Area forecast discussion
National Weather Service New York New York
147 PM EDT Friday may 24 2013
Synopsis...
a cold front moves across the area today. As the front tracks across
the area...a wave of low pressure will develop along the front and
slowly tracks to the Gulf of Maine by Sunday morning. This low will
then lift into the Canadian Maritimes through Monday. High pressure
then builds into the south through Wednesday night. A warm front
will approach on Thursday.
&&
Near term /until 6 PM this evening/...
intermittent showers will continue behind the cold front. Cold
front still needs to cross through eastern sections. Expecting
this to occur within the next 2 hours. Otherwise...just slight
adjustments to temperatures and dewpoints.
As the front moves across the region...winds will shift from the
south to the west...and eventually northwest. With the front
movement...eastern parts of the County Warning Area should see the wind shift by
middle to late afternoon.
Followed a blend of mav/met guidance for highs today. Maximum
temperatures will range from the lower to upper 60s...with the
warmest temperatures across the eastern half of the County Warning Area...and
coolest across the western half. Temperatures will generally fall
through the day...except across the eastern half of the County Warning Area...where
temperatures will rise through midday...then fall with the passage
of the front.
There will be a high risk of rip currents today along the Atlantic
facing beaches of Long Island.
&&
Short term /6 PM this evening through 6 PM Saturday/...
the front continues to slowly slide east with a surface low passing
east of the area. Meanwhile...as the middle and upper level trough
moves over the area...a closed low develops. This should allow any
of the precipitation to transition from showers to more of a
stratiform rain. Model guidance in good agreement with probability of precipitation
continuing through tonight. Probability of precipitation will remain likely/categorical.
Once again...followed a mav/met blend for overnight lows.
Temperatures will fall into the 40s and 50s...with the warmest
locations across the far eastern portion of the County Warning Area...and the
coolest across the western. This will be due to cold air filtering
in on a northwest flow behind the front.
&&
Long term /Saturday night through Thursday/...
GFS/NAM/ECMWF all reasonably close in their intensity and movement
of the closed low and associated low pressure moving slowly NE this
weekend. Likely/categorical probability of precipitation expected everywhere once again on
Saturday. North-northwest winds on the back side of the low should become
rather brisk by Sat afternoon...falling just shy of advisory
criteria at 15-25 miles per hour with with gusts between 30 and 35 miles per hour into
early Sat evening. Can not rule out some gusts to near 40 miles per hour
either. In addition...there is a low chance of a thunderstorm over
eastern CT/Long Island via some elevated destabilization as dry slot
punches in from the SW. Will leave out of the forecast for now with
low confidence. Temperatures will be rather cool for late may...with highs
only 55-60 and dropping into the 40s Sat night.
Steady rain should shift east and taper off in intensity Sat night
as the low pulls east of New England...becoming more showery/isolated in
nature on Sunday via cyclonic low level flow and passage of
transient middle level vorticity maxes pinwheeling around the upper low.
Still cool and breezy on Sat with highs only upper 50s/lower
60s...and gusts 25-30 miles per hour.
Dry weather and a gradual warm-up to near seasonable levels is then
forecast Monday-Wednesday as high pressure moves across. Temperatures on Thursday should
return to more Summer-like levels with the approach of a warm
front...which could bring afternoon showers and possible thunderstorms
mainly to areas west of NYC.
&&
Aviation /18z Friday through Wednesday/...
cold front over eastern Li and CT tracks eastward and offshore this afternoon.
Winds veer to the northwest behind the front and increase through the day.
Northwest winds 15-20 knots with gusts 25-30 knots this afternoon. Sustained near 20
knots tonight...with potential gusts to 30. Gusts may only be occasional
however so slightly lower speeds indicated in tafs.
Sustained northwest winds near 25 knots Sat. Peak gusts may exceed 35 knots.
Areas of IFR ahead of the front...then MVFR behind the front with
ceilings generally around 2k feet. Rain showers can be expected behind the front
as well...with a steadier rain in vicinity of kswf. Ceilings could drop to
around 1500 feet with any rain showers in the city.
