Portsmouth, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

946
FXUS61 KAKQ 232330
AFDAKQ

AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
630 PM EST Sat Nov 23 2024

.SYNOPSIS...
High pressure builds into the Mid-Atlantic tonight and
gradually settles off the Southeast coast by Monday. This will
bring dry conditions and gradually warming temperatures. A cold
front crosses the region early Tuesday with limited moisture.
Unsettled conditions are expected by Thanksgiving as low
pressure approaches from the west.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 330 PM EST Saturday...

Key Messages...

- Clear and cool tonight with patchy frost.

Vertically stacked low pressure is located over Atlantic Canada
early this afternoon. Meanwhile, a broad upper ridge and
surface high pressure extend from the lower Mississippi Valley
across the Southeast. Mostly sunny and breezy this afternoon
with low pressure to the NE and high pressure to the SW.
Temperatures are in the mid 50s to lower 60s with a WNW wind of
10-15 mph gusting to 20-25 mph (strongest NE). Surface high
pressure gradually builds in from the SW tonight as low pressure
begins to fill and lift NE over the Canadian Maritimes. Clear
and cool with lows in the mid 30s to around 40F. Patchy frost is
possible over portions of far s-central VA and interior NE NC
where the frost/freeze program is still active. However, there
is likely limited impact with lows of 34-36F given that we are
in late November.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
As of 330 PM EST Saturday...

Key Messages...

- Gradually warming temperatures are expected Sunday into early
  next week.

- A mainly dry cold front cross the region early Tuesday.

High pressure becomes centered in vicinity of the Southeast
coast Sunday into Sunday night, before settling off the
Southeast coast Monday as an upper trough and associated cold
front drop into the upper Midwest. Sunny and mild Sunday with
highs in the upper 50s to lower 60s with a light SW wind of 5-10
mph and 10-15 mph over the Eastern Shore. Mostly clear and cool
Sunday night. Low temperatures range from the lower to mid 30s
NW to the upper 30s to lower 40s SE. Milder Monday as the
surface high nudges offshore with high temperatures in the mid
to upper 60s inland W and SW of the Ches. Bay and lower 60s over
the Eastern Shore. Continued dry Monday with increasing high
clouds. The upper trough digs across the Great Lakes Monday
night with the associated cold front pushing across the
Appalachians late. Moisture is limited with the front, with a
minimal chc of showers (mainly across the northern tier of the
area) late Monday night into early Tuesday morning with a few
hundredths of an inch of QPF at most. Post-frontal downsloping
westerly flow will result in another mild day Tuesday with highs
in the lower to mid 60s NW to the upper 60s to near 70F SE,
after morning lows in the upper 40s to lower 50s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 330 PM EST Saturday...

Key Messages...

- Low pressure will bring the potential from rain Thanksgiving
  into Thursday night.

- Much colder temperatures are possible late next week into the
  following weekend.

The upper trough deepens and shifts E across the Northeast
Tuesday night into Wednesday. Surface high pressure along with a
dry/cool advection arrive into the area Tuesday night into
Wednesday. Forecast lows Tuesday night drop into the lower to
mid 30s N to the upper 30s/lower 40s SE, followed by highs
Wednesday ranging from the lower 50s N to the upper 50s SE.

Another trough, initially over the Central Plains Wednesday
moves E and deepens over the Eastern CONUS Thanksgiving Day into
Thursday night with developing surface low pressure. There is
improved agreement between the 23/12z GFS/GEFS and EPS/ECMWF
although the EPS/ECMWF are more amplified with the primary
trough and surface low later Thanksgiving into Thursday night.
Therefore, the EPS has slightly higher probs for >= 0.5" of rain
than the GEFS and its shifted more northward. Regardless, rain
is increasingly likely Thanksgiving into Thursday night. Highs
Thanksgiving Day reflect a CAD set-up with upper 40s NW to lower
60s SE. Lows Wednesday night and Thursday night are mainly in
the upper 30s NW to mid/upper 40s SE. GEFS/EPS each continue to
depict a much colder and very dry airmass arriving late this
week into next weekend. Forecast PoPs are below NBM Friday into
Friday night based on the consensus of the timing in the
GEFS/EPS showing drier air surging into the region by Friday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
As of 630 PM EST Saturday...

Low pressure remains well NE of the area this evening. Locally,
VFR conditions are observed as of 00z and should persist
through the period. BKN-OVC stratocumulus at SBY likely
dissipates over the next few hours, with SCT-BKN high clouds
over srn VA and NE NC also gradually dissipating tonight. Dry
and VFR Sunday with sunny or mostly sunny skies. W winds of 5-10
kt are expected tonight, increasing to around 10 kt at all
terminals late morning through the afternoon Sunday.

Outlook: Mainly dry and VFR Sunday night through Wednesday. One
exception will be a cold front early Tuesday that will bring a
minimal chc of showers, mainly from RIC to SBY. Low pressure
will bring an increased chc of rain and degraded flight
conditions by Thanksgiving Day.

&&

.MARINE...
As of 245 PM EST Saturday...

Key Messages:

- Small Craft Advisories remain in effect for the lower James River,
  the Bay, and all coastal waters through 7 PM this evening.

- Benign marine conditions return Sunday through early next week.

Current analysis shows a strong upper level trough over NE US.
Surface low pressure has shifted offshore New England. Winds remain
gusty but are beginning to diminish. Winds are generally NW 20-25 kt
with gusts up to 30 kt across the coastal waters and 15-20 kt with
gusts up to 30 kt in the Bay. Seas and waves are 4-5 ft and 1-3 ft,
respectively. SCAs are in effect for most waters through this
evening. Winds will diminish to sub-SCA conditions for the remainder
of the weekend and into early next week as high pressure builds back
into the area. The next front passage will be Tuesday, which could
bring elevated winds, waves, and SCA conditions.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for
     ANZ630>634-638-650-652-654-656-658.

&&

$$

SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...AJZ
AVIATION...SW
MARINE...KMC