000
FXUS61 KOKX 061140
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
740 AM EDT Thu Apr 6 2023
.SYNOPSIS...
A warm front will lift slowly northward through the area this
morning. A cold front will approach from the west this
afternoon and move through this evening. High pressure will then
build from the west through Friday night and settle over the
area for the weekend. High pressure dominates the area for much
of next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Fog will quickly erode from W to E after daybreak thru mid
morning away from south and east coasts in wake of warm frontal
passage, perhaps taking until this afternoon for immediate
southeast coastal areas under more maritime influence.
Thereafter, developing SW flow and partial clearing to mainly sct
high and mid deck this morning into afternoon. NAM/GFS/ECMWF
and several high res variants have trended towards distinct pre-
frontal/lee trough development this afternoon W of the Hudson
R. This will lend to veering of winds to a WSW/W direction this
afternoon with deep mixing and drying low-levels. This points
towards high end of forecast guidance for temps downwind of
higher elevation and W of Hudson (metro NE NJ into Lower Hudson
River Valley corridor), but also less instability to support
tsra development along/ahead of pre-frontal trough/cold front in
late aft/eve. These models are actually more aggressive with
weak wave development and post frontal rain skirting the coast
after 00z, forced by convectively induced shortwave energy
riding up through the Tennessee River Valley/Mid Atlantic, and
approaching right rear of upper jet.
GEM is less aggressive with lee trough/pre-frontal development
in the afternoon, allowing for more of a backed S/SW flow west
of the Hudson ahead of pre-frontal trough/cold front approach in
the late afternoon. This less mixed and moister environment may
limit max potential for temps, but allows for a bit more
instability ahead of pre-frontal/cold front approach, likely
resulting in more widespread late aft/early eve thunderstorm
activity. This appears to be a lower probability scenario at
this time.
Farther to the east, across LI and much of CT, marine influence
due to S/SW flow will limit mixing and therefore temps as well
as keep any weak instability elevated in the aft/eve.
An isolated strong to severe storm wind threat would be
conditional on the latter scenario described above, mainly west
of the Hudson River, with marginal instability, strong deep
layer shear, and inverted V soundings in late aft/early eve.
Mitigating factors are weak mid-level lapse rates, weak and non-
distinct shortwave forcing, and especially the low-level drying
scenario as depicted in majority of model guidance. Consistent
with this thinking, SPC has also removed the marginal severe
threat for the local area. For coastal areas, best chance of
rain and perhaps a rumble of thunder is actually looking to be
post frontal in the evening with possible wave development
skirting the region.
In terms of temps, good confidence in warmest temps so far this
year west of the Hudson River with record high temps likely for
EWR, and possible for NYC/LGA depending on pre-frontal trough
location/timing of passage. This airmass produced mid 80s temps
in the nation capital and southern Delaware (away from coast)
yesterday. As with previous forecast, will continue to lean to
90th percentile of NBM for downslope areas of NE NJ and Lower
Hud in WSW flow with mixing to 13-15C 850 temp and in a pre-
green- up environment. These setups are notorious for temps to
exceed MOS and deterministic forecast guidances. Elsewhere,
temps should be able to rise into the 70s away from southern and
east coasts. Temps likely hold in the lower to mid 60s with
greater marine influence and slow to scour stratus. A typical
early Spring 20+ degree variation in temp from immediate coast
to interior is likely today.
Shortwave approaches northern New England tonight, with right
rear of upper level jet approaching the area. This setup will
increase the chance for wave development along the cold front,
and post-frontal rain to overspread portions of the coast this
evening. Cold front shifts far enough offshore late tonight to
dry the area out. Otherwise, steady cold advection on a gusty
NW flow tonight, with lows falling into the 40s.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
Gradual deepening of longwave northern stream troughing through
the period as a series of weak shortwaves moves through
northern New England.
First in series of shortwaves slowly crosses northern New
England on Friday. Gusty CAA NW flow on Friday in wake of cold
frontal passage, with considerable jet mid- high deck streaming
thru the area. A return towards more seasonable temps likely on
Fri.
A couple more weak shortwaves/weak cold fronts cross the region
this weekend, with Canadian high pressure progressively
building into the region. These passages will be dry, resulting
in seasonable temps Sat and Sun, with good radiational cooling
conditions for outlying areas at night.
