988 FXUS61 KBGM 201444 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 1044 AM EDT Sat Jul 20 2019 .SYNOPSIS... Today will be the hottest day of our heat wave. However, elevated heat and humidity will persist into Sunday for Northeast Pennsylvania, and the Southern Tier to Catskills in New York. There will be a small chance of thunderstorms this afternoon and evening, then higher chances Sunday into Monday as cooler air eventually pushes into the region. && .NEAR TERM /THROUGH SUNDAY/... 1030 am update... A bit more cloud cover than anticipated this morning due to anvil clouds spreading e/ne from storms over OH and wrn PA...so this has slowed the heating rate this morning. However, a pocket of clearing should work in this afternoon and allow for temperatures to warm quickly into the lower 90s. Also, some minor adjustments to pops/wx to account for a cluster of weak storms rolling along the nrn tier of ne PA this morning. Still expecting increasing destabilization through the day with storms initiating across the area. Some may become strong to severe. 430 AM Update... The ongoing heat wave remains the primary concern in the near term period, though small chances of thunderstorms still have to be considered as well today through tonight. Those chances increase somewhat Sunday, especially in Northeast PA. Excessive Heat Warning remains in place areawide today, except for Heat Advisory for Delaware-Otsego-Northern Oneida NY. While today will definitely be the worst in terms of high heat index values, it has become clear that elevated heat and humidity will persist into Sunday as well for at least the southern part of our area. The Excessive Heat Warning has been extended through Sunday for Lackawanna-Luzerne-Pike PA since the greater Scranton /Wilkes-Barre metro valley as well as lower elevations of Pike County are likely to achieve at least 100-105 maximum heat index Sunday. Further north, there will probably be a set of counties that may need a Heat Advisory Sunday; at this point probably the rest of Northeast PA and the bordering counties of NY. That being said, dewpoints will thankfully be falling fairly quickly Sunday afternoon further north (eventually areawide beyond Sunday) as winds veer northwesterly behind the frontal zone that will be dropping into the area. Crest of the ridge aloft will be passing over the region today into tonight. This will cause a stronger thermal cap and thus convective inhibition compared to yesterday. Despite that, weak waves will still traverse over the top of the ridge and could touch off small clusters of convection. Much will depend on convective complexes upstream, and resulting perturbations/waves that will carry into our region. Despite lower overall chances of thunderstorms, with a majority of locations today probably remaining dry; there is again plenty of convective available potential energy and a high precipitable water environment. If there is development to our west-northwest late today into tonight, it is quite conceivable that some of this convection could sweep into our area and indeed the models often struggle to accurately catch these mesoscale details. On Sunday, the thermal cap will start to erode with 500mb height falls occurring. A west-southwest to east-northeast frontal zone will also start dropping through the area. These factors, plus plenty of energy from heat and humidity persisting along and south of the boundary, suggest a decent chance for thunderstorm development Sunday afternoon especially Twin Tiers-Catskills southward. Shear will be quite limited however. Also, a prefrontal trough may slide south by early afternoon to complicate low level convergence/organization. For now the Storm Prediction Center has us in general thunder for the Day 2 convective outlook but leaves us out of the marginal risk. Weather Prediction Center also does not have us highlighted in the Day 2 excessive rainfall outlook. For now, it is reasonable to anticipate at least some downpours and gusty winds underneath any convective cells Sunday, especially Northeast PA. We will have to still monitor trends in case better organization could result in bigger threats. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... A cold front will continue to move through the region Sunday night. However, the frontal passage continues to slow a bit with each model cycle. This is a likely caused by an area of low pressure which forms and tracks northeast along the front Monday. Enough lift and moisture will be present for a few showers and thunderstorms Sunday night. However, the added surface low pressure system and a mid level trough moving into the region will provide a more favorable environment for more in terms of coverage of showers and thunderstorms Monday and Monday night. It is possible that the rain becomes more stratiform across northern portions of the region as a more stable airmass advects in. If this is case, even though our forecast is a few degrees below blended model guidance a few locations could be several degrees cooler than forecasted with highs Monday. The front should start to slowly clear the area late Monday night. PW values look rather high once again pushing 2 inches. So heavy downpours are the main concern with the showers and thunderstorms which could result in ponding of water in urban areas long with quick rises on streams and creeks where storms occur. Temperatures look to range from the 60's through the 70's. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Although the front moves through late Monday night clearing looks rather slow on Tuesday. As is often the case here behind cold fronts some moisture looks to linger with a northwest flow. We slowed the clearing more than what blended guidance indicated but kept any lingering showers confined to NE PA and the Southern Catskills in the morning hours. The clouds and northwest flow will likely keep highs in the 70's on Tuesday for many locations. By Wednesday, A cool refreshing Canadian airmass will then move into the region with high pressure leading to drier conditions with cooler temperatures for the remainder of the week. Highs should stay in the 70's around 80 with lows in the mid 50's to low 60's on average. With a broad mid level trough in place, a few weak disturbances are likely to dive into the region from the Great Lakes. Moisture though looks rather meager though so exceptions are for any showers to be isolated at best. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... Minor ceiling restrictions will still visit KRME between 12Z- 14Z, otherwise mainly VFR conditions are expected for all terminals today. However, this afternoon-evening, isolated thunderstorms may carry across the area but most locations will stay dry. Thus, confidence is much too low to include in any TAFs. Potential will continue to be monitored. Another wave very late tonight could bring a round of thunderstorms between 07Z- 12Z Sunday to the NY terminals but again low confidence. Winds will become primarily west-southwest 5-10 knots today and not change much overnight. Outlook... Sunday through Sunday Night...Chance of thunderstorms and associated restrictions as a front moves through the region. Monday through Monday night...Rain and restrictions likely as wave of low pressure moves up along front just to our southeast. Embedded thunder possible as well. Tuesday through Wednesday...Mainly VFR other than valley fog for at least KELM in the predawn hours Wednesday morning. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...Excessive Heat Warning until 8 PM EDT this evening for PAZ038>040-043-072. Excessive Heat Warning until 8 PM EDT Sunday for PAZ044-047- 048. NY...Excessive Heat Warning until 8 PM EDT this evening for NYZ015>018-022>025-036-037-044-045-055-056-062. Heat Advisory until 8 PM EDT this evening for NYZ009-046-057. && $$ SYNOPSIS...MDP NEAR TERM...BJT/MDP SHORT TERM...MWG LONG TERM...MWG AVIATION...MDP