139
FXUS61 KAKQ 160718
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
318 AM EDT Tue Jul 16 2024

.SYNOPSIS...
Another hot stretch of weather prevails through most of
Wednesday. An unsettled period returns late Wednesday through
Thursday, as a cold front pushes through the area and stalls
across the Carolinas. Shower chances focus mainly over southern
Virginia and North Carolina Friday, then return to all zones by
Saturday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 935 PM EDT Monday...

Key Message:

- Warm and humid overnight with a light south to southwest wind.

Convection failed to make it into our area earlier today with
another warm and humid evening. All heat headlines were allowed
to expire at 8 PM, and Excessive Heat Warnings/Heat Advisories
remain in effect for nearly the entire area on Tuesday. No
major changes to the going forecast with the evening update.

Previous Discussion as of 330 PM EDT...

GOES water vapor channels depict westerly flow aloft across the
Mid-Atlantic on the northern periphery of a broad ridge that
extends from the Southeast CONUS into the subtropical western
Atlantic. The initial surface trough over the region has pushed
offshore with another lee-side trough developing this afternoon.
Dewpoints actually mixed down into the mid/upper 60s from
central VA into SE VA in the wake of that feature, but are
slowly beginning to recover. Temperatures are in the lower to
mid 90s for much of the area. Heat Indices are generally
100-105F, slightly lower than originally forecast due to the
lower dewpoints pushing farther east. However, there are still a
few more hours of peak heating and dewpoints are nudging up, so
there will be no changes to the heat headlines, which continue
through 8 PM. Given the drier airmass, there is less coverage of
CU this afternoon, tstms are expected to be very limited in
coverage with PoPs only ~20% for the far NW Piedmont and NE NC
near the Albemarle Sound. Otherwise, warm and humid tonight with
lows in the lower 70s W, to mid/upper 70s E. Otherwise, warm
and humid tonight with lows in the lower 70s W, to mid/upper 70s
E.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
As of 330 PM EDT Monday...

Key messages:

- Excessive Heat Warning Tuesday for Southeast Virginia and
  much of Northeast North Carolina

- Heat Advisory for the remainder of the area with the exception
  of the MD beaches.

- Remaining hot Wednesday and humid area-wide but with a higher
  coverage of storms by afternoon (heat headlines are likely for
  some of the area but details are more uncertain).

The combination of heat and humidity peaks Tuesday, as the core
of the upper ridge becomes centered well off the SE coast. The
consensus is for 850mb temperatures similar to today (21-22C),
with slightly higher humidity given the favorable location of
the upper ridge off the SE coast to Bermuda. However, the 15/12z
guidance has nudge dewpoints down slightly, with inland areas
in the upper 60s/around 70F during peak heating, and 72-75F
closer to and along the coast. Therefore, with highs again into
the mid/upper 90s to around 100F, peak heat indices of 105-109F
are expected for much of the area and 110F+ are expected to
prevail over SE VA and NE NC. An Excessive Heat Warning has been
issued for SE VA and much of NE NC (Heat Advisory for
Northampton, NC and Outer Banks Currituck), with a Heat Advisory
for the remainder of the area with the exception of no heat
headline for the MD beaches. Limited rain chances again, with
the CAMs a bit split on where the highest chances will be.
Overall, there is a bit higher chc over the southern piedmont,
but generally PoPs are 15-20%, with less the 15% along the
Atlantic Coast of the Eastern Shore. Warm and humid again
Tuesday night (probably the warmest night with lows 75-80F).

The models remain in decent agreement that Wednesday will be
the last day of hot conditions as the upper ridge eventually
breaks down, as a strong upper trough translates SE from north
central US to the Great Lakes. Dew pts will be more uniform
area-wide (in the mid 70s inland with upper 70s SE), due to
moisture pooling along a pre- frontal trough. Highs will be a
few degrees less Wednesday (mid- upper 90s) but the higher dew
pts may lead to similar heat indices with 110F+ possible in the
E and SE. 15/12z guidance is a little more aggressive with
showers/tstms later Wednesday aftn into Wednesday evening,
especially across the N. A few stronger tstms are possible
initially given a well mixed BL and a high pw airmass. Continued
warm and humid Wednesday night with lows in the lower to mid
70s and the potential for showers and embedded tstms lingering
overnight as a cold front approaches from the NW. Models remain
in fairly good agreement that the upper level trough pushes from
the upper Great Lakes to New England Thursday, but flattens out
to the south as it approaches the strong/persistent upper level
ridge anchored well offshore of the SE US coast. The highest
chances for showers/storms Thursday (~70%) will be for southern
VA/NE NC, with 50-60% N). Locally heavy rainfall will certainly
be possible during this timeframe. Highs Thursday will be highly
dependent upon the timing of the front, for now expecting mid
80s to near 90F.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 300 PM EDT Monday...

Key Messages:

- Heaviest rain pushes south Thursday night as cold front stalls
just south of the area on Friday.

- Daily scattered rain chances persist as the front lifts back north
into the area.

