textproduct: Buffalo

WHAT HAS CHANGED

Minor changes to the forecast with this update.

KEY MESSAGES

1) Rain showers and isolated thunderstorms arrives tonight and through Sunday.

DISCUSSION

KEY MESSAGE 1...Rain showers and isolated thunderstorms arrives tonight and through Sunday.

A plume of subtropical moisture has reached the western Great lakes this morning, and will spread eastward across our region tonight bringing the next round of rainshowers. This plume of moisture will increase PWats over our region to around 1.5 to 1.75 inches, or greater than the 90th percentile for Buffalo sounding climatology for mid September.

Broad scale lift ahead of a few shortwave troughs aloft combined with lower level isentropic lift will generate a period of rain showers tonight through Sunday. Activity will advance northeastward across the CWA with light stratiform rain possible across the North Country by daybreak Sunday morning.

The axis of deeper instability will remain south of a frontal boundary that will remain draped across the midwest, leaving the thunder threat low. However the deepening warm cloud depth to over 12K feet on Sunday combined with the anomalously high moisture content of the airmass will lend to heavy rain as the primary hazard. Basin average QPF will range from around an inch near the state line, to a third/half an inch across the North Country. With the rain showers rather stratiform, falling over a greater duration of time the flood threat will remain low. If any convection were to develop across our southern zones, localized heavier amounts of rainfall would be possible.

These rain showers will shift to the east Sunday afternoon and evening, though a moisture rich lower atmosphere will remain Sunday and into the evening hours with higher terrain low stratus and fog possible.

A broad area of surface high pressure over the province of Ontario will advect a cooler and drier airmass southward later Sunday night and into Monday, possibly bringing a brief period of fair weather before another impulse returns the chances for showers and possible thunderstorms for Tuesday and Wednesday.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Aloft, W'erly to WNW'erly flow and embedded disturbances affect Western and Central NY through 06Z/Sun. At the surface, a ridge exits slowly from our area as the embedded high pressure center wobbles ESE'ward from west-central QC toward the Canadian Maritimes. Simultaneously, a trough overspreads our region slowly from the southwest as a front approaches from near the Lower and Mid OH Valley. Our regional surface winds trend light and variable before 12Z/Sat. From 12Z through 06Z/Sun, our regional surface winds should trend NE'erly to SE'erly around 5 to 10 knots.

Mainly VFR and dry weather are expected through the TAF period. Scattered to widespread cloudiness, especially in the mid/upper- levels, will accompany the disturbances aloft and stream generally E'ward to ESE'ward over Western and Central NY. In North-Central NY, steam mist or fog resulting in MVFR to LIFR is possible along and near the Black River between ~07Z/Sat and ~13Z/Sat, including at/near KART. Between ~03Z/Sun and 06Z/Sun, scattered showers and associated ceilings near 2kft to 5kft AGL should overspread the Western Southern Tier generally from the west as moist ascent occurs along the upper-reaches of the aforementioned front.

Outlook...

Sunday through Sunday night...Periodic showers with MVFR or worse expected. Isolated thunderstorms possible in/near the Western Southern Tier Sunday morning.

Monday...Dry weather and VFR likely.

Monday night through Wednesday...Periodic showers with MVFR or worse possible. Isolated thunderstorms possible Tuesday night and Wednesday.

MARINE

Easterly flow around a surface high pressure that is centered near the Ontario/Quebec province line will elevated waves on the waters west of Hilton, with waves around 3 feet at times this morning, before winds and waves slowly decrease through the afternoon hours.

Winds will then veer to southeast and southerly tonight, with lingering higher wave action forced to the northern waters of the Lower Great Lakes.

A wave of low pressure riding along a frontal boundary late tonight and Sunday will increase winds...first as they back around to northeasterly Sunday and then strengthen further Sunday night as the pressure gradient increases between a Canadian surface high and this frontal boundary. This will likely bring the next round of small craft advisories to our region beginning Sunday night, with these SCA then continuing into the middle portion of next week.

BUF WATCHES/WARNINGS/ADVISORIES

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