617
FXUS61 KAKQ 041903
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
303 PM EDT Thu Jul 4 2024

.SYNOPSIS...
High pressure off the coast gradually settles south into the
western Atlantic through late this week. Heat and humidity build
over the region today through early next week. Daily chances of
mainly afternoon and evening showers and thunderstorms also
return today into the upcoming weekend.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 935 AM EDT Thursday...

Key Messages:

- Hot and humid conditions return today.

- Rain chances return to the forecast for the afternoon into the
  evening on Independence Day and again on Friday and Saturday.
  Best rain chances remain W-NW of the Richmond Metro area into
  the VA Piedmont.

Latest analysis reveals upper ridge building across the
southeast from the gulf coast this morning, with a trough over
Great Lakes. At the surface, high pressure continues to push
farther offshore of the mid-Atlantic coast, with a cold front
well to the NW of the region approaching the Ohio Valley. A
warmer and slightly more humid start to the day with
temperatures in the upper 70s to lower 80s and dewpoints around
70F this morning.

A hotter and more humid Independence Day is expected, courtesy
of increasing SSW flow w/the surface high pushing out into the
western Atlantic. High temperatures range from the upper
80s/lower 90s along the coast, to the mid 90s inland. NBM
dewpoint numbers already verifying a few degrees to high, and
will continue to undercut them by about a category today.
Nonetheless, more humid today, with PWs to climb to ~2.00 by
this evening. Forecast dewpoints in the upper 60s to around 70F
during peak heating result in heat indices well into the upper
90s to lower 100s.

There is a potential for widely scattered showers/tstms later
today. Shortwave energy will ride along the northern periphery
of the sub-tropical ridge over the Ohio Valley and interior
northeast through this afternoon. Isolated to widely scattered
convection is then expected to develop to our northwest, focused
along the pre-frontal/lee trough by early this afternoon.
Showers and storms are then shown by a majority of CAMs pushing
E-NE into the local area late this afternoon, before slowly
weakening and decreasing in areal coverage this evening. Best
rain chances are around 60% for the NW Piedmont, but again taper
to 20-40% central VA to the VA northern neck and eastern shore
in the late afternoon and evening as storms gradually weaken. A
convective Marginal Risk remains in place from the SPC for the
far NW, with gusty winds from wet microbursts the main hazard.

Mainly dry overnight, aside from a lingering shower or two over
the eastern shore. Some patchy fog/low stratus possible late
tonight/early Friday. Otherwise partly cloudy, warm and
muggy/humid tonight with lows in the lower to mid 70s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
As of 340 AM EDT Thursday...

Key Messages:

- Heat and humidity build for Friday and Saturday. Heat index
  values around 100 are expected on the eastern shore, with heat
  indices in the 103-108F range west of the bay. Heat Advisories
  are likely to be needed for much of the area both Friday and
  Saturday.

- Additional chances for late day showers and storms will exist
  both days, again mainly focused over the piedmont.

PWs trend up further for Friday, reaching 2-2.25" by Friday
morning (*near daily max value for WAL), with daily maxes
possibly exceeded (PW 2.25-2.5") by Saturday. Forecast highs
Friday and Saturday should be similar to those of today.
However, it will be a bit more humid and with dewpoints slightly
higher, heat indices at or above 105F are likely for central
and SE VA and into NE NC, and Heat Advisories are likely to be
needed for much of the area.

There is chance of afternoon showers/tstms Friday along the lee
trough lingering over the area. Partly cloudy, warm, and muggy
Friday night with lows in the mid to upper 70s. The weakening
cold front drops into the area Saturday. Once again hot and very
humid ahead of the boundary with highs in the lower to mid 90s
and again heat indices of 105-109F are looking increasingly
likely. This boundary should become the focus for more
showers/tstms by afternoon. A very moist and unstable airmass
will be in place and the H5 flow does increase to 30-35kt across
the NW, so some stronger tstms are possible.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 300 PM EDT Thursday...

Key Message:

- Near or slightly above normal temperatures, but very humid
  through the period. Remaining a bit unsettled with a chance
  for mainly afternoon and evening showers and storms each day.

Not as hot through the period, but high temps will still be
near or slightly above normal ranging from the upper 80s to
lower 90s. It will still be very humid across the area, and with
lee troughs or weak frontal boundaries in the vicinity of the
region, expect chances for mainly aftn/evening showers/tstms
each day. Heat indices will mainly range from the mid 90s to
lower 100s Mon through Wed. Warm and muggy nights with lows
ranging from the upper 60s to mid 70s.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
As of 210 PM EDT Thursday...

