Scientific Forecaster Discussion

Return to Local Conditions & Forecast
Area forecast discussion 
National Weather Service New York New York
811 PM EDT Sat Apr 19 2014

Synopsis...
high pressure will remain over the region through the first part
of the new week. A frontal system will impact the tri- state from
late Tuesday into Wednesday. High pressure then builds into the
region for the end of the week. The next disturbance may impact
the region Friday night into the weekend.

&&

Near term /until 6 am Sunday morning/...
high pressure will slide north of the region with low pressure
drifting east off the southeastern US overnight. The gradient
between the two will keep a cool NE flow across the region
overnight...but conditions clear and dry.

Best radiational cooling will be across interior areas...where
some patchy frost/freeze is possible as temperatures drop into upper 20s
to lower 30s. Otherwise...overnight lows will fall into the 30s
and lower 40s.

&&

Short term /6 am Sunday morning through Sunday night/...
high pressure north of the region will track east. This will allow
winds to shift to more of an easterly flow. The cooler easterly flow
will allow temperatures to be anywhere from 5 to 10 degrees cooler
than today. Highs will climb into the upper 50s to lower 60s across
the interior. Closer to the coast...highs will only reach the 50s.

Otherwise...expect another dry day with sunny skies.

Sunday night will remain dry...with lows falling into the upper 20s
and 30s. Lows in the NYC metropolitan area will remain right around 40.

&&

Long term /Monday through Saturday/...
nearly zonal upper flow to start the week will give way to an
amplifying trough moving into the northeast for the middle week as Pacific
and northern stream energy phase. Models in general agreement with
this evolution...but minor differences exist in the strength of the
trough and shortwave energy rotating around it. A good bit of
sensitivity with this interaction appears to lie in the Pacific
shortwave/ridge complex moving across the West Coast through
tonight...which should be better sampled starting by tomorrow
morning. These differences aloft are resulting in some differences
in strength and speed of the resultant frontal system moving through
our region Tuesday night. Overall looks to be a progressive system...with
increasing potential for showers Tuesday afternoon...and then
greatest likelihood Tuesday night. Amount of precipitation will be predicated
on the depth/strength of shortwave energy...which should clarify
over the next 24 hours. Shower activity likely tapers off Wednesday
morning...with potential for instability showers particularly across
the interior Wednesday after as the trough moves across.

Dry conditions under deep layered ridging as it builds across Wednesday
night through Thursday night. Then the next northern stream
shortwave approaches for the end of the week into the weekend with
the next chance for shower activity. Uncertainty still exists on the
strength and progressiveness of this energy...as pattern becomes
more blocky in nature.

Near seasonable temperatures expected along the coast and slightly above
seasonable across interior with southerly flow Monday and Tuesday ahead of
approaching frontal system. Slightly below seasonable temperatures in the
wake of the system Wednesday with instability clouds and shot of cold air advection...but
then a moderating trend to seasonable and then above seasonable
temperatures through the end of the week with a moderating airmass.

&&

Aviation /00z Sunday through Thursday/...
high pressure gradually builds southward into the region through
early Sunday and then moves off the New England coastline.

VFR through the taf period. Late afternoon seabreeze developed at kjfk
and was heading towards kewr...but may not make it to the
airfield. Speeds are less than 10 knots. North/NE synoptic flow expected
to regain control by 01z and remain in place through the
overnight...then becomes southeast on sun. Moderate confidence in wind
forecast.

Outlook for 00z Sunday through Thursday...
Sun night-Tuesday morning...VFR.
Tuesday afternoon-Wednesday morning...rain showers becoming likely...with MVFR or lower
possible. Northwest-north winds g20-25kt possible late Tuesday afternoon/Wednesday morning.
Wednesday afternoon...most likely VFR...with low chance MVFR. Northwest-north wind
g20-25kt possible.
Wednesday night-Thu...VFR. Northwest-north wind g15-20 knots possible.

&&

Marine...
a moderately tight NE gradient overnight will result in marginal
Small Craft Advisory gusts and seas on the ocean late tonight into Sunday.

Sub Small Craft Advisory conditions then expected Sunday night into Monday night as
high pressure lies across the region.

Southerly winds gradually increase on Tuesday ahead of an
approaching frontal system...with a chance for marginal Small Craft Advisory gusts
and ocean seas Tuesday night ahead of the front. A better chance for
Small Craft Advisory wind gusts on all waters in the wake of the front Wednesday into
Wednesday night. Conditions should gradually subside below Small Craft Advisory Thursday into
Thursday night as high pressure builds towards the region.

&&

Fire weather...
a dry Sunday expected with min relative humidity values between 20-30 percent.
NE/southeast winds generally expected to be 10 to 15 miles per hour with gusts to
20 miles per hour.

With dry fine fuels...this will pose another day with potential
rapid fire spread.

&&

Hydrology...
the potential for significant precipitation is low through the new
week.

We will monitor the strength of a frontal system crossing the region
Tuesday night...but trend with this system has been progressive
which would point against significant rain.

Note...minor flooding continues along the Connecticut River. For
additional information...please refer to the latest flood warnings
from National Weather Service Taunton Massachusetts.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory from 2 am to 4 PM EDT Sunday for anz350-
353-355.

&&

$$
Synopsis...BC/NV
near term...BC/NV
short term...British Columbia
long term...Nevada
aviation...
marine...BC/NV
fire weather...Nevada
hydrology...BC/NV