250
FXUS62 KRAH 141034
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
635 AM EDT Sun Jul 14 2024

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

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 330 AM Sunday...

...A Heat Advisory Has Been Issued for portions of the Central
Piedmont, Sandhills, and Coastal Plain Counties...

A flat but strong upper ridge over the SE US coupled with Bermuda
surface high pressure will result in hot and humid conditions over
the next several days. Meanwhile, the lingering sfc front will wash
out into a lee troughing along the eastern slopes of the
Appalachians. The heat returns in strong fashion today as H8 temps
are forecast to warm from 19 to ~22 C this afternoon, with similarly
impressive increase in low-level thicknesses from 1432m to ~1442m.
Afternoon highs are expected to warm into the mid to upper 90s. A
weak/light westerly downslope component will aide in mixing
dewpoints down into the 60s across the western Piedmont, which will
help to mitigate the heat risk. However, dewpoints across the
remainder of the area will consist in the lower to mid 70s, yielding
heat indices of 104 to 109 degrees across the Central Piedmont,
Sandhills, and Coastal Plain counties. In coordination with our
eastern neighboring NWS offices, will issue a Heat Advisory that
will go in effect at 11 am and continue through 7pm.

In terms of rain chances, a very weak, low-amplitude shortwave will
traverse the mid-Atlantic region during the afternoon and early
evening. Weak lift from this feature, as well as the lee side sfc
trough, amidst very steep low-level lapse rates, will support
isolated to widely scattered showers and storms just about anywhere.
Any convection will quickly dissipate after loss of heating with dry
conditions overnight. Lows in the lower to mid 70s.


&&

.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 /11Z SUNDAY THROUGH WEDNESDAY/...
As of 635 AM Sunday...

An area of fog over the northern coastal plain and associated IFR
restrictions at KRWI will quickly dissipate after sunrise.

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...
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...MWS
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...Danco
AVIATION...CBL/BLS
CLIMATE...RAH