Models in fairly good agreement with the last of the series
digging shortwave on Sunday, phasing with southern stream
shortwave energy, but well south and east of the region. This
will keep resultant coastal low pressure development across the
SE/Southern Mid Atlantic and heading offshore.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
The extended forecast will be dominated by a strong surface high
pressure system under an associated upper level ridge. This will
result in dry and clear conditions from Monday through Friday of
next week. Winds will generally be from the South/Southwest/West
through this timeframe at 10 to 15 mph everyday. This will allow for
a favorable flow for much of the area to see above normal
temperatures through much of the timeframe.
Temperatures as a whole will be above average with the exception of
eastern Long Island and the immediate southern coastal areas as the
ocean remains cold. Highs on Monday will be close to average with
temperatures in the upper 50s to lower 60s for much of the area.
Persistent sunshine and SW flow will bring a warming trend through
late week. Highs on Tuesday increase to the low 60s for Long Island
and coastal areas to the low 70s for inland areas to the west. By
Wednesday and Thursday, inland area will be rising into the upper
70s and possibly low 80s. Eastern areas during this time will be
cooler but still above average, generally seeing temperatures in the
middle 60s to lower 70s.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
A warm front slowly moves northward across the area this morning. A
cold front will then work across the area this afternoon into early
evening.
Widespread IFR/LIFR will begin to improve over the next few
hours. VFR develops by mid to late morning for the NYC and
Lower Hudson Valley terminals, but likely not until afternoon
for the eastern terminals. Chance of MVFR or lower in any
showers along and ahead of the cold front this afternoon into
the early evening. Removed TSRA from TAFs because confidence in
occurrence decreased, but TSRA is still possible from 20-00Z.
Showers may persist behind the frontal passage before coming to
an end from 04-06Z Friday. Fair amount of uncertainty in the
coverage of post-frontal showers after 00Z.
Winds light and variable as a warm front slowly lifts through the
area. Eastern terminals will see S-SW winds develop first
generally at or less than 10 kt with western terminals not
shifting south until around 14Z with the onset of daytime
heating. A few gusts to 20 kt are possible this afternoon for
the NYC metro terminals. NW winds 10-12kt G20kt develop behind
the cold front into early evening.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of improvement this morning may vary by as much as 1-2 hours.
SW G20 kt are possible in the afternoon, especially at KEWR and
KTEB. Low chance but TSRA possible from 20-00Z.
The afternoon KJFK haze potential forecast is YELLOW...which implies
slant range visibility 4-6SM outside of cloud.
...OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: VFR. NW G20kt.
Saturday through Monday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90.-- End Changed Discussion --
&&
.MARINE...
Marine dense fog advy remains for all waters thru this morning
ahead of a warm front, with widespread vsby less than 1 nm.
Gradual improvement in vsby likely from w to e late this
morning through afternoon with daytime heating and flow aloft
veering to the west. Stratus/fog may not totally push east of
eastern waters until cold frontal passage this evening.
Otherwise, Sub-SCA S winds of 10 to 15 kt with gusts to 20 kt
expected today, with marginal 4 to 5 ft ocean seas east of Fire
Island Inlet. WNA/NWPS guidance is initializing a bit high, and
with a strong inversion over the waters, this may keep seas
below 5 ft today across this area. Will need to re-eval later
this morning.
A brief period of marginal SCA gusts possible this evening in
wake of cold frontal passage, and Fri eve in wake of secondary
cold front. Otherwise, sub-SCA conds expected tonight through
this weekend as high pressure begins to exert control. In fact,
a weak pressure gradient over the area thru next week will
likely result in conditions being below SCA criteria for all
waters.
&&
.FIRE WEATHER...
Potential for enhanced brush fire spread Friday with NW gusts of
20 to 25 mph and min rh values in the 20s. An extended period of
dry conditions will continue into this weekend with min rh
values in the 20s, although frequent wind gusts should remain
below 20 mph.
&&
.HYDROLOGY...
No hydrologic concerns expected through early next week.
&&
.CLIMATE...
Record high temperatures for Today April 6:
EWR 80 1947
BDR 70 1991
NYC *79 1947
LGA 80 1947
JFK 73 2010
ISP *71 2010
* Also in previous years
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 2 PM EDT this afternoon for ANZ331-
332-340-345-350-353.
Dense Fog Advisory until noon EDT today for ANZ335-355.
Dense Fog Advisory until 10 AM EDT this morning for ANZ338.
Small Craft Advisory until 6 PM EDT this evening for ANZ350-
353.
&&
$$
SYNOPSIS...NV/MW
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...MW
AVIATION...MW
MARINE...NV/MW
FIRE WEATHER...
HYDROLOGY...NV/MW
CLIMATE...