578 FXUS61 KALY 110538 AFDALY Area Forecast Discussion National Weather Service Albany NY 138 AM EDT Thu Oct 11 2018 .SYNOPSIS... With a continued warm and muggy air mass in place, showers and thunderstorms, some with heavy rainfall, are expected today ahead of an approaching frontal boundary. The front will cross through the area this evening, ending the threat for widespread rainfall. Behind the cold front, a cooler and more seasonable air mass will build into the region Friday into the weekend, along with a few passing lake-effect rain showers for western areas. && .NEAR TERM /THROUGH TODAY/... As of 138 AM EDT...Surface cold front remains well upstream of the region over Great Lakes, extending southward across the Ohio and Tennesse Valleys. However, the first batch of rain showers associated with this storm system is already reaching across central NY and will be moving into our area over the next few hours. This rainfall, aided by the strenghtening low-level jet, is mainly light in intensity, as upstream surface obs and MRMS estimates show rainfall rates of under a tenth of an inch per hour. PWATs will surge up rapidly through the night, getting close to 2.00 inches by daybreak. 3km HRRR suggest precip will start to increase in intensity and coverage after daybreak, especially for the western and northern parts of the area. 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 will last through mid to late morning. 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. As earlier, any shower will be capable of producing locally heavy downpours. If heavy showers repeat over the exact same location, then flash flooding is possible, although this will be fairly isolated. Temperatures overnight are only expected to drop into the 60s with highs on Thursday in the mid 60s to mid 70s. It will remain muggy with dewpoints in the mid to upper 60s. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... Showers will be ending from northwest to southeast as a cold front exits the region Thursday night. Much drier and cooler air will advect in behind the front on Friday, resulting in a more seasonable air mass. On Friday, the tropical system (Michael) will quickly lift into the eastern Atlantic from the Delmarva peninsula but should stay far enough south to keep any additional rainfall south of the forecast area. Upper level heights will also be on the rise, allowing for a dry but cooler day. High temperatures will average slightly below normal, in the low to mid 50s, with overnight lows dipping into 30s and low 40s. An upper level trough looks to swing through Friday night into Saturday, with some light rain showers possible. A few flurries will also be possible in the higher terrain Friday night into Saturday morning. No snow accumulation is expected. High temperatures on Saturday will be on the chilly side under cloudy skies, with low 40s in the high terrain to low 50s elsewhere. Saturday night, temperatures fall into the mid to upper 30s. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... The long term forecast period will begin with mid-level ridging and surface high pressure over the region on Sunday followed by multiple shortwave troughs swinging through the Northeast during early/mid next week. Sunday will remain dry across the region with the exception of the Adirondacks which could see a few isolated lake-enhanced rain showers. Temperatures will be seasonable with highs in the 40s and 50s and lows generally in the 40s. There will be multiple chances for precipitation during the early and mid week as pieces or shortwave energy swing through the region. At least two shots of cold reinforcing air will push into the Northeast with these shortwaves, bringing temperatures down slightly below normal. Global deterministic guidance resolves a low pressure system and associated cold front moving to our North, with a coastal low developing just on its heels Monday into Tuesday. The exact timing and location of cyclogenesis will have implications on the amount and type of precipitation associated with the potential coastal low, and confidence at this time is low. High temperatures will be in the 40s (higher terrain) and 50s (valley regions) with low temperatures in 30s and 40s. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... Rain is gradually working east from central NY but light south wind at low levels is helping low clouds to spread north into the KPSF and KALB areas. The low clouds should spread into KGFL and KPOU through about 09Z. The onset of light rain looks to be around 08Z-10Z at all TAF sites but the intensity should be light with visibilities around 5-6SM through 12Z-14Z. Ceilings look to hover between 900-1500 feet after 09Z and then hold solidly below 1000 feet through this afternoon as a prolonged period of rain and showers affect our region. Visibilities in the steadier rain look to be 3SM or higher but some intervals of IFR visibilities are possible. Steadier rain ends between 22Z-04Z when the rain exits and ceilings and visibilities lift to VFR. Light south winds at 10 Kt or less through this morning will shift more to the southwest this afternoon ahead of the cold front. Winds should become gusty from the south at KALB this afternoon with gusts into the teens. Winds shift to west and northwest this evening at less than 10 Kt. 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... RH values will be elevated through the day today with a widespread wetting rainfall expected. Cooler, drier and breezy conditions are expected on Friday. && .HYDROLOGY... Flash Flood Watch in effect for western New England as well as Greene, Columbia, Rensselaer, Ulster, and Dutchess counties of New York from 8 AM Ttoday through 2 AM Friday. Tropical moisture will be surging northward ahead of an approaching frontal 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 (up to an inch an hour), this rain could cause flooding of urban, poor drainage and low lying areas. Isolated flash flooding may be possible. 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...Flash Flood Watch from 8 AM EDT this morning through late tonight for CTZ001-013. NY...Flash Flood Watch from 8 AM EDT this morning through late tonight for NYZ053-054-058>061-063>066. MA...Flash Flood Watch from 8 AM EDT this morning through late tonight for MAZ001-025. VT...Flash Flood Watch from 8 AM EDT this morning through late tonight for VTZ013>015. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis SHORT TERM...JLV LONG TERM...Cebulko AVIATION...NAS FIRE WEATHER...Frugis HYDROLOGY...Frugis