New York (OKX) — the National Weather Service forecast in plain English · Plaincast

What has changed

Update to Aviation section for 12z airport forecasts.

There is a threat for localized flash flooding Saturday Night into Sunday Morning, conditional on track of low pressure.

Messages

Dry and seasonably warm today and Saturday.

Showers expected Saturday Night into Sunday Morning. A period of heavy downpours and isolated thunderstorms are possible, with a a threat for localized flash flooding.

Dry and seasonable conditions early to mid next week.

Discussion

A few degrees above normal and noticeable lower humidity today with weak CAA and offshore flow in wake of early morning cold frontal passage. Cloudy with a few sprinkles this morning, becoming mostly sunny this afternoon. Generally light northerly flow giving way to late day sea breeze along the south coasts.

Good radiational cooling conditions tonight under moderated Canadian high, with lows in the 40s across outlying areas. Potential for some patchy fog radiational fog across outlying coastal areas and river valleys.

Seasonably warm and dry on Saturday with increasing clouds and gradually increasing humidity in strengthening onshore flow regime as high pressure moves offshore and warm front approaches from the SW.

.KEY MESSAGE 2. Models in good general agreement with a weak southern shortwave along the Gulf coast today, shearing northeast towards the region Sat Night in response to a broad northern stream trough sinking into the Great Lakes and NE US this weekend. At the surface, high pressure slides offshore Sat, with a weak southern frontal system lifting into the Ohio Valley/Mid Atlantic on Saturday and then through the region Sat Night into Sun Am.

Forcing is not overly strong, but deep southwest flow aloft and increasing lift ahead of approaching southern shortwave, aided by RRQ of 60 knot ULJ along with developing 30 knot LLJ, advecting in and lifting an increasingly tropical airmass (Gulf moisture raising precipitable water to 2 1/4", weakly unstable (tall skinny storm energy) and deeply saturated environmental profile with 12-14k ft warm layer) will be sufficient to develop widespread showers (perhaps isolated thunderstorm) over the region Saturday Night into Sunday morning ahead of an approaching warm front/trough and frontal wave.

Primary forecast challenge is the location of the warm front and associated frontal wave with respect to the local area Saturday Night/Sunday AM. Fairly consistent signal in medium range operational models for an axis of heavy rainfall amounts along the track of the frontal wave/warm front in response to the enhanced moisture convergence/lift of the tropical airmass. Along with some brief training potential of heavy downpours/embedded convection (MBE vectors less than 10kt aligned with W-E aligned warm front ahead of surface wave).