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fxus61 kokx 200843 
afdokx

Area forecast discussion
National Weather Service New York New York
443 am EDT Thu Jun 20 2019

Synopsis...
a stationary front to the south of the area lifts north as a
warm front today. Low pressure and a trailing cold front
approach this afternoon and move across tonight. The low and
cold front move offshore Friday with high pressure returning for
the weekend. High pressure moves off into the Atlantic Monday
into Monday night. The next frontal system approaches Tuesday
with an associated cold front moving across during midweek.

&&

Near term /until 6 am this morning/...
the stationary front is currently located across southern PA
through southern New Jersey. The front begins to lift north as a warm
front this morning. A saturated atmosphere along and ahead of
the front supports mainly scattered showers. A weakening area of
showers and embedded thunder is collocated with the front. The
hrrr and 3-km NAM take this activity north through day break as
the warm front approaches. The expectation is that this activity
will continue to weaken with mainly showers and embedded heavy
downpours. Instability is lacking so have left out mention of
thunder. There could also be some fog, but showers may inhibit
anything widespread.

The warm front should continuing lifting north through the
morning. A big question is how far inland will the the warm
front be able to move into the afternoon. It appears that
approaching low pressure associated with a well defined
shortwave trough should allow the warm front to lift north of
the area this afternoon. Confidence in this is scenario is not
high and the warm front could linger across out CT zones this
afternoon.

The next concern will be with convection ahead of the low and
trailing cold front. The 00z suite of cams do not lend high
confidence in location of convection. They mostly paint a broken
line of showers and thunderstorms moving out of PA and into New Jersey
from around 19 to 21z. This activity then moves towards the NYC
Metro 21- 00z. The greatest surface based instability is progged
to lie west of the Hudson River corridor. Surface based
instability drops off significantly east of the Hudson River
corridor due to a strong maritime inversion. Where better
instability is realized, strong to severe thunderstorms are
possible with effective shear values 40-45 kt. Storm Prediction Center has placed
locations from mainly north and west of NYC in a marginal risk
with the main threat damaging winds and possibly hail. Chances
for showers/storms across southern Connecticut and Long Island
appear lower this afternoon and may hold off until later this
evening as the remnants of the convection from the west move
across.

Heavy downpours are also a threat with any showers and
thunderstorms, but no Flash Flood Watch was issued at this
time. Extent of convection remains uncertain and if flash
flooding were to occur, it would mainly be an isolated
occurrence and not widespread.

Temperatures today will range from the lower to middle 70s
across CT to the lower 80s across NYC Metro and NE New Jersey. Will
have to watch to see if more breaks occur west of the Hudson
River corridor which could enhance instability.

&&

Short term /6 am this morning through 6 PM Friday/...
any convection this evening should weaken as it moves across
Long Island and southern Connecticut. The next concern will be
with the passage of shortwave energy and surface low pressure
overnight. Showers and possible thunderstorms should grow in
coverage with decent large scale ascent. The greatest likelihood
looks to be after midnight and mainly across Long Island and
southern Connecticut. The 00z NAM is attempting to close off the
middle level low along the New England coast early Friday
morning. This scenario may be overdone but if it occurs would
enhance rainfall a bit across eastern Long Island and southeast
Connecticut on the backside of the low. Showers gradually end
Friday morning with a return to dry conditions for much of the
area by afternoon. Lingering clouds and possible shower could
hang on across New London County in the afternoon.

Northwest flow behind the departing low and ahead of building high pressure
to the west supports gusty winds on Friday. Gusts 25-30 mph are
forecast with temperatures near seasonable levels.

There is a moderate risk of rip current development at Atlantic
Ocean beaches on Friday.

&&

Long term /Friday night through Wednesday/...
strong westerly upper level jet moves across the region Friday night
into Saturday and become more northwest into Saturday night. Upper
level ridging with the main upper level jet shifting well north of
the area is conveyed in the numerical weather prediction models for
the rest of the weekend into early next week. Next shortwave with
associated jet streak will be weaker and this will be moving in
towards the midweek period.

At the surface, high pressure will slowly build in from the west and
continue building in through the weekend. Dry and warm weather
expected for the weekend.

A frontal system will give the next rainfall event for next week
starting Monday and through midweek. This will be periodic and
without much forcing, not expecting a wide coverage of rainfall.
Some instability is forecast mainly for the western half of the
region during this timeframe for the afternoon to early evening with
possible thunderstorms as a result.

