textproduct: Binghamton

WHAT HAS CHANGED

Forecasted rainfall totals were increased. The Flash Flood Watch was expanded to include the Wyoming Valley plus Wayne and Delaware Counties.

KEY MESSAGES

1) A low pressure system will bring multiple rounds of showers and storms today through Wednesday. Locally heavy rain is possible.

2) Scattered showers will be possible Thursday through the end of the week as this system slowly exits the region. The weekend will start out dry though rain may return by Sunday.

DISCUSSION

KEY MESSAGE 1...

An upper level trough will dig over the Northeast this morning. This trough will become cutoff late today with a stacked low developing over the region. A strong LLJ will develop south of the low and swing over to the east side of it. Once on the eastern side, it will enhance moisture advection as moisture gets pulled from the Atlantic. With the LLJ over the Poconos and Catskills for a period of time combined with terrain effects, enhanced rainfall amounts are expected over those regions, but other areas like the Wyoming Valley may see higher rainfall amounts as well with this strong flow over that region early today.

This system will be slow to move eastward while it remains present near the area heading into the overnight hours. A dry slot will likely push in and bring a period of rain-free conditions for many. However, moisture will wrap around the low and additional showers will develop west of the dry slot, leading to showers continuing throughout Wednesday. Model guidance have a secondary low developing closer to the coast. This low will also be slow moving, so scattered showers are expected to linger through Thursday.

Forecasted rainfall totals will range from 1 to 3 inches across the region. As mentioned, the strong LLJ and terrain effect will likely lead to an area of higher rainfall amounts, where locally totals will push into the 3 to 5 inch range in the Catskills and Poconos. Some of the 00z guidance is concerning given that localized amounts of 6+ inches are shown, and not just in the regions highlighted in the previous statement. Guidance have also been fairly consistent with enhanced totals in the Finger Lakes region after the wraparound showers on Wednesday. In addition, some instability within the warm sector will support isolated to scattered thunderstorms. Storms will also have the potential for moderate to heavy rainfall at times. Shear will be slightly more favorable for isolated stronger storms in the Wyoming Valley today. Despite this system being on our doorstep, there is uncertainty on exactly where the heaviest rain will fall as that will depend on where this system sets up.

With all of the uncertainty in mind, one could make the argument to expanded the watch to all counties in the region, though not all would see hydro issues. To stay in collaboration with neighbors and cover most counties covered by the WPC's Slight Risk, the Flood Watch now covers most of Northeast PA and parts of Central NY along and east of I-81. The watch could be expanded more if confidence increases on where heavier rain will fall.

KEY MESSAGE 2...

This system will drift up the coast into New England by Thursday, through wraparound moisture on the back side of the system will continue to support light showers over the region. These showers will continue through Friday, though a ridge will begin to push in from the west with drier air. Shower activity should come to an end Friday night with a dry start to the weekend expected.

Over the weekend, a trough takes shape over the Northeast once again as a low pressure system develops in the Southwest. The flow around this low will tap into the Gulf and Atlantic, potentially advecting moisture northward into the region. There is uncertainty though if surface high pressure keeps conditions dry through Sunday or if showers develop with the trough digging in. Chances for showers may be better early next week as a cold front drops in from the north.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

A cluster of showers and isolated thunderstorms continues to move the region early this morning. Thunder has been most noted near KSYR and KRME but that should move east by 12Z. An additional round of showers and thunderstorms should work into the region from roughly 14-20Z. Confidence in timing has increased enough to where a TEMPO window is now present at all TAF sites. Ceilings may be more up and down by this evening before lowering tonight with the possibility of some fog as well.

Outlook:

Wednesday through Thursday... Showers and isolated thunderstorms with restrictions through Wednesday then scattered showers Thursday with possible restrictions.

Friday and Saturday...Mainly VFR; low chance of a shower or thunderstorm.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Flood Watch from 11 AM EDT this morning through Wednesday evening for PAZ039-040-043-044-047-048-072. NY...Flood Watch from 11 AM EDT this morning through Wednesday evening for NYZ045-046-056-057-062.