Area Forecast Discussion
Issued by NWS Buffalo, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBUF 220833 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 433 AM EDT Sun Oct 22 2017 .SYNOPSIS...
-- Changed Discussion --
Another fine autumn day today with above normal temperatures, and dry weather. Pleasant weather will start the work week...but will quickly fade as a storm system bears down upon us late Monday and into Tuesday. This system will bring a soaking rainfall and gusty winds Monday night and Tuesday before ushering much cooler air with some lake effect rain Wednesday and Thursday.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
IR satellite imagery this early morning displays batches of mid and high level clouds across the Ohio Valley and Great Lakes region. High pressure along the eastern seaboard will maintain another dry day, with sunshine and passing clouds from time to time. 850 hPa temperatures of 12 to 14C will bring another warm afternoon with highs in the mid to upper 70s. Tonight we`ll continue to see some clouds passing across the region, that will again limit fog formation and maintain mild overnight lows in the mid 50s to lower 60s.
-- End Changed Discussion --
&& .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
-- Changed Discussion --
A mid/upper level trough will gradually dig across the Great Lakes region through mid-week, resulting in a cooler and much wetter pattern. Before this happens, 00Z model consensus provides just enough ridging to keep most of the area dry during the daytime hours on Monday. Showers may spread into far western New York late Monday afternoon, with just increasing clouds elsewhere. Highs will again be well above normal, ranging from around 70 across the interior to the mid 70s across the lake plains where downsloping will help warm things. After this, there is no doubt it will rain with moist southerly 60- 70 kt 850mb flow developing and bringing a band of widespread rainfall across the region. The progression of this LLJ will be slow with minor model differences in timing, but in general this axis will focus across Western New York Monday night and shift to central New York and the Eastern Lake Ontario region on Tuesday. This will bring a half an inch to an inch of rain to most areas. 1-2 inches is possible across the Eastern Lake Ontario region, especially if a second wave develops along the slow moving frontal boundary on Tuesday. In general, the strong flow aloft will remain aloft with breezy (but not damaging) winds. The possible exception is downslope regions such as the lake plains north of the Chautauqua Ridge and the Tug Hill where stronger gusts may mix to the surface. Rain is likely to arrive with the LLJ, and this can sometimes limit the mixing of winds aloft. There is too much uncertainly to issue any wind headlines at this time, but will add a mention to the HWO for potential wind gusts in excess of 50 mph. Otherwise a narrow dry slot should build behind the cold front across far western New York Tuesday afternoon, with mainly dry weather and even some breaks of sunshine. Temperatures on Tuesday will be notably cooler, but still above normal. Highs will run from the upper 50s to lower 60s across far western New York to the upper 60s across the Eastern Lake Ontario region which will still be on the warm side of the front during the morning hours. By Tuesday night the front will be to our east with the upper level trough axis across the eastern Great Lakes. Most model guidance shows some semblance of a surface ridge axis extending into western New York. Temperatures aloft will be cold enough (near 0C at 850mb) for some lake effect rain showers, however a SSW surface flow would focus most of this across Niagara county and into Canada. Otherwise there is a small chance of a lingering shower with the upper level trough.
-- End Changed Discussion --
&& .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Wednesday through Thursday a sharp mid level trough will very slowly cross the eastern Great Lakes and New England. Cool temperatures aloft, wrap around moisture, and increasing lake induced instability will produce scattered showers and some lake effect rain showers both Wednesday and Thursday. The lake effect rain will likely remain disorganized most of the time, with the placement of the mid level low overhead yielding moderate boundary layer shear and short fetch northwest flow. The lake effect rain showers will end by Friday as high pressure briefly builds over the eastern Great Lakes. Model differences become more significant by Saturday, with the GFS being faster than the ECMWF with the next system. Given the model differences, have just gone with a low chance of rain showers for next Saturday. Temperatures will bottom out Wednesday and Thursday as 850mb temps drop to around 0C. This will support highs in the 50s in most areas, with higher terrain possibly staying in the upper 40s if enough cloud cover persists. Temperatures will begin to warm by Friday and Saturday as southwest flow increases ahead of the next system. This warming trend will be temporary however. Looking a little farther ahead, the overall pattern evolution over the next two weeks will be for a steady turn towards cooler weather as a longwave trough becomes established over central and eastern North America. This pattern change will be in part driven by the poleward movement of the remnants of Typhoon Lan in the western Pacific by the middle of next week. The resulting influx of latent/sensible heat and vorticity into the mid latitude westerlies will strongly amplify the Pacific wavetrain, which in turn will drive amplification downstream into North America. By the middle of next week, a strong Aleutian Low will force a ridge to build over the Gulf of Alaska, which will drift to the west coast of North America by next weekend. This western ridge is forecast to last into the first week of November, and aid in forcing a deep longwave trough over central and eastern North America. This will bring more fall like weather for the last week of October, and the possibility of the first wintry weather during the first week of November. Stay tuned. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... For the 06Z TAFS VFR flight conditions are found and these flight conditions are expected to continue through the TAF package...with light winds. Outlook... Monday...VFR. Monday night and Tuesday...MVFR/IFR with occasional rain. Wednesday and Thursday...VFR/MVFR with a chance of showers. && .MARINE...
-- Changed Discussion --
High pressure will maintain light winds today and tonight, generally 15 knots or less. A developing storm system will approach the eastern Great Lakes Monday night and Tuesday. SE downslope winds over SW NYS will reach the Lake Erie waters, with possible small craft advisories as early as Monday evening. Winds will increase to possible small craft advisory levels on Lake Ontario later through the night...with additional periods of stronger winds and higher waves Tuesday and into Tuesday night behind a cold front.
-- End Changed Discussion --
&& .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...THOMAS NEAR TERM...THOMAS SHORT TERM...APFFEL LONG TERM...HITCHCOCK AVIATION...THOMAS MARINE...THOMAS

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.