-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 290732
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
332 AM EDT Thu Jun 29 2017

.SYNOPSIS...
High pressure will continue to shift offshore today. A warm front
will track from the Gulf Coast northeastward into North Carolina on
Friday, bringing a return to warm and humid weather for the upcoming
weekend.

&&

.NEAR TERM /Today and Tonight/...
As of 911 PM EDT Wednesday...

A modified ~1023mb cP surface high will move off the DELMARVA coast
this evening with attendant sfc ridge axis extending east into the
area overnight. Mostly clear skies, light winds and antecedent dry
air in place (BL dewpoints in the mid 50s and PWATS between 0.5-
0.6")will result in good radiational cooling conditions overnight.
So expect another night of below normal low temps, ranging from the
mid/upper 50s to lower 60s, coolest in the typical rural/low-lying
areas.

&&

.SHORT TERM /Thursday and Thursday night/...
As of 135 PM EDT Wednesday...

A relatively dry airmass associated with modified Canadian high
pressure extending westward (from the Atlantic) into the Carolinas
will persist on Thu, albeit with a gradual increase in moisture from
the S/SW during the aft/eve as the surface high moves further
offshore, the ridge weakens, and a light return flow commences.
Upper level moisture will also increase on Thu as a deamplifying
upper level low progresses NE from the TX/LA Gulf coast into the
Deep South. With the above in mind, expect dry conditions and
increasing cloud cover on Thu with highs in the mid to upper 80s,
warmest E/SE. The deamplifying upper level low is progged to make
little progress Thu night, progressing NE into northern AL/northwest
GA. Strengthening southerly return flow /moisture advection/ is
expected to result in the development of stratus from S/SW to N/NE
overnight. As a result, expect much warmer lows than observed in
previous days, in the mid to upper 60s, except in the far NE Coastal
Plain where lower 60s cannot be ruled out. Will introduce a slight
chance of showers after midnight in the far S/SW, though the best
potential for showers should remain upstream in upstate SC,
southwest NC and northern GA where richer low-level moisture will be
juxtaposed with DPVA attendant the upper level low. -Vincent

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 330 AM EDT Thursday...

The weekend will start with a weak upper level trough moving through
the Great Lakes and a surface low over Ontario with an attendant
cold front pushing towards the Appalachians. This will be slow to
arrive however and Saturday will be characterized by southerly flow
with pre-frontal moisture supplying diurnal showers before the front
pushes through on Sunday morning. Despite winds trying to go
northerly on Sunday morning they will quickly switch back to
southerly as the lee trough develops over central NC. This leaves
little airmass change and highs still in the upper 80s to low 90s.

By Monday the ridge axis moves through and begins to weaken brining
more westerly upper level flow. Monday looks like a drier day as
high pressure tries to move in from the north but diurnal showers
and storms are still possible, especially in the far southeastern
counties.  Highs will still be in the lower 90s.  Tuesday looks like
more of the same as zonal flow aloft combine with a lee surface
trough that give us a chance for afternoon thunder but severe
weather is not expected.

Confidence is low for Wednesdays forecast as a lot will depend upon
the development of a surface low either to our northwest (GFS
solution) or pretty much right over central NC. The latter would
bring a much wetter forecast for Wednesday but it is still too early
to hash out those details. Either way it will be hot with highs in
the mid 90s and heat indices beginning to approach 100 degrees.
-- End Changed Discussion --

&&

.AVIATION /06Z Thursday through Monday/...
As of 145 AM Thursday...

High confidence in VFR conditions today through tonight. The center
of high pressure will continue to move out over the Atlantic while
extending back westward across NC into tonight, bringing light
surface flow mainly from the S or SSW. Any cigs will be based above
20,000 ft AGL through 06z Fri, with just scattered afternoon cumulus
based around 5,000 ft AGL expected.

Looking beyond 06z Fri, there is a chance for late-night sub-VFR
conditions late tonight/Fri morning, however models aren`t in good
agreement on this, as there is also a chance that mid and high
clouds will thicken and lower as they spread over the area from the
SW, which would limit radiational cooling and thus limit stratus and
fog development early Fri morning. As a warm front moves into the
area from the SW on Fri, the chances for showers/storms will return
Fri afternoon. Sub-VFR conditions, mostly thick low stratus, are
likely Fri night, starting in the evening and persisting through Fri
night and into Sat morning. Scattered showers/storms will remain
possible through the upcoming weekend, mainly in the afternoon
through early evening. Sub-VFR stratus is again possible early Sun
morning, but with a lower coverage and duration as compared to Fri
night/Sat morning. Shower/storm chances will be lower on Mon,
although a chance remains along/east of I-95. -GIH

&&

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

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...CBL
SHORT TERM...Vincent
LONG TERM...Ellis
AVIATION...Hartfield