Area Forecast Discussion

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

1) The threat of hail and damaging winds with strong to severe thunderstorms exists into this evening.

2) The heat returns Tuesday through the end of next week with increasing humidity and more chances for thunderstorms.

DISCUSSION

KEY MESSAGE 1...

Conditions are becoming favorable for thunderstorm development this afternoon and into the evening hours today. The threat for hail and damaging winds is the greatest concern, but there is also a non-zero threat for a couple low-end tornadoes as well.

A batch of weak, decaying convection rolled eastward across the area this morning and produced mostly a quick 0.2 inch of rain with no lightning. Behind this rain, a pocket of relatively dry air aloft moved in and has left most of the region under partly cloudy skies. A few showers have tried to get going in Oneida County, but any precip so far has been weak.

Our attention is turned toward the 2 PM to 9 PM timeframe where we are expecting a broken line of convection to develop with potentially some individual cells which will move to the east/southeast across the region and potentially evolve into a more solid line as it tracks out of our area. A potent/sharp upper short wave with a 90 kt jet streak is rounding the bottom of the trough across Lake Erie this afternoon. The surface heating and boundary layer moisture will provide the necessary ingredients for convective initiation along the sfc cold front, and the s/w will support large scale lift to help deepen the convection. Plenty of deep layer shear, 30-40 kt, will sustain the convection and allow for mature storm structure. The storms will be able to tap into deep moisture, with PWs around 1.5 inches, so there is also a threat of heavy downpours. However, there is some indication from some recent NUCAPS soundings of a layer of dry air aloft that would likely assist more so in the development and growth of hail.

Damaging wind gusts are the main threat today with an overall dynamic wind environment aloft associated with the short wave. If any of the storms can tap into these winds and transfer that momentum to the surface with any downdrafts/downbursts, the threat for +50 kt wind gusts will be heightened.

We are also watching the threat for a couple tornadoes as well. HRRR hodographs in western NY and parts of n-central PA are looking favorable for potentially a strongly sheared low level environment that could assist any storm in spinning up a quick low-end tornado. This threat will likely be confined to the afternoon (before 5 PM) and along the southern tier of NY and into ne PA. Right now, most surface and low level winds are not backed enough, but if they start to become more southerly, this would increase the tornado potential.

Most of the thunderstorms should be out of the area by 8 PM.

KEY MESSAGE 2...

After a brief reprieve from the heat on Sunday, an upper level ridge starts to build back in from the west by the beginning of the work week. This dome of high pressure will move slowly to the east into the middle of the week with afternoon high temperatures rising back into the mid to upper 80s on Monday and into the upper 80s and lower 90s on Tuesday through Friday.

There does appear to be some concern for a short wave breaking over the northern periphery of the ridge on Wednesday, which would likely lead to another round of thunderstorms...potentially strong to severe. This pattern repeats going into the end of the week as the ridge attempts to build back in and several more waves, with plenty of moisture, try to ride eastward across the Northeast U.S. This will be a more typical summer-type pattern later in the week.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Scattered showers and isolated thunderstorms along a passing cold front are still expected this afternoon and evening. Brief restrictions will be possible for any shower or storm that passes over a terminal. Behind the front, MVFR to Fuel Alt ceiling restrictions are expected at all Central NY terminals late tonight/early Sunday morning. Added moisture from showers may lead to fog at ELM and AVP as skies will scatter out for part of the night and winds will be calm. Elsewhere, winds are expected to be too strong for fog development. Gradual improvements to conditions are then expected after 12z Sunday though RME and SYR will remain under lower ceilings through the end of the TAF period.

Southwesterly winds will be breezy ahead of the approaching front. Sustained speeds of 10 to 15 kts with gusts of 25+ kts are expected through the afternoon. Winds will gradually become calmer this evening and overnight. Then early Sunday morning, winds will begin to pick up once again with sustained speeds of 5 to 10 kts and gusts up to 20 kts.

Outlook:

Sunday Night through Tuesday...Mainly VFR.

Wednesday through Thursday...Scattered showers and thunderstorms may bring occasional restrictions.

BGM WATCHES / WARNINGS / ADVISORIES

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