boosted by increasing upper divergence late Thu night. While this
all supports overcast skies and rising pops, there remains a chance
that the bulk of the rain may be focused at the coast, closer to the
surface frontal zone, within locally enhance low level vorticity and
moist upglide, so for now will keep pops at good chance through Thu
night over central NC. Expect highs from the mid 40s NW to lower 50s
SE Thu, with rebounding dewpoints. With clouds and possible rain
reducing the diurnal temp range, lows Thu night should range from
the mid 30s to mid 40s NW to SE. Any precip is likely to be just
liquid Thu night, based on forecast soundings, although a few sleet
pellets at onset on the NW edge of the precip shield Thu night is
not out of the question. -GIH

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 400 AM Wednesday...

An active pattern sets up for the end of the work week into early
next week.

An amplifying northern stream wave diving SE through the southern
Plains and the sheared remnants of the former Baja upper low will
either phase or come very close to one another INVOF the Lower MS
Valley late Thursday/Thursday night. Despite some subtle model
differences, models agree that the more dominate northern stream
trough will eventually close-off over the Gulf Coast states on
Friday and will track east across the SE US Friday night and into
Saturday before moving offshore Saturday night and Sunday. A strong
Atlantic maritime feed on the cool side of a developing coastal
low/front will fuel overrunning lift and precip across the area on
Friday, especially across eastern and central portions of the area.
After a possible interlude/wane in lift and precip across central NC
late Friday and into Friday night, the arrival of the upper low and
possible secondary coastal low development could result in renewed
lift and a secondary area of rain across the area on Saturday. Given
that the best moisture and lift will reside across coastal sections,
the presence of very warm air aloft and above freezing BL temps will
make any wintry precip very unlikely. However, this system  has the
potential to bring widespread beneficial rainfall of 1 to 2 inches
across eastern eastern NC, with rainfall amounts decreasing sharply
inland.

After mostly dry conditions on Monday, a succession of  northern
stream energy rotating through the base of the long wave trough in
place across the central and eastern CONUS will lead to some
significant trough amplification across the central and eastern
CONUS, with the potential for  another coastal low development off
the NC coast Tuesday and into Wednesday.

Widespread rain and clouds Friday through Sunday will keep daytime
highs well-below normal, with high generally in the 40s to low 50s.
Near normal highs return next week. Lows

Highs are expected to be below normal for Friday through Sunday with
a return to near normal highs in the upper 50s to lower 60s early
next week. -Blaes

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
As of 1250 AM Wednesday...

VFR conditions are likely for the next 24 hours over central NC, as
cold high pressure builds into the region from the N. Only a few mid
and high clouds are expected. Surface winds will remain up overnight
with infrequent gusts to 15-20 kts, but this gustiness will diminish
later tonight (after 09z), leaving light winds from the NE through
the rest of today, and very light from the E and SE tonight.

Looking beyond 06z Thu, VFR conditions will dominate into Thu
morning beneath the surface high pressure ridge, although high
clouds will begin streaming into the region Wed night ahead of an
approaching mid level trough. Sub-VFR conditions are expected to
develop on Thu, starting at INT/GSO, as surface low pressure tracks
along the Southeast coast. Sub-VFR conditions are then likely Thu
evening through much of Sat with high rain chances, especially over
eastern NC. Gradually improving conditions are expected Sat night
into Sun as the coastal low moves NE away from NC. -GIH

&&

.CLIMATE...

Some record minimum and low-maximum temperatures for this week
may be in jeopardy.

DATE          RDU                GSO                FAY
          Min    Low Max     Min    Low Max     Min   Low Max

11/13   23 1977  39 1911   22 1977  35 1907   23 1911  43 1976
11/14   20 1977  39 1976   19 1986  38 1904   23 2013  45 1997

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...CBL
AVIATION...Hartfield
CLIMATE...RAH


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