Scientific Forecaster Discussion
fxus61 kokx 270527
Area forecast discussion
National Weather Service New York New York
127 am EDT Tue Jun 27 2017
weak high pressure builds farther offshore tonight as a cold
front approaches from the Great Lakes. The front moves through
the area Tuesday evening. High pressure will then briefly follow
for the middle of the week. Another frontal system approaches
for the end of the week.
Near term /until 6 am this morning/...
a weak surface trough was across the region from the Hudson
Valley into eastern Pennsylvania and into north central
Maryland. This was the focus of a few light showers, along with
a shortwave rotating through an upper trough. Put
probabilities, slight chance, into the forecast for areas across
the far western zones initially and then slowly east through
the overnight. The hrrr was also supporting the chance of
showers overnight, just a couple of hours too quick. Lower
levels are dry and any precipitation reaching the ground is
expected to be light.
Anomalously strong upper trough across the Great Lakes and Ohio
Valley states pivots eastward the next couple of days with
gradual height falls and increasing daytime instability.
Short term /6 am this morning through 6 PM Wednesday/...
airmass gradually destabilizes on Tuesday with height falls and
approaching cold front over the Great Lakes. However, dry low-
levels and lack of strong surface trigger will be limiting
factors for the development of showers/thunderstorms. The best
chance will be across the interior during the afternoon hours.
Wind shear is also weak, limiting any organization.
Cold front works across the area in Tuesday evening with high
pressure to follow.
Daytime highs will once again be near or just below seasonable
There is a moderate risk for the development of rip currents
Long term /Wednesday night through Monday/...
high pressure will be in control Wednesday through Thursday night,
bringing dry conditions and near normal temperatures across the
area. As high pressure moves offshore, warmer temperatures and
increasing chances of showers and thunderstorms will develop Friday
through Sunday. High pressure builds back on Monday, bringing more
seasonable temperatures and dry conditions across the area.
Aviation /06z Tuesday through Saturday/...
VFR through the taf period. A trough of low pressure passes
across the terminals early this morning, followed by another one
Winds are a bit uncertain through the middle morning hours.
However, speeds are expected to be less than 10 kt. Winds
should veer to the west or northwest in the next few hours over the city
terminals with light and variable elsewhere. Winds will then
gradually become southerly into the morning 10 kt or less. Winds
veer to the SW into the afternoon and evening 10-15 kt, then to
the west-west-northwest overnight around 10 kt.
A few showers are possible early this morning, 08-11z over NYC
terminals, and 10-13z Long Island and southern Connecticut
terminals. An isolated shower/thunderstorm is also possible this
Outlook for 06z Wednesday through Saturday...
Thursday...VFR. Chance of a late day shower/thunderstorm.
Friday and Saturday...MVFR or lower possible in showers and
winds and seas forecast on track.
With an overall weak pressure gradient remaining across the
region, winds and seas are expected to remain below Small Craft
Advisory criteria (25kt winds, 5 ft seas) through Tuesday.
Below Small Craft Advisory conditions expected Wednesday as high
pressure moves south across the area waters. Winds and seas
increase, and Small Craft Advisory conditions are possible later
Thursday and into Saturday.
no hydrologic impacts expected through the beginning of next
astronomical tides are still running high with a low chance of
any minor coastal flooding across the South Shore back bays of
Nassau County with this evening high tide cycle, approximately
between 10pm and 12am. The water levels would only be expected
to touch the minor benchmarks few just a couple of gages so no
statement has been issued.
observations from kfrg (farmingdale, ny) are not available.
Observations from khpn (white plains ny) and khvn (new Haven ct)
are being disseminated through backup methods. All is due to
an FAA communication line outage. Return to service time is