615
FXUS61 KOKX 230002
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
802 PM EDT Wed May 22 2024
.SYNOPSIS...
-- Changed Discussion --
A cold front approaches late tonight and slowly moves through
the area Thursday and Thursday night, moving offshore sometime
early Friday morning. Weak high pressure builds on Friday. A
weak low passes through the area late Saturday into early
Sunday. A deep low pressure system tracks through the Great
Lakes and into Canada late Sunday through Tuesday with the
system`s warm front passing north Monday and its associated cold
front moving through Tuesday into Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH THURSDAY/...
Minor changes were made with this update to POPs and
temperatures. Based on radar, the storms near the Orange county
line have dissipated, so have dropped POPs altogether for the
next few hours. They pick back up only for far western edges of
the CWA in response to a line of storms currently moving through
Central PA. While most of these are expected to break up, its
possible some of them could still reach the western edges of our
CWA before dissipating around 9pm. All POPs after midnight
remain unchanged from the original forecast. Temperatures were
also slightly adjusted this evening and tonight based on current
observations and trends.
A mid-level low, embedded in the broader upper level trough over the
western US, lifts north of the Great Lakes tonight. The associated
surface low will also pass well to our north and west, but will send
a cold front towards our area. Ahead of the front, a S/SW flow has
brought in a hot and humid airmass with 850mb temps around 16 to 18C
and surface dewpoints in the low to mid 60s for most. Moisture will
continue to increase ahead of the front tonight, with guidance
showing pwats peaking around 1.60 inches tonight into early
Thursday. These pwat values are over the 90% moving average for the
12z 05/23 sounding at OKX per the SPC Sounding Climatology Page.
Some showers and thunderstorms have fired up west of the area along
and ahead of a pre frontal trough. Some of this activity could make
it into western portions of the area overnight, mainly north and
west of NYC, but is not expected to be severe with a lack of
shear. The better chances for showers and thunderstorms for our
area will be as the cold front starts to slowly move through
the area Thursday morning. PoPs have trended earlier in the day
with a shift in timing in the 12z CAMs. Given the environment,
with MLCAPE values around 1000-1500 J/kg and 0-6 km shear
increasing to around 35-40 kt, some storms could become strong
to severe. The SPC continues to outline the area in a "marginal"
risk of severe weather, with large hail and damaging winds
being the main threat. Given the high pwats, any thunderstorms
could also produce heavy downpours. At this time, there are no
flooding concerns.
Given the activity in the morning, it will be difficult to
destabilize again for the afternoon and we will likely see just
lingering showers as the front continues to sag through the
area. However, if we end up seeing less or no activity in the
morning, the stronger showers/thunderstorms could be in the
afternoon. For this reason, have left chance of thunder through
the day Thursday.
&&
.SHORT TERM /THURSDAY NIGHT/...
With the front slowly sagging south, a chance of showers and
thunderstorms continue through Thursday night, mainly for the
southern half of the area. The front likely finally passes south
early Friday morning. With plenty of clouds around, above normal low
temperatures are expected. If the front moves through northern
locations a bit quicker and they get under some clearing, some of
these locations could drop lower than the upper 50s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
A cold front exits Friday morning with any lingering precip quickly
exiting with the front. The cold front will not help cool things
down much, with afternoon temperatures still expected to reach the
mid-80s to mid-70s. The front will, however, help dry us out,
reducing any chances for showers or thunderstorms. Sunny to mostly
sunny conditions are expected on Friday.
Zonal flow will remain aloft through the weekend with above normal
temperatures and occasional shortwaves. Moisture will increase late
Saturday with a returning southerly flow. Shower chances will
increase with it late Saturday into Saturday night with slighter
better chances for a few thunderstorms in the western interior
developing along a passing warm front.
Rain chances increase early Monday into Monday night then linger in
the forecast through Wednesday. A Great Lakes low will lead to a
stalled boundary that will pass as a warm front on Monday, then
bring a cold front Tuesday or Wednesday as it tracks into Canada
and/or New England. The warm front will bring us into the warm
sector of the system and bring a chance for thunderstorms across the
area late Monday into early Tuesday. The pressure gradient front the
low passing to the north may lead to breezy conditions late Monday
into early Tuesday. Guidance varies somewhat on the timing and
location of this system so have kept chance POPs throughout Tuesday
and Wednesday. Temperatures will be closer to seasonal Monday
through mid-week aided by an approaching and deepening trough.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Weak surface high pressure will remain just offshore tonight, then
drift farther out to seas late tonight into Thursday as a cold front
approaches. The cold front slowly pushes through Thursday night.
Winds diminish to under 10 kt tonight. Weakening convection moving
in from the west could impact KSWF late this evening with a shower
or a thundershower possible. Any convection and showers will be less
likely to move further east into the city and eastern terminals for
late this evening and into the early portion of the overnight.
Main shower/tstm impact from the NYC metros north/west now looks to
be in the morning from about 13Z-16Z give/take an hour, reaching
KBDR/KISP from 14Z-17Z. MVFR cond likely and brief IFR vsby
possible with this activity, and gusty winds and some hail cannot
be ruled out with any stronger storms. Before that, some low
stratus and fog with IFR cond expected at KBDR/KISP/KGON for the
overnight into Thu morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected through this evening. Amendments may be
needed after 04z if any showers off to the west get further east
than anticipated. Amendments may be needed towards the Thu morning
push if thunderstorm activity arrives earlier than expected.
OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
Thursday night: Chance of showers and possibly a tstm, especially
for the evening, with MVFR cond possible.
Friday: VFR.
Saturday: Chance of afternoon/evening showers and possibly a tstm,
with VFR cond possible.
Sunday: Mainly VFR.
Monday: Chance of showers and possibly a tstm, with MVFR cond
possible.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds and waves will generally remain below SCA criteria through
Thursday night, with wind gusts potentially briefly reaching 25 kt
this evening. A cold front approaches late tonight and slowly moves
through the area on Thursday. Some showers and thunderstorms ahead
and along the front are possible tonight through Thursday night,
with the highest chances being Thursday morning/early afternoon.
Sub-SCA conditions are then expected through Monday night.
&&
.HYDROLOGY...
Thunderstorms are possible tonight through Thursday, with potential
for heavy downpours mainly during Thursday morning/early afternoon.
At this time, no hydrologic impacts are expected through the middle
of next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BR/JT
NEAR TERM...BR/JT
SHORT TERM...JT
LONG TERM...BR
AVIATION...JE
MARINE...BR/JT
HYDROLOGY...BR/JT