textproduct: Binghamton

WHAT HAS CHANGED

Adjustments were made to PoPs today and tomorrow. Coverage was increased for late today and tonight while PoPs were lowered for some areas on Monday.

KEY MESSAGES

1) Beginning today, the pattern becomes more active with several rounds of rain showers and occasional thunderstorms through mid-week.

2) There is uncertainty when a low pressure system departs the region later this week and rain showers may linger beyond mid- week.

DISCUSSION

KEY MESSAGE 1...

Weak waves will move through along an upper level trough today and Monday. These waves will be accompanied by enough moisture to support isolated to scattered showers. Some breaks in cloud cover and shower activity will allow for instability to increase and isolated thunderstorms to develop each afternoon. With weak flow above, 0-6 km shear will be 20 kts or less, storms are expected to be non-severe and short-lived. For those spending time outdoors, any storms that develop may contain gusty winds and even small hail as instability extends into the hail growth zone. For late today, PoPs were added over the Catskills for late today as most guidance show the potential for some diurnally driven showers to develop over that region. Then on Monday, NBM had high PoPs for the Catskills and Poconos in an environment that will favor pulse showers and storms. Adjustments were made to lower PoPs over these regions. Clear skies, light winds, and some moisture from showers will favor fog development late tonight into early Monday morning. The current pattern over the country will allow for vertically integrated wildfire smoke to move over the region today and especially Monday. With this smoke expected to be so high up, there should be little to no impact to air quality.

The upper level trough will dig over the region Tuesday. As it does, a low pressure system will develop, though there remains some uncertainty on where it develops and tracks. The ECMWF develops the surface low over the Great Lakes early Tuesday and pushes it eastward. The GFS is slower to develop the low and has it along the coast south of the region. Either way, this system will bring the next chance for more widespread rain showers Tuesday through at least Wednesday. If this system were to stay more north, strong southerly flow will advect in warmer air and lead to a more unstable environment Tuesday afternoon, especially in areas where rain is slower to develop. However, shear will still be weak so chances for stronger thunderstorms is low.

Within any thunderstorms, there will be potential for heavier rainfall rates. Otherwise, showers may become more stratiform depending on the low's track. Models vary on rainfall amounts during this timeframe though localized amounts of 1.5 to 2 inches are possible. Several dry days has resulted in soil moistures drier than normal, so the region should be able to handle this system. WPC maintains a Marginal Risk for excessive rainfall over the region as this system passes through.

KEY MESSAGE 2...

The second half of the week remains more uncertain. The GFS has this system quickly exiting the region and replaced with high pressure and drier air. Meanwhile, the ECMWF has been consistent with having this system linger over the Northeast with spotty showers Thursday through at least Saturday. Given this, this forecast update will maintain low chances for showers each day. Instability would be more limited, though isolated, afternoon thunderstorms cannot be ruled out. If this system lingers, then total rainfall amounts will increase, potentially adding on another inch onto what will have already fallen early in the week.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Mainly VFR throughout the TAF period. Scattered showers and isolated thunderstorms in the area from roughly 20Z today-00Z Monday. For now, only mention is a VFR shower potential given high uncertainity on timing and coverage. Fog potential overnight 08-12Z Monday at most TAF sites as well with MVFR/IFR visibilities, perhaps lower at KELM.

Outlook:

Monday through Wednesday...Showers and/or thunderstorms may result in occasional restrictions, especially in afternoons. Valley fog possible at KELM late each night/hours up to dawn each morning.

Thursday...Additional isolated to scattered showers and/or thunderstorms and associated restrictions possible.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...None.