Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
413 am EST Friday Nov 27 2015
a sprawling high pressure ridge extending from south of Nova
Scotia to the southeast states will weaken today...allowing a
cold front to approach from the northwest tonight. The front will
pass through early Saturday...then stall across the middle Atlantic
region through the weekend. High pressure will build in from the
north from Sunday night into early next week. A low pressure
system will impact the region during the middle of next week.
Near term /through tonight/...
dense fog advisory was expanded into the rest of southeast CT and eastern Long
Island per ASOS observation showing visibilities 1/4 to 1/2 mile...and likelihood
of areas with visibilities lower than that. ASOS 5-min observation at kewr/kjfk
with rwr 1/8 and 1/2 mile respectively also indicate that it is
just a matter of time before NYC and surrounding burbs fog in
as well. Think fog should burn off by about 14z...but GFS lamp
suggests interior southern CT and the lower Hudson Valley could
hold on to dense fog until 15z-16z.
After fog Burns off...a mostly sunny mild day expected...with
unseasonably high temperatures in the Lower/Middle 60s not too far off
record highs for the date.
Cold front will slowly approach tonight...with slight chance of
showers late except for NYC metropolitan and Long Island. With winds
veering more SW do not think fog will be an issue.
Short term /Saturday through Sunday night/...
cold frontal passage takes place Sat morning. Most of the associated precipitation
will be Post-frontal...with likely pop but low quantitative precipitation forecast for most areas
during the day on Sat.
Think GFS is too quick to build high pressure down from the north
Sat night into Sunday...and have sided with NAM/European model (ecmwf) idea of a
weak impulse riding the front and bringing a second round of
showers Sat night into Sunday...with continued likely pop for
most areas Sat evening...then still chance pop for metropolitan and
coastal sections late Sat night into Sunday morning. Temperatures this
weekend should be closer to average.
Long term /Monday through Thursday/...
weak ridging temporarily builds into the region Monday.
Expect mostly sunny skies and dry conditions. Then another area of
low pressure approaches for Tuesday into Wednesday...with pop ramping
up to chance on Tuesday and likely Tuesday night. High pressure then
returns later in the week.
Temperatures will remain at or slightly below average.
Aviation /09z Friday through Tuesday/...
fog is developing and becoming dense but still yet to fully spread
into the city terminals. Still expecting any remaining VFR to
eventually drop to MVFR/IFR and potentially lower going into
daybreak. Any existing vlifr/LIFR is expected to stay nearly constant
Conditions lift to VFR by around 15z Friday.
Nearly calm winds will become S-SW 5-10 knots...and may be a few knots higher
near the coasts during the day. These diminish again tonight with another
round of fog/stratus possible. However...winds become more west-north overnight
Friday night into daybreak Saturday...so this would allow for lesser
chances of any dense fog.
Confidence is moderate with winds but low on exact timing of
categorical changes. Amendments quite possible to refine the
timing of lowering and improving conditions which could vary 1-2
hours from forecast.
Outlook for 09z Saturday through Tuesday...
Friday night-Saturday night. MVFR or lower possible in fog/stratus
Friday night...and then in possible showers through Saturday night.
North-NE winds with 15-20kt gusts possible Saturday afternoon/evening.
Sunday-Sunday night...VFR likely. Low chance of MVFR.
Tuesday...VFR possibly becoming IFR in rain and fog by afternoon.
Small Craft Advisory for hazardous seas extended through Saturday with
the southeast long period swell being the main contributor to the higher
ocean seas. The seas build today through this evening with prolonged
southerly flow and then winds nearly stay the same speed with the
passage of a weak cold front. The winds will become westerly and then
northerly going into Saturday. Thinking is that the offshore flow
will not be enough to decrease the waves that much with long
period swell from the southeast flow continuing. Therefore Small Craft Advisory
for hazardous seas remains in effect through Saturday. The higher
seas could linger into Saturday evening as well.
With the northerly flow continuing behind the cold front as another
high builds northwest of the waters...eventually ocean seas should
lower by later on Saturday night. The sub Small Craft Advisory conditions will
then continue through the remainder of the weekend as the pressure
gradient weakens further with the approach of the center of the
The sub-Small Craft Advisory conditions are then expected through Tuesday morning.
Winds and seas will increase Tuesday afternoon through Wednesday
as a low pressure system passes near the area waters.
quantitative precipitation forecast Sat into Sunday should range from about 1/10 to 1/4 inch.
Low pressure could bring about 1/2 inch of rain Tuesday into Wednesday.
CT...dense fog advisory until 9 am EST this morning for ctz005>012.
New York...dense fog advisory until 9 am EST this morning for nyz068>075-
New Jersey...dense fog advisory until 9 am EST this morning for njz004-006-
Marine...Small Craft Advisory for hazardous seas from 11 am this
morning to 6 PM EST Saturday for anz350-353-355.
long term...British Columbia