Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
359 PM EDT Monday Mar 10 2014
weak low pressure will pass to the north tonight...followed by
weak high pressure Tuesday into Tuesday evening. Strong low
pressure will move through Wednesday into Wednesday night...
followed by building high pressure Thursday through Friday.
A cold front will pass through on Saturday...with high pressure
building in briefly on Sunday.
Near term /until 6 am Tuesday morning/...
skies clearer enough over NYC metropolitan to allow temperatures to rise to the
lower 50s...and to levels a couple of degrees higher than expected
most elsewhere. Expect partly cloudy skies to continue into early this
evening...then as a middle level shortwave rides east-southeast along a warm
front lifting through the area...clouds should increase especially
North/East of NYC...with some light rain or sprinkles possible.
Depending on how quickly temperatures cool off tonight...could not rule
out some isolated pockets of freezing rain up Orange County way...no
advisory has been issued since probability of occurrence looks too low
at this time. Will let overnight temperatures and radar trends be the deciding
factor there. Weak cold front should pass through late...bringing
an end to any precipitation along with some clearing.
Short term /6 am Tuesday morning through Tuesday night/...
should see partly to mostly sunny skies on Tuesday...which along with
downslope west-northwest flow should help temperatures rise to 55-60 across NYC
metropolitan and most of Long Island...and 50-55 to the north...about 2-4
degree above a 12z GFS/NAM MOS guidance blend.
Clouds increase mainly during Tuesday night ahead of low pressure
developing in the Ohio Valley. Overrunning precipitation should move into
areas mainly north/west of NYC after midnight...and sped this up
about 3 hour ahead of model forecast which is usually too low to
initiate warm air advection precipitation. Precipitation type across the interior is uncertain
and will be dependent on amount of evening radiational cooling and
then late night warm air advection. For now expect a wintry mix at the
onset well inland and across most of southern CT where temperatures
should bottom out around or just above freezing...and all rain
farther south across NYC metropolitan and Long Island where lows in most
spots should be 40-45. Forecast lows are a little warmer than a 12z
GFS/NAM MOS composite.
Long term /Wednesday through Monday/...
deepening low pressure passing through the northeast middle week
remains the main focus for the extended forecast. High pressure
builds in the wake of the low...leading to a period of dry weather.
Precipitation returns to the forecast for the weekend with a cold frontal
passage...though no where to the extent expected with the middle week
12z models continue trending with bringing the center of the low
through the tri-state region. Despite the near similarities of the
track...enough of a difference exists that still brings into
question the form of precipitation expected initially with the onset of the
precipitation. Aloft...watching two pieces of shortwave energy and the
phasing/interaction...which would lead to the path of the associated
surface low. Latest thought in respect to the 12z model suite...low
forms and begins deepening over middle Atlantic region...with center
passing through around 00z Thursday. Soundings generally concur on the
majority of the area starting off as light rain and remaining as
such through at least Wednesday evening. Portions of interior New York and CT
could see a period of a wintry mix around day break Wednesday morning with
the beginning of the precipitation...then transitioning to rain by middle
morning. Surge of strong warm air advection with the southerly flow ahead of the
low helps to keep temperatures above freezing...with temperatures starting off at
least in the middle 30s Wednesday morning. All rain then Wednesday afternoon and Wednesday
evening...with the heaviest precipitation also expected during this time
frame. Will casually mention a low possibility of thunder near the
coast late Wednesday depending on the exact track of the low...but will
not mention in the forecast at this time.
Next uncertainty then is how quickly the colder air wraps around and
moves into the northeast behind the low...and transitioning any precipitation
to snow. General consensus would see snow north and west in the city
by midnight...then pushing to the east by 12z Thursday. However...by
the time the colder air moves in near the city and on east...could
see the precipitation tapering off. With this timing 2-4 inches of snow over
interior regions is possible...with 1 inch or less at the coast...so
Winter Weather Advisory may be needed for interior areas. Have
slight chance probability of precipitation in for the afternoon over eastern areas...but confidence
is increasing all precipitation should clear by 18z Thursday. Another thing to
watch on Thursday will be increasing winds. As the low level jet sets up
across the area...with winds between 50 and 60 knots...could see
stronger winds mixing down to the surface...with gusts between 35
and 45 miles per hour possible.
High pressure builds in the wake of the front. Main story for this
time frame will be the well below normal temperatures with strong cold air
advection pushing 850mb temperatures down to around 20 below Thursday night.
The much colder air will be short lived as the axis of the high
pushes east...returning to a southwesterly flow and warm air
Low pressure moves through southern Canada late Friday into
Saturday...dragging its associated cold front through by middle day
Saturday. Some question on the extent of precipitation with this system as
the very dry air mass as the result of the high Thursday/Friday will be
hard to overcome. Better forcing with the passing shortwave also
looks to be north of the region...so will maintain slight chance
wording for now. Dry weather returns Sunday.
Aviation /20z Monday through Saturday/...
a clipper system will pass north of the region tonight. Weak high
pressure builds into the region on Tuesday.
VFR through the taf period. S-SW winds around 10 knots or less
gradually weaken this evening outside of the city terminals with
city terminals only lowering a few knots. After 06z...winds become
westerly...and increase to 10 knots towards daybreak. Some occasional
gusts to around 15 knots will be possible into early this evening.
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: occasional gusts to 15-17 knots possible before
Kjfk fcster comments: occasional gusts to 15-17 knots possible before
Klga fcster comments: occasional gusts to 15-17 knots possible before
Kteb fcster comments: occasional gusts to 15-17 knots possible before
Khpn fcster comments: occasional gusts to 15-17 knots possible before
Kisp fcster comments: occasional gusts to 15-17 knots possible before
Outlook for 18z Tuesday through Sat...
Tuesday afternoon/night...VFR. Possible gusts to 20kt during the day.
Wednesday-Wednesday night...sub-VFR likely in snow and/or rain. East-southeast-southeast winds around
10 knots gusting up to around 20 knots late Wednesday afternoon-evening then north winds
around 20 knots gusting up to 25-30 knots later Wednesday night.
Thursday...improving to VFR early. Northwest g25-30kt.
Sat...sub-VFR possible in showers.
west-southwest flow 15-20 knots tonight should be enough to push ocean seas to 5
feet late tonight into Tuesday morning per wavewatch...and there could
be some gusts to 25 knots as well. Small Craft Advisory will be issued for this
Increasing winds and seas expected Wednesday with the approaching
low. Could see Small Craft Advisory conditions on the ocean waters by 18z Wednesday...
with high confidence of 25 knots gusts on all the waters by Wednesday
evening. Increasing confidence of gales being reached by Thursday
morning at least on the ocean if not all waters...and lasting
through the day on Thursday. Winds begin to taper off Thursday night into
Friday as high pressure builds across.
Seas remain elevated through Friday morning...with sub-Small Craft Advisory conditions then
expected everywhere the remainder of the day. Increasing flow
ahead of the next cold front could bring occasional 25 knots gusts on the
ocean waters and 5 feet seas on Sat.
there is potential for significant precipitation during the
middle of this week as a storm system tracks near the region.
Basin average quantitative precipitation forecast calls for 0.75 to 1.25 inch...highest north/west.
the National oceanic and atmospheric administration weather radio transmitter that serves the New York City
metropolitan area remains out of service due to radio frequency
interference with the U.S Coast Guard transmitter.
For more information see the following public information
statement (all lower case):
Marine...Small Craft Advisory from 3 am to 11 am EDT Tuesday for anz350.
Small Craft Advisory from 3 am to 9 am EDT Tuesday for anz353.