896
FXUS61 KAKQ 161424
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
1024 AM EDT Tue Jul 16 2024

.SYNOPSIS...
Hot and humid conditions prevail through 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 /THROUGH TONIGHT/...
As of 1020 AM EDT Tuesday...

Key Messages:

- Excessive Heat Warning today for Southeast Virginia and much
  of Northeast North Carolina, Heat Advisory for the remainder
  of the area with the exception of the MD beaches.

- Marginal SVR risk this aftn/evening across the north.

The forecast remains largely on track this morning, with only
some minor adjustments to the temperatures and dewpoints to
account for the latest trends. Heat headlines remain in effect,
with Excessive Heat Warnings for the SE and Heat Advisories
elsewhere (only the MD beaches are not in any heat headline).
Dew pts yesterday mixed down farther to the SE than anticipated
(into the mid 60s to around 70F into Hampton roads), and
therefore yesterday`s Excessive Heat did not reach much above
105 heat indices. Today, with the upper ridge becoming centered
off the SE coast, and a stronger low level SW flow, expect dew
pts will not mix down as much as yesterday. The combination of
heat and humidity is therefore expected to peak today. The
consensus is for 850mb temperatures a touch higher than Monday
as well (rising to 22-23C this aftn). Highs are expected to be
mostly in the range of 97-101F except for locally cooler
conditions at the immediate coast. Dew pts will likely avg in
the mid to upper 70s this aftn over NE NC and mid 70s in SE VA.
While they mix down to some extent, most of metro RIC will
probably see them in the lower 70s this aftn. Peak heat indices
of 105-109F are expected for much of the area and 110F+ in the
warning (locally ~115F possible in some areas on interior NE
NC). Note that heat indices are quite sensitive to just 1 degree
variation in T/Td so a few sites only in the Advisory could
briefly touch 110F.

The CAMs a bit split on where the highest chances will be, the
HRW NSSL rather aggressive compared to the HRRR. Overall, there
is a bit higher chc for storms developing along the mountains
and drifting ESE through the aftn. PoPs are 15-25%, with less
the 15% along the Atlantic Coast of the Eastern Shore. One thing
is that the models do show some increase in mid level lapse
rates late this aftn (to at least 6C in the H7-H5 layer over the
north), so this could allow storms to develop with stronger
updrafts and will need to watch the trends late this morning
into the aftn. SPC has a marginal risk for SVR across the north
for wind/hail.

A few storms possible into the evening, then diminishing
overnight. Warm and humid again Tuesday night (probably the
warmest night with lows in the mid 70s to lower 80s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
As of 340 AM EDT Tuesday...

Key Messages:

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

- Showers/tstms become fairly widespread late Wed/Wed night
  through Thursday. Slight/Marginal SVR risk late Wed, heavy
  rain threat (especially south Thu).

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. 1The 00Z/16 guidance is about the same with
showers/tstms later Wednesday aftn into Wednesday evening,
supporting likely PoPs in the W by mid-late aftn. A few
stronger tstms are possible initially given a well mixed BL and
a high pw airmass (SPC has the N in a Slight Risk and MArginal
elsewhere). 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, especially south. 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 400 AM EDT Tuesday...

Key Messages:

- Heavier 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. Temperatures near to slightly below
  normal.

As the upper trough moves from the Great Lakes into New England
Thursday night into early Friday, a strong enough shortwave is
expected to slide by during the same timeframe, helping push
the cold front just south of our CWA. This will make the highest
rain chances move farther southeast late Thursday evening.
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 for some chc for continued rain and
storms to continue on Friday especially NE NC). Models then
indicate that the upper level 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 mid-upper 80s for the weekend
into early next week, keeping the excessive heat/humidity
at bay.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
As of 700 AM EDT Tuesday...

Mainly VFR conditions are expected to prevail through the 12z
TAF period. There will be isolated late aftn/evening
showers/tstms that would bring brief flight restrictions and
gusty winds, but the coverage is too low to include any mention
in TAFs for now. SCt high clouds early  , SCT cumulus
developing in the aftn. The wind should generally be SSW 10-15kt
(with gusts to 20kt) late this 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...
No record highs or record high mins were set Monday, records are
possible today and Wed.

- Record Highs:

- Site:  Tue 7/16     Wed 7/17

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

- Record High Mins:

- Site:  Tue 7/16    Wed 7/17

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

- Highest 1-hr Heat Index Value on record (P.O.R. 1948-2024):

- RIC:   117 (7/17/1980)
- ORF:   118 (8/18/2017)
- SBY:   122 (7/15/1995)
- ECG:   119 (7/5/1999)

&&

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

&&

$$

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