Area Forecast Discussion
Issued by NWS Upton, 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
000 FXUS61 KOKX 281108 AFDOKX Area Forecast Discussion National Weather Service New York NY 708 AM EDT Sun May 28 2023 .SYNOPSIS... High pressure will be in control through the remainder of the holiday weekend. A backdoor cold front moves through on Monday, otherwise high pressure will dominate the upcoming week, with weakening southern low pressure tracking south of the region. A cold front then approaches Friday and passes though late Friday. Canadian high pressure builds back into the region for the weekend. && .NEAR TERM /THROUGH MONDAY/... A blocking upper high will remain from the Great Lakes into the Northeast through Monday, while an upper low meanders over the southeast states. A shortwave will pass across southeast Canada and the Maritimes tonight helping to push a backdoor cold front through the area on Monday. High pressure will otherwise be in control of the weather. The center of the high will be situated southeast of the area today allowing southerly flow to continue through the day. Coastal locations will see highs in the lower to middle 70s with inland areas and points just NW of the city reaching the upper 70s to around 80 degrees. Temperatures tonight will be milder than the last few nights with lows in the low 60s in the NYC metro and 50s elsewhere. Mostly clear skies are expected through tonight although there will be some cirrus clouds near the coast from time to time. This high level moisture is from the upper low over the southeast. However, the upper ridging and subsidence will keep any of the thicker high clouds well to our south. The backdoor cold front moves through Monday afternoon. The front will move through the region dry, but shift winds to the E and then NE late. Temperatures should still be able to warm into the 70s for most and lower 80s across the Lower Hudson Valley and northeast NJ. The E flow increases in the afternoon as the front moves through bringing a shot of cold advection. Temperatures will begin to fall into the 60s in the mid to late afternoon across Long Island and southern Connecticut and then start reaching the rest of the area in the early evening. E-NE winds 10-15 mph with gusts 20-25 mph are expected, strongest near the coast late in the day. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... A reinforcing high pressure builds over New England Monday night, remaining nearly stationary on Tuesday. The high weakens a bit on Wednesday, but will still dominate the surface pattern. Not much change is anticipated aloft with the blocking upper high remaining in place over the northeast. The upper low over the southeast may slowly lift towards the Middle Atlantic coast into the midweek. However, the upper ridging will continue to provide subsidence and keep any precipitation to our south. Breezy conditions will continue Monday night, especially near the coast. Lows will fall into the middle and upper 40s inland and lower to middle 50s near the coast. Highs on Tuesday will likely end up slightly below normal with continued E flow. Highs will range from the upper 60s (coast) to middle 70s (well NW of NYC metro). Cool conditions are expected again on Tuesday night similar to those forecast on Monday night. Moderating temperatures likely occur on Wednesday as the E flow is much weaker and gradually becomes SE in the afternoon. Highs will range from the lower to middle 70s south to upper 70s and low 80s north. Some cirrus clouds are likely to move overhead as the aforementioned upper low starts to reach the Middle Atlantic. These clouds should not impact sky conditions much with mostly sunny skies both Tuesday and Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Persistent ridging surface/aloft breaks down midweek, allowing the filling southern US closed low to drift northeast towards the area Wed/Thu. Models have trended a bit slower and farther north with this low, eventually shearing it east and offshore Friday ahead of a strengthening SE Canada upper low drifting south. Troughing around the northern upper low will exert its influence on the NE US heading into the weekend. Surface high pressure continues to weaken Wednesday into Wednesday Night, while the weakening southeastern low drifts NE off the Mid Atlantic coast. Its precip shield will get close as the low passes just to the south, with a low probability of skirting southern portions of the area Wed NIght into Thu. There has been a slower and farther northward trend with this low over the last 48 hours, so will have to see if POPs trend upward a bit for Wed Night/Thu. Accordingly, temps will be a bit tricky Thu, based on evolution of the shearing low and amount of associated