-- Discussion containing changed information from previous version are highlighted. --
275
FXUS62 KRAH 192325
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
720 PM EDT Wed Jun 19 2024

.SYNOPSIS...
Anomalously strong high pressure, and sinking and warming air, will
gradually weaken while settling from the Middle Atlantic southward
and across the Southeast through this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 318 PM Wednesday...

An anomalously strong ~598 dam anticyclone at 500 mb will remain
centered over the northern Mid-Atlantic through tonight. At the
surface, ~1030 mb high pressure centered to the SE of New England
will slowly drift south and extend SW into the Mid-Atlantic. This
pattern will continue to support easterly flow both aloft and at the
surface. A pretty extensive deck of scattered to broken flat cumulus
has developed across central NC, but it will remain capped beneath a
strong subsidence inversion around 800-850 mb. Water vapor imagery
depicts a lot of dry air over central NC, and this will also
continue through tonight with PW values only 70-80% of normal. This
is again helping dew points mix out to the upper-50s to lower-60s
this afternoon, which is keeping heat indices well below advisory
criteria and close to the actual air temperatures (mid-80s to 90). A
few light sprinkles off the coast may reach far eastern NC through
early evening, but with so much dry air and subsidence not expecting
anything to make it this far inland. Went on the cooler side with
low temperatures tonight, mostly lower-to-mid-60s, given what
occurred this morning, the dry air in place, and models showing low-
level thicknesses staying very similar.

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 325 PM Wednesday...

An anomalously-strong mid-level ridge over the nrn Middle Atlantic --
with 12Z-observed 500 mb heights that ranked in the top ten in
observational period of records at GYX, CAR, ALB, RNK, WMW, and OKX
- the latter of which tied the highest all-time of 598 dam
previously set in July 2013-- will drift swwd across the OH Valley
through 12Z Fri. A deeply dry and capped environment will remain
over cntl NC, with forecast PWs near to slightly below one inch
(~25th percentile).

Downstream surface high pressure over the w-cntl Atlantic will
likewise drift swd to near and just north of Bermuda, while
continuing to extend wwd across the srn Middle Atlantic and
Carolinas. Related light, ely/sely and onshore flow will be directed
across cntl NC.

With little change in the dry airmass in place and continued onshore
(maritime-regulated) flow, surface dewpoints are likely to mix out
into the upr 50s to lwr 60s and be accompanied by near to slightly
above average temperatures in the upr 80s to around 90. Generally
scattered, fair weather stratocumulus that will develop with diurnal
heating should dissipate through the evening, with following mainly
clear and calm and near average temperatures in the 60s Thu night.

&&

.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 /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
As of 720 PM Wednesday...

VFR conditions and dry weather will prevail across central NC
through the next 24 hours.  A light easterly wind between high
pressure off the Mid-Atlantic coast and a weak low pressure drifting
toward the SE coast will continue overnight and Thursday, supporting
a persistence forecast and the potential for a brief period of
isolated, pre-dawn MVFR vsbys from FAY to RWI by 10Z.

Outlook: VFR and dry conditions are expected to persist through
Saturday. The chance for showers will return Sunday and Monday, which
would result in the next period of possible sub-VFR conditions.
-- End Changed Discussion --

&&

.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...MWS
NEAR TERM...Danco
SHORT TERM...MWS
LONG TERM...np
AVIATION...BLS
CLIMATE...RAH