Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS61 KOKX 191753
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1253 PM EST Tue Nov 19 2019

.SYNOPSIS...
Several upper level disturbances move across the region 
through tonight. Low pressure develops well offshore tonight 
and moves away on Wednesday. High pressure builds into the area 
Wednesday night through Thursday. A cold front will then cross 
the area on Friday afternoon, followed briefly by high pressure 
Friday night into Saturday morning. An area of low pressure may 
impact the region late Saturday into Sunday, before high 
pressure returns for early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Any breaks of sun are filling in again as we head into the
afternoon courtesy of shortwave energy within an upper trough. 
Otherwise, forecast remains on track with dry conditions 
continuing through the afternoon.

Temperatures today will range from the middle and upper 40s 
inland to the lower 50s near the coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
The upper trough continues moving over the region tonight and 
the majority of models show a broad cut-off low developing 
overhead by early Wednesday morning. The main moisture feed will
reside well offshore and associated with the developing low 
pressure. Mostly cloudy to overcast and dry conditions are 
expected tonight with temperatures in the low 30s inland and 
middle and upper 30s elsewhere. 

The low will pass well to the south and east of Cape Cod on 
Wednesday. However, with the trough and upper low moving 
overhead cannot rule out some light precipitation Wednesday 
morning or early Wednesday afternoon. Some of the high 
resolution models such as the 3-km NAM indicate some light 
reflectivity across Long Island and southeast Connecticut in 
simulated radar fields. Think there is enough evidence in the 
models and support aloft to include a slight chance PoP across 
southeast Connecticut and eastern Long Island on Wednesday. The 
PTYPE should be sprinkles or light rain showers, but it is not 
out of the question for some flurries away from the coast in 
southeast Connecticut. Otherwise, the close proximity of the 
upper trough and upper low should keep skies mostly cloudy 
through the day with some potential for clearing late west of 
the city. Highs on Wednesday will be in the 40s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Global models have come into very good agreement through most of the 
period in comparison to about 24 hours ago, when there were large 
discrepancies with the timing of a cold frontal passage on Friday 
and impacts from a potential coastal low late Saturday into Sunday.

A fairly progressive upper flow during the period will feature 
ridging aloft and surface high pressure on Thursday. This will be 
followed by a fast moving shortwave trough across the Great Lakes 
Thursday night and into the northeast on Friday. The latter of which 
will send a cold front through the region Friday afternoon along 
with a chance of showers. Warm advection clouds ahead of the system 
will move in as early as Thursday night with clearing following the 
cold frontal passage on Friday.

There now appears to be enough separation between the former system 
and an opening up southern branch closed low over the Mid 
Mississippi Valley, that a frontal wave develops along the front and 
tracks near or just south of the area Saturday night into Sunday 
morning. There will likely be several iterations of this as we go 
forward in time due to possible interaction with northern branch 
shortwave energy. Some phasing and a more north and west track would 
seem likely. Based on the current forecast, the area would be on the 
cold side of the track, but airmass is marginally cold with perhaps 
a chance of rain or wet snow mixed in across the interior and rain 
at the coast. This system looks to be progressive enough at this 
time for liquid equivalent amounts to be half inch or less. 

High pressure then builds in behind the low Sunday afternoon into 
Monday.

Temperatures through the period will be near or just shy of normal 
with the exception of the warmest day ahead of the cold front on 
Friday, where highs are forecast to get well into the 50s.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
MVFR conditions will continue for much of the afternoon with
some breaks of VFR expected by early evening. A brief period of
VFR conditions will continue through about midnight, then a
return to high end MVFR/low end VFR is expected for the second
half of tonight and Wednesday. 

Westerly winds 10kt or less will become more northwesterly
tonight. Winds on Wednesday will increase 10-15kt with some
gusts to around 20kt possible. 

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts, 
can be found at: http:/www.weather.gov/zny/n90

KJFK TAF Comments: Changing flight categories may be off by an
hour or two.

KLGA TAF Comments: Changing flight categories may be off by an
hour or two.

KEWR TAF Comments: Changing flight categories may be off by an
hour or two.

KTEB TAF Comments: Changing flight categories may be off by an
hour or two.

KHPN TAF Comments: Changing flight categories may be off by an
hour or two.

KISP TAF Comments: Changing flight categories may be off by an
hour or two.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.Wednesday afternoon-Thursday...VFR/MVFR. Some gusts to near
20 kt possible Wed afternoon.
.Friday...Chance MVFR in rain showers. SW gusts 20-25 kt PM.
.Saturday...Chance MVFR/IFR in rain PM hours.
.Sunday...Chance MVFR/IFR in rain in the morning.

&&

.MARINE...
The Small Craft Advisory for the far western ocean zone has been
cancelled as seas have dropped below 5 feet. The Small Craft 
Advisory will continue on the ocean waters east of Fire Island 
through the day as rough ocean seas in long period easterly 
swells only slowly subside. Ocean seas should continue 
subsiding below SCA levels tonight into Wednesday morning. Ocean
seas may build again close to 5 ft late Wednesday afternoon as 
low pressure passes well offshore. Winds will stay below SCA 
levels through Wednesday morning, but then increase Wednesday 
afternoon close to 25 kt as the pressure gradient steepens 
between offshore low pressure and building high pressure from 
the west. 

Winds and seas subside on Thursday as high pressure builds across 
the waters. An approaching frontal system on Friday will likely be 
preceded and followed by SCA conditions developing Friday morning 
and continuing into Friday night. The best chance will be on the 
ocean waters. Winds and seas will then subside on Saturday as high 
pressure briefly builds across the waters. A coastal low may impact 
the waters Saturday night into Sunday.

&&

.HYDROLOGY...
No hydrologic impacts are anticipated through the forecast 
period.

&&

.TIDES/COASTAL FLOODING...
A Coastal Flood Statement is in effect for the south shore back
bays of Nassau and Queens for the high tide cycle early this
afternoon. Water levels in these locations will approach/touch 
minor flood thresholds, otherwise water levels are expected to 
stay below minor flood thresholds for the remainder of the week.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is operating 
at reduced power until further notice.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ350-
     353.

&&

$$
SYNOPSIS...DS/DW
NEAR TERM...CB/DS/DW
SHORT TERM...DS
LONG TERM...DW
AVIATION...BC

National Weather Service Glossary of Abbreviations