Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service New York New York
143 am EDT Friday Apr 18 2014

Synopsis...
high pressure slowly retreats to the northeast through Friday
night. Another area of high pressure system move slowly southeast
across the region Saturday through Monday. Low pressure will move
toward the area Tuesday then east of the area Wednesday followed
by another high pressure system.

&&

Near term /until 6 am this morning/...
forecast for the overnight hours on track and made edits to temperatures
and dew points. Temperatures were dropping a bit quicker than
forecast...likely due to the lack of cloud cover over the area and
the quickly diminishing winds. Lav data also indicating lows a degree
or two below previous forecast with low level clouds still
advecting in by 07-09z.

Still thinking that temperatures will remain above freezing...at
least where the frost/freeze program has started. With the cloud
cover holding off a few more hours...expect some frost to
develop...especially with calm and variable winds. So will keep
the frost advisories that are already in effect. It is possible
that kfok gets to 32 degrees but freezing temperatures will not be
widespread enough for a freeze warning.

Otherwise...expect a dry night with lows falling into the middle and
upper 30s. Of course temperatures may have to be nudged down a bit
of clouds take longer to move in. Went slightly above a mav/met
blend for temperatures tonight.

&&

Short term /6 am this morning through 6 PM Saturday/...
weak high pressure will remain over the region Friday and Friday
night.

A northern stream shortwave will pass north of the region on Friday
and given lack of low level moisture...only expect to see increase
in middle-high clouds on Friday ahead of the shortwave.

Friday night will remain dry...however skies will remain mostly
cloudy with the shortwave passing nearby.

Mav/met guidance in good agreement and used. Temperatures on Friday
will reach the upper 40s and 50s...while Friday night falls into the
30s and lower 40s.

&&

Long term /Saturday night through Thursday/...
dry weather is forecast Saturday through early Tuesday as a slow
moving Canadian high pressure system moves slowly across the region.

For Saturday...with the approach of high pressure and the advection
of strong subsidence...there will be an enhanced risk of fire spread
under full sun as humidities decrease to less than 30 percent and northwest
winds increase to 10-15 miles per hour during the afternoon. Temperatures are
forecast near normal values in the 60s.

For Sunday...a light onshore wind flow will develop as high pressure
moves off the coast causing afternoon high temperatures mainly in the 50s
across Long Island and southern CT...with low 60s north and west of
NYC.

Forecast models show a digging amplifying upper level short wave
approaching Wednesday causing cyclogenesis near the local area with
our next chance of rain...Tuesday afternoon through Wednesday. At
this time...this appears to mainly be a light to possibly moderate
rainfall of 1/4-1/2 inch.

&&

Aviation /06z Friday through Tuesday/...
high pressure centered over the Canadian Maritimes and extending
down the eastern Seaboard will slowly move east while weakening
today.

East flow continues through the day...but local sea breezes this
afternoon will turn winds S/southeast at 10-15 knots. Winds diminish to 5 knots
or less tonight.

Patchy MVFR stratus will spread across the terminals through
daybreak or so. VFR otherwise.

Outlook for 00z Saturday through Tuesday...
Friday night-Monday night...VFR.
Tuesday/Tuesday night...MVFR possible with showers...cold frontal passage.

&&

Marine...
a Small Craft Advisory remains in effect for the ocean waters where
gusts are reaching 25 knots and seas are around 6-7 feet. This small
craft remains in effect through Friday. Sub-Small Craft Advisory conditions are
expected on the remainder of the waters.

Winds and seas are forecast to fall below Small Craft Advisory levels Friday
night...however some lingering 5 feet seas may remain for the first
part of the night...especially across the eastern waters.

Winds and seas are forecast to remain below Small Craft Advisory
levels Saturday through Monday as high pressure moves slowly across
the coastal water.

South winds and seas will increase with the approach of low pressure
on Tuesday and possibly meet Small Craft Advisory levels Tuesday
afternoon. After a brief lull Tuesday night..northwest winds may
increase to Small Craft Advisory levels on Wednesday.

&&

Hydrology...
dry weather is forecast through Tuesday morning. There is a
chance for 1/4 - 1/2 inch rainfall associated with a low pressure
system Tuesday afternoon through the day Wednesday.



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...frost advisory until 9 am EDT this morning for ctz009>012.
New York...frost advisory until 9 am EDT this morning for nyz069>071-
078>081-177-179.
New Jersey...frost advisory until 9 am EDT this morning for njz004-103>108.
Marine...Small Craft Advisory until 6 PM EDT this evening for anz350-
353-355.

&&

$$
Synopsis...BC/gc
near term...BC/ln
short term...British Columbia
long term...gc
aviation...mps
marine...BC/gc
hydrology...BC/gc