textproduct: Binghamton

WHAT HAS CHANGED

No significant changes from the previous forecast. A colder pattern is possible late this weekend.

KEY MESSAGES

1) Threat for strong to severe thunderstorms Tuesday and Wednesday, with isolated hail and strong wind gusts possible along with heavy rain.

2) The warm pattern through the week will break down this weekend and be replaced by much colder air late in the weekend.

DISCUSSION

KEY MESSAGE 1...

Main area of concern is centered around the threat for strong to possibly severe thunderstorms Tuesday and Wednesday.

A large scale synoptic pattern is setting up today and will persist into at least the middle of the week. This pattern is largely defined by a building ridge over the southeast US. The air mass within this dome of high pressure will be increasingly warm and humid, and set the stage for a couple days (at least) of thunderstorms. A large plume of deep moisture from the southern MS Valley will advect northward through the Great Lakes and into the Northeast beginning tonight. A series of weak upper level short waves and co-located surface lows will ride east across the region. The first weak one today has produced only light rain across the region, but the second one on Tuesday will be slightly more potent and combine with warmer temperatures and higher humidity.

There will likely be a number of conditional elements needed to generate severe storms on Tuesday. There is still quite a bit of uncertainty with respect to the timing of the convection with a number of members indicating a late morning/early afternoon round followed by a later afternoon round of storms. If this solution does develop, the threat of severe storms will highly depend on how quickly the morning convection can exit and allow the boundary layer to destabilize again. There are also some solutions that bring the bulk of the convection well to our north and leave central NY and ne PA with minimal storms. The third solution, holds all of the convection off until later in the day and produces the most intense storms between 5-9 PM.

The environment and amount of instability will clearly depend on how much clearing we can realize through the afternoon. There is a consensus among the guidance of anywhere from 500-1500 J/kg of ML CAPE and around 30-40 kt of 0-6km shear. Mid level lapse rates appear favorable, around 6.5 to 7 degC/km...and supportive of deep convection and the threat of some hail. The presence of deep moisture may also preclude the threat of microbursts and localized damaging winds.

The one limiting factor with these storms will be the lack of strong dynamical forcing. The upper short wave is very weak and the lack of amplification could limit the amount of forcing for ascent. Some of the convection could be leftover from western Great Lakes convection, and we will need to monitor the threat for any leftover MCS or MCV formation.

Storms should diminish in intensity and coverage after sunset and leave just lingering clouds or light rain around into the overnight. The next wave begins to move in earlier on Wednesday with the primary sfc front/trough laying east-west across the region through the day. This will allow for showers and storms to develop along this boundary most of the day on and off. The presence of this nearly stationary boundary combined with an axis of deep moisture (PWs around 1 to 1.5") could lead to a threat of heavy rain and training convection which may lead to some localized flooding issue. The threat for severe storms on Wed looks on the low side given the lower amount of instability, but with the presence of the boundary, the low level shear could be heightened, so this will need to be watched.

KEY MESSAGE 2...

The large scale pattern is the main concern later in the week, similar to the message above. An upper trough will dig into the central US by Thursday, which will cause the ridge to the east to amplify and push warmer, more humid air into central NY and ne PA Thursday. High temperatures on Wed and Thu will top out in the 70s and 80s...with dew points in the 60s.

More scattered showers and storms are expected Thursday ahead of the approaching upper trough that will usher in slightly cooler and drier air by Friday as temperatures drop into the 60s and 70s before climbing back into the mid to upper 70s on Saturday.

The pattern will really shift to a colder one starting late in the weekend. An anomalously cold trough is expected to dig into the northern Plains late Sat and rotate to the east across the Northeast US late Sunday into early next week. This system will usher in very colder temperatures, with highs in the 40s and lows in the 30s.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

VFR conditions and isolated rain showers will persist for a few more hours across the area. Restrictions are not expected but a brief, heavy shower hitting a terminal head on may drop visby down to MVFR for a very brief period. The showers are too small and isolated to have any confidence including them in the TAFs for this evening.

Winds will become light and variable to calm as the evening progresses. This will allow for some patchy fog to develop across the area. Guidance is showing RME and SYR having a good chance at IFR and below restrictions tonight, and with the rain showers occurring in the area plus the expected westerly winds tonight that will push lake moisture into the area, confidence in these restrictions occurring is high. There are signals for fog developing at all our other terminals, but confidence is not high. BGM may be able to see some IFR restrictions tonight after it rained at the terminal this evening and winds are expected to become southerly, which is upslope flow that could help produce IFR at the terminal for a few hours. Too many other variables are uncertain at this time to put IFR at ELM/ITH/AVP.

There is a chance for thunderstorms to develop in the afternoon, but how a MCS evolves over the upper midwest tonight and travels east into our area tomorrow morning will impact the thunder chances. A few hours of PROB30 covers the thunder chances across CNY in the afternoon for now with too much uncertainty at this time for anything more definitive.

Outlook:

Tuesday evening through Thursday...Restrictions possible from showers and isolated to scattered thunderstorms.

Friday...Mainly VFR; low chance for lingering showers and restrictions.

Saturday...Additional restrictions look to arrive along with showers and storms late in the day Saturday.

BGM WATCHES/WARNINGS/ADVISORIES

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