862
FXUS62 KRAH 140501
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
100 AM EDT Sun Jul 1342024

.SYNOPSIS...
A strong subtropical ridge will remain over the Southeast through
early to mid-week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 940 PM Saturday...

No convection developed along the Coastal Plain this afternoon. As
the HRRR correctly predicted, there are some high-based showers to
the northwest of the Triad that are slowly moving southeast.
However, the 00Z Greensboro sounding showed greatest saturation at
around 15 kft, and RH values below 80% from 11 kft to the surface.
With automated observations in the area showing cloud heights no
lower than 7 kft, and large surface dewpoint depressions, think that
these showers are likely virga, with precipitation evaporating
before it reaches the ground. Will not make any changes to the
forecast at this time, which has the chance for rain ending now.
Cannot rule out some patchy fog northeast of the Triangle, where the
greatest rainfall occurred over the last 48 hours and is the
location where the wind is the most likely to go calm. Lows will
range from the upper 60s near the VA/NC border to the mid 70s around
Fayetteville.

&&

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
As of 257 PM Saturday...

Steady warming trend begins Sun with temperatures rising into the
mid/upper 90s and heat index values ranging from around 100 to near
105. A lee trough will develop over western NC in between an area of
high pressure over the LA riding up into the Ohio Valley and the
anchored Bermuda High in the Atlantic. This will prompt mostly
southwesterly flow at the surface up through 850mb and advect in
warmer temperatures aloft (850mb 19 to 21C). This will support temps
rising into the mid/upper 90s through the early afternoon. Point
soundings indicate some relatively drier air aloft that will mix
down to the surface and keep surface dew points in mid 60s (W) to
low 70s (E). This should temper heat indices a bit, but still reach
around 100 to near 105 degrees. Isolated locations will likely reach
105 during the afternoon for a brief time, but areal coverage and
confidence is low enough to not preclude a heat advisory at this
time.

Some isolated to scattered showers/storms will be possible Sun
afternoon within a hot and humid airmass. Greatest coverage will
likely be along the lee trough in the western Piedmont as a low
amplitude shear axis sags over the area as well as along the
seabreeze, with subsequent showers/storms possible along convective
outflows. Severe potential remains low as deep layer shear remains
weak (around 20 kts) and warm/dry air aloft will work to combat
sustained deep convection. Isolated strong winds cannot be ruled out
if deeper convection is able to develop with a deeply mixed boundary
layer and DCAPE > 1000 J/kg in place.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
As of 257 PM Saturday...

The main weather story for Monday and Tuesday will be the intense
heat, given the pattern which features weak ridging and flow aloft,
coupled with H8 temp anomalies of 4-6 deg C above normal.  This will
result in highs in the upper-90s both days, and some low-100s can`t
be ruled out.  Heat indices of 105+ are expected from the Triangle
eastward on Monday, perhaps reaching as far west as the Triad by
Tuesday.  In terms of precip chances those days... coverage should
be isolated at best both days given the overall weak forcing over
the region.

PoPs will increase on Wednesday as heights begin to fall in advance
of a trough moving across the Great Lakes. With increasing flow
above the BL, expect to see the Piedmont trough sharpen and improved
low level convergence and subsequent outflow boundaries should be
the primary lifting mechanisms for increased shower activity. Shower
and thunderstorm activity, which may begin by early afternoon, may
help keep high temps limited to the lower 90s.

Rain chances will continue to increase, with well-above climo PoPs
by Thursday and for Friday and possibly Saturday as well as the
aforementioned trough pushes a cold front into the Mid Atlantic and
Carolinas regions before stalling over us.  That boundary, coupled
with another plume of deep moisture will likely result in several
rounds of heavy rains.  However, that will also keep temps limited
to near-climo values.

&&

.AVIATION /06Z SUNDAY THROUGH WEDNESDAY/...
As of 100 AM Sunday...

Aside from some patchy fog at fog prone locations like KRWI, VFR
will generally prevail overnight and into the afternoon. Isolated to
widely scattered diurnally driven showers and storms are possible
area-wide and have handled this low probability with tempo group
between 19 to 22z at all TAF locations.

Outlook: Isolated afternoon storms could result in sub-VFR conditions
at TAF sites early this week, but otherwise VFR conditions are
expected until the next front settles into the region with higher
chances of convection and flight restrictions late Wed-Thu.

&&

.CLIMATE...

Record High Temperatures:

July 14:
KRDU: 101/1954

July 15:
KGSO: 97/1974
KRDU: 99/1997

July 16:
KGSO: 99/1915
KRDU: 101/1887
KFAY: 103/1937

July 17:
KRDU: 100/1887
KFAY: 102/1932


Record High Minimum Temperatures:

July 13:
KGSO: 75/2017
KRDU: 78/2017
KFAY: 78/2017

July 14:
KGSO: 77/1981
KRDU: 77/2017
KFAY: 80/2017

July 15:
KGSO: 74/2019
KRDU: 76/1992
KFAY: 78/2015

July 16:
KGSO: 75/2010
KRDU: 77/2010
KFAY: 78/1992

July 17:
KGSO: 75/2013
KRDU: 80/1887
KFAY: 77/2019

July 18:
KGSO: 76/1986
KRDU: 79/1887
KFAY: 77/2019

July 19:
KGSO: 75/2016
KFAY: 77/2023

&&

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

&&

$$
SYNOPSIS...MWS
NEAR TERM...Green
SHORT TERM...Swiggett
LONG TERM...np
AVIATION...CBL/BLS
CLIMATE...RAH