Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 271343 AFDALY Area Forecast Discussion National Weather Service Albany NY 943 AM EDT MON JUN 27 2016 .SYNOPSIS... A series of cold fronts will move eastward across the region late today through Tuesday night, bringing rounds of showers and thunderstorms. High pressure will then build in from the Midwest by Wednesday night, with dry weather returning. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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As of 930 AM EDT...Line of showers and some embedded thunderstorms per the NLDN were into portions of the Adirondack Park and western Mohawk Valley. Per extrapolation of these showers in conjunction with the HRRR/HRRRX, we will time these showers/storms expanding further eastward with most of the Hudson Valley region by early afternoon under cloudy conditions with scattered convection as weak surface trough passes through. As for temperatures, after a mild start to the day, there remains enough sun over the eastern 2/3rds of the local county warning area to keep the expected high temperatures (mainly upper 70s to mid 80s).
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&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... The aforementioned pre-frontal trough will stall and become diffuse near western New England tonight. So will only mention isolated to widely scattered showers. It will be another mild night with a southerly breezy persisting, with low temps in the 60s. Tuesday is expected to be the most active day of the week in terms of convective potential. At the surface, a cold front will gradually push eastward across the region during the afternoon and evening. Aloft, a positive to neutral tilt upper level trough is forecast to deepen just to our west over the eastern Great Lakes. Height falls and cyclonic vorticity advection aloft combined with low level convergence along the cold front should result in fairly widespread showers and thunderstorms to develop, especially during the afternoon across eastern NY spreading eastward to western New England by evening. There is a marginal risk for some of the thunderstorms to become severe if sufficient instability can develop. Some breaks of sunshine are expected ahead of the cold front, but it is unclear how unstable it will get as model guidance differs with the GFS indicating 500-1500 J/Kg of SBCAPE, while the NAM has more robust values of around 1500-3000 J/Kg. Should more sunshine materialize, the NAM values would be reasonable, but this is uncertain at this time. Deep layer shear will be increasing to around 25-40 kt, so organized severe storms will be possible given ample buoyancy. Will mention the marginal risk in HWO. Showers will continue Tuesday night, as the cold front only gradually makes eastward progress, while the upper level trough axis remains to our west with a continued cyclonic flow. Coverage/intensity of thunder should decrease by late evening though as instability is forecast to wane. Will continue to mention chance pops for scattered showers with isolated thunder for Wednesday, siding with the slower ECMWF/NAM guidance compared to faster GFS. The upper level trough may become a closed low, which would slow its progress. The more progressive GFS continues to show and open wave. Max temps Wednesday should be cooler than recent days, but close to normal for late June. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... The period is expected to start out with fair weather and seasonably warm temperatures. At the surface high pressure is expected to be over the region. While aloft, the region is expected to be between short wave trough. A cold front will be on the approaches from the northwest as we close out the work week and head into the long holiday weekend. Convection is expected as the front approaches on Friday and crosses the region Friday night. Guidance indicates an upper level low should develop over the Great Lakes region with it becoming stacked. This stacked low then is modeled to move gradually eastward across eastern Canada over the holiday weekend as short waves rotating about it maintaining an upper level trough over the region. At this time, it appears the weather across the local area should be fair for the holiday weekend as the upper low is modeled to remain far enough to our north while the cold front that moves through is forecast to stall far enough to our south. A wave of low pressure is expected to move eastward along this boundary. Subtle changes in the expected locations of these features will result in changes to a fair weather forecast. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... High pressure along the Atlantic seaboard will weaken and slide offshore today. In the meantime, a cold front will approach from the west. Heights will fall across the region however upper level support will remain well to the west. convection to move across across the local area today impacting the TAF sites mainly during the afternoon into the evening. Expecting VFR conditions to prevail through much of the evening. MVFR conditions are expected to develop overnight initially due to ceilings then some fog is expected to form. South-southwest flow will increasing to 10 to 12 knots with some gusts into the 20s. The winds will decrease in the evening. Outlook... Tuesday Night: High Operational Impact. Likely SHRA...TSRA. Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Moderate Operational Impact. Chance of SHRA...TSRA. && .FIRE WEATHER... A series of cold fronts will move eastward across the region late today through Tuesday night, bringing rounds of showers and thunderstorms. High pressure will then build in from the Midwest by Wednesday night, with dry weather returning. Minimum relative humidity values this afternoon are expected to be around 35 to 50 percent. RH values will then increase to between 80 and 100 percent tonight. Minimum RH values on Tuesday will be around 50 to 60 percent. Winds today will be southerly around 10 to 15 mph with gusts around 20 mph. Southerly winds will decrease to 5 to 10 mph tonight. Winds on Tuesday will be south-southwest at 5 to 15 mph. && .HYDROLOGY... No widespread hydro problems are expected over the next 5 days. There is a chance of showers and a few thunderstorms today, as a weakening frontal boundary approaches. There will be a better likelihood of showers and thunderstorms across the region on Tuesday, ahead of and along a cold front. Two day rainfall totals could reach one half to one inch, with some isolated higher amounts. Ponding of water will occur within any persistent thunderstorms. A few lingering showers are possible Wednesday with light qpf amounts. Dry weather will return by Thursday, with high pressure moving back in across the region. The latest drought monitor now has most of our region labeled `Abnormally Dry` (D0). In fact, over the past 30 days, most of our region is approximately 1-3 inches below normal in terms of rainfall. 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...JPV NEAR TERM...BGM/JPV SHORT TERM...JPV LONG TERM...IAA AVIATION...IAA FIRE WEATHER...JPV HYDROLOGY...NAS/JPV www.weather.gov/albany

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