548 FXUS61 KBGM 110837 AFDBGM AREA FORECAST DISCUSSION National Weather Service Binghamton NY 437 AM EDT Thu Apr 11 2019 .SYNOPSIS... A developing warm front will cause thickening clouds today, and even a few light showers for some locations. After a quiet night, warm conditions are expected Friday with initially dry conditions. However, showers will sweep through the region late Friday into Friday night with the passage of a weak frontal system. This will leave Saturday dry with warm temperatures. && .NEAR TERM /THROUGH FRIDAY/... 215 AM Update... Passing weak wave with warm front aloft, will cause clouds and in some cases light showers today. As the warm front presses north tonight into Friday, temperatures will trend higher, however a weak front will be approaching with increasing chances for showers late in the day. Some sizable adjustments needed to be made to the very near term for today. A previously poorly-resolved shortwave is now being better picked up by most of the models, currently riding over the upstream ridge, and it is set to translate through our region today. It will harness the forced ascent of the right entrance region of a strong jet centered over New England, as well as isentropic lift of warm air advection aloft, while carrying a pool of mid-to-upper level moisture. The result of all of this is much more cloud cover especially, but also even a chance for a few light showers falling out of those midlevel clouds from the Central Twin Tiers to Finger Lakes to Syracuse- Norwich areas in late morning-early afternoon. Before there appeared to be too much dry air in the low levels but with the model trends, there will probably be enough moisture for it to not be just virga; some showers will make it to the ground. In fact, with fairly low dewpoints at the surface contributing to wetbulbing, some snowflakes could even be mixed in at higher elevations early. Indeed this is already occurring upstream across parts of lower Michigan. At a minimum, evaporative cooling and thicker cloud cover will cause temperatures to not be as mild as had been anticipated, with highs mainly mid 40s- near 50 in NY and upper 40s-mid 50s in PA. Quiet conditions are still expected tonight with strengthening southeasterly flow in the low levels, warm air advection, and plenty of clouds preventing temperatures from falling below upper 30s-lower 40s; indeed those lows will be early and then things creep up overnight. Marine layer moisture may bank into the terrain for spotty drizzle/very light rain in the Poconos and other higher elevations of Northeast PA towards morning. On Friday, as a deep cyclone tracks through the western Great Lakes region, its trailing front/occlusion will approach the forecast area late in the day. As is typical with cutoff or stacked lows this time of year, things continue to trend slower. Much of Friday will likely be dry, despite plenty of clouds, with pre-frontal enhanced southerly flow push afternoon highs into the mid-upper 50s in Poconos-Catskills and mostly lower to mid 60s elsewhere. Downsloping winds will give northern Finger Lakes to NY Thruway Corridor-Syracuse areas the warmest readings. Late in the day, shower chances finally increase along with a small chance of embedded thunder, as the occluding front gets into our vicinity. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... 430 AM update... Frontal zone is slowing down with the latest guidance and should linger across CNY/NEPA Friday evening. Categorical PoPs for showers and a few thunderstorms (very limited amounts of instability is forecast) continue until around midnight along I-81 corridor, then finally moves out of our southeast zones during the predawn hours Saturday. These showers and thunderstorms could bring a brief period of locally heavy rainfall as they move through. Basin average rainfall amounts still look to be on the order of 0.25-0.50 inches; but again locally higher amounts are possible in any t'storms. Any discernible cold air behind the boundary should track well north into Canada, with a broad SW flow still prevalent on Saturday. Although some higher level clouds should be around Saturday, there is expected to be some filtered sunshine as well. This, combined with a fairly mild air mass, should allow readings to climb well into the upper 60s, to even mid-70s in the normally warmer valleys of the NY southern tier and NE PA. Southwest winds increase a bit; between 8-15 mph by afternoon. Surface high pressure remains in control of our weather for Saturday night, keeping much of the area dry. Increasing clouds through the night as the next weather system begins to approach from the Ohio Valley late. Cannot rule out a shower or two toward daybreak south and west of Binghamton. Lows only dip down between 35-45 for most locations. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... 430 AM Update...The next significant weather maker is still slated to arrive on Sunday, in the form of a southern stream low, coming out of the Lower MS/TN Valleys. As opposed to the prior storm, which will have tracked well to our west, this one seems destined to track right into central NY by later Sunday night/early Monday, with a much better flow of moisture and source of jet dynamics. PWATS increase to around 1.5 inches by Sunday evening and night. Models are also indicating at least some instability Sunday afternoon and night; especially across the NY southern tier down into NE PA. Therefore added in slight chances of thunder into the forecast. As a result, a period of steady to occasionally heavy rain seems quite likely, with the steadiest/heaviest rainfall probably occurring from late Sunday into Monday morning. The latest EPS and WPC guidance still points to the possibility of 1-2.5"+ of rain for NEPA and the western Catskills. We'll continue to watch this system over the next few days as significant rises on area rivers and streams is becoming a possibility. With the forecast area likely in the warm sector of this storm system bumped temperatures up a bit...however cloud cover and rain will hold down the temperatures as well. Looking for highs mainly in the 60s both Sunday/Monday...with some 50s possible north. Early next week, slow improvement is foreseen, as the above referenced storm tracks through the Canadian Maritimes and then out to sea. Upper level low moves over the area late Monday, Monday night and Tuesday morning. This will keep a cooler northwest, cyclonic flow in place with chances for rain showers, and even some wet snow showers during the overnight period. Cooler by Monday night, with lows in 30s. Highs only recover into the mid- 40s to low 50s across central NY Tuesday, with low to mid-50s for NE PA. Transient upper level ridge is progged to move overhead late Tuesday and Tuesday night...likely bringing a period of dry and seasonable weather. Uncertainty remains in the forecast for mid to late next week. Another boundary sets up west to east across the area by next wednesday, with increasing clouds and at least a chance of rain showers develop. Another lows pressure system then could approach from the mid- mississippi valley late in the week, with increasing rain chances. For now used a blend of guidance for this timeframe and capped PoPs at high chance Wednesday night and next Thursday. Near average temperatures expected. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... VFR conditions will persist through the TAF period to 06Z Friday with variable or east to southeast winds less than 8 knots. A passing weak wave aloft, associated with a developing warm front, will cause ceilings to develop and lower to between 5-10 kft agl. A few sprinkles could fall at times out of that deck midday to afternoon KELM-KITH-KBGM-KSYR but not included in TAFs due to low confidence and also they will be of no consequence in terms of restrictions. Outlook... Late Thursday night through most of Friday...Mainly VFR. Late Friday through Friday night...Passing front will cause some restrictions from showers; thunder also possible. Saturday into Sunday...Mainly VFR again expected. Sunday night into Monday...Restrictions probable, with lower ceilings and a period of steadier rain. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...MDP NEAR TERM...MDP SHORT TERM...MJM/Jurewicz LONG TERM...MJM/Jurewicz AVIATION...MDP