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Area forecast discussion 
National Weather Service New York New York
149 PM EDT Friday Aug 22 2014

Synopsis...
multiple upper level disturbances cross the tri-state through
Saturday...as high pressure builds down from southeastern Canada.
This high continues to build over the area early next week...then
passes east by middle to late week.

&&

Near term /until 6 PM this evening/...
17z water vapor imagery indicating middle level shortwave/associated
weak vorticity maximum moving through central New York. Forcing with this wave is
fairly weak...just working to trigger scattered convection over the
interior regions. Flow aloft weak yet again today so any shower
that does form could result in a brief heavy rainfall. Continued
chance probability of precipitation well north/west of NYC metropolitan. Onshore along the coast
keeping a more stable airmass in place...so went slight chance right
around the city...then dry to the east. Isolated thunderstorm possible well
inland...but lower end threat with the thinking it will be more
just shower activity.

Broken-overcast sky cover persisting...and combining with the easterly
flow...seeing temperatures a few degrees below normal...generally in the
70s.

&&

Short term /6 PM this evening through Sunday night/...
700-500 hpa trough axis approaches tonight...then pushes to the S
Saturday. Do restrict probability of precipitation this evening mainly to the northwest 1/2 of
the County Warning Area...and mention of thunder to the SW 1/2 of the County Warning Area - as
this is the only area where have any forecast instability - once
again mainly aloft. Precipitation chance fall off fairly rapidly
after midnight Friday night. Note the European model (ecmwf) is the only model
showing any precipitation late Friday night/Saturday morning so
have discarded as an outlier for now. Do expect rain showers to return
mainly across the northern tier Saturday afternoon ahead of the
final vorticity lobe right in the wake of the 700-500 hpa trough
axis.

For lows tonight used a blend of mav/met guidance with NAM 2-meter
temperatures...with once again abundant cloud cover expected. Lows
should be near to slightly above normal. For highs Saturday...with
the potential for some sunshine in the late afternoon...used
a blend of mixing down from 875 hpa with NAM 2-meter temperatures
and a blend of mav/met guidance. Highs should be around 5 degrees
below normal.

Even with NE low level flow...will see gradual clearing from
Saturday night through the remainder of the weekend as deep
layered ridging builds over the area and surface high pressure
builds down from southeast Canada. Expect this time frame to be dry as a
result.

Lows Saturday night were based on a blend of mav/met guidance with
NAM 2-meter temperatures...and should be near to slightly below
normal. For highs Sunday used a blend of mav/met guidance with NAM
2-meter temperatures and a mix down from 875 hpa per BUFKIT
soundings. This yields values a couple of degrees below normal.
For lows Sunday night used a blend of mex/men/ekd/ece/ecm/wpc
guidance with NAM 2-meters. Expect lows to be around 5 degrees
below normal.

&&

Long term /Monday through Thursday/...
amplified pattern early on with large ridge building through Tuesday
before flattening and giving way to upstream trough later Wednesday
and Thursday.

Surface high pressure over the area slowly drifts offshore Tuesday
and Wednesday...as a cold front approaches Thursday from the west.

Expect dry and seasonable conditions through the middle of next week
courtesy of the ridge. Temperatures slowly modify from slightly below normal
Monday...to near or even above normal by middle week.

&&

Aviation /18z Friday through Wednesday/...
high pressure slowly builds southward into the region through the
taf period. Conditions vary between mainly VFR to localized MVFR
transition to mostly MVFR tonight. Late tonight into early
Saturday morning...ceilings could possibly lower at times between
1k-1.5kft. Shower activity confined to near kswf. Generally flow
around 070 to 110 degrees around 8-10 knots. Klga more NE flow until
late this afternoon.

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)

Kjfk fcster comments: there is a chance ceilings could lower to MVFR
between 2k-3kft before 02z.

Klga fcster comments: there is a chance ceilings could lower to MVFR
between 2k-3kft before 02z. NE flow could last 1 hour later than
indicated in taf before switching to more east flow.

Kewr fcster comments: there is a chance ceilings could lower to MVFR
between 2k-3kft before 02z.

Kteb fcster comments: there is a chance ceilings could lower to MVFR
between 2k-3kft before 02z.

Khpn fcster comments: there is a chance ceilings could lower to MVFR
between 2k-3kft before 02z.

Kisp fcster comments: there is a chance ceilings could lower to MVFR
between 2k-3kft before 02z.

Outlook for 18z Sat through Wednesday...
Sat...becoming VFR with east-northeast flow.
Sun-Wed...VFR.

&&

Marine...
winds and seas forecast appears on track for today.

For now forecasting sub-Small Craft Advisory conditions on all waters through
Sunday night. However a persistent east-NE flow of 10-15kt with gusts
up to 20 knots from tonight into Sunday night over the coastal ocean
waters could possibly builds seas to at least 5 feet by late
Saturday. However...latest wavewatch iii guidance shows seas only
reaching 4 feet...so have forecasted accordingly for now but cannot
rule out seas ultimately being 1-2 feet higher than this over the
coastal ocean waters from late Saturday into Sunday night.

Elsewhere through Sunday night...winds will be mainly 10 knots or
less over the remainder of the waters around Long Island.

High pressure builds over the waters Monday and Tuesday resulting in
light winds and rather tranquil seas.

&&

Hydrology...
forecasting generally couple tenths of an inch or less with any rain showers/thunderstorms
through this afternoon...then mainly dry through Saturday. No significant
hydrologic impact is expected from any precipitation through the
first half of next week.

&&

Okx watches/warnings/advisories...
CT...none.
New York...none.
New Jersey...none.
Marine...none.

&&

$$
Synopsis...maloit/pw
near term...Sears
short term...maloit
long term...precipitable water
aviation...jm
marine...maloit/pw
hydrology...maloit

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