Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service New York New York
1024 PM EDT Thursday Apr 24 2014

Synopsis...
high pressure will build in overnight...and move east on
Friday. A frontal system will approach Friday night...with low
pressure developing over the middle Atlantic region and passing over
or just south of the region late at night. High pressure will
build into the region this weekend into Monday. Unsettled and
cool weather is forecast to return Tuesday and last through
Thursday.

&&

Near term /until 6 am Friday morning/...
winds continue to diminish. Temperatures are still expected to fall
rather quickly in spots as winds diminish and skies remain clear.
Very dry air should allow ample radiational cooling to
occur...allowing temperatures to fall through the 40s...and into the 30s
many locales. Middle and upper 20s are anticipated over the normally
colder locations.

Nudged overnight lows up slightly for a few locations due to
uncertainty of winds...and possible higher level clouds later on.

However...will not make any changes to frost/freeze hazards.

&&

Short term /6 am Friday morning through Friday night/...
clouds will gradually lower and thicken during Friday...but more
noticeably in the afternoon. Given the previously dry air mass and
subsidence from high pressure shifting through the area...
moistening ahead of the next system will be slow. As such...
little precipitation is expected during the afternoon. By
evening...light rain will develop from west to east...becoming
steadier overnight and quickly moving offshore by Saturday
morning.

&&

Long term /Saturday through Thursday/...
as a low pressure system moves east of the area Saturday...high
pressure will build into the region behind the front on Sunday and
Monday. With upper troughing lingering on Sat and an upper low
with very cold temperatures aloft expected to pass through...kept chance
pop through the day on Sat and slight chance for Sat night.
Would not be surprised to see thunderstorms with gusty winds and small
hail late day Sat into Sat evening as the upper low passes across.

High temperatures on Saturday should be above normal for
this time of year with highs in the middle to upper 60s. On Sunday
and Monday temperatures drop to below normal after the frontal
passage...with highs in the upper 50s to around 60.

Unsettled and cool weather is forecast to return Tuesday through
Thursday...with highs in the middle to upper 50s and lows in the middle
40s.

&&

Aviation /03z Friday through Tuesday/...
weak high pressure builds over the terminals overnight and moves
east Friday as a low pressure system approaches from the west.

VFR.

Northwest to north wind 10 knots or less will become light and variable
overnight into early Friday. Southeast to south wind develops in the
morning as low pressure approaches. Timing of southeast wind Friday
dependent on how quickly the low moves east.



Outlook for 00z Saturday through Tuesday...
Friday night-Sat...MVFR in rain through Sat morning. Areas of MVFR Sat
afternoon with rain showers possible.
Sun-Tue...VFR.

&&

Marine...
as winds continue to diminish...will drop the Small Craft Advisory. There could be
a few nearshore gusts to 25 knots over the eastern waters.

Expect sub-Small Craft Advisory conditions across the area Friday as a high
pressure ridge enters the region. These tranquil conditions prevail
through the day...with winds increasing from the south late in
the day...but still under 15 knots.

Low pressure developing along an approaching frontal system and
passing over or just south of the waters should lead to Small Craft Advisory conds
beginning late Friday night. The eastern-most sound and ocean waters could
see a brief period of southeast gale force gusts just ahead of the low...but
not of long enough duration to warrant a gale watch.

Small Craft Advisory conds are expected this weekend after the low passes east.
Then...sub-sca conditions return late Sunday into Monday as high
pressure builds over the area. Small craft conditions may return
Tuesday-Wednesday as low pressure moves across.

&&

Fire weather...
as winds diminish and temperatures cool...will allow the red flag
warnings to expire...cancelling it for NYC metropolitan. Better conditions
expected Friday via lighter winds...and higher relative humidity in developing
onshore flow.

&&

Hydrology...
around a half an inch of rain is expected Friday evening into
Saturday morning. However...no hydrologic concerns are expected
through early next week.

&&

Okx watches/warnings/advisories...
CT...freeze warning from 3 am to 9 am EDT Friday for ctz005>012.
New York...freeze warning from 3 am to 9 am EDT Friday for nyz067>070-079-
081.
Frost advisory from 3 am to 9 am EDT Friday for nyz078-080.
New Jersey...freeze warning from 3 am to 9 am EDT Friday for njz002-004-103.
Marine...none.

&&

$$
Synopsis...mmd/fig/Goodman
near term...mmd/Goodman/pw
short term...mmd/Goodman
long term...figure
aviation...met
marine...fig/Goodman/pw
fire weather...
hydrology...mmd/fig