Portsmouth, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

845
FXUS61 KAKQ 171755
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
155 PM EDT Thu Jul 17 2025

.SYNOPSIS...
High pressure prevails off the Southeast coast today bringing
hot and continued humid conditions. A weak cold front drops into
the region Friday and Saturday bringing an increased chance of
mainly afternoon and evening showers and thunderstorms with
heavy rain.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 700 AM EDT Thursday...

Key Messages:

- Heat Advisories have been issued for central and southeastern
  VA, the Eastern Shore, and northeast North Carolina.

- Afternoon/evening isolated showers and thunderstorms are
  possible.

GOES water vapor channels show a ridge off the Southeast US
coast, with zonal flow across the Mid-Atlantic on the northern
periphery of the ridge. High pressure is co-located at the
surface offshore. Meanwhile, low pressure and a cold front are
located well NW of the region across the Great Lakes associated
with a stronger upper level trough. Partly to mostly cloudy and
very warm and humid early this morning with temperatures in the
mid 70s to around 80F as of 700 AM.

850mb temperatures rise to 19-21C today. This should support
highs in the lower to mid 90s, with dewpoints remaining in the
mid 70s during peak heating due to recent wet conditions. This
will yield heat indices in the 100-105F range over the Piedmont
and 105-109F along and E of the I-95 corridor in VA and E of the
Chowan River in NE NC. Heat advisories remain in effect and
have been expanded to include some more of central and s-central
VA as well as NE NC E of the Chowan River. A subtle shortwave
trough slides across the northern Mid-Atlantic later this
afternoon, and this could trigger a few showers/tstms across the
western and northern tier of the area mid-aftn to early
evening, with PoPs generally 15-30% from the Piedmont across
central VA to SE MD. There will be a little more shear today, so
any tstms could become more organized and pose at least a
marginal damaging wind threat. Breezy today with a SW wind of
10-15 mph gusting to 20-25 mph. Warm and humid tonight with
lows in the mid to upper 70s.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 350 AM EDT Thursday...

Key Messages:

- Afternoon and evening showers and thunderstorms will bring a
  threat of additional heavy rain Friday and Saturday.

- Heat advisories may be needed across far southeast Virginia
  and northeast North Carolina Friday.

The aforementioned trough and cold front push from the Great
Lakes to the Northeast tonight into Friday. A milder and drier
airmass will remain well N of the region, but the associated
cold front is progged to drop into the local area Friday. This
will interact with an airmass with PW values >2" and mid 70s
surface dewpoints. Notably, the 00z/17 GEFS mean PW is 2.2-2.3"
00z Saturday and the EPS mean is 2.1-2.2" across most of the
area. In addition, the 00z/17 HREF 3hr PMM has a couple 30%
contours of 3"/3hr neighborhood probs from central VA to NE NC.
Given this combined with wet antecedent conditions, the threat
for heavy rain from showers/tstms will return with the Day 2 ERO
being upgraded to `slight`. There is also 30-35kt of 500mb
flow, which could result in better storm organization and a
marginal threat for damaging wind gusts. Continued hot and
humid, with 105+F heat indices possible across far SE VA and NE
NC.

The front lingers in vicinity of the region Saturday.
Meanwhile, another shortwave trough digs across the region
during the afternoon and evening. EPS/GEFS mean PW values remain
2.1-2.3". Therefore, the threat for heavy rain from
showers/tstms will continue with the new Day 3 ERO featuring a
`slight risk` for excessive rainfall. The combination of the
shortwave feature and the front attempting to lift back N as a
warm front could allow the heavy rain threat to linger later
into the evening. Seasonally hot and humid Saturday with highs
in the mid 80s to around 90F, after morning lows in the lower to
mid 70s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 350 AM EDT Thursday...

Key Message:

- Generally seasonal temperatures and humidity late this weekend
  into the middle of next week.