high/mid clouds. Have stayed close to NBM deterministic based on this uncertainty, although noted that deterministic is running between the 10th and 25th percentile of NBM ensemble spread. With WNW flow aloft advecting in a very warm airmass (building across Ontario and Quebec midweek) ahead of an approaching cold front, this still presents very warm conditions across the area (upper 80s to around 90s for NYC/NJ metro and point N&W to upper 70s/lower 80s for the coast) . The weak flow, leading to progressive afternoon seabreeze development, along with potential cloud cover, would limit potential to reach the max temp potential of lower to mid 90s across interior and well into the 80s for the coast signaled by the NBM ensemble 50th percentile. Greatest potential for hot and dry conditions appears to be Friday with continued W/NW flow aloft advecting in 850hpa temps of 16-17C, downslope flow, and deep mixing above 850mb. Timing of cold front passage is one caveat, although medium range guidance has trended slower with this, more towards evening. NBM deterministic is currently running at or below the NBM ensemble 10th percentile, which is still lower 90s NYC/NJ metro and interior and well into the 80s for the coast (about 15 degrees above seasonable). Have blended NBM deterministic with NBM ensemble 50th percentile based on ideal downslope heating setup, which may still be too conservative based on NBM deterministic performance in these events. Potential for forecast high temps to trend into the lower to mid 90s across NYC/NJ metro and interior, and upper 80s to lower 90s for much of the coast if the downslope set-up become realized. Heat indices will likely be at or below ambient temps due to the dry airmass. The cold front passes through sometime Friday eve, although timing is still uncertain. Moisture and forcing will be limited in NW flow regime, which should limit shower/tstm activity to isolated at best with passage. Canadian maritime high pressure builds towards the area Friday Night into Saturday with gradual caa and dry conditions, but temps still likely running a few degrees above seasonable in the upper 70s to lower 80s Saturday. Canadian maritime airmass may become more entrenched Sunday, with continued dry conditions but temps falling to near seasonable. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/... High pressure gradually weakens and moves offshore today into tonight. A backdoor cold front approaches Monday late morning/afternoon. VFR conditions. Light S/SW flow for the morning push, gives way to afternoon S/SSE 10-15kt seabreeze development this afternoon. S winds diminish during the evening push, becoming light and variable tonight. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Light S/SW flow, gives way to afternoon S/SE 10-15 kt seabreeze. Timing of seabreeze could be off by an hour or so. A few gusts to 20 kt possible for KJFK/KLGA in the late afternoon. OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... Monday: VFR. Light NE winds for early AM push, then fropa with E winds 15G20-25kt during the late morning. Fropa could be as early as tail end of morning push. Tuesday through Thursday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/ && .MARINE... Cold water headlines continue through the holiday weekend for cold water immersion threat from sub 60 degrees waters. A relatively weak pressure gradient this weekend will keep conditions below SCA levels through Sunday night. Winds may approach 25 kt Monday afternoon and evening on the ocean, LI Bays and eastern LI sound as a backdoor cold front moves through. Ocean seas may also reach 5 ft late Monday afternoon into Monday night. Have held off on an SCA issuance for now based on collaboration with neighboring offices. The gradient relaxes by Tuesday morning with sub SCA conditions continue through the end of the week. Persistent SE swells gradually subside middle to late week. && .HYDROLOGY... The prolonged stretch of dry weather continues through the upcoming week. && .TIDES/COASTAL FLOODING... A moderate risk of rip current development at Atlantic Ocean beaches continues today with 3ft@7-8 second SE swells today. An increasing E flow Monday may bring seas close to 5 ft late Monday afternoon. A moderate risk of rip current development continues, but a high risk may be needed for Monday afternoon if the seas build several hours faster than currently expected. Rip current activity will likely be enhanced in vicinity of groins, jetties, and piers through this period with E to W longshore current. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...DS/NV NEAR TERM...DS SHORT TERM...DS LONG TERM...NV AVIATION...NV MARINE...DS/NV HYDROLOGY...DS/NV TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.