Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service New York New York
449 am EDT sun Apr 20 2014

Synopsis...
high pressure builds over the region through the start of the new
week...and then a cold front moves across the region late Tuesday
and Tuesday night. Low pressure exits to the east on Wednesday...
followed by high pressure building in through Thursday night. This
high slides to the east Friday...allowing for a storm system to
impact the tri-state from late Friday into Saturday.

&&

Near term /until 6 PM this evening/...
high pressure over eastern Canada continues to press to the south and
east...and will become centered over Cape Cod later today.

As the high builds south...any clouds over southern zones should
be pushed to the south...and skies will clear out during the day.
Winds shift from the north to the east...and then to the southeast
by afternoon. The flow off the ocean will usher a cooler airmass
into most of the region...resulting in highs about 5-10 degrees
cooler than that of Saturday. The warmest temperatures will be across
interior portions of the lower Hudson Valley where highs will be
in the low to middle 60s. Elsewhere...highs will range from the low
60s to the upper 50s near the coast.

&&

Short term /6 PM this evening through Tuesday night/...
high pressure keeps conditions quiet through Monday night. With southerly
flow...highs on Monday across the interior will top off in the
middle to upper 60s across the interior...but coastal areas will
remain in the 50s. Highs will be a few degrees warmer on Tuesday.
Tonight...radiational cooling conditions away from NYC will allow temperatures
to fall into the 20s. Otherwise...lows will be in the 40s
in/around NYC and in the 30s elsewhere. With increasing clouds
Monday night...lows will range from the upper 30s to upper 40s.

Cold front/upper trough approaches on Tuesday. This will bring an
increasing chance for showers late in the day and during the
evening. Showers taper off from west to east after midnight
Tuesday night. Will cap probability of precipitation at likely...and will focus on
western and northern zones.

&&

Long term /Wednesday through Saturday/...
a full latitude...deep layered trough exits to the east as it
negatively tilts on Wednesday. Given associated cold pool building
in aloft...due have slight chance probability of precipitation for -shra Wednesday...
mainly over western sections.

Deep layered ridging builds in Wednesday night-Thursday
night...then slides to the east on Friday. Associated subsidence
under the ridge should keep things dry with minimal cloud cover
Wednesday night-Thursday night. Will see increasing cloud cover
Friday...with a chance west/slight chance east of light rain by
afternoon as a warm front approaches from the SW.

A northern stream cutoff low moves to southeast Quebec/SW Ontario by late
Saturday. Multiple shortwaves move over the area ahead of it
Friday night and Saturday warranting chance probability of precipitation this time frame.
For now it appears warm front will probably stay to the S Friday
night...then lift to the north Saturday morning...so went with rain
Friday night and showers Saturday in the warm sector.

For temperatures in the long term used a blend of
mex/men/ekd/ece/ecm/wpc guidance. Based on this...forecasting
below normal temperatures Wednesday/Wednesday night...near normal
temperatures Thursday/Thursday night...above normal temperatures
Friday/Friday night...then near normal temperatures on Saturday.

&&

Aviation /09z Sunday through Thursday/...
high pressure gradually builds southward over the region this
morning...then slowly retreats to the northeast into tonight.

VFR through the taf period.

Winds slowly veer from NE-east-northeast to east by 12-14z...then southeast by early to
middle afternoon. Speeds generally around 8-13 knots for coastal
terminals...and 10 knots or less for inland terminals. Winds become
light and variable this evening for all but kjfk and klga.

Outlook for 06z Monday through Thursday...
late Sunday night-Tuesday morning...VFR.
Tuesday afternoon-Wednesday morning...rain showers becoming likely...with
MVFR or lower possible. Northwest-north winds g20-25kt possible.
Wednesday afternoon...most likely VFR...with low chance MVFR.
Northwest-north wind g20-25kt possible.
Wednesday night-Thursday...VFR. Northwest-north wind g20-25 knots possible.

&&

Marine...
with high pressure building east...a persistent easterly flow develops
on the waters today. Not expecting Small Craft Advisory gusts...but seas on the
ocean will build to 3 to 5 feet. Will convert Small Craft Advisory to Small Craft Advisory for
hazardous seas...and will run it through today.

Sub Small Craft Advisory conditions then expected tonight into Monday night as high
pressure lies across the region.

Southerly winds gradually increase on Tuesday ahead of an
approaching frontal system...with a chance for marginal Small Craft Advisory gusts
and ocean seas Tuesday night ahead of the front.

Small Craft Advisory conditions are likely on the coastal ocean
and eastern waters from Wednesday afternoon into Thursday in gusty
northwest winds behind a departing coastal low. Small craft conditions
are possible on the remainder of the waters during this time
frame.

&&

Fire weather...
a dry Sunday expected with min relative humidity values between 20-30 percent.
Northeast winds at 10 to 15 miles per hour will shift to the east by the
middle of the day...and then to the southeast late.

With dry fine fuels...this will pose another day with the
potential for rapid fire spread.

&&

Hydrology...
dry conditions expected through Monday night.

A cold front will move across the region late Tuesday and Tuesday
night...but at this point...it looks like quantitative precipitation forecast will be less than
1/4 inch and not pose flooding issues.

Note...minor flooding continues along the Connecticut River. For
additional information...please refer to the latest flood warnings
from National Weather Service Taunton Massachusetts.

No significant rainfall is expected from Wednesday through the end
of the work week.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...Small Craft Advisory for hazardous seas from 8 am this morning
to 6 PM EDT this evening for anz350-353-355.

&&

$$
Synopsis...mps
near term...mps
short term...mps
long term...maloit
aviation...maloit
marine...maloit/mps
fire weather...
hydrology...maloit/mps