254
FXUS61 KAKQ 220718
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
318 AM EDT Sat Jun 22 2024

.SYNOPSIS...
High pressure off the Mid Atlantic coast slowly shifts through
today, leading to an extended period of hot weather this
weekend and again next week. There is a small chance for rain
Sunday evening into Monday, and again later next week, but most
locations will remain dry.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 315 AM EDT Saturday...

Key Message:

- Hot today with heat advisory in place for portions of the area.

Early morning analysis shows surface high pressure well offshore and
~596 dm high pressure aloft over portions of the Deep South. With
light southerly flow, could see some very patchy fog or low stratus
develop in NE NC through sunrise where dew points are higher.
Otherwise, clear skies with morning lows in the upper 60s to lower
70s.

The main story for today remains the heat. Consensus among the near-
term guidance is for widespread highs in the upper 90s. Locally
around 100 F is possible in the Richmond metro and surrounding I-95
corridor. With the expectation that dew points mix out into the low-
mid 60s, we are forecasting highs a degree or two warmer than NBM.
This reasoning aligns with the dry conditions of late. Right along
the coast, it is expected to remain in the low-mid 90s with a SSE
wind. With those lower dew points, heat indices will only be a few
degrees warmer than air temp and in the 98-105 F range (highest ern
and SE VA, except on the eastern shore with the onshore wind). While
we are not seeing widespread heat indices of 105 F or greater, will
maintain the heat advisory and continue to err on the side of
caution given this is the first big hot spell of the summer season.
The advisory goes through 8 PM this evening. Lows tonight will not
provide a ton of relief and only drop into the mid 70s inland and
upper 70s along the bay/ocean.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 315 AM EDT Saturday...

Key Messages:

- Hot temperatures expected Saturday and Sunday with maximum
temperatures both days in the mid/upper 90s to around 100 F.

- Highest heat indices (105+ F) expected Sunday, with heat
advisories probable for most of the area.

- Isolated to scattered storms possible later Sunday through Monday
afternoon.

The core of the heat is expected to shift E/SE some for Sunday,
though hot temps will remain over the entire forecast area. High
temperatures will be similar to Saturday and probably a degree or
two warmer for eastern and SE VA, NE NC, and the eastern shore.
Highs range from the upper 90s for most of the area to around 100 F
in the urban corridor within and surrounding Richmond. Clouds
increase some later in the day across the NW so something to keep an
eye on there. Guidance continues to advertise higher dew points
Sunday due to strengthening southwesterly sfc flow. Soundings indeed
show more moisture at and above the surface. This would lead to
higher levels of humidity and thus heat indices in the afternoon.
The current forecast has heat indices between 103 and 108 F, with
the highest values across eastern VA (including the eastern shore)
where the highest humidity will reside. Still, there is some
uncertainty given the recent dry conditions, which could lead to
more mixing and lower dew points/heat indices. While a few locations
could near a 110 F heat index, coverage is too low for any excessive
heat watches. Either way, WBGTs in the upper 80s to around 90
suggest the potential for significant heat stress for those outdoors
and especially those participating in strenuous activities.
Additional Heat Advisories will likely be needed for much of, if not
all, of the forecast area Sunday. Will hold off on issuing these for
Sunday and let most of today`s headline play out to avoid confusion
on the WWA map. Lastly, will need to keep an eye on the aftn
relative humidities as a gusty SW wind and the recent dry conditions
could lead to some fire wx concerns. There again will not be much
relief from the heat Sunday night with lows in the mid to upper 70s.

Isolated to widely scattered showers and storms are still a
possibility Sunday afternoon and especially in the evening and
overnight hours ahead of a weak cold front. Also expecting a weak
sfc trough to set up east of the mountains. As is typically the
case, the NAM is most aggressive regarding convective coverage and
intensity. This could be related the model being slightly more
amplified and having higher dew points. SPC continues the marginal
risk for the northern third of the area. This makes sense as shear
is higher with northern extent (though it only peaks at ~20 kt).
Overall, this suggests loosely organized storms capable of strong to
marginally severe wind gusts given steep low-level lapse rates and
high DCAPE. PoPs are 20-30% in the afternoon, increasing to 30-60%
(highest N and NE) in the evening and early overnight period. Chance
PoPs linger through most of the night with the boundary nearby.
Still, this does not look to be a widespread beneficial rainfall to
alleviate the developing drought over the area, with only ~0.10-
0.20" of QPF in the forecast for portions of the area through Sunday
night.

The front will be located across the SE Monday and continue to trend
the best chances for showers and storms further SE. If current
trends in the guidance continue, it may stay dry for most of the
area, outside of far SE VA and NE NC. There will be ample
instability along and ahead of the front so any storm again will be
capable of producing strong to marginally severe wind gusts, in
addition to frequent lightning and heavy rain. It also continues to
look hot with high temps in the low-mid 90s. The highest dew points
will reside across the SE VA and NE NC and heat indices of around
105 F are expected. The one caveat is storms could initiate as early
as late morning or early afternoon in these areas given the
moist/hot/unstable airmass, potentially preventing the high-end temp
potential from being realized. Overnight lows in the mid-upper 60s
inland and lower 70s closer to the coast.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 315 AM EDT Saturday...

