715 FXUS61 KALY 111123 AFDALY Area Forecast Discussion National Weather Service Albany NY 723 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 with a few passing lake-effect rain showers for western areas. Chilly weather will continue this weekend with some additional showers on Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 626 AM EDT...Surface cold front remains well upstream of the region over Great Lakes, extending southward across the Ohio and Tennessee Valleys. At the same time, TC Michael continues to weaken as it quickly lifts northeast across the Southeastern US. Well ahead of the front, a batch of rain showers associated with this storm system is already moving across the northern half of our area. This rainfall, aided by the strengthening low-level jet, is light to moderate in intensity. Rainfall rates have ranged up to a third of an inch per hour, although most rates have generally be in the one to two tenths per hour range so far. With the increasing low-level jet, PWATs have surged up through the night. This is thanks to the strong meridional flow in place, which has allowed plenty of tropical air to move up all across the eastern CONUS. Even though the core of TC Michael will remain well southeast of the area today, the overall pattern is supportive of bringing plenty of moisture into our region. Blend satellite TPW values are already reaching around 2 inches from Florida northward through the mid-Atlantic and into Pennsylvania and Upstate New York. 3km HRRR suggest on and off rain showers will continue this morning, especially from the Capital Region on north and west. 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. Despite widespread cloud cover, enough elevated instability may be present for some isolated thunder as well, especially this afternoon. 00z HREF suggest any meaningful updraft helicity values will remain well south of the area over the mid-Atlantic. Strong low- level inversion should also help prevent much of any strong winds aloft from reaching the surface as well, so the threat for severe wx today looks fairly low. There may be a brief break or lull in the shower activity around mid-day before the next round of heavier showers (and embedded t-storms) rolls through for the afternoon hours. 3km HRRR/NAM suggest the best chance of seeing heavier showers this afternoon will be for the southern and eastern half of the region. As earlier, any shower will be capable of producing locally heavy downpours, especially considering these showers will be lifting northward out of the mid-Atlantic, where moisture will be high. If heavy showers repeat over the exact same location, then flash flooding is possible, although this will be fairly isolated. Despite widespread cloud cover, highs today should reach the upper 60s to mid 70s for most areas. Dewpoints will remain very muggy in the 60s. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... One final line of showers looks to roll through the region from west to east ahead of the cold front. This should be fairly progressive and narrow, so no additional hydro impacts are anticipated this feature. Behind the cold front, cooler and drier will start to rush into the region with lows quickly falling into the 40s and 50s. Friday will be a drastic change from the past few days and a stark reminder of what weather is normally like for the Autumn season in Upstate NY and western New England. Strong cold air advection will be in place, resulting in temps in the mid 40s to mid 50s and a northwest breeze of 10 to 20 mph. Dewpoints will have fallen into the 30s as well. With the northwest flow over the eastern Great Lakes, stratocu clouds will be around and some lake-effect rain showers will impact parts of the western Adirondacks and Mohawk Valley. Any rainfall will be light. A fast moving shortwave trough will be headed towards the region for Friday night into Saturday. Clouds will quickly increase and a few light showers are possible late at night and into Saturday morning, especially for southern parts of the area. Temps will fall into the mid 30s to mid 40s for Fri night. With chilly temps aloft, it's possible for some wet snowflakes to mix in with the showers for areas about 2000 ft, but the boundary layer will be too warm for any accumulation. As the shortwave departs, showers will end and clouds will start to break up for Sat afternoon into Sat evening. With the clearing skies, temps will fall into the 30s for Sat night and some frost will be possible, especially for higher elevation and outlying areas. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... General broad cyclonic upper flow with fall like temperatures expected through the middle of next week. Sources of guidance/ensembles are in some disagreement on the timing and track of upper impulses within the upper flow. Sunday should be mainly dry with highs in the mid to upper 50s but upper 40s to around 50 in higher terrain. Monday through Wednesday, there are signals for a couple of upper impulses that could bring some periods of scattered showers into our region but again, the timing and coverage of the showers is in question. Based on the latest sources of guidance/ensembles the best chances for some showers are in the Monday through early Tuesday time frame. However, with colder boundary layer temperatures and low level flow off the Great Lakes, clouds and some isolated showers could linger into Wednesday. There could also be some snow shower activity mixed in during the nights in the southern Adirondacks. Highs Monday in the mid 50s to around 60 but upper 40s to around 50 northern areas. Highs Tuesday in the lower to mid 50s but a few upper 50s southern areas and mid to upper 40s higher terrain. Highs Wednesday in the mid to upper 50s but upper 40s to around 50 higher terrain. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Light rain is falling over all areas except KPOU, where the rain will move in later this morning. Ceilings look to hover between 500-1500 feet with MVFR visibilities in the rain through the day. Visibilities could drop to around 1SM in heavier rain later this morning and into this afternoon. 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 mid 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 and continue light through tonight. Outlook... Friday Night: Moderate Operational Impact. Chance of SHRA. Saturday: Moderate Operational Impact. Chance of SHRA. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: Low Operational Impact. Isolated SHRA. Monday: Moderate Operational Impact. Scattered SHRA. Monday Night: Moderate Operational Impact. Scattered SHRA. Tuesday: 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. RH values will drop down to 50 to 65 percent on Friday with northwest winds of 10 to 20 mph. && .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 today 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 if repeated heavy showers occur over the same areas, but widespread flash flooding is not anticipated. 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. There may be a few rain lake-effect rain showers on Friday for western areas and some passing showers on Fri night into Saturday, but this precip will have little to no impact on area rivers and streams. 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 through late tonight for CTZ001-013. NY...Flash Flood Watch through late tonight for NYZ053-054-058>061- 063>066. MA...Flash Flood Watch through late tonight for MAZ001-025. VT...Flash Flood Watch through late tonight for VTZ013>015. && $$ SYNOPSIS...Frugis NEAR TERM...Frugis SHORT TERM...Frugis LONG TERM...NAS AVIATION...11/NAS FIRE WEATHER...Frugis HYDROLOGY...Frugis