-- Discussion containing changed information from previous version are highlighted. --
726
FXUS62 KRAH 200723
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
322 AM EDT Thu Jun 20 2024

.SYNOPSIS...
Anomalously strong high pressure centered over the Northeast will
gradually weaken while shifting into the Middle Atlantic late in the
work week before moving into the Tennessee Valley over the weekend.
A cold front will approach the region on Monday.
&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
As of 322 AM Thursday...

The anomalously strong upper level ridge centered over the mid-
Atlantic, which was sampled at 599 dm at KIAD, KPIT and KOKX this
past evening, will begin to undergo gradual weakening as it starts
to retrograde southwestward into the Tn Vally by Friday morning.
Surface high pressure parked off the mid-Atlantic coast will
maintain a light easterly flow into the area as a small/weak area of
low pressure near Bahamas drifts westward towards the east coast of
Florida.

A dry and subsident airmass, void of any appreciable instability,
will continue to yield dry conditions across central NC as flat cu
dots the afternoon skyline.

A modest increase in low-level thicknesses(+5-7m) and H8 temps(+2-
2.5C) may yield 1 to 2 degrees of warmth in some locations.
Otherwise, highs will be very similar to the past couple of days
with highs ranging from upper 80s north to lower 90s across the
south. The mixing of drier air to the surface will continue to
mitigate the heat, as afternoon dewpoints fall into the lower/mid
60s. Lows tonight in the 60s.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
-- Changed Discussion --
As of 322 AM Thursday...

Under the continued influence of the weakening, but still quite
strong ~595 dm ridge centered over the Tn Valley/mid south, low-
level thicknesses and h8 temps will increase over central NC.
Atlantic high pressure will continue to extend west into the area as
an inverted sfc trough extends north along the SE US coast from the
weak area of low pressure moving inland into the Florida.

Still one day away from the oppressive 70-75 dewpoint air advecting
into the area, heat indices will be comparable to the dry bulb temps
Friday afternoon, topping out in the lower/mid 90s.

Models do indicate the development of weak instability of 500-1000 J
across the far SE zones, which may allow a convective cell or two to
survive as it`s move inland. Otherwise, continued dry.

Expect milder overnight lows and rising humidity as the low-level
becomes increasingly south-southeasterly. Lows in the upper 60s to
lower 70s.
-- End Changed Discussion --


&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 318 PM Wednesday...

..Dangerously Hot Temperatures Expected this Weekend and into Early
Next Week...

Heat will continue to be the primary weather story as we head into
the weekend, thanks to the mid/upr ridge and it anomalously hot
airmass that is currently blanketing areas to our north. That ridge
and it`s airmass will shift south and by Friday will be centered
over the TN Vally, with its airmass extending across our area thanks
to mid/upr northerly flow on the east side of the ridge.  It`s worth
noting an upper trough off of Carolina coast, which will reinforce
the mid/upr northernly flow and aforementioned airmass.  Meanwhile,
the sfc trough that NHC is currently keeping an eye on that is
currently east of the Bahamas is expected to be inland, well to our
south, by Friday morning with no impact on our weather.  The
expansive sfc ridge that`s currently centered just off the Mid-
Atlantic Coast will weaken a bit and drift south by Friday, thus
resulting in low level flow over our area taking on a more s/sw
direction, which will in-turn begin to increase low level moisture
advection across our area for the weekend and into next week (thus
further increasing humidity).

The end result of this pattern will be hot and mostly rain-free
conditions for central NC Friday and this weekend, with intensifying
heat and humidity resulting in highs reaching the mid/upper 90s by
Saturday and perhaps continuing into early next week.  With dew
points in the 70s by then, heat indices of 100-105 F will be
possible with Sunday and Monday expected to pose the greatest heat
risk. This level of heat will affect anyone without effective
cooling and/or adequate hydration.

By late Sunday and Monday we`ll finally have PoPs in the forecast,
perhaps in the 20-30 percent range, thanks to increasing moisture in
advance of a short wave trough that will approach late Sunday and
cross our region on Monday.  Hopefully scattered showers/tstms late
Sunday and Monday may provide at least some temporary relief to the
heat. Thereafter, continued hot with below-climo PoPs Tuesday and
Wednesday in the wake of the aforementioned short wave trough.

&&

.AVIATION /05Z THURSDAY THROUGH MONDAY/...
As of 110 AM Thursday...

Subsidence and associated with the anomalously strong upper level
ridge extending over the region will continue to support
predominately dry, VFR conditions through the forecast period.
The exception is the potential for a brief period of sub-VFR vsbys
at fog prone RWI during the predawn hours. Offshore surface high
pressure will continue to yield light easterly surface winds.

Outlook: VFR and dry conditions are expected to persist through
Saturday. An approach of a northern stream trough and attendant cold
front into the region will support scattered showers and storms
and related sub-VFR restrictions.

&&

.CLIMATE...

Record High Temperatures:

June 22:
KRDU: 100/2022
KFAY: 101/2022

June 23:
KRDU: 100/1986
KFAY: 102/1981

June 24:
KRDU: 99/2010
KFAY: 102/1914

June 25:
KRDU: 100/1952
KFAY: 102/1914


Record High Minimum Temperatures:

June 22:
KGSO: 75/1981
KRDU: 78/1933

June 23:
KGSO: 74/2015
KRDU: 77/1890
KFAY: 77/2017

June 24:
KGSO: 76/2015
KRDU: 76/1888
KFAY: 79/2010

June 25:
KGSO: 75/2015
KRDU: 77/2010
KFAY: 75/1952

&&

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

&&

$$
SYNOPSIS...cbl
NEAR TERM...cbl
SHORT TERM...MWS
LONG TERM...np
AVIATION...cbl
CLIMATE...RAH