VFR conditions prevail as of 18z with surface high pressure
centered off the Southeast coast. The wind is mainly S to SSW
~10kt with FEW-SCT CU developing with bases of 5-6kft. A cluster
of showers/tstms has developed over the higher terrain to the W
and is currently crossing the Blue Ridge. These showers/tstms
are expected to approach RIC after 20z, and mainly in the 21-23z
timeframe. The latest guidance suggests much of this activity
dissipates from 23-01z prior to reaching the remaining
terminals. These showers/tstms could produce some stronger wind
gusts at RIC along with brief vsby restrictions in rain.
Otherwise, VFR conditions should prevail tonight into Friday
morning under a partly cloudy sky with a 5-10kt SSW wind. By
Friday aftn, there is a ~30% chc of showers/tstms at RIC, and a
15-20% chc at the remaining terminals. The wind should mainly be
SSW 8-12kt Friday aftn, but locally variable and gusty in and
near any tstms.

A weakening and slow moving cold front settles into the region
Saturday. This will bring a higher chc (40-60%) of aftn/evening
showers/tstms. This front settles near the coast Sunday and
washes out, with a remnant boundary lingering over the area
Monday/Tuesday. The highest chances (30-40%) shift into SE VA/NE
NC Sunday, and then generally 30-40% inland and 15-30% toward
the coast Monday and Tuesday.

&&

.MARINE...
As of 340 AM EDT Thursday...

Key messages:

- Small Craft Advisories are in effect across portions of the
  Chesapeake Bay and Virginia coastal waters late this afternoon
  into tonight.

- There is a high rip risk today across the northern beaches
  and a moderate rip risk across the southern beaches.

- A period of elevated, diurnally-driven southerly winds is
  possible Friday and Saturday with Small Craft Advisory
  conditions possible.

High pressure remains offshore through the weekend with multiple
shortwaves moving through, providing the chance for daily diurnal
storms. Winds were generally S 10-15 kt with a few gusts up to 20 kt
across the upper Ches Bay this morning. Meanwhile, waves and seas
were 1-2 ft and 2-3 ft respectively. Expect winds to become SE/SSE
this afternoon, increasing to 15-20 kt by mid-late afternoon. Gusts
up to 25 kt are possible across the VA coastal waters late this
afternoon into this evening. Wind probs for 18kt winds were 40-70%
across the middle and lower bay with probs for 25 kt gusts across
portions of the VA coastal waters of 20-30%. Wind probs were much
lower across the upper bay. Therefore, SCAs are now in effect for
the middle and lower bay from 4-10 PM and for the coastal waters
from Chincoteague to Cape Charles Light from 6 PM until 4 AM Fri
(due to a combination of gusts up to 25 kt and seas of 4-5 ft).
Additionally, 00z CAMs have come into better agreement in showing a
line of storms moving off the Blue Ridge mountains and towards the
coast this afternoon into this evening. While uncertainty remains
regarding coverage of storms, the outflow may move across the local
waters this evening, allowing for winds to briefly become NW and
gusty.

Winds become S 10-15 kt with gusts up to 20 kt across the bay and 12-
20 kt across the coastal waters tonight, becoming SW late. While
some hires guidance shows the potential for SCA conditions
continuing across the bay, winds (and confidence) have trended
lower. A period of diurnally driven elevated afternoon/evening S
winds is likely to continue Fri and Sat. Each day, S/SSE winds
increase to 15-20 kt with gusts up to 25 kt (mainly across the
coastal waters) during the afternoon and evening before becoming
SW/SSW overnight. As such, SCAs may be needed for either/both days.
Winds diminish Sun into early next week as a weak cold front
approaches and becomes washed out near/over the local waters.
Additionally, daily chances for afternoon/evening storms are
possible into the middle of next week.

There is high rip risk today across the N beaches due to 12-14
second period SE swell amidst 3-4 ft waves. A moderate rip risk
exists across the S beaches where the onshore swell direction is
weaker and less shore normal for the long period 12-13 second swell
and where the shore normal swell is 7-9 seconds. There is a moderate
rip risk for all area beaches on Fri due to 9-10 second period
onshore swell and 3-4 ft waves. There is a potential for an upgrade
to a high rip risk Fri across the N beaches due to a more dominant
(and stronger) SE swell (as opposed to conflicting swells like
today).

&&

.CLIMATE...
Record High Temperatures Through Sat (July 4-6)

        7/4          7/5       7/6
RIC   100/2002    102/2012   105/1977
ORF    98/1997     98/2012   102/1881
SBY   100/1919    102/2012   102/2010
ECG   100/1997    100/2012    99/2012


Record High Minimum Temperatures Through Sat (July 4-6)

         7/4         7/5       7/6
RIC    77/1900     79/2012    80/2012
ORF    79/2012     80/1999    80/1999
SBY    78/2012     81/2012    77/2012
ECG    78/2012     77/2018    78/1999

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ631-
     632-634.
     Small Craft Advisory from 6 PM this evening to 4 AM EDT Friday
     for ANZ652-654.

&&

$$

SYNOPSIS...AJZ/MAM
NEAR TERM...AJZ/MAM
SHORT TERM...AJZ/MAM
LONG TERM...TMG
AVIATION...AJZ
MARINE...AM/RMM
CLIMATE...AKQ