Area forecast discussion National Weather Service Buffalo New York 1029 PM EDT Wednesday may 22 2013 Synopsis... a warm and humid airmass will remain in place through tonight with showers and thunderstorms at times. Rain will continue through Thursday night as a cold front moves slowly across the region. The rain will end Friday morning with much cooler and drier air moving into the region for Friday into the weekend. && Near term /through Thursday/... radar imagery showing a broken line of convection about to exit the east end of the County Warning Area across the Eastern Lake Ontario region. This line continues to weaken as the boundary layer stabilizes with the onset of nocturnal cooling. Elsewhere the rest of the County Warning Area has dried out for the most park except for one shower moving through northwest Monroe County. Upstream radars show a broken line of showers and a few isolated storms over Northern Ohio and Central Lake Erie...in association with the main middle level trough. Ascent will slowly increase across western New York later tonight with the approach of this trough...so shower chances will again increase. With ongoing stabilization however...expect coverage to remain scattered in nature. Any storms should remain isolated and tame given the slackening instability. For tomorrow an area of low pressure will lift north of Lake Ontario and drag a cold front across the western half of New York state. While instability will be less tomorrow additional lift along the cold front boundary should produce more widespread showers. Will mention thunder across The Finger lakes region where the greatest instability within the County Warning Area will be found...with sbcapes around 500 j/kg. Showers will likely continue after the cold front passage with the upper level cool pool still to the west. Cooler tomorrow with highs reaching the lower 70s. && Short term /Thursday night through Saturday night/... northern stream trough will be digging southeast through Ontario and the northern Great Lakes at the start of the period. Secondary cold front will be just off to our west Thursday evening...then pass across the area Thursday night. Widespread shower activity Thursday night and early Friday ahead of the front will taper off behind the frontal passage...with drier and much cooler air advecting into the region...as a broad and strong Canadian surface high builds southward through the Great Lakes and toward the East Coast. This will put an end to the precipitation threat for the beginning of the Holiday weekend. Mainly clear and cool conditions for Friday night and Saturday. Overnight lows Friday night falling into the middle 30s and lower 40s and highs Saturday in the lower to middle 60s. The gradient may stay up enough Friday night to keep the potential for frost to a minimum but a few locations may nudge toward the freezing mark. && Long term /Sunday through Wednesday/... cool Canadian high pressure will reside over the area through the period. This will result in a quiet weather pattern with no precipitation expected. The dry airmass in place will likely result in a wide diurnal range in temperatures. The coolest period looks to be Sunday and Monday with overnight lows falling into the middle 30s and lower 40s and highs in the lower to middle 60s. These temperatures would suggest some frost potential especially for the normally colder locations of the southern tier and areas east of Lake Ontario. It is likely that headlines will be needed at some point during this period. A gradual warming trend will then occur through middle week as the high shift slightly to the east allowing for a more southerly flow with highs reaching normal or slightly above normal by middle week with readings in the 70s. && Aviation /03z Thursday through Monday/... a broken line of storms will exit the Eastern Lake Ontario region through 0330z with brief/isolated IFR coming to an end there. Otherwise the rest of the area has dried out this evening with VFR prevailing. A few more showers upstream over Ohio and Central Lake Erie may spread into western New York overnight as a middle level trough approaches the region. Coverage should remain scattered in nature with VFR prevailing most of the time. There should be enough wind overnight in the boundary layer to preclude much in the way of fog formation despite the very moist airmass in place. Through Thursday a cold front will slowly sag south across the region. This will provide additional focus for showers...especially during the afternoon as the bulk of the rain begins to take residence behind the surface cold front. Ceilings/visibility should initially be VFR...although a drop to MVFR is possible late Thursday following the surface cold front as the low levels moisten. Outlook... Thursday night IFR/MVFR in showers. Friday...mainly VFR with a chance of showers. Saturday through Monday...VFR. && Marine... a few spotty showers or an isolated thunderstorm are expected overnight with southwest winds generally in the 10-15 knot range away from the influence of any storms. An area of low pressure will cross just to the north of Lake Ontario tomorrow and drag a cold front across the lakes on Thursday. Colder air behind this frontal boundary will bring a slight increase in waves heights on both lakes...though waves will likely remain below 4 foot through Thursday night. Small crafts may be needed early Friday when wave heights peak...possibly at the 4 foot mark. && Buf watches/warnings/advisories... New York...none. Marine...none. && $$ Synopsis...Hitchcock/Thomas near term...Hitchcock/Thomas short term...tma long term...tma aviation...Hitchcock marine...Hitchcock/Thomas