Outside of Friday night, most temperatures are forecast to be
slightly above normal.

&&

Aviation /09z Thursday through Monday/...
a warm front will slowly lift through the area today, as low
pressure approaches from the west this afternoon and tonight.

LIFR conditions should continue until at least 12-13z, then as
the warm front lifts through and surface temps warm, should see
gradual improvement at the NYC metros, with MVFR conds expected
by 16z-17z. Conds will take longer to improve North/East, til
about 18z-20z at khpn/kbdr/kswf, and 22z at kgon. Timing of
these improvements could be too fast and will reassess with
later scheduled amd's.

As showers with the warm front lift NE this morning, can't totally
rule out a rumble of thunder at the NYC metros into the am push.
More significant thunder chances expected the lower Hudson Valley
and the NYC metros after 20z-21z until 24z-01z as a line of
showers/tstms approaches. Some of these storms could produce brief
IFR vsby and gusty winds. Mainly MVFR conds expected thereafter with
any lingering showers or stray tstms. May have to watch for a
return of LIFR/LIFR cigs at kisp/kgon/kbdr tonight.

..NY Metro enhanced aviation weather support...

Detailed information, including hourly taf wind component fcsts,
can be found at:
http://www.Weather.Gov/zny/n90

Kjfk taf comments: warm fropa 12z. Unscheduled amend possible to
fine tune changes in flight Cat, especially after fropa. The
afternoon haze potential forecast is red, which implies slant
range visibility less than 4sm outside of cloud.

Klga taf comments: warm fropa around 14z, unscheduled amend
possible to fine tune changes in flight Cat, especially after
fropa. The afternoon haze potential forecast is yellow, which
implies slant range visibility 4-6sm outside of cloud.

Kewr taf comments: warm fropa 12z. Unscheduled amend possible to
fine tune changes in flight Cat, especially after fropa. The
afternoon haze potential forecast is green, which implies slant
range visibility p6sm outside of cloud.

Kteb taf comments: warm fropa 12z-13z. Unscheduled amend possible
to fine tune changes in flight Cat, especially after fropa.

Khpn taf comments: LIFR conds could last up to an hour longer
than fcst.

Kisp taf comments: warm fropa 12z-13z. Unscheduled amend possible
to fine tune changes in flight Cat, especially after fropa.

Outlook for 06z Friday through Monday...
late tonight...MVFR likely, IFR possible in showers/sct tstms.
Friday...chance showers early with MVFR conds, then VFR with northwest
winds (right of 310 mag) 15g20kt.
Friday night...VFR. Northwest winds g20kt in the evening at the NYC
metros.
Saturday and Sunday...VFR.
Monday...chance of afternoon/evening showers/tstms with brief MVFR
or lower conds.

&&

Marine...
weak flow on the waters will result in conditions remaining below
Small Craft Advisory through this evening. Ocean seas begin to build overnight and
should remain elevated around 5 ft into Friday. Winds also increase
behind a cold front passage tonight with marginal Small Craft Advisory gusts possible
on all waters. For now, have issued an Small Craft Advisory on the ocean for mainly
seas tonight into Friday. Wind gusts near shore may end up stronger
during Friday afternoon, but have held off on an Small Craft Advisory for the near
shore zones with this forecast package.

Winds and seas may continue to linger around Small Craft Advisory conditions
Friday night into Saturday. Ocean seas of 5 to 6 ft are forecast
for Friday night and gusts over the ocean plus the Long Island
Sound up to 25 kt for Saturday. Otherwise, looking at sub-Small Craft Advisory
conditions across the waters for the long term (friday night
through Monday night).

&&

Hydrology...
basin average rainfall amounts through Friday morning should
range from about a 1/2 inch to around 1 inch. Locally higher
amounts are possible in heavier showers and thunderstorms. The
location of the highest amounts is still a bit uncertain, but
would tend to favor from the NYC Metro north and west. Minor
urban and poor drainage flooding is the main threat, but
localized flash flooding cannot be ruled out.

No significant hydrologic impacts are expected this weekend
through the middle of next week.

&&

Tides/coastal flooding...
astronomical tides will remain relatively high through this evenings
high tide. Do not anticipate any coastal flooding with tide levels
remaining below minor coastal flooding benchmarks.

&&

Equipment...
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) remains off
the air.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory from 10 PM this evening to 6 PM EDT
Friday for anz350-353-355.

&&

$$
Synopsis...jm/ds
near term...ds
short term...ds
long term...jm

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