Scientific Forecaster Discussion
fxus61 kokx 242006
Area forecast discussion
National Weather Service New York New York
406 PM EDT Mon Jun 24 2019
high pressure will move offshore tonight as a warm front
approaches from the west. The warm front will move through on
Tuesday, followed by a cold front passage Tuesday night. A weak
upper level disturbance will move across Wednesday night,
otherwise high pressure will be in control through at least
Friday. A cold front will pass through on Saturday. Followed
again by high pressure for Sunday.
Near term /until 6 am Tuesday morning/...
upper ridge axis builds overhead this evening with surface high
pressure continuing to move offshore. The ridge axis will slide
to the east after midnight and will be followed by a gradual
trend of height falls in the middle and upper levels. A warm
front draped across western PA approaches and should near the
region towards day break.
Clouds will increase through the night as the warm front
approaches. Warm advection ahead of the front coupled with
lowering heights will be enough to support a band of showers
entering the lower Hudson Valley and northeast New Jersey around
day break. The timing amongst the high resolution models is in
fairly good agreement and any showers remain west of the NYC
Metro before 6am. A rumble of thunder cannot be ruled out with
increasing elevated instability.
Humidity levels increase tonight as dew points climb into the
60s. Low temperatures will be in the middle and upper 60s.
Short term /6 am Tuesday morning through Tuesday night/...
band of showers and a few rumbles of thunders translates across
the NYC Metro, Hudson River corridor, western Long Island, and
southwest Connecticut during the morning commute. There could
be pockets of moderate to heavy rain with the main concern being
urban and poor drainage flooding. The showers should largely
hold off further east until after the morning commute.
Some of the high resolution convection allowing models are
weaker on the southward extent of the showers, which could
mean less coverage. Have gone with persistence and the
expectation that warm advection, a decent middle level
shortwave, and height falls will support a fairly solid band of
showers through the region. Model forecast soundings show a
strong inversion above the surface with much of the instability
lying above 900 mb. No concerns for severe weather at this time
due to lack of surface instability and no apparent wave along
the warm front to enhance low level shear.
The showers and embedded storms continue working east across
Long Island and southern Connecticut through the morning. The
warm front may slow down a bit as the associated shortwave
encounters the deeper ridging just offshore. Some of the
guidance indicates enhancement of the showers as they move
across eastern Long Island and southeast Connecticut. However,
this may be overdone as noted with the ridging being nearby
preventing any of this enhancement from occurring. These trends
will need to be monitored since rainfall amounts and chances for
more widespread minor flooding could be realized if the
enhancement of showers does indeed occur out east.
The focus then turns to the warm sector later Tuesday afternoon.
Dewpoints likely reach the upper 60s to near 70 with a more
tropical feel to the air. Temperatures should reach the middle
80s in the NYC/New Jersey Metro and the combination of the higher
humidity may make it feel closer to 90.
Forecast soundings indicate significant drying aloft in the
afternoon. There will also be a warming vertical temperature
profile and when combined with the significant dry air aloft,
any convective development will be isolated at best. This chance
is further reduced with loss of heating in the evening. The
cold front passage Tuesday night should be dry with no
precipitation forecast. Lows will be in the 60s for much of the
There is a moderate risk of rip current development at the
Atlantic Ocean beaches on Tuesday.
Long term /Wednesday through Monday/...
with the exception of an upper level disturbance moving across and
possibly sparking an isold tstm well northwest of NYC Wed eve, high
pressure will dominate through the end of the week, with a very warm
but dry air mass remaining in place. Daytime high temps should reach
the upper 80s and lower 90s away from south facing shorelines, a
little above composite GFS/European model (ecmwf) MOS and consistent with both 800 mb
temps +16c and 500 mb-10 thicknesses above 570 dm. With dewpoints in the
upper 50s and lower 60s, apparent temperatures will run very close
to air temperatures.
A closed low dropping se into ern Canada should drive a cold front
through on Sat, with sct showers/tstms. With temps still running on
the very warm side, dewpoints increasing to the mid 60s, and northwest flow
aloft, would anticipate some of these to be on the strong side.
After fropa, Sat could still be very warm via downslope northwest flow but
dry. A return to near seasonable temps not expected until Mon, with
highs from the upper 70s to mid 80s.
Aviation /20z Monday through Saturday/...
high pressure will be centered offshore this afternoon, then a
warm front will approach tonight.
VFR continuing through the evening. MVFR or IFR in showers
expected after 09z-11z.
Southerly winds into early evening at around 10 kt or less.
Winds back towards southeast later this evening/overnight and lighten.
... Metro enhanced aviation weather support...
Detailed information, including hourly taf wind component forecasts,
can be found at: http:/www.Weather.Gov/zny/n90
Kjfk taf comments: no unscheduled amendments expected.
Klga taf comments: no unscheduled amendments expected.
Kewr taf comments: no unscheduled amendments expected.
Kteb taf comments: no unscheduled amendments expected.
Khpn taf comments: no unscheduled amendments expected.
Kisp taf comments: no unscheduled amendments expected.
Outlook for 18z Tuesday through Saturday...
Tuesday PM...becoming VFR.
Wednesday through Friday...VFR.
Saturday...mostly VFR. Chance of a tstm with MVFR or lower
a warm front will approaches tonight and move across on Tuesday,
preceded by showers and isolated tstms, mainly in the morning
and early afternoon. Winds on the eastern ocean/sound/bays could
approach 20 kt as the warm front passes late morning into the
afternoon. Quiet thereafter from Wed through Fri with high
pressure in control.
Sat could feature sea breezes gusting to near 20 kt on the near
shore ocean waters and South Shore bays, also showers/tstms as a
cold front approaches.
basin average rainfall of 1/2 inch expected late tonight into
Tuesday. Higher average amounts of 3/4 to 1 inch are possible
across southeast Connecticut and eastern Long Island if enhancement of
showers occurs. Main concern would be minor urban and poor
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) remains off