Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 301852
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
250 PM EDT SAT JUL 30 2016

.SYNOPSIS...
Hot temperatures and scattered afternoon and evening showers and
thunderstorms will persist through the rest of the weekend and into
early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 250 PM Saturday...

Scattered showers and tstms have developed as expected across
central NC, invof of the Piedmont trough, and to our west over and
just east of the mountains.  Aloft, sw flow persists across our area
on the east side of a broad trough centered over the Ohio and
Mississippi valleys.  For the rest of this afternoon into this
evening, the aforementioned showers and tstms will move east across
our cwa, but given the scattered nature, not all locations will see
rain, so for now will keep pops capped at 50%, implying the
scattered coverage. As for tstm intensity, latest mesoanalysis shows
plenty of instability, esp from the US-1 corridor eastward, but
shear is pretty weak, so look for mostly pulse storms, with perhaps
some modest clustering north and northeast of Raleigh where the
effective shear is the highest in our cwa. Given the instability, an
isolated severe cell (wind or hail the main threats) can`t be ruled
out, but given the weak shear, any severe cells won`t remain severe
very long.  Again, the best chance for a strong or severe cells will
be north and northeast of Raleigh closer to the better shear.

Look for shower/tstm activity to wind down around midnight, with the
remainder of the night partly cloudy. With little or no pattern or
airmass change, will lean toward persistence for temps.  Low`s
tonight in the mid 70s.

&&

.SHORT TERM /Sunday through Sunday night/...
As of 250 PM Saturday...

Sunday will start off much like today, with pc skies and isolated
showers or sprinkles perhaps lingering on old outflow boundaries.
Like today, isolated-to-scattered showers and tstms are expected to
develop invof of the Piedmont trough during the early-to-mid
afternoon.  Then during the early evening, guidance is suggesting
that a broken band of thunderstorms, first having formed over the
mountains, will move east across our cwa.  This band of tstms may
have a little better coverage since it will be supported by a
shortwave embedded in the sw flow. That shortwave is currently
moving across the central plains.  Despite this upper support, 0-6km
shear is still progged to be aob 25 kt. So once again, most storms
should remain below severe limits, but an isolated severe cell
or two still can`t be ruled out given the instability.

Speaking of instability, temps and dew points on Sunday will be
similar to today, given that the airmass will have changed little.
However, with slightly increased shower/tstm coverage, our
confidence of hitting heat advisory criteria in our eastern counties
is not particularly high. For now, will forecast highs in the lower
90s and heat indices around 100.  Nevertheless, it will still be
uncomfortably hot, so folks need to continue exercising the heat
precautions that we`ve been advertising.

&&

.LONG TERM /Monday through Saturday/...
As of 245 PM Saturday...

Relatively flat upper level trough will extend from New England into
the Carolinas at the beginning of the week. Perturbations rounding
the base of this trough will interact with available moisture
(precip water values hovering around 2 inches Mon and Tues) and
instability to trigger scattered convection. The bulk of the
convection will occur during the afternoon-early evening hours and
concentrated along a sw-ne orientated surface trough bisecting our
region.

An upper level ridge centered over the lower MS Valley/southern
plains is projected to amplify northward in response to an upper
level low crossing the Pacific NW. This should lead to building
heights over central NC the later half of the work week, leading to
a decreasing chance for afternoon/evening convection.

High temperatures early in the week will average close to normal due
to anticipated cloud and convection coverage. High temperatures will
likely return to above normal levels later in the week as the upper
level ridge exerts its influence on our weather.


&&

.AVIATION /18Z Saturday through Thursday/...
As of 250 PM Saturday...

24-Hour TAF period: Through 31/04z, scattered showers and
thunderstorms will locally reduce cigs and vsbys to mvfr or ifr
category. Outside of thunderstorms, look for VFR conditions and
winds generally from the w-sw 10-15kt. Higher/variable gusts near
tstms.  After 31/04z until 31/12z, look for mostly VFR conditions
with light s-sw wind.

From 12z Sunday and beyond:  similar conditions Sunday-Tuesday with
scattered afternoon/evening tstms and associated reduced flight
conditions. Patchy morning fog possible as well. During the mid-week
period, we may see decreased daily shower/tstm chances as slightly
drier air moves in the from the north.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for NCZ028-043-078-085-086-
088-089.

&&

$$

SYNOPSIS...np
NEAR TERM...np
SHORT TERM...np
LONG TERM...WSS
AVIATION...np



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