Scientific Forecaster Discussion
fxus61 kokx 210628
Area forecast discussion
National Weather Service New York New York
228 am EDT Sat Sep 21 2019
high pressure will dominate through the weekend. A cold front
approaches on Monday and moves through Monday night. High
pressure follows for the midweek period, then a weakening cold
front approaches late in the week.
Near term /until 6 am this morning/...
light winds and a dry airmass have allowed for ideal radiational
cooling with temperatures outside of the NYC Metro generally a
few degrees lower than previously forecast. Thus, have adjusted
lows down to account for this trend.
Valley fog is possible once again this morning.
Short term /6 am this morning through 6 PM Sunday/...
large ridge remains in place. With westerly flow around sfc high
that is centered to our south, and expected temps at the top of the
mixed layer around 16-17c, forecast high temperatures should rise
into the 80s under a good deal of sunshine.
Temperatures Saturday night will once again average above normal,
with a range from the lower 50s interior to mid 60s in NYC,
quite a spread between radiational cooling locations, and urban
heat island effect.
There is a high risk of rip currents at the Atlantic Ocean beaches
on Saturday. Long period swells lessen as the day progresses, so
conditions may improve late in the day.
Long term /Sunday night through Friday/...
high pressure will be centered to our south over the western
Atlantic on Sunday. A return SW flow and 850mb temps at around 15c
will allow for highs above normal across the forecast area. Highs
generally in the 80s except for eastern Li and southeast CT, particularly
along the coasts.
A longwave trough shifts through the Great Lakes on Monday and moves
into the northeast Tuesday. This will send a cold front through the
area Monday evening. There will be a chance of showers in the
afternoon into the evening ahead of the front, then chances drop off
during the overnight hours. Have added a slight chance of thunder
for some areas as CAPES of a few hundred j/kg are forecast by some
models, combined with some shortwave and jet streak lift. High
temperatures on Monday will once again reach the 80s for most areas.
High pressure then keeps US dry Tuesday and Wednesday along with
high temperatures closer to normal. A cold front associated with low
pressure tracking through southern Canada then approaches on
Thursday. The upper flow is progged to be more zonal than cyclonic,
so the front therefore weakens as it approaches US. Will still go
with a slight chance of showers with this front for Thursday. High
pressure builds back in on Friday with dry weather.
Aviation /06z Saturday through Wednesday/...
high pressure remains over the terminals through the taf
period. VFR conditions are expected.
Light and variable winds outside of NYC terminals going into
early Saturday while NYC terminals will have 5-7 kt SW-west-northwest flow.
S-SW flow of 5-10 kts expected Saturday afternoon with sea
breeze expected to move into coastal terminals so kewr will have
a more southeast flow late in the day.
Winds decrease to around 5kts or less and become more variable
in direction outside NYC terminals at night.
Outlook for 06z Sunday through Wednesday...
late Saturday night through Sunday...VFR.
Monday...MVFR possible. Chance of showers afternoon into night
with a slight chance of thunderstorms. SW gusts 15-20kt day
into early evening.
rough ocean seas of 5 to 6 ft from long period easterly swells
continue tonight, and into early Saturday morning. These seas
however are expected to subside as swells subside by afternoon. Will
extend the Small Craft Advisory through Saturday morning, but later shifts may be
able to cancel it before the noon hour.
Otherwise, high pressure remains south of the waters, and
west/southwest winds will persists through Saturday night.
A cold front approaches on Monday and passes through the waters
Monday night. Small Craft Advisory conditions are likely on the ocean due to both
wind gusts and wave heights, and 25 knots gusts will be possible for
eastern Li sound and all of the bays surrounding Li.
Winds and seas then diminish on Tuesday, with all waters below
advisory criteria by Tuesday night. Relatively tranquil conditions
then continue through Wednesday with a weak pressure gradient and
lack of significant swell.
no significant hydrologic impacts are expected through the middle of
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) remains off
New York...high rip current risk through this evening for nyz075-080-081-
Marine...Small Craft Advisory for hazardous seas until noon EDT today