830 FXUS61 KALY 100252 AFDALY Area Forecast Discussion National Weather Service Albany NY 1052 PM EDT Tue Oct 9 2018 .SYNOPSIS... A large area of high pressure will provide above normal temperatures and humidity levels through Wednesday. A cold front will approach from the west Wednesday night with clouds and chances for showers on the increase. The cold front will provide focus for widespread showers and isolated thunderstorms Thursday. Storms will produce locally heavy rainfall with the tropical air mass in place. A cooler and more seasonable air mass will build into the region Friday into the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... A large and expansive upper level ridge over the western Atlantic just east of the Mid Atlantic Coast will continue to dominate the weather over the East Coast. Anomalous warmth and humidity is being funneled from the subtropics/tropics into the local forecast area. Hurricane Michael continues to churn along in the Gulf of Mexico. Please refer to forecasts issued by the National Hurricane Center for the latest on Michael. Stratus is forming to the south and east of the Capital District and will continue to expand overnight. Not expecting widespread fog as clouds expected to dominate. Fog is most likely in and along the major valleys with the abundance of low-level moisture in place. Lows tonight are expected to be in the lower to mid 60s with some upper 50s over some the higher terrain of the western Adirondacks, eastern Catskills and southern Green Mountains. Note: Albany's record high minimum for October 10th is 64F set back in 1913. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... Tomorrow...Another anomalously warm and humid early October day is expected with the ridge axis holding on with H500 heights 1 to almost 2 STD DEVs above normal. Morning stratus and patchy fog will burn off. H850 and H925 temps will continue to 1-2+ STD DEVs above normal based on the latest 12Z GEFS. The actual H850 temps will be similar to today in the +14C to +16C range. A backdoor cold front begins to dip southward towards the St Lawrence River Valley and northern Maine late in the day. It should be mainly dry or rain-free with perhaps a few pop-up showers or an isolated thunderstorms near the southern Adirondacks again. Convection potential will be limited since H500 temps are about -7C to -9C, which is warm for this time of year. The upper level trough upstream moves towards the central and upper MS River Valley, and the cyclone lifts into the Upper Midwest and western Great Lakes Region. Highs tomorrow should be similar today with upper 70s to spotty lower 80s in the valley areas or below 1000 ft, and upper 60s to mid 70s will common over the hills and mtns. Humidity levels will feel uncomfortable with dewpts in the mid and upper 60s. Wed night...The forecast area is firmly in a tropical air mass with dewpts well into the 60s. A south to southwest flow of tropical air ushers in PWATs 2 to 4+ STD DEVs above normal overnight. The 12Z GEFS shows the +v-component of the wind /southerlies/ increasing 1-2+ STD DEVs above normal. The mid and upper level ridge axis shifts downstream of eastern NY and western New England overnight. The 12Z GFS is most aggressive backing in the cold front from the north/northeast with a weak wave moving along it. This may increase the chance of showers over the northeast zones away from the Capital Region after midnight. Clouds will be thickening and lowering from the west ahead of the cold front moving eastward. Meanwhile, Tropical Cyclone Michael will be lifting out of the Deep South/FL panhandle region towards the Southeast and lower Mid Atlantic Region. We started to increase the POPs after 06Z, north and west of the Capital Region with prefrontal shower activity and perhaps a weak short-wave impulse in the southwest flow. Lows will continue to be balmy in the lower to mid 60s, except for some upper 50s over southern VT, and the southern Adirondacks. Thu-Thu night...The greatest impact period for heavy rain will be Thursday as the cold front approaches from the Great Lakes Region, Ohio Valley, and Mid Atlantic Region. A low-level southwesterly jet will continue to focus some heavy rain showers with PWATS in the 1.66-2.0" range. The synoptic lift will increase as the H850/H925 low-level theta-e ridge will be over the forecast area in the late morning into the early to mid afternoon. The QG Lift or synoptic forcing increases ahead of the front with some upper level divergence. The better jet streak looks like it will lag upstream of the region over the over the central and eastern Great Lakes Region. The better focus for the right entrance region of the H250 jet streak of 125+ knots remains a bit out of phase from the low-level theta- ridge and anomalous PWAT air for a classic Predecessor Rain Event or PRE documented in the CSTAR research. A rain axis well northeast of Michael is possible, but the placement and amounts of QPF are still uncertain. The latest NAM was the most aggressive with 1-3" of rainfall from southern VT, the Berkshires southwest through the Taconics, mid Hudson Valley, and the eastern Catskills. The GFS has the heavier rain amounts from the Capital Region/Mohawk Valley northward with 1-1.5+ inches. The 12Z ECMWF has a general half an inch to an inch for Thu-Thu night. We believe a widespread rainfall is possible with bands of heavier showers and isolated thunderstorms due to small amounts of instability in place. We are not confident for the potential of widespread flooding yet, and we are forecasting about three quarters of an inch to an inch and an inch and third of rainfall through THU night. The high PWAT