Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
739 PM EDT Monday Aug 3 2015
a slow moving cold front will approach tonight then stall across
the area Tuesday. The cold front moves offshore Wednesday as weak
high pressure builds into the area. Several waves of low pressure
may impact the area for the end of the week. High pressure builds
back in for the weekend.
Near term /until 6 am Tuesday morning/...
the cold front is slow to move east and remains across the eastern
Great Lakes and into the Ohio Valley. Showers and thunderstorm
developments remains scattered to isolated with a cap in place.
Scattered showers and thunderstorms will be possible overnight in
association with the front...though some guidance suggests
precipitation splits around NYC and Long Island with greater
chances to the north and south. Lowered the probability of precipitation through the
overnight with more scattered development expected.
There is a high risk for the development of rip currents at the
ocean beaches through this evening. A rip current statement is in
Short term /6 am Tuesday morning through Tuesday night/...
the front is forecast to stall across the area Tuesday with a
chance of afternoon showers and thunderstorms. Very little
appreciable difference will be felt with temperatures remaining
above normal and similar humidity as Monday. Late Tuesday night
the upper trough builds farther south and east...forcing the
attendant surface front farther offshore with lower dew points
advecting into the region. A subsequent decrease in humidity will
be felt as this occurs. By morning...thunderstorms will mainly be
confined to the offshore waters.
There is a high risk for the development of rip currents at the
ocean beaches through Tuesday morning through Tuesday evening.
A rip current statement is in effect.
Long term /Wednesday through Monday/...
cold front continues to slowly move offshore with high pressure
building into the area on Wednesday. Upper level trough remains over
the area into Thursday.
Upper level trough departs the area Wednesday night into Thursday.
Models have come into better agreement with surface low over the middle-
west trekking east Wednesday night and affecting the area mainly
from Thursday night through at least Friday night. However...there
is still uncertainty on where it tracks and therefore how much rain
we do receive. However...it does appear more certain that a
widespread heavy rain event is in store for this time period.
Isentropic lift out ahead of the approaching low noted in both the
12z GFS and 12z European model (ecmwf)...mainly late Thursday night...so thinking
this will be more stratiform rain. Surface low continues its
approach Friday morning. Models differ in the placement of the low.
The 12z European model (ecmwf) and 12z GFS agree with the low being over the northern
Middle-Atlantic States by 06z Saturday. Thereafter...models differ
quite a bit in their solutions. 12z European model (ecmwf) treks the low northeast in
side the 40/70 benchmark through the day Saturday while it slowly
strengthens while the GFS weakens the low over the old frontal
boundary offshore and weaker waves of low pressure riding along
it...while the 12z Canadian is an outlier being more progressive than
the other models. Therefore...sided more along the lines of the GFS
and European model (ecmwf) and keep chance probability of precipitation in the area through the day Saturday
Low pressure pushes away from the area late Saturday night into
Sunday as weak high pressure builds back into the region for the
second half of the weekend with a return to dry conditions.
Outside of Friday...temperatures should be seasonable for this time
of year. Rain and clouds will keep temperatures down on Friday...not
making it out of the 70s region-wide. In fact...temperatures may
prove to be a bit lower than what is currently forecast.
Aviation /00z Tuesday through Saturday/...
most of the rain showers/thunderstorms and rain that were approaching the local airspace
have tapered off and become isolated. Will go ahead and remove
mention of thunderstorms and rain this evening from the tafs.
Cold front continues to approach from the west and will pass
through late tonight. Will tempo thunderstorms and rain for a few hours during the
late night hours...from 06-09z over far western terminals to
08-11z over most eastern terminals. Will leave out of kgon for
now...as it is hard to tell if thunderstorms and rain will make it there.
South winds will diminish to 5-10 knots this evening. After frontal
passage...winds shift to the SW and increase to 8-12 knots. Gradient
tightens Tuesday afternoon. Local sea breezes possible at coastal
... Metropolitan enhanced aviation weather support...
Detailed information...including hourly taf wind component forecasts
can be found at: http://www.Erh.NOAA.Gov/zny/n90 (lower case)
Kjfk fcster comments: best chances for thunderstorms and rain will be after 07z.
Klga fcster comments: best chances for thunderstorms and rain will be after 07z.
Kewr fcster comments: best chances for thunderstorms and rain will be after 06z.
Kteb fcster comments: best chances for thunderstorms and rain will be after 06z.
Khpn fcster comments: best chances for thunderstorms and rain will be after 07z.
Kisp fcster comments: best chances for thunderstorms and rain will be after 08z.
Outlook for 00z Wednesday through Sat...
Tuesday night...slight chance for thunderstorms mainly coastal terminals in the
evening. Becoming VFR overnight. SW flow becoming northwest overnight.
Wed-Thu...VFR. Generally west flow.
Friday...MVFR or lower in rain. Winds becoming NE.
Sat...MVFR or lower possible in rain. NE winds.
wind and seas forecast on track. Updated the weather for this
evening through early Tuesday morning for lower chances of showers
and thunderstorms with the cold front well west of the
waters...through the eastern Great Lakes...approaching the waters
early Tuesday morning.
Winds out ahead of the front will remain strong into late tonight
before lightening with the approach of the front.
Ocean seas build due to the increase in these winds. A Small Craft
Advisory remains in effect on the ocean waters through early
Ocean seas will be subsiding Tuesday night...but 5 feet seas may
linger on the eastern ocean until Wednesday morning. Weak high
pressure passes over the waters on Wednesday with sub Small Craft Advisory
conditions expected. Several waves of low pressure may pass over
the waters for the end of the week. Occasional Small Craft Advisory conditions are
possible on Friday...especially on the ocean.
Weak high pressure passes over the waters on Wednesday with sub Small Craft Advisory
conditions expected. Low pressure may pass over or near the waters
for the end of the week into the first half of the weekend.
Occasional Small Craft Advisory conditions are possible on Saturday...especially on
a tenth to a quarter inch of basin average rainfall is possible
tonight into Tuesday. Locally higher amounts are possible in any
A widespread significant rainfall is possible late Thursday into
Friday. However...uncertainty exists in where and when the
heaviest of the rain will fall. Antecedent dry conditions should
limit flooding potential. However...any thunderstorms that do
develop would have the potential for localized flooding.
New York...high rip current risk until 9 PM EDT this evening for nyz075-
High rip current risk from 6 am EDT Tuesday through Tuesday
evening for nyz075-080-081-178-179.
Marine...Small Craft Advisory until 8 PM EDT Tuesday for anz350-353-355.