Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
637 am EST Wednesday Dec 4 2013
high pressure will be over the area today. A warm front approaches
tonight and passes through on Thursday. A cold front approaches
Thursday night and moves across the area Friday. High pressure
builds this weekend. Another storm system will impact the area
Sunday night and Monday...with a cold front moving east Tuesday.
Near term /until 6 PM this evening/...
a high pressure ridge will be in the vicinity today as ridging
occurs aloft. This will help keep US dry today with varying
amounts of cloud cover. Middle/high clouds will push through mainly
during the morning...then lower stratus could reach southern zones
late in the day out ahead of a warm front. In any case...high
temperatures are expected to be a little warmer than normal.
Short term /6 PM this evening through 6 PM Thursday/...
a warm front to the south moves closer to US through the night.
Strengthening isentropic lift ahead of the front with increasing
Theta-E advection should lead to some overrunning precipitation. Moisture
is on the shallow side with the bulk of it below 800mb...so light
rain and/or drizzle would be most likely precipitation type. Thermal
profiles do not support frozen precipitation of any type. Mav and NAM MOS
guidance for probability of precipitation look too low with the given setup. Will go above
these numbers...but still keep probability of precipitation in the chance category. With the
warm front remaining to the south all night...areas of fog can be
anticipated as well.
The warm front pushes north through the forecast area during
Thursday with a cold front advancing...but still to our west late in
the day. Looks like the best chances of light rain/drizzle would be
with the lift associated with the warm front. A weak wave of low
pressure could form along the front as suggested by some of the
models. This could complicate the timing of the frontal
passage...making it slower than what guidance consensus would
suggest. Will therefore keep chance probability of precipitation in the forecast through the
day...but it does look like most of the day would be dry for most
spots. High temperatures once again end up higher than normal due to
warm air advection.
Long term /Thursday night through Tuesday/...
global models and GFS ensemble members analyzed during this very
active timeframe...with subtle differences noted. However...with
such a complex forecast and pattern...the models are in decent
agreement with regard to overall features.
Large ridge moves off the East Coast...with broad southwest flow
extending across a good portion of the country. This SW flow
downstream from impressive trough over the West Coast late this
Embedded shortwaves move quickly across the area in the SW flow
Thursday night and Friday. Eventually...West Coast trough will track
across The Rockies and toward the middle section of the
country...possibly phasing with Canadian trough in time. This occurs
early next week...with trough axis still located to our west by
At the surface...warm front well to the north Thursday night...with
a cold front approaching from the west. This front looks to move
through early Friday...with a wave of low pressure riding along it.
This front will not move too fast to the east...as it remains nearly
parallel to the upper flow. In time...high pressure begins to build
from the Upper Middle west...moving across northern New England by late
this upcoming weekend. If this holds true...classic cold air damming
setup to the Lee of the Appalachians will occur.
As West Coast trough ejects toward the middle section of the country as
mentioned earlier...low pressure and associated warm front will
approach from the south...impacting the area Sunday night and
Monday. As one would expect...ensemble spreads increase...although a
general agreement is observed.
By Monday the low and warm front move well to the north...with a
trailing cold front moving through sometime Monday night or Tuesday.
Some question on whether or not this front moves far enough to the
east to end any precipitation threat Tuesday...although latest GFS and
European model (ecmwf) both show front clearing the area...replaced by plenty of dry
air to allow precipitation to end Monday night.
As for sensible weather...mainly plain rain showers expected
Thursday night and Friday with the cold front. Likely probability of precipitation by Friday.
By late in the day Friday and through the night Friday
night...enough cold air moves in from the north for a possible rain
to snow transition. This transition will occur from northwest to southeast. Light
snow accums are possible...depending on how quickly precipitation wraps
Dry Saturday through Sunday morning. Then snow to wintry mix to rain
is expected later Sunday and Sunday night. Mainly rain for Monday
Expect changeable temperatures through this time frame. Temperatures
will be quite mild Thursday night ahead of the cold front. In
fact...overnight lows should remain higher than our normal high
temperatures for this time of year.
Temperatures rise slightly Friday...then will fall behind the
front...setting up near to below normal temperatures into the weekend.
Above normal readings return Monday as area is once again in the
warm sector...with a return to near or below normal readings Tuesday
behind the front.
Followed NAM and GFS statistical guidance Thursday and Thursday
night. Thereafter...blended mex/wpc numbers with previous forecast.
Aviation /12z Wednesday through Sunday/...
high pressure slides offshore today. Warm front approaches
tonight and moves through the area Thursday.
High confidence in light and variable winds today with winds
shifting to more southerly overnight.
Moderate confidence in ceilings through the taf period. Expect ceilings to
lower through the evening with the approach of a warm front and drop
to 1-3k feet by Thursday. Amendments may be needed for the timing
of the lowering ceilings.
-Shra also possible Thursday morning and through
the day. With the scattered nature expected...will include vcsh
for all terminals for Thursday morning.
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)
Kewr fcster comments: no unscheduled amendments expected.
The afternoon kewr haze potential forecast is yellow...which implies
slant range visibility 4-6sm or greater outside of cloud.
Kjfk fcster comments: no unscheduled amendments expected.
Klga fcster comments: no unscheduled amendments expected.
Kteb fcster comments: no unscheduled amendments expected.
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 12z Thursday through Sunday...
Thursday...areas of IFR and -shra. Light SW flow.
Friday...IFR possible...especially in periods of rain. Wind shift to
Sun...MVFR or lower late. Chance -sn/pl away from the immediate coast.
with a high pressure ridge in the vicinity...winds will be light
today. The pressure gradient then tightens a little tonight...with
winds picking up out of the southeast late at night. Sub-Small Craft Advisory conditions
will still prevail. Winds and seas remain below advisory criteria
through Thursday with a warm front passing through the waters.
A cold front approaches Thursday night...and tracks across the
waters early Friday. Southerly winds ahead of the front shift to the
These northerly winds continue through Friday night...and eventually
shift to the northeast and east Sunday ahead of the next storm
Seas will build and remain rather rough across the ocean waters
Thursday night through Friday. Seas should subside somewhat later
Saturday into Sunday before building yet again as the next storm
system impacts the waters.
Wave watch iii output looks reasonable for the ocean waters...with
wind/sea buoy climatology followed for the sheltered waters surrounding
the next chance for any significant precipitation will be Thursday
night through Friday night...as well as late Sunday through Monday.
Each event could bring possibly an inch of precipitation across
the hydrologic service area.
the combination of astronomically high tides and residual surge of 1
to 1 1/2 feet is expected to have water levels touching or slightly
exceeding minor thresholds for a few spots along the South Shore
bays of Queens...Brooklyn...Nassau County and Staten Island during
the high tide cycle this morning. A coastal flood statement has
therefore been issued to address this anticipated localized minor
flooding of low lying coastal areas.
due to interference issues with the U.S. Coast Guard
emergency broadcast channel...the New York City National oceanic and atmospheric administration all hazards
weather radio station kwo35 remains out of service. The National
Weather Service is working with several U.S. Government agencies
to isolate and resolve this technical problem.
During this time...the transmitter may be returned to service
intermittently for use of the National oceanic and atmospheric administration all hazards weather radio
during potentially dangerous weather situations...for routine
weekly tests of the warning system...and to determine if the
interference issue has been resolved.
long term...precipitable water