000
FXUS61 KOKX 221520
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1120 AM EDT Fri Mar 22 2024
.SYNOPSIS...
High pressure will be in control today. Low pressure approaches
from the south tonight into Saturday morning and moves across
the area late in the afternoon to evening. High pressure ridges
down from the north Sunday into Monday and remains into Tuesday.
A frontal system then approaches from the west Wednesday and
moves through the area into Thursday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The forecast is mainly on track. Slight adjustments were made
to morning hourly temperatures and dewpoints.
High pressure ridge will be over the area today. Sunny to
start, then clouds start to increase by late, but probably not
overcast until after sundown. High temperatures will be around 5
degrees below normal - mostly in the lower and middle 40s.
Winds will at least be lighter this time around.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
An elongated area of low pressure over the Southeast tonight
moves into the Mid-Atlantic Saturday morning, with the more
northern of two circulation centers shifting through the
forecast area Saturday afternoon into night. The system will be
to our east by Sunday morning.
Rain chances begin this evening and become likely during the
late night hours. Rain then continues through the day Saturday
and ends generally west to east during the first half of
Saturday night. The rain could begin as a wintry mix across the
northern fringe of the forecast area, but would likely not last
for long as temperatures aloft warm up.
Plenty of ingredients are coming together for periods of moderate to
heavy rainfall. The nose of a 850mb theta-e ridge will be slowly
shifting through the area starting late tonight with PWATs
eventually climbing to 2-3 standard deviations above normal for this
time of the year. Even more influential will be the various sources
of lift available to interact with this moisture. Frontogenetic
forcing ahead of the approaching low center, a strong low level
jet, and a dual jet structure (left front and right rear
quadrants) in the upper levels are all expected to pass through
at some point from around noontime Saturday through Saturday
night. CAMs even show a convective line developing and shifting
through roughly the eastern half of the forecast area late
afternoon into the evening. MUCAPES are low, but with deep lift
in place, cannot rule out a rumble of thunder with this line.
Looks like the most likely period when heavy downpours could
occur will be from approximately mid afternoon through early
evening for most spots. A Flood Watch is now in effect for the
entire forecast area. See the hydrology section below for more
details on the rainfall and potential impacts.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
There has not been much change to the forecast thinking in the
extended period. Ensemble means depict mean troughing over the
northeast to start the period, with mean ridging building through
the remainder of the week. NBM was used as the basis for this
forecast, with local adjustments.
*Key Messages*
* Dry Sunday through Tuesday. Unsettled, wet weather returns
late Tuesday into Thursday.
* Gusty northerly winds likely on Sunday. Remaining gusty,
especially east, into Monday.
* Near normal temperatures expected Sunday through Wednesday with a
slight warm up toward the end of the week.
Sfc low pressure continues to pull away from the region on
Sunday. Winds will remain elevated for at least the first half
of Sunday as cloud cover continues to decrease with the
departing system. Thereafter, high pressure builds in to the
north which will result in extended NNE flow, and dry conditions
though late Tuesday.
The high then heads east of the Canadian Maritimes as a surface
low develops over the Northern Plains and heads northeast. This
system will bring a frontal system to the area Wednesday and
Thursday, with increasing precip chances starting late Tuesday.
Some global guidance is hinting at a secondary low developing
along the cold front to the south, potentially prolonging
precipitation chances into Thursday. Given this, have maintained
chance PoPs through much of Thursday into Thursday night.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pressure today into this evening. Low pressure then approaches
early Saturday and moves over the terminals through the day.
VFR into tonight with lowering ceilings. MVFR in -RA for the
Sat AM push, with the onset after 06Z Sat. 18z-03z IFR or lower
likely. Periods of +RA across most terminals. Isolated TS not
out of the question Sat afternoon and evening.
Winds become W and then S around 10 kt this afternoon. Winds
then shift more SE tonight into early Saturday and increase to
around 15-25kt late morning Saturday and continuing in the
afternoon. Some stronger wind gusts likely to work down to near
the surface during the day on Saturday especially NYC terminals
east where brief gusts to 40kt possible during the afternoon and
evening.
LLWS starting around 12Z for KNYC terminals and points east,
with at least 50kts of flow at 2kft, and guidance showing around
40kts of shear through the layer. Highest potential across LI
and SE CT.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments expected. Timing of LLWS onset early
Saturday may be +/- an hour or two.
OUTLOOK FOR 18Z SATURDAY THROUGH TUESDAY...
18z Saturday: IFR or lower in rain. Rain heavy at times into
evening. SE wind gusts 20-25kt during the day with LLWS possible
city east, becoming N all areas with gusts 30-35kt at night.
Sunday: VFR. A slight chance of rain. N-NE wind gusts around 25kt.
Monday: VFR. NE gusts 20-25kt.
Tuesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Relatively tranquil conditions today with a high pressure ridge
overhead. Winds and seas then increase ahead of a low pressure
system on Saturday. The storm passes through in the afternoon to
evening hours, then a tight pressure gradient with a gusty N to
NE flow follows for Sunday. Have issued a gale watch for all
but NY Harbor and Western LI Sound for Saturday through Sunday
morning. Relatively strong low level inversion will be in place
Sat aftn/evening, but 925mb winds still potentially 60-70kt in
a llj during this time. Gales therefore possible during this
period, mainly in heavier downpours. Better chances of gales
after early Sat evening, continuing into Sunday morning on the
back side of the storm with the tight pressure gradient and cold
air advection. Gales will be possible in the Harbor and Western
Sound Sat night into Sunday, but have held off on issuing a
Watch such that subsequent shifts can get a look at newer model
data and see if confidence increases. SCA conds are otherwise
possible for these two zones Saturday afternoon, and then more
likely Saturday night into Sunday.
Gales on the ocean waters and Eastern LI Sound will continue into
midday Sunday. SCA conditions are likely elsewhere into Monday.
Gales may remain on the western ocean waters through late day
Sunday, and on the eastern waters into Monday night as offshore low
pressure remains nearby. Thus, gale headlines may need to be
extended through Sunday.
&&
.HYDROLOGY...
Total rainfall tonight through Saturday night is expected to range
mostly 2.5 to 3.5 inches across the area. Locally higher amounts
will be possible. Best chances of heavy downpours will be from
approximately mid afternoon through early evening Saturday for
most spots, but brief heavy downpours will be possible as early
as late Saturday morning. Minor flooding is likely along at
least a few quick-responding small rivers and streams. Can`t
even rule out localized moderate flooding. Also anticipating at
least scattered minor urban/poor drainage flooding with a
localized flash flood threat.
No hydrologic issues are expected Sunday through the middle of
next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch from Saturday morning through late Saturday night
for CTZ005>012.
NY...Flood Watch from Saturday morning through late Saturday night
for NYZ067>075-078>081-176>179.
NJ...Flood Watch from Saturday morning through late Saturday night
for NJZ002-004-006-103>108.
MARINE...Gale Watch from Saturday morning through Sunday afternoon for
ANZ331-332-340-345-350-353-355.
&&
$$
SYNOPSIS...JC/DBR
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...DBR
AVIATION...DBR
MARINE...IRD
HYDROLOGY...JC/DBR