Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
333 am EDT Sat Sep 20 2014
high pressure to our north moves east over the Atlantic on Saturday.
A cold front crosses the area Sunday night. High pressure returns
on Monday and remains in control through the end of the week.
Near term /until 6 PM this evening/...
southerly flow across the region...combined with low level moisture
will result in stratus across the region this morning. Any stratus
will gradually dissipate during the morning hours...leading to a
partly/mostly sunny afternoon.
The uncertainty with high temperatures today continues with the NAM
MOS temperatures running 3-6 degrees higher than GFS MOS. With
uncertainty in amount of sun...have stayed close to previous
forecast which is basically a compromise of the NAM and GFS MOS.
Widespread stratus returns tonight...with the chance of light rain
or drizzle. Models are not depicting any significant
precipitation...so will keep low chance probability of precipitation with drizzle wording.
There will be a moderate risk of rip currents at Atlantic Ocean
facing beaches Saturday.
Short term /6 PM this evening through Sunday night/...
model guidance remains in fairly good agreement through the short
term as an area of low pressure develops off the southeast coast and
moving northeast as it gets picked up by the approaching digging and
amplifying upper level short wave.
Most models keep the majority of the precipitation off to the
east...however some of the rainfall could get into the Long Island
and southern CT region. In addition...showers and possibly some
thunderstorms are possible ahead of the approaching cold front.
For now...will keep slight chance or chance probability of precipitation in for much of the
day...however there is a possibility that sun could come out for a
period Sunday afternoon especially across Long Island if the low
remains further east.
The cold front moves across the region Sunday night with winds
becoming westerly. Little to no precipitation is possible with the
actual passage of the cold front. So expect probability of precipitation to gradually
decrease late Sunday night.
Long term /Monday through Friday/...
cool Canadian high pressure builds into the region Monday and
Tuesday and remain in place through Friday with temperatures
averaging at least 5 degrees below normal. No rain is forecast
during this time as drying continues.
Aviation /08z Saturday through Wednesday/...
high pressure continues to drift eastward into the Atlantic
today...while a weak coastal wave and cold front approach late
tonight into Sunday.
5 to 10 knots southeast winds this morning...increasing and becoming gusty
S/southeast this afternoon. Winds should gradually weaken and back east/NE
MVFR stratus development likely this morning. There is uncertainty
with this and start/end times will vary for individual sites with
occasional fluctuation between MVFR and VFR quite possible as
well. Ceilings expected to gradually rise to VFR this afternoon and
scatter...but occasional broken ceilings possible across NYC metropolitan and
MVFR conds likely to re-develop late this evening into
tonight...with potential for patchy drizzle or light rain.
Outlook for 06z Sunday through Wednesday...
late Saturday night-Sunday...MVFR...locally IFR conds after 04z
with patchy drizzle or light rain shower. Conditions improve to
VFR in the morning. Isolated showers or thunderstorm in the
Sunday night...showers ending with conditions improving to VFR.
sub-Small Craft Advisory conditions on the waters today as seas continue to gradually
subside. Winds will be from the southeast and increase late in the
day with some gusts to near 20 knots.
Winds increase further later Sunday into Sunday night through Monday
night. The increasing winds will result in seas to build. Seas will
approaching Small Craft Advisory levels on Sunday...and reach Small Craft Advisory
levels Sunday night. Seas will remain above Small Craft Advisory through Monday.
Winds and seas fall below Small Craft Advisory levels on Tuesday.
Increasing east winds will develop by Wednesday as seas gradually build as
strong high pressure moves across northern New England.
less than 1/4 inch of rain is forecast Sunday through Sunday night
as a low moves offshore followed by a cold front Sunday night.
Otherwise...dry weather is forecast.
near term...British Columbia
short term...British Columbia