684
FXUS61 KOKX 131129
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
729 AM EDT Sat Jul 13 2024
.SYNOPSIS...
A stationary front along the east coast, from Maine into the
southeastern states, remains into Saturday as a weak wave of low
pressure over the Delmarva tracks slowly northward. The front
moves slowly east and washes out just southeast of the area late
Saturday and Saturday night. High pressure returns Sunday with a
thermal trough setting up over the region Monday and Tuesday. A
cold front then approaches from the west on Wednesday, moving
offshore Thursday. High pressure may return on Friday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Frontal boundary and axis of PWATs around 2 inches shift east across
the area today. The combination of focused moisture convergence near
the boundary with shortwave and jet streak lift will continue to
bring showers with an isolated thunderstorm possible for much of the
area. Heavy downpours are still anticipated with a chance of at
least isolated flash flooding, so no changes to the Flood Watch at
this time. Most of the shower activity should be offshore by the end
of the day, but also maybe an isolated shower/thunderstorm well NW
of the city this afternoon as instability builds after some sunshine
develops.
Muggy tonight, but at least dewpoints won`t be as high as they have
been for the past couple of nights as winds shift NW-W
overnight.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Weak high pressure will be in control during Sunday. Some global
models and CAMs hint at a chance of an afternoon shower or
thunderstorm over western areas as sufficient CAPE might combine
with some upward forcing from a subtle shortwave. Have therefore
included a slight chance of a thunderstorm. Thinking is that any
convective debris clouds that would occur would arrive late enough
in the day to not have too much of a factor on high temperatures.
Models continue to show 850mb temps at mostly 17-19C during the
afternoon - highest over western zones. Highs in the upper 80s to
lower 90s for the most part. Given boundary layer dewpoints and a W-
SW low level flow, surface dewpoints should be able to mix out a
little during peak heating outside of any seabreeze/onshore wind.
NBM dewpoints still looked too high, so a blend of NBM, CONSALL and
superblend was used in most spots.
Models show more disagreement regarding 850mb temps for Monday,
possibly owing to the timing of a potential shortwave headed our way
that would help trigger some afternoon showers and thunderstorms
with plenty of CAPE in place. Temps at this level would otherwise
probably be around 20C. Have gone with NBM for highs, but it might
be a couple degrees too low, especially if there`s no interference
from convective cloud cover. Regardless, it appears that there will
be more areas that reach heat indices of at least 95 degrees.
Heat advisories have now been posted in areas where widespread heat
indices of at least 95 degrees will more likely occur for both
Sunday and Monday. This includes NYC, Nassau County, and the urban
corridor of NE NJ.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The heat continues into Tuesday with another shortwave potentially
triggering afternoon/evening showers and thunderstorms. 850mb temps
climb even higher, reaching the low 20s C, with ambient temperatures
possibly reaching 100 in spots across NE NJ. Highs in the 90s
elsewhere. A good portion of the forecast area could see heat
indices reaching 100, and it is not out of the question for the heat
index to touch 105F in the urban NE NJ corridor.
A more amplified and deeper trough is likely to approach next
Wednesday. This will send a cold front into the area. Ahead of the
front, temperatures should once again reach the upper 80s and lower
90s. Dew points could end up slightly higher compared to Monday and
Tuesday, so heat indices peak in the middle to upper 90s, especially
away from the immediate coast and far northern interior.
A widespread convective event remains possible Wednesday
afternoon/evening into Wednesday night. Still some spread in global
ensembles, but it continues to look like the front will help usher
in a drier and more seasonable regime behind it late next week.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
A frontal boundary lingers near the terminals today before pushing
east tonight.
Pockets of MVFR/IFR this morning as showers push north and east
through the region. A thunderstorm or two is also possible, though
this threat appears rather isolated. Precip ends generally between
15Z and 18Z from west to east and conditions gradually return to VFR
by late afternoon. Possible fog or low stratus development overnight
could lead to restrictions, but confidence too low to include
in TAF at this time. Otherwise, VFR on Sunday.
Southerly with speeds generally at or under 10 kt through this
evening. Frontal passage overnight will cause flow to lighten before
a N direction is established into Sunday AM. Flow turns S or SW by
the afternoon, with speeds remaining light.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence in TSRA coverage later this morning.
Timing of category improvement could be off by a couple of hours.
Possible vsby/cig restrictions Sunday morning.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
Late Tonight: VFR. Light and variable winds.
Sunday: VFR.
Monday through Wednesday: Mainly VFR. A chance of afternoon into
early evening showers and thunderstorms with MVFR possible.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A lingering swell is keeping ocean waves 4-5 ft this morning.
Not enough confidence to drop the SCA with this update, but
might be able to do so for all zones by the end of this morning.
For the non- ocean waters, winds and seas remain below advisory
levels.
Winds and seas largely remain below SCA criteria tonight through the
middle of next week. Ocean seas may begin to approach 5 ft late
Wednesday ahead of an approaching front.
&&
.HYDROLOGY...
Additional rainfall of a half to 1.50 inches is anticipated today
with still a chance of locally higher amounts. Mostly small stream
and minor urban/poor drainage flooding are anticipated for any
impacts, but at least isolated instances of flash flooding will
still be possible. Any flooding impacts are more likely to occur
this morning into early afternoon.
&&
.TIDES/COASTAL FLOODING...
There is a high rip current risk along all ocean beaches through
this evening. A moderate rip current risk is expected on Sunday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Flood Watch until 6 PM EDT this evening for CTZ005-009.
NY...Flood Watch until 6 PM EDT this evening for NYZ067>075-176>179.
Heat Advisory from noon Sunday to 8 PM EDT Monday for
NYZ072>075-176>179.
High Risk for Rip Currents through this evening for NYZ075-080-081-
178-179.
NJ...Flood Watch until 6 PM EDT this evening for NJZ002-004-006-
103>108.
Heat Advisory from noon Sunday to 8 PM EDT Monday for NJZ004-
006-103>108.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ350-
353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/DS
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JC/DS
AVIATION...DR
MARINE...JC/DS
HYDROLOGY...JC/DS
TIDES/COASTAL FLOODING...