Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 221956 AFDOKX Area Forecast Discussion National Weather Service New York NY 356 PM EDT Sat Oct 22 2016 .SYNOPSIS... Deepening low pressure moves through Maine and southeastern Canada through Sunday. Another cold front associated with the low moves through the area late Sunday night into early Monday morning. Canadian high pressure builds behind the front Monday through Wednesday. Low pressure approaches and moves across the area Thursday into Friday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Deepening low pressure will continue to move north through Maine and into southeastern Canada tonight, reaching as low as 978 MB by Sunday morning. The low was making little eastward progress as a result of a full latitude, closed off, and negatively tilted upper trough. Deep layered moisture was wrapped around the low and with vort maxes rotating through the trough areas of light rain continues. Expected rain to end around 06Z as the last of the vorts rotates through the trough. Weak cold advection also continues and with low level winds to around 50 KTs some of these winds were mixing to the surface. With cloud cover and precipitation mixing was limited. With the best mixing through this evening there is still the potential for gusts and perhaps some sustained winds to reach wind advisory criteria. Have ended the advisory at 04Z for Nassau county and the NYC zones at 04z, and continue through 10Z for the remainder of the zones that were in the advisory. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Sunday is expected to be dry with the upper trough remaining and the upper low beginning to cut off. Gusty winds remain however low level winds will be diminishing and cold advection shuts off 09Z to 12z and weak warm advection starts. Winds early in the morning will be the strongest and an occasional gust may approach 45 MPH across the eastern zones before winds diminish. A northern stream shortwave moves quickly through the northern tier of the United States and moves into the upper trough Sunday evening. A re enforcing cold front and the shortwave then move through 06Z to 12Z Monday with a chance of showers. With minimal lift will have only chance probabilities. && .LONG TERM /MONDAY THROUGH SATURDAY/... Upper trough remains across the northeastern portion of the country early to mid week, as ridge to the west eventually flattens per global models. Differences arrive with handling of shortwave that develops across the upper mid west as it traverses east late in the week. At the surface, low pressure associated with lingering upper trough moves slowly across eastern Canada, as high pressure builds out of central Canada and into the Great Lakes Region through mid week. The high briefly slides across the area Thursday before giving way to low pressure Thursday and Friday. Frontal boundaries, first warm front followed by the cold front, impact the area from late Thursday, into Friday. For Saturday, forecast becomes less clear. A possible weak frontal boundary may move through Saturday, but confidence in this remains low at this time. Generally dry conditions are anticipated Monday through Wednesday night as initial shortwave and front clears the area, and high pressure slowly builds. Cyclonic flow could result in more cloud cover each day, especially into New England Tuesday and possibly Wednesday. The best chance for rain looks to be late Thursday, Thursday night into Friday. ECMWF slower with upstream system compared to usually quicker GFS. Temperatures will initially average right around normal Monday. Then cooler canadian air settles in and expect readings to remain below normal Tuesday and Wednesday. Temperatures slowly moderate closer to normal Thursday through Saturday. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... Low pressure moves into Northern New England and southeast Canada through Sunday with high pressure building to the southwest. WNW winds winds becoming 20-25 kt with gusts around 35 kt through early this evening. An occasional gust up to 40 kt is possible, especially near the coast. Gusty WNW winds will continue tonight into Sunday. Strongest gusts may decrease a bit after 04z to around 25 to 30 kt before increasing again during the day Sunday with peak gusts up to 35 kt. Flight categories continue improving to VFR, but there is a chance for brief ceilings around 030 at city terminals through around 21z. KGON will be the last terminal to see improvement late this afternoon. -RA remains possible, especially across eastern terminals. .Outlook for 18Z Sunday through Thursday... .Sunday...VFR. WNW winds G25-35 kt. .Sunday night-Monday morning...Mainly VFR, NW winds G20-25 kt possible early. Chance of showers after midnight. .Monday afternoon-Tuesday...VFR, NW winds G20-25 kt. .Wednesday-Thursday...VFR. && .MARINE... Deepening low pressure continues to track slowly to the north from the coast of Maine into southeastern Canada through Sunday night. Winds and gusts have increased across the forecast waters with gale conditions, in gusts, this afternoon. As the low continues to deepen into Sunday morning, and with cold advection into Sunday morning, gale conditions will continue. The winds and gusts will begin to gradually diminish late Sunday morning into Sunday afternoon. Gale conditions may end by Sunday afternoon across NY harbor and the western Long Island sound. Will leave gale warning posted across all the forecast waters through Sunday. Gusty NW winds 25-30 kt are likely Monday through Tuesday as the pressure gradient remains rather tight. Winds and seas are forecast to decrease on Wednesday and into Thursday as high pressure builds. && .HYDROLOGY... Up to an additional tenth of an inch of rainfall is possible across the region through this evening. Dry late tonight through Sunday evening. Sunday night around a tenth of an inch of rainfall is possible. Rainfall amounts of 1/2 inch or more are possible Thursday into Friday. No hydrologic impacts are anticipated. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Wind Advisory until 6 AM EDT Sunday for CTZ007-008-011-012. NY...Wind Advisory until 6 AM EDT Sunday for NYZ078>081. Wind Advisory until midnight EDT tonight for NYZ072>075- 176>179. NJ...None. MARINE...Gale Warning until 6 PM EDT Sunday for ANZ330-335-338-340-345- 350-353-355. && $$ SYNOPSIS...MET/PW NEAR TERM...MET SHORT TERM...MET LONG TERM...PW AVIATION...DS MARINE...MET/PW HYDROLOGY...MET/PW is the U.S. government's official web portal to all federal, state and local government web resources and services.