865
FXUS62 KRAH 141720
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
120 PM EDT Sun Jul 14 2024

.SYNOPSIS...
A strong subtropical ridge will remain over the Southeast through
early to mid-week. A cold front will approach from the northwest on
Wednesday and stall out over the region into the weekend, resulting
in unsettled weather to close out the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 120 PM Sunday...

Heat indices along and east of US-1 are currently between the lower
100s and 108-109, highest in the Sandhills to southern Coastal
Plain. The Heat Advisory will remain in effect until 7 pm as the
continued heat will pose a risk for those without effective cooling
or hydration. West of US-1, dewpoints have mixed out as expected in
the upper 60s, with some middle to low 60s in the Triad. This has
led to heat indices largely in the upper 90s.

Satellite imagery reveals two areas to watch for shower/storm
development. Visible satellite shows that one area is along the
Foothills tied to a lee trough, where some isolated storms have
already developed. The second area is along the southern Piedmont,
Sandhills, where some agitated cumulus have developed perhaps along
a subtle moisture boundary separating the low/higher dewpoints. The
latest CAMs show that nearly any location could see a spotty
isolated storm into early evening. However, the more focused chance
(30-percent) would appear over the west/northwest Piedmont along the
lee trough, as well as over the Sandhills to central Coastal Plain
along the subtle boundary and where instability is highest. While we
do not expect any organized severe into the evening, with some 20
kts of deep layer shear, cannot rule out an isolated storm putting
out some brief strong gusty winds with high DCAPE (900-1200 J/kg)
over the region.

Any storms will die out around sunset with the loss of heating.
Overnight lows will be quite mild and muggy with mid to upper 70s,
except low 70s in outlying areas of the Piedmont.


&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
As of 330 AM Sunday...

...Dangerous Heat Persist...

...Record Breaking Temperatures...

The Carolinas will remain under the influence of the upper ridge and
Bermuda high pressure. Models continue to suggest that the heat will
continue to build ever so slightly with record breaking high temps
expected at 2 of our 3 climate sites(GSO and RDU-see climate section
below) as most locations warm into the upper 90s, with some triple
digits/lower 100s possible in the typically warmer locations. A Heat
Advisory in all likelihood will be needed for the same area with
heat indices again topping out in the 105 to 109 degrees.

Some short term relief may come in the form of some widely scattered
convection as the area remains vulnerable to weak disturbances
moving through the area, with the seabreeze expected to be a little
more active.

Balmy overnight lows in the mid to upper 70s, which will also
challenge record hi-min temps.


&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 400 AM Saturday...

Broad mid-level ridging extending from the western Atlantic into the
Southeast US will begin to shift east on Tuesday as troughing moves
into the Upper Midwest associated with a closed low over southern
Canada. This will help shift the mid-level flow from purely zonal to
more WSW, bringing in Gulf moisture and above-normal PW values of
around 2 to 2.25 inches. Thus shower and storm chances will be on
the increase, and model guidance has overall trended wetter on
Tuesday compared to last night. Still, there will be a lack of
shear, and little in the way of upper forcing means POPs are capped
at slight to 30-40%. The best chances for diurnal convection will be
focused near the Piedmont trough and sea breeze. It remains unclear
exactly how much clouds and precipitation will affect Tuesday`s
temperatures, but the latest forecast is slightly less hot given the
wetter trend. Still, forecast highs are in the mid-to-upper-90s,
with heat indices of 105+ from the Triangle south and east.

A very wet pattern looks to set up for the rest of the extended
period. PW values and precipitation chances increase further on
Wednesday as the mid-level troughing digs into the Great Lakes and
the flow aloft over central NC turns even more southwesterly as
heights fall. This trough will drag a strong cold front that looks
to reach the OH and TN Valleys on Wednesday/Wednesday night. So POPs
are likely across the whole area. Another hot day is expected, with
forecast highs mostly mid-90s and heat indices around 105 possible
in the south and east. However, temperatures may again be kept down
by the clouds and precipitation. Low temperatures Tuesday and
Wednesday nights won`t provide a lot of relief, only dropping to the
mid-to-upper-70s.

Thursday and Friday have the greatest rain chances as the wavy cold
front approaches central NC and slows down, possibly retreating back
NW on Saturday. Deep southwesterly flow aloft ahead of mid-level
troughing that really digs into the lower MS Valley will continue to
bring in PW values of 2 to 2.5 inches. So there will be plenty of
moisture and instability for this front to tap. Ensemble mean QPF
from Thursday through Saturday is 1.5 to 3 inches, greatest south
and east, and of course locally higher amounts will always be
possible. WPC already introduced a marginal (level 1 of 4) risk for
excessive rain on Thursday. While this much rain for multiple days
in a row may cause some flooding concerns, it will also provide more
welcome drought relief. It will also help bring down high
temperatures to upper-80s to lower-90s on Thursday and only upper-
70s to mid-80s on Friday and Saturday.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
As of 1255 PM Sunday...

While conditions are likely to remain VFR through the 24-hour TAF
period, there remains the chance of some isolated to widely
scattered diurnally driven storms that could impact the terminals,
mainly between 19 and 23z along a lee trough and upper disturbance
The best chance appears at RDU/FAY/RWI. There is no clear signal for
fog or low ceilings Mon morning, but if a shower impacts any of the
terminals, there could be some sub-VFR restrictions overnight.

Outlook: Isolated storms remain in the forecast early this week, but
generally VFR is expected. A better chance of widespread showers and
storms, and thus flight restrictions,  occurs in the Wed-Fri period
as a front settles into the region.

&&

.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...
Heat Advisory from 11 AM this morning to 7 PM EDT this evening for
NCZ008>011-025>028-040>043-075>078-084>086-088-089.


&&

$$
SYNOPSIS...Kren
NEAR TERM...Kren
SHORT TERM...CBL
LONG TERM...Danco
AVIATION...Kren
CLIMATE...RAH