Montclair, New Jersey Weather Forecast Discussion

803
FXUS61 KOKX 250312
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1112 PM EDT Wed Sep 24 2025
.SYNOPSIS...
A frontal boundary will remain nearly stationary across the area
overnight before lifting northward Thursday morning as low
pressure tracks up into the eastern Great Lakes. A pre-frontal
trough will follow Thursday evening and then a cold frontal
passage Friday morning. Weak high pressure briefly builds into
the area Friday night into Saturday. There will be chances for
showers through early next week until stronger high pressure
builds into the area from Canada.
&&
.NEAR TERM /THROUGH THURSDAY/...
A closed upper low over the Great Lakes gets dislodged as
northern branch energy kicks the system eastward overnight into
Thursday. A stationary front will remain across the area for
much of the overnight, but then lifts northward Thursday
morning as surface low pressure lifts up into the eastern Great
Lakes. The latter of which will also send a pre-frontal trough
and cold front toward the area.
Anomalously high PWAT values (+2-3SD) increasing to around 2
inches combined with deep-layered lift will produce rounds of
showers and embedded thunderstorm for the overnight into
Thursday. Anything before then should be relatively isolated.
Instability during this time is modest around 500 J/kg,
possibly a bit higher Thursday afternoon/early evening north and
west of the NYC metro. SPC has the area under a marginal risk
for severe, which means there is the potential for isolated
severe. However, the main issue will be brief heavy downpours.
SPC HREF showing low probabilities for an inch/hour and 3"/3hr.
The storms look progressive enough to limit the flood threat.
However, event totals will likely average 1 to 2 inches with
localized higher amounts. NBM probs for 1 to 2 inches are pretty
high, with the latter 50 to 70 percent from NYC north into the
Lower Hudson Valley. SPC HREF PMM 24-hr QPF has amounts of 2 to
3 inches in narrow bands. This may represent a good upper end.
The good news is the FFG remains high do to the prolonged
stretch of dry weather coming out of summer. Thus, expect most
flooding issues to be of the minor nuisance variety.
The area will get into the warm sector Thursday afternoon and
activity likely becomes more scattered or isolated in nature
ahead of the pre-frontal trough. CAMs all show a line of
convection with the pre-frontal trough from late afternoon into
early evening for locations north and west of NYC. This would be
the time for the best chance of isolated severe weather.
It will remain warm and humid with lows about 10 degrees above
normal tonight. Highs on Thursday will be tempered by the cloud
cover and rain, but still a few degrees above normal.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
A line of convection associated with the pre-frontal trough will
work across the remainder of the forecast area Thursday night with
pockets of heavy rain, especially across LI and coastal CT.
Rain chances will diminish from west to east through Friday
morning with mainly showers by daybreak. The cold front will
pass through mainly dry in the morning. However, with the upper
trough axis pivoting through the area Friday, an isolated shower
cannot be ruled out.
Above normal temperatures will continue during this time with
Friday highs even warmer behind the front due to much drier
air. Many locations will top out around 80 in a westerly flow.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A stalled upr trof over the Appalachians will produce chances for
shwrs Sun into Tue in a mild, humid environment. Although it is not
expected to rain the entire period, pieces of energy embedded in the
flow should act on the available moisture to produce shwrs at times.
Do to the amount of moisture expected attm, added in some fog for
Sat ngt and Sun ngt.
A strong Canadian high in the 1030s is modeled to begin building into
the area by late Tue. This would result in an increasing nely llvl
flow and a general drying of the airmass, reducing pcpn chances and
cloud cover.
Stuck with the NBM for the fcst outside of the addition of fog.
Temps abv normal thru at least Mon, then falling blw normal by
Wed.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
A stationary front remains nearby overnight. The front will lift
north as a warm front into Thursday.
Mainly IFR and LIFR overnight. Ceilings will likely vary between
LIFR and IFR in relation to shower activity. Showers become more
widespread later in the overnight into Thursday morning.
Winds will be light out of the E and SE throughout overnight, then S
closer to 8-13 kt by Thu afternoon, especially at the NYC metros and
closer to the coast as the warm front starts to lift north. Some
spots could see corresponding flight cat improvement to MVFR after
16Z, and as late as 20-21Z Thu further east. Any improvement may be
less and of shorter duration for eastern most terminals.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments expected overnight with ceilings varying at times.
Uncertainty exists around any improvement Thursday afternoon with
amendments possible during the afternoon.
.OUTLOOK FOR 00Z FRIDAY THROUGH SUNDAY...
Thursday night: Periods of MVFR or lower cond with showers and
isolated tstms possible, mostly before midnight. Slow and gradual
improvement to MVFR and VFR later at night. Winds becoming SW.
Friday and Saturday: VFR.
Sunday: Chance of showers with MVFR cond, mainly at the NYC metro
and Long Island terminals.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
A strengthening southerly flow ahead of an approaching cold
front on Thursday could produce a period of 5 ft seas on the
ocean late in the day and into the night. Confidence was low and
used a blend of the NWPS and Wavewatch to account for a recent
high bias in the NWPS. Wind and seas will subside heading into
Friday morning.
Winds and seas are modeled to remain blw sca lvls Sun into Mon.
Winds and seas could build to sca lvls Mon ngt, especially on
the ocean.
&&
.HYDROLOGY...
Showers and a few thunderstorms are capable of producing
widespread rainfall of 1-2 inches, with locally higher amounts
possible, overnight into Thursday. With the potential of brief
moderate to heavy rainfall, expect brief nuisance flooding in
urban and poor drainage areas. Antecedent conditions have been
notably dry though, so the risk for flash flooding is low.
&&
.TIDES/COASTAL FLOODING...
There is a high rip current risk Thu due to swell and sly
winds. There is a moderate to high risk for Fri, depending on
how quickly swell subsides.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Thursday evening for NYZ075-080-
     081-178-179.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JMC/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...JMC
AVIATION...JE
MARINE...JMC/DW
HYDROLOGY...JMC/DW
TIDES/COASTAL FLOODING...

NWS OKX Office Area Forecast Discussion