Area Forecast Discussion
Issued by NWS Upton, NY

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509 FXUS61 KOKX 191129 AFDOKX Area Forecast Discussion National Weather Service New York NY 729 AM EDT Thu Sep 19 2024 .SYNOPSIS... Low pressure hovers southeast of Long Island through early this evening and then moves slowly farther out into the Atlantic thereafter through Friday night. Low pressure lingers offshore through Saturday. High pressure builds in from the northeast Sunday through Tuesday. A frontal system approaches from the west Wednesday into Thursday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Upper levels depict an overall a trough pattern but are devoid of any jet streaks or wind maxima over the local region. A mid level trough remains across the area. PVA increases across eastern sections of the region for the afternoon into early evening. Low level jet starts to develop to the west and northwest of the low center, potentially expanding and getting over eastern portions of the region late today into early this evening. Low pressure remains nearly stationary southeast of Long Island right near the 40N/70W benchmark through today. Low pressure does deepen during this timeframe, dropping nearly 4mb. NAM appears to have more rain across the local area compared to the GFS, ECMWF and Canadian models. Conditions have been drier than previously forecast so going to continue with a downward trend in POPs. BUFKIT model soundings are also indicating lots of dry air between 900 and 600 mb, limiting moisture needed for collision coalescence. Favoring the overall drier consensus with regards to the rainfall forecast. Expecting mainly dry conditions through today. Slight chance to chance POPs spread from east to west across Eastern Long Island and SE Connecticut this afternoon. Max temps today use 3/4 MET (cooler) and 1/4 MAV (warmer).
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&& .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
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Upper levels continue to indicate both a trough pattern and the lack of any jet streak or wind speed maxima. Mid level trough moves slowly east of the region, and eventually becomes a cutoff low that slightly deepens Friday through Friday night. Higher PVA remains mainly across eastern sections of the region, Southern CT and Long Island. Low level jet remains west to northwest of the low center and stays just outside of the region or just brushing over the eastern parts of the region within SE CT and Eastern Long Island. Low pressure slowly moves farther out into the Atlantic and remains within a few mb of its previous central pressure tonight through Friday night. Canadian and ECMWF models show more rain moving in from NE to SW late tonight into early Friday to better agree with the NAM. GFS still keeping the area dry. GFS still mainly dry Friday into early Saturday and NAM for this particular time frame also decreased the rain. The ECMWF and Canadian models depict relatively more rain across the area, especially for Southern CT and Long Island, compared to the NAM and GFS. POPs adjusted to have chances for eastern sections, likely for Friday with otherwise slight chances to the west for this tonight through Friday night timeframe. Drier conditions and less clouds and thereby warmer temperatures for more western locations Friday compared to more eastern locations. Min temps tonight use MAV/MET even blend. Max temps Friday use NBM. Min temps Friday night use NBM with a slight adjustment up for Pine Barrens LI.
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&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/... **Key Points** *Improving conditions Saturday into Sunday as high pressure builds into the region. *Downward temperature trend to slightly below normal temperatures expected by early next week. *A frontal system Wednesday into Thursday will bring with it additional chances for showers. Global guidance continues to depict the slow moving upper low/trough situated over New England to start the period. There are varying degrees of eastward progression on Saturday, though there is consensus that heights will begin to rise as the low moves east by Saturday afternoon. Thus, expecting a cloudy, and windy, Saturday with perhaps some lingering showers thRough Saturday evening, primarily for eastern Long Island and SE CT. Northeast winds will begin to relax by Sunday afternoon as the low departs and the pressure gradient weakens. Thereafter, upper ridging begins to build in with surface high pressure nosing in from the north. Dry conditions are generally expected Sunday through Tuesday. A slightly cooler airmass advects into the area for Monday and Tuesday under easterly flow and highs in the upper 60s and low 70s. The airmass begins to moderate somewhat on Wednesday, though still below normal in the low 70s, with increasing cloud cover and a chance of showers from an approaching frontal system to the west. Guidance varies on timing, with some starting showers as early as Tuesday night, while others keep the rain away until Thursday morning. Overall, not expecting this to be a very impactful system, rather just another chance for passing showers as the low passes north with a front dragging through our area. The NBM was primarily used for the forecast, except some adjustments were made to POPs using CONSALL and some low temperatures were blended with BCCONSALL on Saturday, Sunday and Monday nights. && .AVIATION /11Z THURSDAY THROUGH MONDAY/...
