Area Forecast Discussion
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FXUS61 KOKX 222159
Area Forecast Discussion
National Weather Service New York NY
559 PM EDT FRI JUL 22 2016
Showers and thunderstorms are possible across parts of the Tri-
State Area this evening as a system moves across the area. Drier
air is expected in the wake of this system for Saturday, however,
it will remain hot. A dry cold front will pass across the area
Saturday night. High pressure will then be in control on Sunday
before a cold front moves across the area Monday into Monday
night. High pressure returns for Tuesday through Thursday. Another
front moves through the area on Friday.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
We are starting to see a few showers and thunderstorms get going
over Upstate New York and the northern tier of Pennsylvania this
afternoon. So far, looking at the operational models, the WRF
looks about the best with handling convection for this evening
both the placement of QPF and with timing. A surface pressure
trough is expected to accompany the convection as it works
southeast later this evening aiding in lift. Although PWATs are
relatively high (around 1.5 inch per the latest SPC Mesoanalysis),
forecast soundings show most of the moisture is confined to a
small layer around 4,000 feet above the surface. Thus, it will
take a while for the atmosphere to moisten and there is some
concern as to just how much convection will fill-in this evening
as the trough gets closer to the coast. As a result, I leaned
toward the WRF with some blending toward the RAP and HRRR which
looked about the next best in-line. Forecast soundings continue to
show an inverted V signature so the dry low-level environment
will aid in the transfer of momentum down to the surface and make
gusty winds the main threats in and near storms. However, given
the high moisture content to the air we cannot rule out isolated
heavy downpours in any stronger thunderstorms. The best timing for
showers and thunderstorms looks to be late this evening working
toward The City from the northwest with activity weakening as it heads
toward the coast. Thus, I kept enhanced wording mainly from The
City north and west and over CT as activity should be in a
weakening state as it heads across Long Island.
In any areas that see rain this evening, patchy fog may develop
later tonight from whatever ground moisture there is. We also may
see patchy fog on The Island and along coastal Connecticut as the
warm, moist southerly flow advects fog inland from the coastal
waters. Any fog should clear out shortly after daybreak.
Otherwise a steamy night in The City and urbanized areas of NJ
with lows 75 to 80.
A high risk for rip current development at ocean beaches remains
through this evening due to southerly wind waves increasing to 3
to 5 ft and a residual 2 ft se swell.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Seriously, despite the passage of a trough this evening, we will
not cool off much for Saturday and another hot day will be seen
across the area. However, with winds trending toward the west to
northwest at all levels, this will advect in drier air that will
drop surface dewpoints into the 50s to lower 60s by the afternoon.
Thus, heat index values will not be as high as today and in some
ways it may feel a little better. However, the west to northwest
flow will `downslope` and thus drag the hotter air out even toward
the coast. I leaned toward the hotter end of statistical guidance
for highs as a result. The Heat Advisory will remain up for The
City and we added urban parts of Essex and Union Counties in NJ as
well as Hudson County where actual temperatures could get to 100
(most likely at Newark which would be about the average highest
temperature of the year). No records are in threat at Newark or in
the City though as we are competing against the Heat wave of 2011
when Newark set an all-time record high of 108.
Another more vigorous trough passes across New England tomorrow
evening, both aloft and at the surface. There may be enough
moisture in interior new London County to pop off a shower or
thunderstorm but otherwise it should be dry. Saturday night will
be a little cooler.
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
High pressure builds into the area on Sunday. High temperatures on
Sunday will be in the upper 80s to low 90s for most areas, but will
be in the low to mid 90s for NYC, portions of NE NJ, and southern
portions of the Lower Hudson Valley. With a west to northwest flow,
dewpoints should not be as high as Saturday, resulting in heat
indices below 95 degrees.
High pressure moves offshore Sunday night. Meanwhile a low pressure
over eastern Canada will push its associated cold front through the
area Monday, scattered showers and thunderstorms will develop over
western areas and spread east as that front advances and pushes
through the region Monday night.
Highs on Monday will be in the low to mid 90s, and heat indices will
top off in the mid to upper 90s. Monday night will be very warm and
humid with lows near 80 around NYC, and in the low to mid 70s
elsewhere. Areas of fog are likely as well.
High pressure builds into the area on Tuesday, ushering in cooler
and dryer air. Highs on Tuesday will be in the low to mid 90s, and
with surface dewpoints in the 60s, heat indices will once again top
off in the mid 90s.
High pressure will continue to build across the area through
Thursday. Temperatures will be in the upper 80s to low 90s on
Wednesday, and mid to upper 80s on Thursday. Another cold front is
then forecast to impact the local area later on Thursday and into
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
A weak cold front approaches tonight and moves through early
Saturday. Convection is very limited as of late afternoon, but we
do expect some isolated convection to develop with a pre-frontal
trough this evening. Movement will be from about 300 degrees.
Otherwise, VFR conditions expected through the TAF period with
the exception of some patchy fog and MVFR vsbys early Saturday
morning outside the NY metro.
S-SW winds will diminish overnight.
NY 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: Chances for TS in the terminal area are low
KLGA TAF Comments: Chances for TS in the terminal area are low
KEWR TAF Comments: Chances for TS in the terminal area are low
KTEB TAF Comments: Chances for TS in the terminal area are low
KHPN TAF Comments: Chances for TS in the terminal area are low
KISP TAF Comments: Shower chances in the terminal area are low
.OUTLOOK FOR 21Z SATURDAY THROUGH WEDNESDAY...
.SAT AFTN through SUN NGT...VFR. W gusts up to 20 KT possible
.MON...Mainly VFR, except MVFR or lower possible in scattered
late day/evening thunderstorms.
.TUE and WED...VFR.
Wind gusts at area observation sites have mainly been between 25
and 30 kts with buoys showing 4 foot waves south of Long Island.
With the approaching trough, winds will still remain up until this
feature passes and as a result the Small Craft Advisory will be
left up. The threat of showers and thunderstorms will be greatest
over the western coastal waters this evening into early tonight.
There may also be patchy fog late tonight given the warm, moist
air mass in place over the area.
Waves and winds will decrease tonight after the trough passes on
through. Lighter offshore flow on Saturday will keep waves on the
High pressure will influence the area waters on Sunday. A cold front
moves through the waters Monday night, and then high pressure
returns for the middle of next week.
Below small craft advisory conditions expected for the
Any stronger thunderstorms that get going this evening could
produce locally heavy downpours given PWATs around 1.5 inches.
The main threat looks to be more on the side of minor ponding or
poor drainage flooding in urbanized areas.
Scattered showers and thunderstorms will impact the region Monday
afternoon and Monday night, resulting in the potential for locally
NY...Heat Advisory until 7 PM EDT Saturday for NYZ072>075-176-178.
High Rip Current Risk until 9 PM EDT this evening for NYZ075-
NJ...Heat Advisory until 7 PM EDT Saturday for NJZ006-106-108.
Heat Advisory until 7 PM EDT this evening for NJZ004-103>105-
MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ350-353-
Small Craft Advisory until 11 PM EDT this evening for ANZ345.