932 FXUS61 KALY 101636 AFDALY Area Forecast Discussion National Weather Service Albany NY 1236 PM EDT Wed Oct 10 2018 .SYNOPSIS... A strong upper level ridge will continue to allow for warm temperatures and humid conditions today. An approaching cold front will bring showers and thunderstorms late tonight into tomorrow, with some locally heavy downpours possible. Behind the cold front, a cooler and more seasonable air mass will build into the region Friday into the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 1215 PM EDT...A large and expansive upper level ridge continue to be situated over the western Atlantic just east of the Mid Atlantic Coast. This 500 hpa ridge (about 592 dm which is 1-2 STD above normal for mid-October) continues to allow for a warm and muggy airmass over the Northeast. Meanwhile, a large upper level trough is moving from the Rockies into the Great Plains, while large and dangerous Michael continues to move northward across the eastern Gulf of Mexico. The approaching upper level trough will be causing Michael to lift north and eventually northeast by later today, but this storm is forecast to track well south/east of our region. Latest satellite imagery shows numerous breaks of sunshine so have increased the amount of sun forecast for this afternoon and have also bumped up the temperatures several degrees. Highs are now expected to range from the upper 60s across the highest terrain to the upper 70s to lower 80s in the valleys. A backdoor frontal boundary will be located close to the International Border, but it looks to stall north of the region and any associated showers with this front should stay to the north. As a result, will keep forecast rain-free through this evening. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... Upper level trough will be moving across the Upper Midwest tonight and surface low pressure will be lifting across the western and northern Great lakes towards southern Canada. Meanwhile, the cold front will be pushing eastward across the Ohio and Tennessee Valleys overnight. Although the evening will start off dry with increasing cloud cover, the chance for rain showers will be increasing by late in the overnight (after 2 AM or so) from west to east as isentropic lift increases over the area. PWATs will be surging up rapidly through the night, getting close to 2.00 inches by daybreak Thursday. With high freezing levels and high PWATs, will expect warm rain processes to dominate, allowing for efficient rainfall and high rainfall rates. This may result in some heavier showers producing downpours that result in street flooding and ponding of water in low lying and poor drainage areas. This initial shot of rainfall looks to occur between the late night hours and through mid to late morning on Thursday. Despite widespread cloud cover, enough elevated instability may be present for some isolated thunder as well, but no severe threat due to the lack of surface-based instability. There may be a brief break or lull in the shower activity before the next round of heavier showers (and embedded t-storms) rolls through ahead of the cold front from around mid-afternoon through the evening hours Thursday. As earlier, any shower will be capable of producing locally heavy downpours. If heavy showers repeat over the exact same location, can't rule out an isolated flash flood, but we are not anticipating this to be a widespread threat at this time. Showers look to be ending from west to east Thursday evening into Thursday night. As the cold front moves through, much drier and cooler air will quick start working into the area, with a noticeably cooler air mass in place for Friday. With strong cold air advection in place, Friday will feature breezy and cooler conditions. Highs only look to reach the 50s (with some high terrain areas remaining in the 40s). Along with the northwest breeze, it will be a stunning change from the mild and muggy weather from the mid-week. With cooler air working in aloft, some lake-effect rain showers will develop off Lake Ontario and a few of these may sneak into the western Adirondacks and western Mohawk Valley for Fri into Fri night. By Friday night, temps will fall into the mid 30s to mid 40s across the region with a partly clear sky and a diminishing wind. Most clouds will be in areas down wind of Lake Ontario. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Temperatures will be very much typical fall through the period with general broad cyclonic upper flow over eastern North America. However, there is considerable uncertainty in the tracking and timing upper impulses and associated unsettled weather within the fast broad cyclonic flow. Sources of long range guidance/ensembles have considerable spread in the timing and track details. One piece of upper energy tracks through our region Saturday with limited moisture. So, more clouds than sun to start the day with gradually improving sky cover through the afternoon. Some isolated to scattered showers in the morning will also be mainly confined to the southern Adirondacks. Highs Saturday in the 50s but some 40s in the higher terrain. Sunday has the potential to be a dry day with intervals of sun before the next piece of upper energy approaches Sunday night. Highs Sunday in the mid to upper 50s but around 50 higher terrain. The next upper impulse with better defined warm advection and isentropic lift approaches our region Sunday night into Monday with chances of showers. Then the upper energy departs and the cold advection and associated low level forcing continues our chances of showers Monday night into Tuesday morning. Highs Monday in the upper 50s to around 60 but lower 50s higher terrain. Highs Tuesday in the lower to mid 50s with a few upper 50s southern areas and mid to upper 40s southern Adirondacks. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... VFR conditions are expected at all TAF sites up until between 03Z and 07Z at which time conditions will deteriorate rapidly to MVFR/IFR with some LIFR cigs possible as rainfall along with low clouds and lower visibilities overspread the region. By 12Z ceilings at most TAF sites will be between 800 and 1500 feet with visibilities generally 3SM. Light south to southwest winds at less than 10 kts will prevail through the TAF period ending at 18Z Thursday. Outlook... Thursday Night: Moderate Operational Impact. Chance of SHRA. Friday: No Operational Impact. NO SIG WX. Friday Night: Low Operational Impact. Slight Chance of SHRA. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: Moderate Operational Impact. Scattered SHRA. Monday: Moderate Operational Impact. Scattered SHRA. && .FIRE WEATHER... Low clouds will break for some sun today. RH values will fall as low as 70 percent by this afternoon with a southerly winds at 5 to 10 mph. RH values will be elevated tonight into tomorrow with a widespread wetting rainfall expected. Cooler, drier and breezy conditions are expected on Friday. && .HYDROLOGY... Dry weather is expected today into this evening, allowing for river and stream levels to mainly hold steady across the region. Late tonight into tomorrow, a frontal boundary will be approaching from the west. Tropical moisture will be surging northward ahead of this boundary, allowing for PWAT values to reach close to two inches across the entire area. Bands of showers and isolated thunderstorms, some locally heavy, are expected to move across the region. With high rainfall rates expected (possibly up to an inch an hour), this rain could cause flooding of urban, poor drainage and low lying areas. Although unlikely, an isolated flash flood cannot be totally ruled out. Larger river and streams levels may see some rises, but basin average rainfall amounts (about 0.75 to 1.50 inches) won't be enough to cause flooding of main stem rivers and streams. The rain should be done by Friday morning, allowing for water levels to recede slowly, as a cooler air mass will return to close the week and enter the weekend. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis/11 SHORT TERM...Frugis LONG TERM...NAS AVIATION...11/NAS FIRE WEATHER...Frugis HYDROLOGY...Frugis