410
FXUS61 KOKX 151548
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1148 AM EDT Wed May 15 2024
.SYNOPSIS...
Low pressure slowly approaches from the south today into tonight
and departs to the southeast Thursday into Thursday night.
Brief high pressure builds from the northeast Friday. This will
be followed by another frontal system and potential wave of low
pressure over the weekend. High pressure then builds in for
early next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Widespread light rain continues, with a band of some heavier
showers now moving through western CT. There could be a lull in
the activity early this afternoon where PoPs drop to chance, but
rain chances then increase from south to north later this
afternoon.
Low pressure will continue to slowly approach from the south and
is currently just off the Delmarva coast.
Numerical weather prediction models convey that forcing for lift
increases as shown by mid level positive vorticity advection
later this afternoon. Also indicated is isentropic lift,
allowing for the rain to be overspreading and expanding
throughout the area this afternoon. The models also indicate a
continuously moist environment with layer precipitable water
reaching values mainly between 1.2 and 1.4 inches.
Temperatures stay in the 60s today with the rain which for most
locations will be periodic or intermittent.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
The low gets closest to Long Island tonight and then slowly
makes its way out into the Atlantic Thursday into Thursday night.
High pressure will briefly build in from the Canadian Maritimes for
Friday and Friday night.
Models overall have shifted farther north with the low and the
speed of the low appears to be lower compared to previous
forecasts also. This has resulted in higher POPs for tonight and
Thursday with rain likely for much of the two time periods.
Also with the closer proximity of the low, low level omega is
forecast to increase especially across eastern sections of the
forecast region. In addition, the pressure gradient will become
tight, making for gusty winds from the NE tonight into Thursday.
Models have also depicted Showalter Indices getting near zero across
mainly the southern coastal areas for Thursday, so have a slight
chance of thunderstorms.
The rain tonight into Thursday is expected to be steady and light to
moderate at times. Some brief locally heavy rain will be possible as
the layer precipitable waters will be very similar to the previous
day.
Chances for rain remain Thursday night and eventually diminish
late Thursday night as low pressure moves farther away. Drier
air will eventually come into the area late Thursday night into
Friday. Dry conditions are forecast to persist through Friday night.
Temperatures still mainly in the 60s for highs Thursday with a
rebound of high temperatures on Friday back to near to slightly
above normal values, mostly upper 60s to mid 70s with more sun
and decreasing NE flow compared to the previous day.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The NBM was generally used for the extended period with no major
changes in the forecast. There still remains a good deal of
uncertainty with the handling of the next surface low pressure
system in the vicinity of the area over the weekend and into early
next week. The previous discussion follows:
Another system very much like the one preceding it midweek will
potentially impact the area over the weekend. However, there is
quite a bit of spread in the globals with the southern branch closed
low as it moves near the Mid Atlantic coast at the end of the
weekend and offshore early next week. This seems partly due to the
interaction of a northern stream shortwave trough lifting across the
Great Lakes Friday and into eastern Canada over the weekend. While
the two streams remain separate, their influence on one another will
determine the placement of the upper low. The latest ECMWF takes the
upper low and shears it off with the bulk of the energy moving into
the Southeast U.S. The GFS and Canadian have the low track much
farther north with the potential for the area to get into the better
forcing just north of its track. The ECMWF is a mainly dry forecast
with surface ridging remaining in place. Thus, the NBM was followed
with some adjustments based on the aforementioned operational run
and the latest consensus forecast. This gives the area increasing
chances of rain Saturday afternoon/evening through Sunday. Weak high
pressure may move into the area on Monday.
There is quite a bit of uncertainty in the forecast over the
weekend. There is good reason to expect changes in the forecast with
subsequent issuances.
Highs during the period will be closer to normal on Monday, but
several degrees below over the weekend due to the chances of rain.
This could very well change due to the differences previously
mentioned in the low track. Lows will be on the mild side due to a
prolonged period of cloud cover forecast.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Low pressure off the Middle Atlantic coast slowly tracks towards
the area through tonight.
Conditions will continue to deteriorate this morning with
mainly IFR for most terminals, but MVFR to VFR could linger out
east towards KGON. There is a chance ceilings briefly improve
late morning/early afternoon to MVFR before going back down to
IFR late afternoon and evening. IFR prevails tonight and
potentially continues into Thursday morning. Confidence in the
timing of category changes due to cigs is low.
Light rain continues for much of the day. Rain continues tonight
as the low approaches.
ESE-E winds to start will slowly become E-NE this afternoon. NE
flow prevails tonight. Wind speeds increase this morning,
becoming 10-15 kt in the afternoon. Gusts 18-25 kt are possible,
especially near the coast. Gusts become frequent tonight into
Thursday morning near the coast.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely through the TAF period for changes in flight
categories. Some fluctuations between IFR and MVFR are probable
this morning into early afternoon.
Wind gusts may be occasional this afternoon.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Thursday: IFR to MVFR early, possibly improving to VFR late in
the day. A chance of showers, especially early. NE winds G20kt.
Friday: VFR. Slight chance of a shower late.
Saturday and Sunday: IFR/MVFR possible. Chance of showers. SE winds
G15-20kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Conditions trend from below SCA much of today to SCA level wind
gusts late this afternoon along the ocean mostly. Then all
waters will have SCA levels gusts tonight through much of
Thursday. Some SCA gusts could linger into Thursday night.
Below SCA gusts expected Friday into Friday night.
Seas on the ocean start out below SCA today and then get into
SCA range tonight and likely remain at SCA levels thereafter
through Friday night. SCA level seas also forecast for extreme
Eastern LI Sound (East of the Mouth of the Connecticut River)
tonight into Thursday. Otherwise, non-ocean waters look to
remain below SCA levels during the short term that goes through
Friday night.
Lingering wave heights near 5 feet on the ocean will result in SCA
conditions continuing on Saturday. The waters then look to remain
below SCA thresholds through Sunday but exact placement in a low
pressure system to the south may change the forecast.
&&
.HYDROLOGY...
No hydrologic impacts are expected through the beginning of
next week.
Rainfall in the today through Thursday time frame with amounts
on average between 0.25 and 1.25 inches. Can not rule out a few
isolated higher amounts near 1.5 inches with Long Island being
the best spot to see those higher values.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 6 PM this evening to 6 PM EDT
Thursday for ANZ331-332-335-338-340-345.
Small Craft Advisory from 4 PM this afternoon to 6 PM EDT
Thursday for ANZ350-353-355.
&&
$$
SYNOPSIS...JM/JT/MW
NEAR TERM...JM/JT
SHORT TERM...JM
LONG TERM...MW
AVIATION...DS/MW
MARINE...JM/MW
HYDROLOGY...JM/MW