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Low pressure remains offshore, southeast of Long Island, through Friday. VFR. Winds remain NE to N increasing overnight, especially at the coast terminals, then winds increase during the day today with gusts 20-25kt. Gusts may drop tonight, but pick up again tomorrow 20-25 kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... No amendments expected. Should any be needed, it would likely relate to wind gusts and/or directions being off. OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... Saturday: VFR. MVFR east of the NYC terminals possible in showers, but low chance of occurring. NE gusts around 25kt possible. Sunday: VFR. NE gusts 20-25kt possible. Monday...VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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&& .MARINE...
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SCA level seas remain on the ocean and are expected to stay through Friday. SCA level winds will be more difficult to get but are expected to get more into that range for Friday. SCA kept for non- ocean waters as some model guidance continues to indicate SCA level gusts for this afternoon and tonight. However, due to decreasing confidence did not extend non-ocean zones through day on Friday with SCA. Friday night, likely ocean remains with SCA with non-ocean waters having some locations get SCA level gusts probably. 5-7 ft waves and 25-30kt gusts will continue to be an issue on ocean waters this weekend and at the start of next week. While the LI Sound and Bays may not see 5+ ft waves, gusts near 25 kt will be possible until Sunday night.
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&& .HYDROLOGY... There are no hydrologic issues through the middle of next week. && .TIDES/COASTAL FLOODING...
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Multiple rounds of coastal flooding are expected through this weekend with low pressure churning offshore, giving a steady NE flow and piling of water. That along with building seas, and a recent full moon are leading to higher total water levels forecasts. Today and tonight will feature minor coastal flooding for much of the coastline across SW CT, NYC, and Western Long Island. Statements and advisories are out to address this. It appears the morning into afternoon today will be relatively higher of the total water levels forecast looking through tonight. This continues but with more surge on Friday. Widespread minor for most coastal flooding Friday. Some coastlines Friday as a result will have their total water level forecasts reach into the moderate coastal flood category, particularly within the South Shore Bays and along the Western Long Island Sound coastlines. This is where a coastal flood watch has been issued. ETSS and just the 50th percentile of Stevens are indicating this moderate coastal flood forecast. In addition, Eastern Long Island and SE Connecticut could get minor coastal flooding Friday. More coastal flooding can be anticipated for this weekend during the times of high tide. There will be minor to locally moderate coastal flooding.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Coastal Flood Advisory until 2 PM EDT this afternoon for CTZ009. Coastal Flood Advisory from midnight tonight to 3 AM EDT Friday for CTZ009. Coastal Flood Watch from Friday morning through Friday afternoon for CTZ009. NY...Coastal Flood Advisory until 2 PM EDT this afternoon for NYZ071-073-078-176-177. Coastal Flood Advisory from midnight tonight to 3 AM EDT Friday for NYZ071. Coastal Flood Watch from Friday morning through Friday afternoon for NYZ071-073-176-177. Coastal Flood Advisory until 11 AM EDT this morning for NYZ072- 074-075. Coastal Flood Advisory from 8 PM to 11 PM EDT this evening for NYZ074-075. High Risk for Rip Currents through Friday evening for NYZ075-080- 081-178-179. Coastal Flood Advisory until 2 PM EDT this afternoon for NYZ080. Coastal Flood Advisory from 8 PM this evening to 2 AM EDT Friday for NYZ080-178-179. Coastal Flood Advisory until noon EDT today for NYZ178-179. Coastal Flood Watch from Friday morning through Friday afternoon for NYZ178-179. NJ...Coastal Flood Advisory until 11 AM EDT this morning for NJZ006- 106-108. Coastal Flood Advisory from 8 PM to 11 PM EDT this evening for NJZ006-106-108. MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ331-332-335- 338-340-345. Small Craft Advisory until 6 PM EDT Friday for ANZ350-353-355.
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&& $$ SYNOPSIS...JM/BR NEAR TERM...JM SHORT TERM...JM LONG TERM...BR AVIATION...BR MARINE...JM/BR HYDROLOGY...JM/BR TIDES/COASTAL FLOODING...JM