values may favor localized rainfall rates on an inch or so an hour in a few spots. Based on the NHC forecasts, Michael will stay south of the entire forecast area. Please see the hydro section for more details. Temps will likely be mild in the 60s to lower 70s on Thu, and the front should swing through by the early evening with the showers ending from west to east early on. Cold advection will be strong with the frontal passage with H850 temps falling to +1C to +6C from Albany north and west, and +6C to +13C south and east. Lows in the 40s to lower 50s across the forecast area and it will be breezy with west to northwest winds of 10-15 mph. && .LONG TERM /FRIDAY THROUGH TUESDAY/... The long term forecast period will exhibit cool Fall weather with multiple chances for precipitation. The jet stream looks to transition to a more amplified pattern and could result in a large scale pattern shift to cool/wet weather. Friday and Saturday...Tropical remnants from Michael are expected to slide to our southeast on Friday into Saturday therefore tangible impacts from the system are not expected over eastern NY/western New England at this time. High pressure will build in from the Midwest resulting a west/northwest flow across Lake Ontario. Sub-freezing 850 hPa temps are expected as well resulting in a very small amount of low level instability/enhanced low level lapse rates, and therefore the possibility of lake-enhanced precipitation over the western Adirondacks and Mohawk Valley. Surface temperatures are expected to be in the low 40s with forecast thermal profiles suggesting all rain at this time, but there is a small chance for a few snow flakes to mix in over the highest terrain. Went ahead and increased sky cover from blended guidance over the entire region as well due to the ample amount of moisture expected to be present. Highs will be in the 40s over the higher terrain with valley locations climbing into the 50s. Lows will generally be in the 40s with the higher terrain dropping into the 30s Friday night. Sunday through Tuesday...Sunday looks to remain dry and partly cloudy as high pressure builds over the region. Global guidance diverts greatly at the beginning of next week. The GFS develops a coastal low Monday into Tuesday resulting in rain and cooler temperatures for our region, while the ECMWF has a cold front, associated with a low traversing to our North, sweeping through the region which would result warmer temps on Monday followed by rain. Confidence in the forecast temperatures and precipitation is very low due to these aforementioned reasons. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... With high pressure anchored off the east coast and a large and expansive upper level ridge in place it will be warm and humid across the region through the TAF period; 00Z/Thursday. The low-level southerly flow will favor the formation of stratus and mist tonight with IFR/LIFR conditions expected to develop by 08-09Z/Wednesday. A gradual improvement as the day progresses Wednesday with VFR conditions expected by afternoon. A light southerly flow through the overnight will increase to 7 to 10 knots by Wednesday afternoon. Outlook... Wednesday Night: Moderate Operational Impact. Chance of SHRA. Thursday: High Operational Impact. Definite SHRA...TSRA. Thursday Night: Moderate Operational Impact. Slight 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. && .FIRE WEATHER... A large ridge of high pressure centered off the Mid Atlantic Coast will provide above normal temperatures and humidity levels tonight through Wednesday. A frontal boundary will approach from the west Wednesday night with clouds and showers increasing. The cold front will focus widespread showers and isolated thunderstorms with locally heavy rainfall Thursday into Thursday night. A cooler and more seasonable air mass will build into the region Friday into the weekend. The RH values will remain high tonight and Thursday morning in the 90 to 100 percent range, and only lower to 55 to 75 percent tomorrow. The winds will be southerly at less than 10 mph tonight, and increase from the south at 5 to 15 mph tomorrow, and continue from the south to southwest at 5 to 15 mph Wednesday night A widespread soaking rainfall is expected for late Wednesday night through Thursday. && .HYDROLOGY... Little or no rainfall is expected prior to late Wednesday night in the Albany Hydro Service Area /HSA/. Any light rain over the southern Adirondacks will have little impact on river flows that should continue to slowly recede. Late Wednesday night into Thursday, 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 1.66-2.0+ inches across the entire HSA. Bands of showers and isolated thunderstorms, some with locally heavy rainfall, are possible for late Wed night into Thu evening. With high rainfall rates possible in the tropical air mass (possibly up to an inch an hour), this rain could cause flooding of urban, poor drainage and low lying areas. Ponding of water on roads is also possible. Also, an isolated flash flood could occur if any showers or thunderstorms repeatedly move over the same areas. The latest MMEFS guidance does not have any river points reach flood. None of the NERFC forecast points are forecast to reach minor flooding at this time. River and streams levels may see some notable within bank rises, although how much they rise will depend on the exact amounts of rainfall and where they occur, which is still uncertain at this time. The rain showers 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...IAA/Wasula NEAR TERM...IAA/Wasula SHORT TERM...Wasula LONG TERM...Cebulko AVIATION...IAA/KL FIRE WEATHER...Wasula HYDROLOGY...Frugis/Wasula