Issued by NWS Upton, NY
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983 FXUS61 KOKX 191445 AFDOKX Area Forecast Discussion National Weather Service New York NY 1045 AM EDT Sun May 19 2024 .SYNOPSIS... High pressure over the Northeast will gradually strengthen and build south to the Mid Atlantic states into Monday. The high will then gradually slide east through midweek. A cold front approaches from the west Wednesday night and moves across Thursday into Thursday night. Brief weak high pressure returns towards the end of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... High pressure was strengthening over the northeast and building into the region as the offshore low gradually shifts to the east. Updated to remove the slight chance probabilities across the eastern zones. And with more clearing across the inland areas temperatures have responded to increased incoming solar radiation, and raised afternoon highs a degree or two, especially inland. Although there looks to be enough low-level moisture coupled with daytime heating to allow clouds to reform across this area. Ridging builds in both aloft and at the surface through tonight. This will keep the area under a NE-E flow. Late day clearing is then expected from west to east. Highs today look to be touch warmer than Saturday`s, ranging from the lower to mid 60s across eastern LI/SE CT and the south shore of LI, to the lower and mid 70s for NYC and points north and west. This is very close to normal. For tonight, low clouds may once again reestablish themselves, especially for coastal locations east of NYC. Some drizzle may be possible out on the twin forks of LI. Lows will be in the 50s, which is again close to normal. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/... Early morning low clouds on Monday, especially areas east of NYC, will gradually lift and dissipate by early afternoon. A high amplitude upper level ridge moves across the area Monday into Tuesday, with surface high pressure along the coast gradually sliding east out into the Atlantic. This will be a dry period along with steady climb in temperatures. Highs across the interior will go from the mid ad upper 70s Monday, to the lower and mid 80s on Tuesday. Coastal locations will rise into the lower and mid 70s during this time, except cooler along the immediate south of LI. Lows will be on the climb as well with some locations only getting as low as the lower 60s Tuesday morning. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... *Key Points* ** Summerlike temperatures away from the coast Wed and possibly Thu. ** A cold front approaches Wed Night and crosses the area Thu into Thu Night, bringing a chance for showers and thunderstorms. Upper ridging nosing into the region from the southern US will become suppressed late in the week in response to a closed upper low drifting northeast across southern Ontario/Quebec. Still quite a bit of model spread on the evolution of this upper low between more progressive GEFS and slower ECE/GEPS, which manifests in timing and progressiveness differences in the resultant surface low, and cold front pushing towards the region Wed Night into Thu, and through Thu/Thu Night. Before then, good agreement in high pressure along the coast Monday, sinking SE of the region and developing a return deep SW flow into the region midweek. A shearing shortwave tracks east into northern New England Tuesday Night, with weak surface wave along warm front, but appears this disturbance should remain well north of the region. Otherwise, summerlike temps away from the coast Wed, and potentially Thu (about 10 to 15 degrees above normal). NBM distribution has trended slightly higher than 24 hrs ago, while bias corrected NBM has sunk to near near the 25th percentile. Based on synoptic setup, and 850mb temps 16-17c (a slight upward trend), have continued to utilize the warmer NBM 50th percentile (highs in the mid to upper 80s) for NE NJ and areas to the NW for Wed. NBM 75th percentile has temps in the lower 90s in this area, which is plausible with deep mixing and more of a SW flow. Meanwhile, S/SW flow off mid 50 degree waters will likely keep temps in 70s along the south coast, but still slightly above seasonable. Similar temp distribution possible on Thu if slower progression of cold front (ECE/GEPS) materializes, otherwise a GEFS solution would likely hold temps in the lower to mid 80s for NYC/NE NJ and interior, with 70s coast. Shower/tstm potential exists ahead/along pre-frontal trough and cold front, but coverage/intensity will be dependent with aforementioned upper low and frontal timing differences. A a slight chance for Wed aft/eve west of Hudson, with better chance Thu aft/eve. CSU MLP marginal severe storm threat for areas west of the Hudson River Wed eve, and marginal for much of the region (away from marine influence) and sliver of slight from Mid-Atlantic into NE NJ looks reasonable based on synoptic and thermodynamic setup. Model consensus signals drying conditions on Friday in wake of initial cold front, although secondary cold front/surface troughing likely lingers. Cooler temps than Wed/Thu, but still could be several degrees above normal (70s to lower 80s) with lagging weak caa. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... Weak surface high pressure remains over the area through Monday. Improvement to VFR expected by noontime for most terminals. MVFR cig redevelopment likely late tonight into Monday AM push for most terminals. NE winds around 10kt through today, but a little stronger for KJFK/KISP/KGON. Gusts near 20 kt east of the city. Winds may veer to E/SE in the afternoon. Light E/NE winds tonight. ..NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing and amount of veering of winds from NE to E/SE this afternoon may need amending. OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... Monday...MVFR morning, then VFR. NE winds AM, then SE PM. Tuesday-Wednesday...VFR. S/SW winds with occasional aft gusts to 20 kt. Thursday...VFR, a chance of MVFR with showers and thunderstorms. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Sub-advisory conditions anticipated across all waters through the middle of next week. The exception will be the potential for marginal southerly SCA gusts and ocean seas in and around the entrance to NY Harbor with coastal jet formation Wed aft/eve, and potentially Thu aft/eve dependent on cold frontal timing. Wind/wave conditions likely relax on Friday in wake of the cold front. && .HYDROLOGY... There are no hydrologic concerns through the upcoming week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...NV/DW NEAR TERM...MET/DW SHORT TERM...DW LONG TERM...NV AVIATION...JC/NV MARINE...MET/NV/DW HYDROLOGY...NV/DW