-- Discussion containing changed information from previous version are highlighted. --
730
FXUS61 KAKQ 221028
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
628 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/...
-- Changed Discussion --
As of 630 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. Am
seeing some very patchy fog over interior SE VA and NE NC, but
this should dissipate over the next couple hours. Temps as of
630 AM are in the upper 60s-mid 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.
-- End Changed Discussion --

&&

.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 /12Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 625 AM EDT Saturday...

Prevailing VFR through the period. Very patchy fog currently
located over interior portions of SE VA and NE NC. Intermittent
vsby reductions possible at ECG through 12z, but little to no
impact expected from 12z onward. SKC or FEW250 for the rest of
today. S/SSE winds around 5 kt this morning becomes 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.
-- End Changed Discussion --

&&

.MARINE...
As of 335 AM EDT Saturday...

Key messages:

-The wind increases Sunday afternoon into Sunday night with SCA
 conditions likely Sunday afternoon into early Monday morning.

-Moderate Rip Current Risk continues through the weekend.

High pressure is centered off the Carolina coast early this
morning. The wind is mainly SSW 10-15kt with seas ranging from
2-3ft S to ~3ft N and waves in the Ches. Bay ~2ft. High pressure
settles off the Southeast coast today into tonight. Similar
conditions should persist through early aftn, before 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).
The wind shifts to SW later tonight and will mainly be 10-15kt,
with 15-20kt possible across the middle Ches. Bay, and 15-20kt
for the northern ocean zones. Marginal SCA conditions are
possible for the middle Ches. Bay for a 3-6hr period late
tonight into early Sunday. However, SCA flags will not be issued
at this time given that it is borderline. Seas build to 3-4ft N
late this aftn into tonight (mainly 2-3ft S) with waves in the
Ches. Bay building to 2-3ft with the diurnal wind shift and
increase in wind speed.

A weakening cold front slowly approaches from the NW later
tonight through Sunday night. The pressure gradient tightens
over the ocean Sunday aftn/evening with a 30-40kt LLJ developing
Sunday night. A 20-25kt SSW wind is expected to develop over
the ocean, with minimal gustiness as a very warm airmass advects
over relatively cooler water. This is expected to result in
seas building to 4-6ft N of Cape Charles later Sunday aftn into
Sunday night. SCA conditions are likely for the ocean later
Sunday aftn into Sunday night. However, there is still some
uncertainty with respect to convection (or convective outflows)
and what impact that will have on the synoptic flow, so no SCAs
have been issued at this time. Additionally, a SW wind
increases to 15-20kt for the Ches. Bay Sunday night with
marginal SCA conditions possible for the Bay (and potentially
the lower James and Currituck Sound). 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 this weekend for all
beaches with some SE swell ~3ft with ~8s periods. Confidence of
moderate is higher for the northern beaches today 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
CLIMATE...