000
FXUS61 KOKX 061236
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
836 AM EDT Tue Jun 6 2023
.SYNOPSIS...
Low pressure over the Canadian Maritimes remains nearly
stationary through midweek, sending a cold front through the
area this afternoon. The low will then weaken the second half of
the week drifting south into the Gulf of Maine. Weak high
pressure builds in Saturday and moves offshore Sunday as a cold
front approaches. The front moves through the region late Sunday
into Monday.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Updated to include thunder early this morning along and west of
Hudson River corridor. Elevated convection has worked its way
into the Lower Hudson Valley. MUCAPE currently is limited closer
to the coast, but even low values further north have been enough
to get several lightning strikes going.
Smoke from wildfires across eastern Canada working across across
the area with some visibility restrictions down to 4-5sm. With
the onset of daytime heating and mixing, visibilities may
improve, but haze and possibly odor will remain. In addition,
the HRRR and RAP smoke fields continue to show high
concentrations in the low levels later this afternoon into this
evening. Thus, have maintained smoke and haze in the forecast
into tonight. This potential looks to continue beyond this time.
Otherwise, a cutoff low will remain over the Canadian Maritimes
through the end of the week, gradually weakening during this
time. An omega block across North America will result in very
little change in the upper air pattern during this time as a
series of fronts/troughs drop across the area. The first of
which will move across the area this afternoon. Steep lapse
rates (7C) from the surface into the mid levels will combine
with marginal to moderate instability to produce scattered
showers and a few thunderstorms, mainly this afternoon. A
significant dry sub- cloud layer could be a limiting factor for
instability, however, it cold also enhance gusty surface winds.
CSU Machine Learning Severe probabilities shows a marginal risk
for hail and wind. This scenario would seem more plausible were
the NAM profiles with CAPE values approaching 1000 J/KG
realized. The GFS has considerably less instability with its
extremely deep mixed layer, while the HRRR and SPC HREF show
values in the 500-750 J/KG range. Current thinking is that this
will be a sub-severe event. The best chance for convection looks
to be this afternoon with not only cold front but with a mid
level short wave dropping down the backside of the upper low.
Rainfall amounts will should be under a quarter inch.
NW winds at times today may gusts as high as 20 to 25 mph. This
combined with the low RH values (30 to 35 percent) across NE NJ
will enhance the spread of any brush fires that do develop.
Highs today will be near seasonable levels in the 70s, perhaps
around 80 across metro NE NJ. Lows behind the cold front tonight
will be a few degrees below, ranging from the upper 40s inland,
to the upper 50s across NYC.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
Deep-layered cyclonic flow and disturbances rotating about the
upper low will bring clouds each afternoon with a chance of
showers. There will be a bit more instability Thursday afternoon
and perhaps an isolated thunderstorm north and west of the NYC
metro. Temperatures will gradually cool down through Thursday.
For Thursday, leaned toward the cooler MOS versus the NBM due to
more cloud cover as the upper low retrogrades west across
northern New England.
Smoke and haze issues may linger into Wednesday, especially for
the western half of the forecast area.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Omega blocking will persist into Saturday as a large closed
upper low remains over the northeast and into eastern Canada.
The low weakens Saturday and drifts northeast as additional
energy rotates into the upper trough. That low deepens and
becomes closed off Sunday and remains into Monday. Overall, the
extended period will be unsettled except for a brief dry period
late Saturday into Sunday as weak ridging builds into the
northeast. Temperatures will be generally just below seasonal
normal levels, except for Sunday with the ridge and dry weather.
There is a chance of showers into Saturday with a slight chance
of thunderstorms inland late Friday where there will be better
instability and forcing. Additional showers and thunderstorms will
be possible with a cold front Sunday and Monday. Generally
followed the NBM guidance except with a few adjustments to the
probabilities.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
A cold front will approach early this afternoon and move through
during through mid to late afternoon.
MVFR cond are possible with any TSRA that develops ahead of the
approaching front early afternoon at KSWF and mid afternoon farther
SE. Strongest cells may even produce gusty winds and hail. Best
chance of thunder should be at the CT and Long Island terminals,
especially KGON where brief IFR cond may be possible.
Light WNW should increase by afternoon, with gusts near or just over
20 kt. Winds shift NW after fropa, them diminish this evening.
Smoke from Quebec wildfires will limit slant range visibility at
times today, also sfc visibility in the NYC metro area and lower
Hudson Valley for a few hours late today after cold fropa.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
The afternoon haze potential forecast is YELLOW, which implies slant
range visibility 4-6SM outside of cloud.
AMD may be needed today to pinpoint tstm timing/coverage.
OUTLOOK FOR 06Z TUESDAY THROUGH SATURDAY...
Late tonight: VFR.
Wednesday: VFR. W-NW winds G20kt. MVFR vsby again possible in
smoke/haze at the NYC metros from 20Z-24Z.
Thursday through Friday: Mainly VFR. Chance of afternoon and early
evening showers both days.
Saturday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Winds and seas likely remain below SCA levels through Saturday
night as low pressure over the Canadian Maritimes weakens. Weak
low pressure will then remain in the vicinity of the forecast
waters through Saturday.
&&
.FIRE WEATHER...
NW winds at times today may gust as high as 20 to 25 mph. This
combined with the low RH values (30 to 35 percent) across NE NJ
will enhance the spread of any brush fires that do develop.
&&
.HYDROLOGY...
No hydrologic impacts expected through the beginning of next week.
&&
.TIDES/COASTAL FLOODING...
Low pressure over the Canadian Maritimes continues to produce E
swell that in tandem with high astronomical tides is keeping water
levels higher than usual, especially in the back bays of Nassau.
Followed the Stevens NYHOPS bias-corrected central forecast and
issued a coastal flood advisory is in effect for the high tide cycle
late this evening. Water levels there may barely touch minor
thresholds with the high tide cycles both Wed/Thu nights as well.
There is a low risk for the development of rip currents at the
ocean beaches today and Wednesday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Coastal Flood Advisory from 9 PM this evening to midnight EDT
tonight for NYZ179.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...MET/DW
NEAR TERM...DS/DW
SHORT TERM...DW
LONG TERM...MET
AVIATION...BG
MARINE...MET/DW
FIRE WEATHER...
HYDROLOGY...MET/DW
TIDES/COASTAL FLOODING...