-- Discussion containing changed information from previous version are highlighted. --
031
FXUS62 KRAH 131040
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
640 AM 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 330 AM Thursday...

The latest surface analysis shows surface high pressure centered
along and just off the mid-Atlantic coast early this morning with a
very weak pressure gradient across NC. The deep layer airmass across
central NC remains rather dry with PW values around or just over an
inch which is about 70% of normal. Further aloft, the main
westerlies generally traverse the U.S/Canadian border, however a
weak shortwave trough will move across the region early this morning
and then push off the coast toward midday.

Dry and generally fair weather is expected today across central NC.
Some widely scattered convection is expected across the Mountains
and just off the coast with little chance of precipitation across
central NC. Expect patches of cirrus clouds to move across the
region in association with the mid and upper level trough with the
cirrus clouds tending to wane during the afternoon as this feature
shifts east. Expect another round of late morning and afternoon
stratocumulus to develop again today, perhaps with a little less
coverage than Wednesday. The airmass across central NC will be a
little warmer than on on Wednesday and expect highs today to climb
into the upper 80s to around 90 which is about 1 to 4 degrees above
average. Lows tonight will range in the lower to mid 60s. -Blaes

&&

.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 /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 640 AM Thursday...

VFR conditions are generally expected to continue across most of
central NC for the 24 hour TAF period as weak high pressure ridges
into the region with a drier than average airmass across the region.
There are a few patches of MVFR fog early this morning mainly in the
Piedmont and Coastal Plain. A couple of disturbances aloft will
bring some patches of cirrus clouds across the region along with
some SCT to BKN daytime stratocumulus clouds with bases of 5-7kft
that are apt to develop during the late morning and continue into
the afternoon. Mainly light to calm winds early this morning from
the southeast to east will increase to between 4 and 8kts during the
day and become more southerly to southeasterly with very light winds
tonight.

Outlook: Generally fair weather with VFR conditions are expected
through early next week. A cold front will move through the region
late Friday into Saturday and could produce a shower or storm across
the north on Friday night, 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. -Blaes
-- End Changed Discussion --

&&

.CLIMATE...
-- Changed Discussion --
Record High Temperatures for Friday June 14:

KGSO: 98/1926
KRDU: 97/1944
KFAY: 100/2022
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...Blaes
NEAR TERM...Blaes
SHORT TERM...Blaes
LONG TERM...Danco
AVIATION...Blaes
CLIMATE...RAH