Upper trough will move from the Great Lakes into New England
Thursday night into early Friday. A shortwave will also slide by
during the same timeframe, helping push the cold front just south of
our CWA. This will make the highest rain chances move further
southeast late Thursday evening. Slightly drier air will attempt to
push into the northern tier of the area on Friday as high pressure
drops into the Great Lakes/western New England region. Dewpoints
across the north look to fall into the low to mid 60s on Friday, and
with high temperatures in the mid 80s, it will be a fairly pleasant
day. On the other hand, southern/southeastern locations will keep
the humidity in place allowing rain and storm chances to continue on
Friday. Models then indicate that the area of high pressure offshore
will retrograde back to the west closer to the Southeast coast by
the weekend. The stalled front will then lift back north into the
local area keeping daily scattered rain chances in place. Dewpoints
in the 70s will creep back northward, but thankfully temperatures
will remain in the upper 80s for the weekend keeping the excessive
heat/humidity somewhat at bay.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
As of 740 PM EDT Monday...

VFR conditions are expected to prevail through the 00z TAF
period. Mainly clear tonight-Tue AM with SCT cumulus developing
Tue aftn. There is a slight chc of a tstm Tue aftn-evening (PoPs
~20%). The wind should generally be SSW 5-10kt tonight, then SW
10-15kt (with gusts to 20kt) late Tuesday morning into the
aftn.

A cold front approaches from the NW Wednesday aftn with an
increasing chc of showers/tstms later Wednesday aftn into
Wednesday night. This front will push through the area Thursday
with a continued chc of showers/tstms. Periodic flight
restrictions are expected later Wednesday into Thursday. The
front will push farther S on Friday as drier air attempts to
push in from the NW, and then the boundary lifts back N
Saturday. The chc for showers/tstms is less Friday (except over
far SE VA/NE NC) and then increases again Saturday.

&&

.MARINE...
As of 315 AM EDT Tuesday...

Key messages:

- Small Craft Advisories are possible late Wednesday into Thursday
  ahead of an approaching cold front.

High pressure well offshore is resulting in sub-SCA SW winds 10-15
kt with gusts to 20 kt along the eastern Ches Bay and coastal waters
while the western half of the bay, tidal rivers, and Currituck Sound
are ~10 kt with gusts to 15 kt. Waves are 1-2 ft with seas 2-3 ft.

SW winds continue today, increasing to 10-15 kt by late afternoon. A
period of SCA winds is possible late tonight into early Wednesday in
the Ches Bay but given marginal speeds and relatively short duration
will not issue any headlines with this forecast. SW flow persists on
Wednesday ahead of a cold front. Latest guidance continues to show
the potential for a period SCA conditions Wednesday evening into
Thursday as pressure gradient tightens ahead of a cold front. The
front now looks to move through the northern half of the area on
Thursday morning, stalling across the southern waters before moving
just south of the area by Friday morning. Scattered to numerous
showers and thunderstorm are possible Wed/Thur ahead of the front,
some of which could be strong to severe with locally enhanced
winds/waves/seas. Waves in the bay maintain 1-2 ft today with 2-3 ft
possible overnight and Wednesday with the stronger SW winds. Seas
will generally stay 2-3 ft today but increase to 3-4 ft tonight. A
period of 4-5 ft seas is possible Wednesday night into Thursday for
the northern coastal waters. Flow becomes N and NE 5-10 kt behind
the front on Friday.

Low rip current risk at all beaches today. A moderate rip current
risk is forecast for the northern beaches Wednesday and
Thursday.

&&

.CLIMATE...
Record Highs and record high mins may be challenged Mon-Wed.

- Record Highs:

- Site: Mon 7/15    Tue 7/16    Wed 7/17

- RIC:  100 (1995)  101 (1980)  100 (1980)
- ORF:  101 (1995)  102 (1879)  100 (1887)
- SBY:  100 (1995)   99 (1915)   99 (2012)
- ECG:   97 (1997)   98 (1995)   99 (1942)

- Record High Mins:

- Site: Mon 7/15    Tue 7/16    Wed 7/17

- RIC:   77 (1993)   77 (1983)   76 (2005)
- ORF:   82 (1992)   80 (1995)   80 (2021)
- SBY:   79 (1995)   78 (2013)   80 (1983)
- ECG:   78 (1993)   79 (2012)   80 (2019)

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for MDZ021>024.
NC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for NCZ012-102.
     Excessive Heat Warning from 11 AM this morning to 8 PM EDT
     this evening for NCZ013>017-030>032.
VA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for VAZ048-060>062-064>069-075>089-092-099-100-509>522.
     Excessive Heat Warning from 11 AM this morning to 8 PM EDT
     this evening for VAZ090-093-095>098-523>525.
MARINE...None.

&&

$$

SYNOPSIS...AJZ/LKB
NEAR TERM...AJZ/ERI
SHORT TERM...AJZ/LKB
LONG TERM...JKP
AVIATION...AJZ/ERI
MARINE...RHR
CLIMATE...