textproduct: Binghamton

WHAT HAS CHANGED

Nothing. Heat headlines remain and the concern about severe weather and flash flooding potential continues.

KEY MESSAGES

1) Heat and humidity becomes unhealthy and dangerous in some areas for the rest of this week.

2) Several rounds of scattered thunderstorms may occur mainly over Central New York into next weekend. Severe weather and locally heavy rainfall and flooding will be possible within the favorable warm and humid conditions.

DISCUSSION

KEY MESSAGE 1...

No significant changes to the guidance are noted with heat still expected to increase within a building thermal ridge this week. Temperatures in the 90s with oppressive upper 60s to mid-70s dewpoints remain on target with little variance to the ensemble statistics thus confidence in the event is high. We start with marginally dangerous heat indices today (Tuesday) and will continue the heat advisory as previously advertised. Peak performance of the heat/humidity combo looks to be from Weds-Thurs with enough of the sensitive demographic areas (cities and deep valleys) still within the crosshairs of extreme heat criteria (HI greater than 104 F). There are several caveats that could prevent high temperatures from reaching their fullest advertised potential. Dew point temperatures could mix lower during afternoons dropping the HI and convective activity could trim temperatures during the peak hours. We still have some time before carving out the patchwork of future advisories and warnings, so let's get today's under our belt. The heat watch will remain in place for now.

KEY MESSAGE 2...

Very tricky weather pattern over the coming days as we will be close to the periphery of the upper ridge. Depending on how strong and amplified the ridge becomes will determine our fate for thunderstorm chances this week. Right now SPC has our far north in a Slight Risk for Tuesday into Wednesday with Marginal extending to the southwest. Surface based CAPE values are well outside the norm for the Northeast over the next couple days and shear is sufficient to develop and maintain severe weather. Excessive rainfall is also possible with diffluent thickness fields over our area angling back toward the moisture axis surging in from the Ohio Valley. Upstream MCS turning through the Great Lakes over the ridge could easily propagate south into our part of NY. Due to the extreme instability for this region, even lasting into the nighttime hours, the potential for a long lasting MCS or Derecho exists for somewhere in the Northeast U.S. in the coming days, but at this time, it is not possible to pin down timing or location, but this will be something to monitor.

Triggers for storms are tough to pin down if they even reach our area or scoot off into New England as several models suggest the driving shortwaves will do. There will be a sufficient warm layer aloft as noted by 700 mb temps rising to around 12C and forecast soundings showing minor inversions around 850 mb through the period, so we really will need triggers to touch off more than isolated to scattered storms.

Forecasters will be monitoring upstream thunderstorm complexes over the coming days and confidence will increase for severe weather if we start seeing a long live MCS pushing across southern Ontario, Canada...Stay tuned.

Some relief appears on the horizon after Thursday as the flow aloft turns more westerly and then pivots into more of a flat trough for the weekend which should bring increased cloud cover, some cooling and more unsettled showery conditions.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

VFR conditions across the area today as a strong high pressure system will be in control of the weather pattern.

A shortwave trough is modeled to ripple through the edge of the high, bringing a chance for thunderstorms across portions of the area, especially east of I-81, late this morning into the afternoon hours. Model guidance remains uncertain as to timing and location of the storms, so the highest confidence we can exude in the TAFs is a PROB30 group for TSRA at SYR and RME. Storms may pop up across other portions of the area, but confidence in their development remains too low to include at any of the other TAF sites.

Guidance is starting to hint at the possibility of some patchy fog and MVFR or lower restrictions at ELM/ITH/RME, but confidence is too low to include in the TAFs at this time.

Outlook:

Wednesday through Saturday...Mostly VFR, but intermittent restrictions will be possible with isolated to scattered showers and thunderstorms each afternoon.

CLIMATE

Current High Temperature Records:

6/30: BGM - 92 (1964), SYR - 94 (1971), AVP - 97 (1964) 7/1: BGM - 90 (2018), SYR - 94 (2018), AVP - 95 (2018) 7/2: BGM - 92 (1966), SYR - 96 (1963), AVP - 98 (1966)

Forecasts for 7/1 and 7/2 are at or near the daily records.

BGM WATCHES/WARNINGS/ADVISORIES

PA...Extreme Heat Watch from Wednesday morning through Friday evening for PAZ038>040-043-044-047-048-072. NY...Extreme Heat Watch from Wednesday morning through Friday evening for NYZ009-015>018-022>025-036-037-044>046- 055>057-062. Heat Advisory from noon today to 8 PM EDT this evening for NYZ015>018-022>025-036-037-044-045-055-056.