Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
645 PM EDT sun Aug 2 2015
high pressure tonight will give way to a slow moving cold front
Monday and Monday night. The cold front moves east of the area on
Tuesday...and then weak high pressure builds over the area on
Wednesday. Several areas of low pressure may impact the area for
the end of the week.
Near term /until 6 am Monday morning/...
forecast remains on track. Will update hourly grids based on
latest surface observation...but no significant changes made otherwise.
Upper level shortwave...jet dives from Canada toward the northern
and western Great Lakes region tonight...amplifying the trough
with resultant lowering of heights upstream.
For our area...warm air advection is underway. Southerly low
level flow continues and humidity levels slowly rise. Perhaps a
few higher level clouds move in from the west...but mainly clear
skies are anticipated overall.
As such...patchy fog is forecast for later tonight. As previous shift
mentioned...some stratus is possible...but current thinking is fog
development the more likely result.
Temperatures will fall into the 60s and 70s per MOS. Blend used.
There is a moderate risk for the development of rip currents at
the ocean beaches through this evening.
Short term /6 am Monday morning through Monday night/...
persistent trough/closed low will make slow progress east through
this time frame. Surface cold front approaches from the west...making
slow progress toward the area late Monday and Monday night.
A dry start to the day is forecast...with increasingly humid
Under a good deal of sunshine...and warm air advection ahead of the
upper trough and surface frontal boundary...temperatures will warm well into
the 80s...and will approach or exceed 90 away from the south
coasts. Blended met/mav and ecs.
12z model suite continues to show slow movement to the front and
upper level lift and thus slow progression and development of any
showers/thunderstorms into our area. Much of the area remains dry
through late afternoon. Better chance Monday night due to
approaching middle level lift as it pivots around the trough...and as
the surface frontal boundary moves across the region. NAM looks to be
slightly slower with cold frontal progression east. Coverage of
convection should remain scattered at best.
As for storm strength...if any storms make into our northwest zones late in
the day...ample wind shear along with marginal to moderate
instability could help sustain a few stronger storms. This is true
into Monday night as well.
Another warm night is anticipated as clouds increase and S/SW deep
There is a high risk for the development of rip currents at the
ocean beaches Monday afternoon and evening. A rip current
statement is in effect.
Long term /Tuesday through Sunday/...
cold front moves east of the area during the day Tuesday.
Meanwhile...a deep closed upper low over central Canada moves into
eastern Canada. This will result in an upper trough that will
linger over the northeast for the middle to the end of the new
week. Generally cool and unsettled conds on tap for this period.
Showers taper off from west to east Tuesday morning as the cold
front works its way across the region. Conds dry out from late
morning through early afternoon...and then an upper shortwave will
rotate around the base of the upper trough and through the
northeast. This will touch off some scattered showers/thunderstorms across the
region in the late afternoon. Since it will take some time for the
cooler and less humid air to make its way into the local
area...can expect highs in the upper 80s to around 90. Surface
dewpoints will fall into the low 60s across western zones during
the day...but dewpoints will remain in the upper 60s for eastern
zones. As a result...the heat index will generally be around 90
Surface high pressure then passes through the region on Wednesday. No
precipitation expected...and a cooler and dryer airmass spreads into the
region with highs generally in the 80s and dewpoints in the 50s.
High pressure moves off the middle-Atlantic coast Wednesday night.
From Thursday through Sunday...with an upper trough over the
northeast...several waves of low pressure will develop at the base of
the trough and will pass through the mid-Atlantic/northeast during
this time. Models have had a hard time picking up on the track of
each low and have resulted in different tracks with each run...but
it is still too far out in time to say what will happen. Will
carry chance probability of precipitation during this time...as at least 2 different areas
of low pressure will track through the region with conds drying out by
Temperatures will run several degrees below normal during this time with
highs in the upper 70s to low 80s.
Aviation /00z Monday through Friday/...
high pressure builds into the region tonight.
S seabreezes for coastal terminals and south-southeast seabreezes at
kewr/kteb. S winds relax this evening. SW winds pick up once again
VFR at most terminals...with exception of kgon which should
fluctuate between VFR and MVFR overnight on this first night of
Outlook for 18z Monday through Thursday...
Monday afternoon...gusty S flow. Chance of thunderstorms late at kswf.
Monday night-Tue...chance of thunderstorms. Cold frontal passage with S winds shifting
to west. Patchy fog across outlying terminals Monday night.
Wednesday...VFR. West flow.
Thu-Fri...MVFR or lower conds possible in mainly
southerly winds will continue tonight as high pressure passes east.
A cold front approaches the waters Monday...moving close to the
waters Monday night. Winds out ahead of the front increase Monday
afternoon into Monday night before lightening with the approach of
Ocean seas build due to the increase in these winds. After collab
with surrounding offices...will issue Small Craft Advisory beginning 20z Monday
afternoon and through Monday night.
Winds and seas will gradually subside below Small Craft Advisory levels on
Tuesday...and then weak high pressure passes through the waters on
Wednesday. For the end of the week...several areas of low pressure may
pass across the waters...resulting in occasional Small Craft Advisory conds for at least
the ocean waters.
locally heavy rainfall is possible in thunderstorms late Monday/Monday
night and again Tuesday afternoon/evening east of NYC...which could lead to minor
poor drainage flooding.
New York...high rip current risk from Monday afternoon through Monday
evening for nyz075-080-081-178-179.
Marine...Small Craft Advisory from 4 PM Monday to 6 am EDT Tuesday for