-Ra tonight and MVFR. Ceilings expected to slowly lift above MVFR levels on
Sat.
There is the potential for gs in rain showers Sat with cold temperatures aloft.
Although tops will be blw 20k feet...isolated lightning possible.
New York 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)
Kewr fcster comments: visibility may drop to around 4sm if heavier rain showers
develop near the Airport.
Kjfk fcster comments: visibility may drop to around 4sm if heavier rain showers
develop near the Airport.
Klga fcster comments: visibility may drop to around 4sm if heavier rain showers
develop near the Airport.
Kteb fcster comments: visibility may drop to around 4sm if heavier rain showers
develop near the Airport.
Khpn fcster comments: visibility may drop to around 3sm if heavier rain showers
develop near the Airport.
Kisp fcster comments: amendments possible if activity over the
ocean allows for 1k feet ceilings to linger.
Outlook for 18z Saturday through Tuesday...
Sat afternoon...mainly VFR with areas of MVFR. Showers. Northwest gusts
around 35 knots.
Sun...VFR. Chance showers mainly in the morning. Northwest gusts 30-35kt. Forecast
may change if departure of storm slows.
Monday...VFR.
Tue-Wed...MVFR or lower possible in vicinity of a warm front.
&&
Marine...
fog continues with reduced visibilities to less than 1 mile across
eastern waters. The dense fog advisory runs until 4pm. Patchy fog
is possible on the central ocean waters and portions of western
Long Island Sound. Expecting the fog to break up after the frontal
passage with greater northwest winds towards late afternoon.
Small Craft Advisory remains up for the ocean waters through at least Friday night
as a lingering swell likely keeps seas up over 5 feet over a good
portion of the ocean waters. Gusts to 25 kts will be possible as
well during parts of this period on the ocean waters. Non-ocean
waters through Friday should see gusts peak at around 20 knots...but
a few gusts to 25 knots cannot be completely ruled out.
Northwest flow on the back side of the low as it moves into New
England...should strengthen gusts to gale force Sat
afternoon/evening. Gale watch in effect for the ocean waters...as
well as the eastern sound and Peconic and gardiners bays for
Saturday and Saturday night. For the remainder of the
waters...have went with a Small Craft Advisory where gusts may
fall just short of gales. It is possible where the small craft is
on Saturday and Saturday night...gales may be needed.
Conditions fall back to Small Craft Advisory conditions late Saturday night and
continue on all waters into Sunday afternoon...then gradually taper
off on the ocean and then eastern sound/bays Sunday night. Quiet
conditions expected Monday-Tuesday via building high pressure.
&&
Hydrology...
most remaining showers through the afternoon will result in rain
amounts of less than a quarter of an inch and around a quarter of
an inch for some eastern sections. For the most part...small
stream levels have stabilized...with only minor rises expected in
the wake of any shower activity.
Around 0.2-0.3 of inch of rainfall is expected tonight - with
locally higher amounts possible. Precipitable waters do decrease
to under 1 inch by late tonight. As a result...the risk of minor
urban/small stream flooding looks to be minimal.
Basin average quantitative precipitation forecast of 1/2 to 3/4 inch expected Sat into Sat night...then
only minimal quantitative precipitation forecast in lingering showers on Sunday.
For details on specific area rivers and lakes...including observed
and forecast river stages and lake elevations...please visit the
advanced hydrologic prediction service /ahps/ graphs on our website.
&&
Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory from 6 am Saturday to 6 am EDT Sunday for
anz335-338-345.
Dense fog advisory until 4 PM EDT this afternoon for anz330-
340-350.
Gale watch from Saturday morning through late Saturday night
for anz330-340-350-353-355.
Small Craft Advisory until 6 am EDT Saturday for anz350-353-
355.
&&
$$
Synopsis...BC/Goodman
near term...jm/BC
short term...British Columbia
long term...BC/Goodman
aviation...jmc
marine...BC/Goodman
hydrology...Nevada
