529
FXUS62 KRAH 131721 RRA
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
120 PM EDT Thu Jun 13 2024

.SYNOPSIS...
Surface high pressure over the northern mid-Atlantic will drift east
and move off the mid-Atlantic coast this morning. An area of low
pressure will move off the east coast of Florida later today and
then lift northeast off the mid-Atlantic coast through late Friday.
A cold front will then slide southward into the area Friday night
and Saturday.

&&

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

As the surface high slips offshore, associated E-SELY low level flow
into the area will lead to warming temps and building humidity
levels.  Expect another round of scattered to occasionally broken
afternoon stratocumulus as highs today range from mid 80s north,
upper 80s central area, to around 90 across the southern, which is
about 1 to 4 degrees above average.

Otherwise, the total air column across central NC remains rather dry
with below PW values well below normal. This dry air coupled with
the lingering mid level cap will squash any weak diurnally driven
lift and showers that tries to develop over interior NC.

The mid and high clouds associated with the extremely weak shortwave
moving through the SE US and developing offshore coastal low will
pass east of the area this evening , leaving behind mostly clear
skies. However,  probabilistic guidance indicates a low end chance
for some fog/stratus across the far eastern/coastal plain counties
towards sunrise. Lows similar to this past morning, ranging from
lower 60s north,  to mid/upper 60s central and southern areas.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 400 AM Thursday...

* Hottest day of the season thus far expected on Friday.

Friday still appears like it will be the hottest day of the season
thus far in many locations. Surface high pressure will be well off
the mid-Atlantic and New England coast on Friday as low pressure
organizes and develops off the GA/FL coast and then moves northeast
and off the VA Capes by Saturday morning. In addition, a cold front
will move across the Mountains of WV/and VA on Friday afternoon and
then push across central NC late Friday night and early Saturday
morning before reaching the SC border around daybreak Saturday. The
airmass across central NC remains rather dry and becomes only weakly
unstable on Friday afternoon. Mid level lapse rates are not too
impressive and convection allowing models keep most of central NC
dry during the evening and into the overnight. Have accordingly kept
most of central NC dry with the just a slight chance of a shower or
thunderstorm across the northern Coastal Plain and near the VA
border where CAMs suggests the best chance of a storm exists.

With subsidence between the approaching front and the area of low
pressure off the coast, the air mass across central NC moderates
further with Friday morning low level thickness values generally in
the 1400-1405m range. While objective guidance has nudged highs down
a degree or two than previous runs, still expect highs in the lower
to possibly mid 90s. Still expect enough mixing to keep dew points
in the 60 to 65 range which should keep max heat index values in the
lower to mid 90s. There is still concern about the impact of heat on
vulnerable populations as this will be the hottest day of the year
thus far in many locations. Muggy lows in mid 60s to around 70 are
expected on Saturday morning. -Blaes

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 335 AM Thursday...

NNE flow behind the cold frontal passage on Friday night and
Saturday morning will advect slightly cooler and drier air into
central NC. This will provide some relief from the heat and humidity
this weekend, but it will still be hot and slightly warmer than
normal. Forecast highs both Saturday and Sunday are upper-80s to
lower-90s, with lows generally in the 60s. Dew points will only be
in the mid-50s to lower-60s, aided by NW downsloping flow aloft
around a mid/upper ridge that will be over the Deep South. If the
progression of the cold front is slow enough, a small minority of
GFS/ECMWF/Canadian ensemble members indicate a shower or storm can`t
be ruled out in the extreme SE (mainly southern Sampson County) on
Saturday afternoon and evening, so continue slight chance POPs
there. But even this may be overdone as the forecast keeps trending
drier.

The anomalous mid/upper ridge will continue to strengthen through
the rest of the period, from 592 dam to possibly as much as 600 dam
by midweek if the 00z ECMWF is to be believed. The ridge will
initially centered to our west over the southern Appalachians on
Sunday/Monday before moving north to PA/Upstate NY and the Lower
Great Lakes by Wednesday. At the surface, high pressure will move
off the New England coast on Sunday and linger in the western
Atlantic into midweek, shifting the low-level flow over central NC
to a SE direction. This will bring increased clouds, particularly in
the west. Upslope showers and storms also may develop over the
Mountains, and while they should largely stay to our west, ensemble
probabilities indicate a few could drift into our far W or NW
counties. Thus continue slight chance POPs there each afternoon from
Sunday through Wednesday. Otherwise and elsewhere, dry air and
subsidence from the mid/upper ridge should preclude any convective
development. The building ridge will also help temperatures increase
once again, with forecast highs from Monday through Wednesday mostly
in the lower-90s and forecast lows in the upper-60s to lower-70s.
Models agree there will be enough mixing to keep dew points from
getting too oppressive (generally in the 60s), but heat indices will
still peak in the lower-to-mid-90s each day.

&&

.AVIATION /18Z THURSDAY THROUGH MONDAY/...
As of 120 PM Thursday...

Dry VFR conditions are expected through the period. The possible
exception could be at KRWI, where probabilistic guidance indicates a
very low end chance for some fog/stratus across the far
eastern/coastal plain counties towards sunrise Friday morning. Winds
will remain light through the period.

Outlook: Isolated showers are possible late Friday as a moisture
starved cold front moves through the region. Otherwise, generally
dry weather is e expected. Some patchy late night/early morning fog
or stratus is possible across mainly southern and eastern locations
into the weekend.

&&

.CLIMATE...
Record High Temperatures for Friday June 14:

KGSO: 98/1926
KRDU: 97/1944
KFAY: 100/2022

&&

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

&&

$$

SYNOPSIS...Blaes
NEAR TERM...CBL
SHORT TERM...Blaes
LONG TERM...Danco
AVIATION...CBL/BLAES
CLIMATE...RAH