064
FXUS62 KRAH 160739
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
338 AM EDT Tue Jul 16 2024

.SYNOPSIS...
A strong subtropical ridge will gradually weaken over the Southeast
though mid-week. A cold front will settle into the Carolinas on
Thursday, then become quasi-stationary while weakening into the
weekend.

&&

.NEAR TERM /TODAY AND TONIGHT/...
As of 330 AM Tuesday...

...Dangerous and Near Record Heat Continues...

...Heat Advisory Remains in Effect from Noon Today to 8 PM...

There is very little to no change in the synoptic pattern and
antecedent airmass in place as subtropical ridging and Bermuda high
pressure unite to sustain dangerous and near record heat across the
region. Highs will be very similar to yesterday, in 95-100 range,
with heat indices ranging from lower 100s in the NW Piedmont to as
high as 109-110 across interior and eastern/southern portions. As
such, Heat Advisory has been issued for generally the same
climatological divisions across central NC.

PWATs are progged to inch up slightly to around 2.2-2.3" and there
remains a signal in the hi-res models that convective coverage
should be higher than recent days as weak upper impulses emanating
through the ridge and atop lee troughing could potentially help to
drive a west to east moving cluster of showers and storms across
central NC between 18 to 03z. Given the moist environment, some
locally heavy rain rainfall and minor flooding is possible. Also,
given the high CAPE/steep lapse rate environment, cannot rule out an
isolated strong/severe downburst.

Bulk of convection should dissipate by midnight. Balmy overnight
lows in the mid to upper 70s, except for some lower 70s across the
far northern Piedmont counties.


&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 330 AM Tuesday...

...One Last Day of Dangerous Heat....

Moisture will continue to increase in advance of an upper trough and
attendant cold front that will progress SEwd into the Ohio and Tn
Valley late Wednesday-Wednesday night. The influx of ~2.5" PWATs
into the area will result in an uptick in showers and storms
Wednesday afternoon and Wednesday night as another parade of vort
impulses spread through the region during max heating/
destablization. While the increase in cloud cover and PoPs will
temper the dry-bulb temps more into the lower/mid 90 ranges, there
will be less mixing out of afternoon dewpoints. Thus, we`ll see one
last day of heat advisory criteria of heat indices in the 103-107
range across much of the same area.

Deep layer shear is forecast to increase to ~25kts, which is higher
than recent days. As such, SPC has introduced a level 1/marginal
severe threat across the northern half of the forecast area, with
wind the primary threat.

Given the moist airmass and weak height falls starting to spread
into the region , convection could linger well into the overnight
hours. Lows in the 70s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
As of 315 PM Monday...

The long term period is shaping up to be unsettled each day, and
potentially wet on Thursday and Friday.  The period will start off
Wednesday with a trough digging and moving east over the Great Lakes
region.  A sfc front during this time will be moving across the Ohio
Valley.  Meanwhile, over our region, moist sw flow, pwat well over 2
inches, along with an ongoing Piedmont trough will set the stage for
scattered showers and tstms during the afternoon and evening.  Until
these storms move through, look for highs to quickly climb into the
mid 90s with heat index values in excess of 100 across much of the
state and possible heat advisory criteria across the eastern half of
our CWA.

Thursday and Friday still look to be the wettest days in the long
term period with the aforementioned front moving into our area and
tapping the moist air mass thats in place.   Given the slow-moving
nature of the front, there could be slow-moving and repetitive
showers/tstms both days.   The latest WPC ERO for these two days
basically show marginal across the western half of the state and
slight across the eastern half of the state, while marginal exists
across the entire state on Friday.  Given the anticipated cloud and
shower/tstm coverage, temps will be cooler both days with highs in
near 90 on Thursday and perhaps mid 80s on Friday.

The upper trough will gradually lift out over the weekend and by
Monday the ridge will become re-established over the Southeast.   As
such, the late-week front will lift back to the north and become
stationary invof the VA/NC border by late in the weekend and for
Monday. That boundary, along with the typical Piedmont trough over
the area, will result in daily mostly-diurnal aoa climo PoPs each
day Sat through Mon.  Temps during this time may continue to be held
back by cloud cover, so will lean toward lower end of the temp
guidance envelope, with highs in the upper 80s to around 90.

&&

.AVIATION /05Z MONDAY THROUGH SATURDAY/...
As of 127 AM Tuesday...

VFR conditions are mostly expected overnight. However, based on
persistent, cannot rule out isolated pockets of fog, mainly at KRWI.

Shower and storm coverage this afternoon and evening is expected to
be higher than the past couple of days, with a general consensus
that a cluster of storms will move west to east across the area
between 18 to 00z. Have added a prob30 for all TAF sites.
Convection should dissipate between 03 to 06z.

Outlook: Mainly VFR conditions are expected to continue away from
diurnally-driven convection, which will gradually increase in
coverage through Wed. A cold front will move into NC late Wed-Wed
night, then become quasi-stationary over the region Thu-Sat. Higher
chances of flight restrictions, both in and away from diurnally-
maximized convection, will consequently result Thu-Sat.

&&

.CLIMATE...
Record High Temperatures:

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

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


Record High Minimum Temperatures:

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

July 20:
KGSO: 75/2019
KRDU: 76/2020

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon today to 8 PM EDT this evening for
NCZ007>011-023>028-039>043-073>078-083>086-088-089.

&&

$$

SYNOPSIS...MWS
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...np
AVIATION...CBL/Luchetti
CLIMATE...RAH