textproduct: Buffalo

SYNOPSIS

Expect an extended period of dry weather for the later half of the Labor Day holiday weekend and into the first half of the week, as surface high pressure dominates overhead of the Great Lakes. Cool nights, will give way to mostly sunny and warm afternoons, as there will be a day to day warming trend through the early portions of the week. The next chance of rain will arrive in the later half of the week with a cold frontal passage.

NEAR TERM /THROUGH TONIGHT/

Surface high pressure sliding east across the lower Great Lakes today before becoming parked overhead tonight will support dry weather to persist.

With the mainly clear skies early this morning, ample radiational cooling will support temperatures to fall below model guidance, so leaned towards the the lower end of the NBM distribution, especially across the Southern Tier supporting lows to fall into the mid 30s briefly across the cooler valleys, though upper 30s to low 40s will be more common.There may be some light, patchy frost in a few spots, but coverage will not be enough to justify an advisory. Additionally, expect typical river valley fog as well across the Southern Tier early this morning.

Despite the cool start today, daytime temperatures will be a few degrees higher than the day prior, as 850mb temperatures climb toward 10 degrees Celsius. This will result in highs in the low to mid 70s across much of the area.

Similar to early this morning, clear skies again tonight will support another cooler night with lows tumbling into the low to mid 40s across the Southern Tier and upper 40s to low 50s elsewhere. Additionally river valley fog will likely develop across the Southern Tier.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

A sfc high over the area to start the period will slowly shift east through Tuesday, providing for mostly dry conditions across the entire area to end the holiday weekend and to start the new work week. The exception to this will be for portions of the north country later Tuesday where some showers may be possible. This will occur as a weak upper level trough over the region for most of the period pulls some Atlantic moisture into the area and daytime heating increases instability some. Additional guidance is starting to increase this potential for later Tuesday as well.

With the sfc high over and then shifting east through the period, temperatures will continue to warm some for both Monday and Tuesday, with both days in the low 70s to near 80.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

During the remainder of the week upper-level ridging will amplify across western North America...while downstream a deepening upper- level trough will once again overspread the Great Lakes and Northeast. Meanwhile at the surface...an attendant...elongated surface low and cold front will make their way east and across our region...with forcing and moisture return along/ahead of this boundary currently looking sufficient for another round of fairly numerous showers...and perhaps a couple embedded thunderstorms depending upon its timing.

Speaking of which...the various guidance packages continue to exhibit quite a bit of spread with respect to the timing of this next system...with this likely to be a function of just how much phasing occurs with a possible southern stream trough/surface wave. This results in an envelope of possibilities ranging from Wednesday night/Thursday on the fast end to Friday/Friday night on the slow end...with the consensus currently lying somewhere in the Thursday/ Thursday night time frame. Given the resulting uncertainty...have leaned more toward the latter and have capped PoPs in the likely range for now for areas east of the Genesee Valley. For areas farther west, categorical POPs have been introduced as certainty is starting to increase for the rain potential in these areas.

Behind the passing cold front, cooling temperatures at the sfc and aloft along with a lingering trough and cyclonic flow, lake enhanced/effect rain will develop downwind of both Lake Erie & Ontario. Timing of this will be dependent on timing of fropa, but currently looks like Friday night through Saturday will have this potential. Gusty winds will also be possible late in the week and into the start of the weekend with the frontal passage, CAA and height falls.

What is more certain is that the gradual warming trend from earlier in the week will be brought to an abrupt halt by the passage of this system...with the much cooler airmass following in its wake driving temps back to notably below normal levels by the end of the week/ start of next weekend.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

As of 12Z, mainly clear skies dominate the region supporting widespread VFR conditions, due to surface high pressure sliding overhead this morning. Due to the clear skies, ample radiational cooling has allowed for typical river valley fog to develop across the Southern Tier. and Black River early this morning creating local LIFR conditions.

The valley fog will burn off by mid morning, leaving VFR to prevail today with scattered diurnal cumulus with VFR bases inland from Lake Erie and Lake Ontario midday through afternoon. River valley fog will again be possible tonight, likely developing after 06Z Monday.

Outlook...

Monday through Wednesday...Mainly VFR. Local IFR in river valley fog each late night and morning across the Southern Tier. Thursday...MVFR with rain showers and gusty winds along a cold frontal passage.

MARINE

Moderate northwesterlies will continue to weaken below Small Craft Advisory conditions across the western end of Lake Ontario this morning with waves continuing to be choppy.

High pressure will then settle over the eastern Great Lakes Sunday through Labor Day with light winds and flat wave action.

BUF WATCHES/WARNINGS/ADVISORIES

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