textproduct: Binghamton

WHAT HAS CHANGED

Increased coverage of showers and thunderstorms this afternoon. Also lowered temperatures tomorrow with it looking like convection will start earlier in the day.

KEY MESSAGES

1) Isolated to scattered thunderstorms expected today and on the 4th across NY and PA. Some of these storms could be severe with damaging wind gusts along with very heavy rain that could lead to localized flash flooding.

2) Hot and humid conditions expected through Tomorrow, before cooling off towards average highs next week.

3) An area of low pressure moves slowly through the region early next week bringing widespread rain with locally heavy downpours.

DISCUSSION

KEY MESSAGE 1...

With temperatures already in the upper 80s and low 90s across NY and PA early this afternoon, SPC mesoanalysis has 3000 to 4000 J/kg of surface based CAPE. Water vapor imagery does show a deep layer of dry air above the boundary layer so as heating continues, some dry air will mix down into the boundary layer so dew points likely will slowly fall. An outflow boundary from storms near Lake Erie this morning is moving through the Finger Lakes and eventually through the rest of the Twin Tiers and CNY by the late afternoon. This boundary will likely be the focus of a few thunderstorms that would generate their own outflow and spark likely off more storms.

The dry air aloft and the dry air mixing into the boundary layer will make for favorable conditions for downburst and microburst with any storm that develops this afternoon. It will not take a very large storm to get dry air entrainment into the updraft causing a collapse, then dry air and steep lapse rates below the LCLs will help downdrafts accelerate to the surface. DCAPE is already over 1000 J/kg, SPC mesoanalysis page does over estimate DCAPE but this is well into the needed DCAPE for severe winds with downdrafts.

Tomorrow is looking nearly the same as we remain on the NE side of the large ridge. The 500 mb heights do start to fall late tonight into tomorrow, with CIN eroding a little earlier tomorrow than today so convection may pop off more late morning into the early afternoon.

KEY MESSAGE 2...

Today is another day in the upper 80s and 90s across the region with dew points remaining in the upper 60s or higher. If thunderstorms can hold off until 3 pm, heat indices will climb back near 100 to 110 for valleys and urban areas. Tomorrow is looking cooler with recent trends in models with the ridge flattening out starting this evening. 500 mb heights fall from around 590 dm today to around 584 dm tomorrow, and 850 mb temperatures fall from the upper teens to mid teens. Forecast soundings show less cin as well so storms will likely fire earlier in the day, prior to being able to reach peak heating. Right now, heat indices should remain below 100 for NEPA and below 90 for NY so no new advisories were issued. Clouds and rain begin to move in Sunday with more average temperatures for the second half of the weekend into next week.

KEY MESSAGE 3...

The NE edge of the ridge will likely dip south of the region late this weekend into early next week as the large ridge retrogrades to the west. Models have been consistent with a weak area of low pressure that slowly traverses through the Great Lakes into the Mid Atlantic bringing clouds and rain to our region. Given moist flow through the central US into the Great Lakes region, this low will have plenty of moisture to work with, as PWATs will be near 2 inches Sunday through Tuesday. Showers will be persistent basically Sunday night through Tuesday. Monday afternoon and Tuesday afternoon has a flash flood risk as breaks of sun leads to instability and potential for slow moving thunderstorms with heavy rain. Since we remain near the edge of the ridge through the rest of next week, frequent shortwave will keep the pattern active but at least not as hot.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Still monitoring isolated showers and thunderstorms across the region early this evening. However, none are expected to hit any of the TAF sites at this time. Kept a persistence forecast for hints of VFR fog overnight at KRME and KELM. Mainly VFR conditions are expected through the night and morning hours Saturday. Additional showers and possible thunderstorms should begin to develop in the late morning and afternoon hours. Coverage, timing and locations impacted is still somewhat uncertain so just a mention of showers for now.

Outlook:

Saturday night through Sunday...Mostly VFR, chances for additional showers and thunderstorms with restrictions.

Sunday Night through Monday...Restrictions possible due to widespread showers and afternoon isolated thunderstorms.

Thursday...Mainly VFR with a chance for showers and isolated thunderstorms.

Wednesday...Mainly VFR with a low chance for showers, mainly at ELM, BGM, and AVP.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Extreme Heat Warning until 8 PM EDT this evening for PAZ038>040-043-044-047-048-072. NY...Extreme Heat Warning until 8 PM EDT this evening for NYZ009- 015>018-022>025-036-037-044>046-055>057-062.