-- Discussion containing changed information from previous version are highlighted. --
417
FXUS62 KRAH 200601
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
200 AM EDT Thu Jul 20 2017

.SYNOPSIS...
A weak upper level low over will drift slowly east and out into the
Atlantic tonight. A hot upper level ridge will build east from the
Plains to the Carolinas through Saturday, before breaking down
Sunday and Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 920 PM Wednesday...

No convection across the area at this time and skies have begun to
clear overhead. GSO sounding this evening was very dry and that is
expected to be the case overnight. Since dry conditions prevail at
all levels, no fog or low stratus is expected overnight tonight.
Winds will be calm or light and variable. Low temperatures overnight
in the upper 60s to lower 70s.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 208 PM Wednesday...

Heat and heat indices will start to become more of an issue Thursday
as the upper ridge builds east. Mostly sunny to sunny skies are
expected with only about a 10 percent chance of a storm at any one
location. The increase in sun and lack of cloudiness will help
temperatures reach the mid 90s (except lower 90s NW) Thursday. The
dew points are expected to range in the mid 60s NW and 67-70 in the
east during peak heating. This would give heat indices of 100 to 103
in the east, and 95-98 in the NW. A heat advisory is not anticipated
Thursday. However, that should change Friday. Lows Thursday night
are expected to be in the lower to mid 70s (as the dew points slowly
come up).

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 208 PM Wednesday...

An upstream ridge (over the lower MS river valley) and a downstream
ridge (offshore the SE coast) extending into the Carolinas Fri/Sat
will de-amplify Sun-Mon as an upper level ridge amplifies over the
Intermountain West, cyclonic flow aloft strengthens across the OH/TN
valley and Mid-Atlantic, and a closed low retrogrades westward along
the Gulf coast.

Fri-Sat: Expect temperatures several degrees above normal Fri/Sat,
with heat indices ~105F (primarily Triangle south/east), depending
on surface moisture/dewpoints. Heat advisories may be needed for
portions of the area Fri/Sat. With westerly flow aloft over the
central Appalachians and a lee trough extending southward through
central VA/NC in the midst of moderate diurnal destabilization,
expect a potential for scattered convection during the afternoon and
evening hours Fri-Sat, though activity could be suppressed over
eastern portions of the state depending on the strength/orientation
of the offshore ridge.

Sun-Wed: Above normal temps/humidity may persist into Sunday, though
chances for convection will also increase as cyclonic flow aloft
strengthens over/upstream of the Mid-Atlantic. With an unseasonably
complex synoptic pattern over the mid-latitudes, uncertainty
increases significantly by early/mid next week. At this time, will
indicate near normal temperatures and near climatological chances
for convection Mon-Wed, in assoc/w a synoptic pattern generally
characterized by ridging over the western CONUS and troughing over
the eastern CONUS. -Vincent

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 200 AM Thursday...

24 hour TAF period...VFR conditions will perist in subsidence in the
wake of the broad upper low/trough moving off the SE coast. Winds
will be light and generally west to southwest with lee troffing over
the western Piedmont through the period.

Outlook for Friday through Monday... Generally VFR conditions are
expected Friday and Saturday. Scattered PM thunderstorms may return
Sunday and Monday with associated MVFR to IFR conditions.
-- End Changed Discussion --


&&

.CLIMATE...
RDU Records:
Date     | High   Year  |  High Min  Year
------------------------------------------

20 July  |  102   1942  |     76     1981
21 July  |  102   2011  |     78     1932
22 July  |  103   2011  |     78     2011
23 July  |  105   1952  |     78     2011
24 July  |  101   2011  |     79     2011

GSO Records:
Date     | High   Year  |  High Min  Year
------------------------------------------

20 July  |  100   1977  |     75     1986
21 July  |  102   1926  |     76     2011
22 July  |  101   1926  |     77     2011
23 July  |   99   1952  |     78     2010
24 July  |   99   1914  |     78     2010

FAY Records:
Date     |  High  Year  |  High Min  Year
-------------------------------------------

20 July  |  104   1932  |     80     1996
21 July  |  105   1932  |     79     1977
22 July  |  107   1932  |     79     2011
23 July  |  103   2011  |     79     1998
24 July  |  105   1952  |     79     1945

&&

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

&&

$$

SYNOPSIS...Badgett
NEAR TERM...Ellis
SHORT TERM...Badgett
LONG TERM...Vincent
AVIATION...CBL/mlm
CLIMATE...RAH