textproduct: Binghamton

WHAT HAS CHANGED

No significant changes to forecast. Next main batch of rain is Wednesday midday through evening.

KEY MESSAGES

1) A widespread half inch to one inch of rain is forecast through midweek, mainly from a low pressure system that will be in the region Wednesday afternoon through evening.

2) A cool air mass settles into place late this week through the weekend leading to below average temperatures, scattered shower chances and the possibility for frosts or freezes during the overnight hours.

DISCUSSION

KEY MESSAGE 1... Most of the afternoon to early evening showers had a lot of dry air to contend with, indeed much of it virga evaporating before reaching the ground, so rain amounts were spotty and light. Overnight we will have a break in the precipitation between areas of low pressure, with residual moisture leading to low stratus across most of the region, with some hill and ridge top fog possible.

For Wednesday, another low pressure system moves into the Northeast, with better moisture in place. A few rain showers will try to develop late morning into the early afternoon with some instability aloft and a weak 500 mb shortwave passing through. A more robust 500 mb shortwave moves in Wednesday afternoon into the overnight hours along with the surface low. This trough does have a bit of a negative tilt to it. Rainfall rates could briefly hit quarter to half inch per hour as the trough swings through in the heavier showers but the trough is moving fast so the heavy rain will not last long in any given location. All told, a widespread half inch to one inch of total rainfall is expected through Wednesday night, most of it in afternoon-evening, with locally higher amounts possible. Embedded thunder cannot be ruled out with the instability aloft, but nothing severe. Flooding is not expected, though this rain will maintain the elevated water levels that are persisting in the Finger Lakes.

KEY MESSAGE 2

Once the set of lows are through, then a long wave trough sets up over the northeast leading to cool north to northwest flow keeping temperatures below average Friday into early next week. 850 mb temperatures could fall to around -5C, especially overnight Friday and Saturday, which would be cold enough for snow to mix in if precipitation can persist into the overnight hours. With the cold air aloft and strong solar heating at this time of the year, instability will likely develop each afternoon with scattered showers developing. Graupel would be possible with the low freezing levels in the stronger showers. Overnight lows around freezing will lead to frost potential if skies clear for long enough and even some localized freezes. It will be dependent on low level moisture as showers could bump up dew points enough for fog development.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Very gradual lowering of ceilings into MVFR range is anticipated overnight, between two areas of low pressure. Uncertainty exists for when KELM-KITH and possibly KBGM-KSYR slip into fuel alternate required levels below 2000 feet during the morning. However, with a wet low pressure system moving into the region, there will be a more decided degradation in conditions Wednesday afternoon with developing rain and ceilings dropping in some cases into IFR especially KITH-KELM-KSYR; at least into fuel alternate required levels at the other terminals. While embedded thunder cannot totally be ruled out, anticipated coverage is isolated at worst; confidence much too low to include in TAFs.

Outlook:

Wednesday night through early Thursday...Rain in evening, diminishing overnight, but persistent restrictions from low clouds and/or fog on the backside of departing wet system; likely IFR-or-worse. Gradual improvement Thursday morning.

Thursday through Saturday...Isolated to scattered showers popping up each day with associated intermittent restrictions possible. Otherwise VFR much of the time.

BGM WATCHES/WARNINGS/ADVISORIES

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