Marine Weather and Tide Forecast for Fort Montgomery, NY

NEAR TERM /THROUGH TONIGHT/
Key Points...

* Scattered to numerous instances of flash flooding possible across NE NJ and LoHud. Isolated to scattered instances of flash flooding possible for NYC and SW CT. Flood Watch in Effect from 2pm to midnight.

Shortwave trough axis over eastern Great Lakes/Ohio Valley this morning slides east towards the region late this afternoon/evening and slowly across the area tonight into early Tue Am, with a weak surface trough across central NY/PA sliding east towards the region this afternoon and across this evening into early Tue AM.

Convection across the Poconos/Catskills should continue to wind down early this morning as it traverses east into the Lohud/NE NJ, but with a marginally unstable and moist airmass potential for scattered heavy downpours/isolated convection for the early morning commute well N&W of NYC. Otherwise, morning stratus and fog should give way to breaks of sun in the afternoon, particularly away from the immediate south coasts.

Daytime heating is expected to develop at least marginal surface instability (locally moderate with more extensive breaks of sun N&W of NYC). In a tropical environment with approaching shortwave, this will be supportive of scattered tstm development along outflow from decaying AM convection and sea- breeze boundary to the N&W of NYC this afternoon, and then scattered to numerous tstm development along/ahead of approaching pre-frontal trough late this afternoon/evening.

Primary threat will be for torrential downpours from tstm activity with 2+"/hr rainfall rates likely in a tall and narrow CAPE profile environ, PWATS approaching 2.25" (+2 std), deep warm cloud layer of 12-13kft, and weak SW steering flow (15kt)
aligned with trough/seabreeze/outflow boundary. Highest coverage/confidence in this activity is across NE NJ and LoHud in vicinity of sea-breeze/outflow convergence boundary and then followed by approaching trough, with scattered to numerous instances of flash flooding possible (15-25% prob w/i 25 miles of a point). Farther east across NYC and SW CT, confidence in coverage of convection is slightly lower (5-15% prob w/i 25 miles of a point prob) as sea-breeze/outflow activity likely ends up to the N&W, with more organized trough activity late in the day potentially weakening in intensity with waning instability, although this could be counteracted by potential increase in llj and shear/helicity with hints of weak surface wave development. In any case, a lower confidence on flash flood threat for this area, presenting more of an isolated to scattered flash flood instance threat.

Weak low-level shear/helicity profiles and weak llj appear to be a limitation for sustained updraft and backing-building storms and a moderate flash flood threat for NE NJ/LoHUd, with late trough approach and waning instability in the evening a possible flash flood limitation for NYC and SW CT.

After collab with WPC and surrounding offices will issue Flood Watch from 2pm to Midnight today for NE NJ, LoHud, NYC and interior SW CT for above flash flood threat, with a widespread 1-3" of rainfall likely, and locally as high as 5", for NE NJ and LoHud where most persistent/widespread convection is likely based on predicted synoptic/mesoscale environment and CAM output. HRRR showing a 50% prob of 3"/3 hr across NE NJ, which is a rare signal. Meanwhile, a widespread 1/2 to 1 1/2" of rainfall is likely with localized rainfall totals of up to 3" possible for NYC and SW CT. Most of this could fall in as little as 3 hr period this aft/eve.

In addition, isolated strong to severe wet downburst possible in marginally unstable airmass this afternoon as well, mainly N&W of NYC.

Shortwave trough axis slowly slides east tonight into early Tuesday morning, with weak surface trough axis sliding southeastward through LI/CT. Convective coverage and intensity will wane overnight into early Tue AM with waning instability, but potential for locally heavy downpours and embedded tstm activity to continue in vicinity of the trough and possible weak wave development, particularly across NYC/LI/SE CT.

Seasonably warm and very muggy conditions today into tonight.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
Key Points...

* Moderate potential for heat indices of 95-100F on Wednesday

Shortwave trough axis slowly slides east Tuesday morning, with weak trough axis likely dropping south. Potential for locally heavy downpours and embedded tstm activity in vicinity of the trough across LI/SE CT Tue AM, then gradual mid-level drying conditions expected Tue afternoon in wake. Low chance of afternoon shra/tsra activity for NYC and pts N&W Tue aft during peak heating.

Seasonable temps and very humid conditions continue Tue into Tue Night. Patchy stratus/fog development possible Tue Night/Wed Am in the moist and weak flow environment, particularly along the coast.

Shortwave ridging surface/aloft should allow for more in the way of sunshine on Wednesday, with warm advective SW flow establishing around Bermuda high. Potential for start of a mid to late week heat wave, with widespread daytime temps in the upper 80s to lower 90s, and Tds in the lower to mid 70s.
Widespread heat indices of 95-100F possible. Late day/evening convection possible with approach of southern shortwave/pre- frontal trough.