The ridge breaks down Saturday night into Sunday as a trough
digs across the Northeast. EPS/GEFS each retrograde the ridge to
the west early-middle of next week as lower 500mb heights
develop over New England and Atlantic Canada. This may actually
push a front through the area with PW values returning to near
seasonal normals with highs in the 80s. However, the Mid-
Atlantic will be in a NW flow regime between the trough to the
NE and the ridge to the SW. Therefore, slight chc to chc PoPs
will continue, highest S.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
As of 150 PM EDT Thursday...

VFR conditions prevail at the terminals at this hour with SCT-
BKN cumulus in the 3000-4500ft range. Mainly VFR through tonight
with a SW wind of 10-12 kt. Gusts to 20-25kt are possible
through this evening. There is a slight chc of showers/tstms
between 20-02z, but not enough confidence to mention anything in
the TAF. PoPs this evening are generally 15% or less elsewhere.

A cold front settles into the region Friday into Saturday
bringing scattered to numerous aftn and evening showers/tstms.
Any showers/tstms will be capable of producing reduced vsby in
heavy rain and locally strong wind gusts. Unsettled conditions
continue Sunday and Monday, but chances of aftn/evening
showers/tstms are not as high as Friday and Saturday. Primarily
VFR outside of showers/tstms.

&&

.MARINE...
As of 300 AM EDT Thursday...

Key Messages:

- Small Craft Advisories are in effect today for the Chesapeake Bay,
rivers, and coastal waters offshore of VA.

- Benign marine conditions return Friday through the weekend with
daily chances of showers and thunderstorms.

Low pressure over the Great Lakes and strong high pressure offshore
is leading to a period of elevated southwesterly winds this morning.
Observations are generally reflecting 15-20 kt wind speeds with
gusts upwards of 25 kt. Small Craft Advisories are in effect for
most waters through at least this morning, with the exception of the
far northern and far southern coastal waters and Currituck Sound.
Although wind speeds should drop off some as we head into the
afternoon hours today, gusty SW winds are likely to continue across
nearshore areas of the lower bay and James and York Rivers. Have
therefore extended the SCA for these areas until 7 PM this evening.
Another period of elevated SW winds are possible tonight, but the
latest model guidance generally suggests sub-SCA winds. There is
some uncertainty regarding the wind forecast for Friday as a slow-
moving cold front drops into the region. Regardless, a wind shift to
the N/NNE is expected Friday morning, followed by rather
variable/sea breeze-dominated wind directions by the afternoon as
the front stalls over the area. This front is also expected to
trigger rather widespread shower and thunderstorm activity in the
afternoon-evening Friday, with significantly higher wind gusts and
waves possible in and near storms.

S-SW flow returns for the weekend with generally benign/variable
marine conditions expected. Daily shower/storm chances also continue
through the weekend.

Waves in the Chesapeake Bay of 2-3 ft are expected through most of
today. On the ocean, seas generally stay in the 3-4 ft range,
but could briefly touch 5 ft in the northern waters later this
morning. 1-2 ft waves and seas prevail from later Friday into
the weekend. A low risk of rip currents is expected today
through the upcoming weekend.

&&

.HYDROLOGY...
As of 350 AM EDT Thursday...

A Flood Warning remains in effect for the Blackwater river in
Dendron.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...Heat Advisory until 8 PM EDT this evening for MDZ021>025.
NC...Heat Advisory until 8 PM EDT this evening for NCZ014>017-031-
     032.
     Heat Advisory from 11 AM to 8 PM EDT Friday for NCZ012>017-
     030>032-102.
VA...Heat Advisory until 8 PM EDT this evening for VAZ064-075>078-
     081>086-088>090-092-093-095>100-511>525.
MARINE...Small Craft Advisory until 7 PM EDT this evening for
     ANZ630>632-634>638.

&&

$$

SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ/KMC
LONG TERM...AJZ/KMC
AVIATION...ERI
MARINE...SW
HYDROLOGY...AKQ