Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 290806

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

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


.NEAR TERM /Today through tonight/...
As of 335 PM Thursday...

The glorious below-normal temps and low humidity of the last few
days are sadly showing signs of coming to an end. The surface ridge
responsible for the quiet weather of late is continuing to shift
offshore, and the ensuing low level flow primarily from the south
will open the gates for a return of the temps and humidity more
typical of late June/early July. But today should provide us with
one last day of abundant sunshine (albeit filtered by high thin
clouds, especially across the north and west) and somewhat low
dewpoints as the surface ridge still extends back westward over the
area, while brief weak mid level ridging covers the Carolinas. We`ll
remain on the southern edge of the nearly zonal westerlies today,
meaning that cirrus blowing off widespread convection over the
central Plains and mid Miss Valley is likely to brush across our
northern sections during the day. And as the mid level wave now
sitting over LA begins to lift slowly to the NNE, accompanied by a
low level frontal zone extending along the central and eastern Gulf
Coast, the shield of mid and high clouds to the NE of the wave will
begin to spread into our SW sections. We`re also currently seeing
shallow moist upglide around 300K just to our SW across SW NC and
adjacent upstate SC, and a few of these could drift into our W
sections through dawn. All of this will translate into mostly sunny
skies for much of the area, except partly sunny for most of the day
in the western CWA. Clouds will become more opaque late today
through tonight with coverage increasing from SW to NE and lowering
bases, as deeper moisture and higher PW spreads in from the SW. We
may also see some low late-night stratocumulus develop as the 925 mb
flow from the SE and SSE pulls in low level Atlantic moisture, which
will also facilitate a rise in dewpoints tonight. Expect highs today
of 86-90, with slightly below normal thicknesses balanced with
decent insolation. Lows tonight from 62 NE (where the drier
dewpoints will hang on longer) to 68 SW. -GIH


.SHORT TERM /Friday through Friday night/...
As of 405 PM Thursday...

The baggy mid level low over LA early this morning will open up and
lift ENE across the Carolinas Fri. The increasing forcing for
ascent, including mid level DPVA and subtle upper divergence, will
arrive in conjunction with a surge in PW to over 2.0". Despite the
moisture, however, the light low level flow will result in very weak
mass convergence, and the models project fairly low MUCAPE Fri
afternoon with only the SE CWA seeing values approaching moderate,
along with deep layer shear under 25 kts. Considering all, will
bring in a chance of showers/storms from SW to NE Fri, highest (50-
60%) SW and just isolated in the NE, peaking in the afternoon. This
is in line with the consensus of model guidance which all develop
precip over the CWA with maxima largely in different locations.
Expect precip to trail off after nightfall as the mid level wave
heads to our NE with waning lift mechanisms, a weakening low level
frontal zone, and a slight decline in PW. Will retain just low
chances of mostly showers overnight. While thicknesses climb further
Fri, the clouds and expected precip should hold temps down a bit.
Expect highs in the mid-upper 80s (coolest west). Lows Fri night in
the upper 60s to lower 70s under overcast skies. -GIH


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.


.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





NEAR TERM...Hartfield
SHORT TERM...Hartfield
AVIATION...Hartfield is the U.S. government's official web portal to all federal, state and local government web resources and services.