Key Messages:

- The heat builds again midweek, with temperatures again increasing
well into the 90s.

- Scattered showers and storms possible with a cold front Thursday.

- Flash drought conditions developing across most of the area.

The cold front does very little to provide any heat relief as temps
Tuesday remain in the lower 90s. Even hotter Wednesday and we again
could be talking about temps nearing 100 F, though the latest NBM is
a degree or two shy of triple digits. Heat indices increase increase
to 100-105 F, but this is again dependent on the degree of BL mixing
in the afternoon. An isolated storm or two could also spill into our
western counties. By Thursday, another cold front approaches from
the NW and will continue chance PoPs for the area. Models favor the
highest coverage over the S and SE. Still, widespread rainfall is
not expected with this feature and probabilities of such remain
quite low through the extended period. Guidance is warmer in
the late week period and most areas may stay in the lower 90s.

The upcoming dry conditions will only exacerbate the recent dry
spell and it looks to set us up for what is considered a "flash
drought". More information on this can be found on CPC`s
Probabilistic Hazards Outlook page at www.ncep.cpc.noaa.gov or
drought.gov.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
As of 135 AM EDT Saturday...

Primarily VFR conditions are expected through much of the 06z
TAF period, with mainly clear sky through the late night hours.
There is some potential for MVFR CIGs to work into far SE
portions of the area over the next few hrs and already seeing
sporadic reports of CIGs around 1500 ft. Greater confidence at
ECG vs ORF. Not expecting impactful VSBY restrictions, though
could briefly drop to MVFR (3-5 SM) at ECG. S/SSE winds around
5-7 kt early this morning, becoming 5-10 kt this aftn (E-SE
along the coast with the sea breeze).

Outlook: Dry and VFR conditions are expected to prevail through
Sunday afternoon, as high pressure remains centered off the
coast. There is a low chance for some isolated to widely
scattered storms Sun evening and again on Mon afternoon into
Mon evening.

&&

.MARINE...
As of 945 PM EDT Friday...

Key messages:

-Sub-SCA conditions expected through Sunday morning.

-Winds increase on Sunday with SCA conditions likely Sunday
 afternoon into Monday morning.

-Moderate Rip Current Risk continues through the weekend.

Winds S-SW 5-15 kt expected tonight. Waves on the Bay, Rivers
and Sound 1-2 ft, with seas 2-3 ft.

High pressure settles off the Southeast coast Saturday into Sunday.
A SSW wind will generally be 5-10kt Saturday morning into early
aftn, with a late aftn/early evening diurnal shift to SSE and
increase to ~15kt for the Ches. Bay and ocean N of Cape Henry (10-
15kt elsewhere). Seas build to 3-4ft N (mainly 2-3ft S) with waves
in the Ches. Bay building to 2-3ft with the diurnal shift and
increase in wind. A weakening cold front slowly approaches from the
NW Saturday night through Sunday night. A SW wind potentially
increases to 15-20kt for the Ches. Bay and northern ocean late
Saturday evening into early Sunday, with marginal SCA conditions
possible in the Ches. Bay. The pressure gradient tightens over the
ocean Sunday aftn/evening with a ~20kt SSW wind possible, which
could result in seas building to 4-6ft N of Cape Charles later
Sunday aftn into Sunday night. Additionally, a SW wind potentially
increases to 15-20kt for the Ches. Bay Sunday night with marginal
SCA conditions possible. The pressure gradient slackens Monday into
Tuesday as the weakening cold front settles into the area and washes
out. High pressure rebuilds offshore by the middle of next week with
sub-SCA southerly flow returning. Seas will mainly be 2-3ft Monday
into the middle of next week with 1-2ft waves in the Ches. Bay.

Rip currents: A moderate rip risk will continue today for all
beaches with some SE swell ~3ft with ~8s periods. An elevated rip
risk likely continues through the weekend. Confidence of moderate is
higher for the northern beaches Saturday and Sunday, but southerly
flow and a longshore current may preclude a high risk.

&&

.CLIMATE...
Record high temperatures for Saturday, June 22:

- RIC: 101 (1933)
- ORF: 99 (1981)
- SBY: 98 (1988)
- ECG: 98 (1942)

Record high minimum temperatures for Sunday, June 23:

- RIC: 76 (2010)
- ORF: 79 (2015)
- SBY: 75 (1925)
- ECG: 78 (2015)

Record high temperatures for Sunday, June 23:

- RIC: 101 (1988)
- ORF: 99 (2015)
- SBY: 99 (1988)
- ECG: 99 (2011)

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for VAZ048-061-062-064-068-069-075>078-080>086-088>090-
     092-093-095>098-509>525.
MARINE...None.

&&

$$

SYNOPSIS...AJB/SW
NEAR TERM...SW
SHORT TERM...AJB/SW
LONG TERM...SW
AVIATION...SW
MARINE...AJZ/AM
CLIMATE...