LONG TERM /THURSDAY THROUGH SUNDAY/
Key Points...

*While still some uncertainty, there is the potential for a heat wave to continue Thursday and Friday for many areas with max heat index values between 95 and 105.

*Relatively active pattern with chances for several days of afternoon showers and thunderstorms.

A frontal boundary will likely stall just offshore and linger, possibly lifting north of the area Thursday. A frontal system may then impact the area later in the week. Aloft, the pattern stays the same through the period. Although we are under some high heights, we are somewhat on the eastern end of a broad upper level trough centered over central Canada and few shortwaves likely pass through.

With strong Bermuda high in place, a S/SW flow will allow plenty of moisture to be sent our way. This combined with above normal high temperatures brings some potential for a heat wave, with heat index of 95-105 Thursday and Friday. However, there still is uncertainty especially given the potential for convection and slight inconsistencies in a late week frontal system among the guidance.

Too early to talk specifics when it comes to severe or flooding concerns with the aforementioned convection. These details will be ironed over the next few days. There is plenty of moisture around with pwats 1.75-2.00+ for Thursday and Friday so any convection that does develop will likely be able to produce heavy downpours. As for severe, while we are pretty unstable, shear looks weak through much of the period.

AVIATION /09Z MONDAY THROUGH FRIDAY/
A weak cold front gradually approaches the area today, crossing tonight.

VFR to MVFR expected through daybreak today with IFR possible towards daybreak, mainly for eastern terminals, but cannot be ruled out even in for the metro terminals. Conditions improve to VFR around midday today or into the afternoon at all the terminals. There continues to be a lot of uncertainty with the timing of flight change categories. Scattered showers will move through, mainly for the metro terminals.

Showers and embedded thunderstorms across the Lower Hudson Valley will move through KSWF between 10Z and 11Z this morning, possibly a bit earlier. By that time, thunder is not expected, but cannot be totally ruled out. Showers and thunderstorms are then possible this afternoon. Higher confidence for the metro terminals, KSWF, and KHPN with less confidence for eastern terminals. Best timing is 22Z today through 02Z Tuesday, though thunder may occur anytime after 18Z today. Thunder become less likely after 02Z Tuesday, but an isolated thunderstorm may still move through the terminals. Showers with heavy rain is more likely, which will continue to reduce flight categories to MVFR or lower through the remainder of the forecast period.

Light SE winds less than 10 kt through daybreak today. A more southerly flow develops this afternoon with speeds to around 10 kt.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Amendments expected due to changes in flight categories changes and timing through the forecast period.

Higher confidence in thunderstorms this afternoon at KEWR and KTEB.


OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY

Monday Night: MVFR or lower in showers or thunderstorms.

Tuesday-Friday: Mainly VFR. MVFR or lower in any showers or thunderstorms in the afternoon and evening.

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

MARINE
With a weak pressure gradient, winds and waves likely remain below Small Craft Advisory criteria through the coming weekend.
However, a relatively active pattern is expected next week with chances of afternoon showers and thunderstorms for several days.
Winds and waves will be higher in any storms.

HYDROLOGY
*Flood Watch issued from 2pm to Midnight today for NE NJ, LoHud, NYC and interior SW CT.

A widespread 1-3" of rainfall is likely, and locally as high as 5", for NE NJ and LoHud where most persistent/widespread convection is likely based on predicted synoptic/mesoscale environment and CAM output. A widespread 1/2 to 1 1/2" of rainfall is likely with localized rainfall totals of up to 3" possible for NYC and SW CT. Most of this could fall in as little as 3 hr period this aft/eve.

Highest coverage/confidence in this activity across NE NJ and LoHud in vicinity of sea-breeze/outflow convergence boundary followed by approaching trough with scattered to numerous instances of flash flooding possible (15-25% prob w/i 25 miles of a point).

Rainfall rates of 2+"/hr possible with stronger and/or repetitive convection, which would cause localized instances of severe flooding.

At this time, there are no significant flood concerns Tuesday through next weekend.

TIDES/COASTAL FLOODING
For Atlantic Ocean beaches, the rip current risk is low on Today and Tuesday with generally a 10kt or less onshore flow and a weakening S/SE swell.

OKX WATCHES/WARNINGS/ADVISORIES
CT...Flood Watch from 2 PM EDT this afternoon through this evening for CTZ005-006-009.
NY...Flood Watch from 2 PM EDT this afternoon through this evening for NYZ067>075-176-178.
NJ...Flood Watch from 2 PM EDT this afternoon through this evening for NJZ002-004-006-103>108.
MARINE...None.