textproduct: Buffalo

WHAT HAS CHANGED

Only minor adjustments with this update.

KEY MESSAGES

1) Warmth and humidity are expected across the region for the second half of the week.

2) The chance for showers and thunderstorms increases day to day through the end of the week. Heavy downpours are possible Thursday and Friday.

DISCUSSION

Key Message 1...Warmth and humidity are expected across the region for the second half of the week.

An upper level ridge and surface high pressure will continue to support seasonal weather and low humidity across the region today. These two features will move east off the east coast tonight. A southwest flow will begin to deepen across the region Wednesday. A feed of warm air and moisture will filter across the region through the end of the week. High temperatures will range from the low to mid 80s. Heat index values are expected to rise into the upper 80s to possibly 90 across the lake plains including the Finger Lakes region.

Key Message 2...The chance for showers and thunderstorms increases day to day through the end of the week. Heavy downpours are possible Thursday and Friday.

An upper level trough will move across the Northern Plains to the Central Great Lakes region through the end of the week. Multiple shortwave troughs are expected to move within the trough and support periods of showers and thunderstorms. Warm, moist air will return to the region Wednesday, and diurnally driven scattered convection is expected to develop from the western Southern Tier to the Rochester area during peak heating. Dry air and subsidence should limit rain chances across the eastern Lake Ontario region. While shower chances will linger Wednesday night, another round of diurnally driven convection is expected Thursday. A shortwave wave and approaching front may produce better coverage of showers and thunderstorms. The flow remains weak, so the severe threat is low, however with PWATS remaining above the 90th percentile, heavy rain is possible.

A slow moving cold front is expected to reach the region Friday. Another round of scattered to numerous showers and thunderstorms are expected across the region with heavy rain being the main hazard. There is uncertainty in the timing and intensity of thunderstorms and therefore the risk for flooding is low.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

High pressure will remain over the northern Mid-Atlantic through tonight allowing for VFR conditions to persist for most locations. The exception to this will be KJHW and other valley locations across the Southern Tier, where there will be potential for valley fog again early tomorrow morning. With a little bit more wind present, radiational cooling will not be as pronounced, so fog coverage should be a more patchy, and mostly in the 3-5 mile range. Soon after sunrise tomorrow morning, VFR conditions will return across the Southern Tier soon after sunrise, with VFR continuing through the day tomorrow.

Outlook...

Wednesday Night through Sunday...Periodic showers and thunderstorms with MVFR or worse conditions are expected, especially each afternoon through early evening.

MARINE

High pressure will reside across the lower Great Lakes through tonight and support light winds and waves. The chance for showers and thunderstorms increases the second half of the week. No small craft headlines are expected through the rest of the week.

BUF WATCHES/WARNINGS/ADVISORIES

NY...None. MARINE...None.