Area Forecast Discussion
Issued by NWS Albany, NY

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777 FXUS61 KALY 190725 AFDALY Area Forecast Discussion National Weather Service Albany NY 325 AM EDT Thu Jul 19 2018 .SYNOPSIS... Tranquil weather will remain across the region through the remainder of this week and into the start of the weekend. However, unsettled conditions is expected to return over the second half of the weekend as waves of low pressure along and ahead of a frontal system slowly approaching from the west. && .NEAR TERM /THROUGH FRIDAY/... As of 300 AM EDT...Rather delightful summer-like weather across the region with high pressure dominating the pattern. The ridge both at the surface and aloft continue to increase which will support lots of sun and nearly clear skies at night. Dewpoints remain in the comfortable 40s to around 50F with a slow increase expected tonight into Friday where we should climb into the 50s and southerly winds increase in the wake of the departing surface high off the northeast coastline. Base on upstream temperatures and a slow increase in those H850 temperatures from 10C to 15C, afternoon highs will generally range from the 80s into valley locations and 70s elsewhere. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/... Friday night those aforementioned southerly winds will continue to advect in low level moisture with dewpoints approaching upper 50s to near 60F. This will begin our pattern change toward a warmer and moist regime as we watch for a potential wave developing from convection across the southeast CONUS through Saturday. At this time, per the NCEP Model Suite and international guidance, we will hold back PoPs/Wx for areas south of I90 until later in the afternoon. This is in response to low level ageostrophic flow shifting toward the east where the surface and mid level ridge axis remains in place for drier conditions. Either way, clouds will increase Saturday from south to north as this will have an impact to forecast highs as we will place cooler values south and remain rather mild along and north of I90. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... There remains increasing consensus that an upper low will develop in the OH Valley and Great Lakes while upper energy and moisture in the SE U.S. rotates around the eastern periphery of the cyclonic upper flow into the northeastern U.S. This upper energy looks to be timed for Saturday night and Sunday with moisture and a boundary layer wind maximum tracking north from offshore the Mid Atlantic into New England and eastern NY. The upper energy, subtropical moisture and low level wind energy should support showers or a steady rain Saturday night into Sunday. There could be some locally heavy rain but with the dry conditions in many places this summer, it should be a beneficial rain in most cases. Flood potential will have to be watched though as we get closer based on the increasing tropical moisture over our region through the beginning and middle of next week. There remains uncertainty regarding the exact manner in how this energy tracks northward along or off the coast which will influence rain amounts, as a track further east could greatly limit areal coverage and intensity of rainfall across the region during this time. Once the upper energy and low level forcing exit later Sunday, there is a general consensus that the upper low in the OH Valley slowly weakens, retrogrades west and south while very strong upper ridging in the north Atlantic builds west toward our region. As upper heights rise over our region and weak southerly upper flow sets up, a south/north oriented zone of deep tropical moisture is expected to be relatively stationary near or over our region, leftover from the upper low and anchored on the western periphery of the developing upper ridging off the northeast coast. So, with tropical moisture in place, numerous showers and thunderstorms with locally heavy rain are possible each day, Monday through Wednesday, with slightly decreasing coverage possible each night. It should be noted that low level southerly wind and PWAT anomalies depicted by the 00Z/19 GEFs are +2 SD to at times +3 SD through much of the period in our region, with best anomalies wobbling west and east at times. Highs Sunday in the 70s to around 80. Highs Monday through Wednesday in the lower to mid 80s but upper 70s to around 80 higher terrain. Lows Sunday night, Monday night and Tuesday night in the humid and uncomfortable upper 60s to lower 70s but mid 60s higher terrain. High temperatures could be warmer Monday through Wednesday if there are breaks in the clouds each morning and early afternoon before the storms increase in coverage through the afternoon, especially by Wednesday as the boundary layer flow may veer into the southwest and downslope in some areas. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... High pressure in control of the weather through Thursday. Few clouds, if any through Thursday, but some fog is possible at KPSF and KGFL, mainly between 07Z-10Z/Thu, when brief periods of IFR could occur. Otherwise VFR conditions through Thursday evening. Winds will be light/variable through daybreak, then remain variable at 4-7 KT Thursday, with local topographical effects affecting the wind direction. These effects should favor west/northwest winds at KALB and KPSF, NW to N at KPOU, and SE at KGFL. Winds should become nearly calm shortly after sunset. Equipment KPSF electrical work is ongoing on the field. Power has been cut to ASOS. Therefore TAF is issued as AMD NOT SKED. Outlook... Thursday Night: No Operational Impact. NO SIG WX. Friday: No Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: Low Operational Impact. Slight Chance of SHRA. Sunday: Moderate Operational Impact. Chance of SHRA...TSRA. Sunday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Monday: Moderate Operational Impact. Chance of SHRA...TSRA. && .FIRE WEATHER... Fair and dry weather will persist through the remainder of this week and the start of the weekend. Unsettled conditions may return over the second half of the weekend as a frontal system slowly approaches from the west. RH will fall to 30-40 percent this afternoon and recover to 80-100 percent late tonight, with areas of dew formation possible. Winds will be from the north to northwest at 10 mph or less today, then become light/variable tonight. Winds will be mainly from the southerly direction at 5-10 mph Friday. && .HYDROLOGY... Dry weather is expected through at least Saturday. A slow moving frontal system approaching from the west, along with a several waves of low pressure tracking northward within a very moist airmass in place, could lead to frequent showers and thunderstorms, some with locally heavy downpours for Sunday through at least the middle of next week. 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...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...KL/NAS AVIATION...KL/NAS FIRE WEATHER...KL/BGM HYDROLOGY...KL/BGM is the U.S. government's official web portal to all federal, state and local government web resources and services.