454
FXUS61 KOKX 232347
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
747 PM EDT Tue Jul 23 2024
.SYNOPSIS...
A stationary boundary lingers near the area through Wednesday,
with a weak area of low pressure passing southeast of the
region. A cold front approaches late Thursday and moves through
Thursday night into early Friday morning. High pressure builds
in from the west Friday and Saturday, then remains into the
beginning of next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
The forecast remains on track tonight. Current update reflects
adjustments to PoPs and temperatures. Showers have weakened
across the area over the last several hours. Still a chance of a
shower through late evening, but these should be quite
isolated in nature.
The area remains on the eastern side of a broad upper level
trough, with a series of convectively enhanced shortwaves
approaching from the SW tonight through Wednesday. At the
surface, a weak stalled frontal boundary lingers over/near the
area. General agreement on a wave/s of low pressure approaching
from the Tennessee Valley tonight into Wednesday, likely
tracking just se of the region.
General agreement on increase in shower and embedded tstm
activity from sw to ne late tonight with increasing synoptic
lift ahead of approaching shortwave/vort train and strengthening
llj ahead of surface wave. General agreement that the surface
wave tracks south of the region tonight into Wednesday morning,
moving east Wed PM. This track would keep the primary focus for
training heavy shra/tsra activity south of the region tonight
into early Wed AM, where it taps into the higher
theta-e/instability environment exists. Generally light to
moderate rain shower/stratiform activity for the local area,
but can`t rule out an embedded localized heavy downpour/tsra.
Could have some invigoration of the localized heavy
downpour/tsra activity, particularly along the coastal plain
after daybreak Wed AM, as shortwave continues to move through
aloft, combined with diurnal instability development, and in
vicinity of weak surface boundary. Localized rainfall
rates of 2"/hr possible with this activity. This appears to be
the main threat period for localized flash flooding, but low
confidence on location and occurrence, based on CAMs.
Distinct shortwave energy and surface wave appears to move east
Wed Aft with drying conditions from w to e. This should allow
for some breaks of sun across western areas, and potential for
isolated aft/eve diurnal shra/tsra activity across far interior
areas in a marginally unstable and still moist environment.
Onshore flow will likely strengthen low-level capping and
stabilize the coast.
High temperatures will be a few degrees below normal with cloud
cover and onshore flow, upper 70s/lower 80s.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
The area remains on the eastern side of a broad upper level
trough, with sharpening trough axis over the Great lakes Wed
night, beginning to pivot towards the area on Thursday.
Stationary front, to the south of LI, appears to sink farther
south Wed Night in wake of departing surface waves from Wed.
Meanwhile a pre-frontal trough approaches from the west late Wed
night, with a cold front approaching late Thu.
Indications of some mid-level drying Wed Night into Thu AM as
SW flow pick up aloft. This combined, with region being in
between two boundaries, should allow for drier conditions during
this time.
Then potential for scattered aft/eve convection with of shortwave
trough and as pre-frontal trough begins to slide east across
the region. A this point, appears to be a marginally unstable
environment with moderate to strong deep layer shear. This could
bring potential for isolated strong to severe tstms, with
strong wind gusts and heavy downpours the main threat in a
nearly unidirectional wind profile. Strong steering flow
perpendicular to the pre-frontal trough and a bit of mid-level
drying, should promote progressive storm motion and present more
of an minor urban/poor drainage flood threat, despite PWATS
still remaining near 1.75".
Highs near seasonable in mid to upper 80s.-- End Changed Discussion --
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Key Points:
*Drier conditions develop late this week with high pressure
maintaining sunshine through the weekend
*Daytime high temperatures run several degrees above normal, but
lower humidity will make it feel more tolerable
Behind the fropa Thursday night, the trough axis shifts east Friday.
Conditions dry out entirely as subsequent northerly flow develops
ahead of a building surface high from the Great Lakes. As it does
so, an upper ridge over the Central US amplifies as it slides east
toward the region through the weekend. This will allow a much more
tranquil, and drier, pattern to take hold. In fact, the next chance
of any precipitation may not arrive until next Tuesday, depending on
the timing and placement of a potential shortwave rounding the
ridge, but even this is not a guarantee at this point.
Abundant sunshine prevails Friday through the weekend. Temperatures
average a few degrees above normal thru the period, with afternoon
highs in the low to mid 80s Friday and the weekend, increasing into
the mid to upper 80s early next week, with lower 90s possible in the
urban NE NJ corridor. Humidity levels creep up very gradually thru
the period, with afternoon dew pts around 60 to start, increasing
into the mid to upper 60s by Monday as the high slips offshore and
return flow sets up.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A frontal system remains just south of the region through
Tuesday night.
Mostly VFR conditions expected across area terminals through
tonight. Cigs will then lower to MVFR as showers increase across
the area, especially overnight. Showers may be heavy at times,
bringing conditions briefly to IFR. Very low chance of TSRA.
Light S to SE flow around 10 kt, will become light and variable
overnight. Low confidence on the wind direction details.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely with flight categories changes. Large
uncertainty in wind direction given track of weak lows, frontal
boundary position, and overall general weak flow.
OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
Wednesday through Thursday: MVFR or lower in SHRA/isolated
TSRA.
Friday: MVFR or lower possible in the morning with SHRA,
otherwise VFR.
Saturday through Sunday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
With a weak pressure gradient over the area, winds and seas/waves
remain below Small Craft Advisory criteria through the weekend.
Periods of moderate to heavy showers and thunderstorms will be
possible with multiple waves of low pressure passing near the area
through Wednesday night.
&&
.HYDROLOGY...
Potential for locally heavy downpours and embedded tstms Wed
AM. Rainfall rates of 2"/hr are possible in stronger convection,
but at this point convective coverage appears to be limited and
predictability on boundary placement as a focus for training
showers and thunderstorms is low. So overall, the primary threat
is for scattered minor urban and poor drainage flooding, with a
localized flash flood threat.
Scattered diurnal shower and thunderstorm activity likely on Thu
aft/eve, bringing primarily a minor urban and poor drainage flooding
threat.
This is outlined by the marginal risk of excessive rainfall through
Thursday.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip current development at the ocean beaches
will remain through Thursday as a 3 to 4 ft S/SE swell at 7 to
8 seconds continues. Rip activity could be locally high due to
the Spring tides.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...NV
NEAR TERM...DBR/NV
SHORT TERM...NV
LONG TERM...DR/NV
AVIATION...20
MARINE...DR/NV
HYDROLOGY...DR/NV
TIDES/COASTAL FLOODING...