Marine Weather and Tide Forecast for Balmville, NY

KEY MESSAGES
1) Isolated strong to severe thunderstorm and flash flood threat on Thursday and Friday afternoon and evening. Increasingly warm and muggy on Thu and Fri, with heat indices peaking in the lower to mid 90s for one day on Friday.

3) Mainly dry conditions for the upcoming weekend with seasonably warm temperatures.

DISCUSSION

KEY MESSAGE 1

Good agreement on Mid-Mississippi River valley closed upper low shearing towards the region Thu aft/eve, with a resultant weak surface low pressure wave tracking across the northern Mid- Atlantic, and lee/pre-frontal surface trough developing and approaching from the west.

These features should be able to provide a trigger/focus for scattered showers and thunderstorms across NYC/NJ metro and N&W in a marginally (locally moderate) unstable and weak shear environment.
Severe threat should be limited in this environment, but can't rule out an isolated damaging pulse wet microburst threat, particularly if there is more in the way of sun allowing for moderate instability development. Environment is more conducive to an isolated flash flood threat with high PWATs (2-2.25"), a deep warm cloud layer, and mbE vectors less than 5kt. Higher flash flood threat appears to be across SE PA/S NJ with higher instability and enhanced moisture transport/convergence with the weak surface wave. Still an isolated flash flood risk is signaled for the NYC/NE NJ metro region in the high res- guidance, depicted thru being on the edge of HRRR 10% ensemble prob for 3"/3hr, and HRSW ARW and NSSL WRF indicating max NY/NJ metro neighborhood value of 2 1/2 to 3" in 3/hr in WPC URRD.
Will address in HWO, and let midnight shift evaluate any northward trends. Diminishing severe/flash flood threat in the late evening in wake of trough.

On Friday, northern stream shortwave digs into northern New England, with a bit more in the way of mean troughing across the region, while a convectively enhanced shortwave approaches the region Friday aft/eve. At the surface, this will have a stronger cold front approaching the region in the afternoon/evening. Trigger and focus is once again there for another round of scattered showers and thunderstorms Fri aft/eve, with an isolated severe/flash flood threat. A slightly better severe threat on Friday aft/eve with 30-35kt deep layer shear profile to complement marginal to locally moderate instability environment. Damaging wind gusts would be the main threat. Flash flood threat looks a bit lower than Thursday with slightly lower PWATS (mid- level drying in wake of Thursday pre- frontal trough) and quicker anticipated storm movement.
Flash flood threat will ultimately be contingent on moisture pooling ahead of cold front, storm coverage, and potential SW to NE training along frontal boundary based on mbE vectors.

Temperatures will continue to moderate to near seasonable levels on Thursday with highs in the lower to middle 80s. Highs could come close to 90 degrees in the NYC metro and NE NJ with most other spots reaching the upper 80s On Friday, with max heat indices should reach the low to mid 90s.


KEY MESSAGE 2

General model agreement in mean upper troughing sliding across the NE US this weekend and offshore on Monday, while at the surface Canadian high pressure builds down from southern Canada thru the weekend and overhead by Monday.

This pattern should keep conditions mainly dry through the weekend with temperatures near seasonably warm levels. The general synoptic pattern could persist into early next week with only a slight uptick in temperatures.

AVIATION /20Z WEDNESDAY THROUGH MONDAY/
Mainly VFR conditions are expected through Thursday afternoon.
Scattered showers and thunderstorms will be possible Thursday afternoon at the NYC area terminals, as well as at KSWF. PROB30 groups were maintained during the timeframe where TSRA is most likely, which is generally between 18Z and 22Z Thursday, depending on location (on the earlier side for the terminals farther to the west; on the later side to the east).

Winds have shifted to S/SW at less than 10kts and will remain that way through Thursday afternoon. Winds pick up slightly at 10-15kts Thursday afternoon, with locally higher gusts in any thunderstorms.

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

No unscheduled amendments expected.

OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY

Thursday afternoon through Friday: Mainly VFR. Chance of afternoon and evening showers and thunderstorms each day with brief MVFR to IFR conditions possible.

Saturday through Monday: VFR.

MARINE
Sub-SCA conditions expected Thu and Fri with modest S/SW flow of 15g20kt. Occasional gusts to 25 kt possible fro ocean waters west of Fire Inlet, entrance to NY Harbor, and adjacent southern bays each day with coastal jet development. Seas generally 3 to 4 ft.

Sub-SCA conditions likely continue for the weekend into MOnday with high pressure building towards and then over the waters.

Rip Currents: A moderate risk of rip currents persists through Friday, due to a mixture of 1-3 ft S wind wave and lingering 1-3 ft SE/E swells.

OKX WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...None.
NJ...None.
MARINE...None.