Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service New York New York
147 PM EDT Wednesday Apr 16 2014

Synopsis...
high pressure builds over the region today and drifts northeast
tonight and Thursday. High pressure remains over the northeast
Friday into the weekend as multiple low pressure areas ride a
stalled front to the east. The high finally pushes off to the
east beginning of next week with low pressure returning for middle
week.

&&

Near term /until 6 PM this evening/...
minor adjustments made to temperatures and dew points to reflect current
observation. Lowered high temperature forecast slightly in spots.

Ridge builds into the region this afternoon. Gusty northwest flow
continues to diminish through the day. With mixing to around 3500
feet...high temperatures will be well below normal with highs in the
40s. Normal highs are around 60.

&&

Short term /6 PM this evening through 6 PM Thursday/...
ridge remains across the region tonight into Thursday as surface
high remains to the northeast and ridges down along the eastern
slopes of the Appalachians. The cold air mass will remain in place
tonight into Thursday. Temperatures will again approach or fall
below freezing across the area. A freeze watch has been posted for
the same areas that had the freeze warning this morning.
However...there is less certainty of widespread freezing
temperatures being realized across the city and adjacent zones.
No records are expected to be broken tonight unless temperatures
fall lower than forecast as skies will be clear and winds will
initially be light in the evening. Then with the high building to
the northeast winds will increase from the northeast bringing in
cooler northern Atlantic air later tonight into Thursday.
Thursdays highs will only be a couple of degrees higher than
todays highs.

&&

Long term /Thursday night through Tuesday/...
initially dry weather Thursday night as the center of the surface
high pushes north and east while the area remains under broad
ridging. Global models suggest weak low pressure development along a
stalled front offshore that could bring light precipitation into the area by
Friday morning...then slowly spreading to the north Friday night into
Sat. 00z GFS a bit more pronounced in the development of the low and
the resulting precipitation with the suggestion of interaction between a
southern stream shortwave with the northern stream trough/closed
low. All other models keep a distinct separation between the two so
went ahead and maintained the slight chance/chance probability of precipitation for now with
uncertainty on just how widespread the precipitation occurs. An approaching
front Sat could trigger scattered rain showers as the upper level trough
swings through. Things then dry out for Sat night-Sunday with zonal flow
setting up aloft and high pressure building south into the
northeast.

Some model discrepancies in the handling of the next low pressure
system next week. 00z GFS lingers the high over the northeast then
brings a weak front in from the west while European model (ecmwf) and CMC both
develop a decent area of low pressure off coastal Florida and track
to the north along a stalled front. Flow aloft suggests more of a
GFS solution in this case...so sided more to a GFS/wpc
blend...bringing probability of precipitation in Monday night and keeping them in place
through Tuesday with the front remaining in the vicinity and
multiple shortwaves riding the flow aloft.

Cooler weather in store for the tri state area Thursday night/Friday as
the positioning of the high keeps a cooler easterly/northeasterly
flow despite warm air advection aloft. However...as winds shift for the
weekend...expect temperatures to warm back to near normal. Overall...temperatures
expected to remain warm enough with timing of precipitation to keep precipitation in
the form of rain. Thursday night will be the coldest night in the
extended...though currently not expecting frost/freeze issues in
areas currently in the growing season.

&&

Aviation /18z Wednesday through Monday/...
high pressure builds over the area into this evening...then shifts
NE over the Canadian Maritimes on Thursday.

VFR.

Northwest winds 10 to 15 knots with gusts 20 to 25 knots into early afternoon.
Gusts will end around 21z with sustained winds slowly diminishing
this evening as directions veer to the north.

Overnight...winds will veer to the NE at 5-12 knots. Winds continue to
veer to the east Thursday morning with speeds increasing 10 to 15 knots.

... 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)

Kjfk fcster comments: wind direction may vary 310-340 mag this
afternoon. End time of gusts may be off +/- an hour.

Klga fcster comments: wind direction may vary 320-350 mag this
afternoon. End time of gusts may be off +/- an hour.

Kewr fcster comments: 310-340 mag. End time of gusts may be off +/-
an hour.

Kteb fcster comments: end time of gusts may be off +/- an hour.

Khpn fcster comments: end time of gusts may be off +/- an hour.

Kisp fcster comments: end time of gusts may be off +/- an hour.

Outlook for 18z Thursday through Monday...
Thursday...VFR. East wind gust around 20kt possible.
Thursday night-Friday night...possible MVFR ceilings.
Saturday...possible MVFR conditions with low chance of -shra.
Saturday night-Sunday...VFR
Monday...VFR

&&

Marine...
Small Craft Advisory on the sound/Li bays/New York Harbor has been dropped now that
frequent gusts are below 25 knots. On the ocean...just occasional
gusts to 25 knots this afternoon...but a building southeast swell is
expected to keep seas above 5 feet. There could be a period over the
western ocean waters this afternoon and early evening where Small Craft Advisory
conditions are not being met...however...the expectation is for
building seas and strengthening winds later on in the night.

Small Craft Advisory conditions continue on the ocean waters on Thursday. For the
other waters...occasional gusts to 25 knots possible.

Brief period of 25 knots gusts on the ocean waters Thursday night...with
winds diminishing heading into Friday as high pressure builds over the
waters. Winds remain sub-Small Craft Advisory conditions through the beginning of
next week. Seas remain elevated on the ocean during the
period...finally subsiding by late Sat. Seas then expected to remain
below 5 feet into next week.

&&

Hydrology...
dry today through Thursday. Then no significant precipitation
that would have hydrologic impacts is currently forecasted
Thursday night through the middle of the next week.

Note...minor flooding continues along the Connecticut River.
Additional heavy rainfall will likely cause water levels to continue
to rise through the week...with potential for moderate flood levels
to be reached. Monitor the latest flood warnings from National Weather Service Taunton Massachusetts.

No significant precipitation is expected from Thursday into early
next week.

&&

Climate...
record lows for Thursday morning April 17:

Ewr - 30 in 1980 forecast low - 33
bdr - 30 in 1962 forecast low - 31
NYC - 28 in 1875 forecast low - 34
LGA - 32 in 1980 forecast low - 36
JFK - 33 in 1980 forecast low - 35
isp - 30 in 2005 forecast low - 30

&&

Okx watches/warnings/advisories...
CT...freeze watch from late tonight through Thursday morning for
ctz009>012.
New York...freeze watch from late tonight through Thursday morning for
nyz069>075-078>081-176>179.
New Jersey...freeze watch from late tonight through Thursday morning for
njz004-006-103>108.
Marine...Small Craft Advisory until 6 PM EDT Thursday for anz350-353-
355.

&&

$$
Synopsis...Sears/met
near term...jc/met
short term...met
long term...Sears
aviation...ds
marine...jc/Sears/met
hydrology...Sears/met
climate...