


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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
059 FXUS61 KOKX 191441 AFDOKX Area Forecast Discussion National Weather Service New York NY 1041 AM EDT Sat Apr 19 2025 .SYNOPSIS... A cold front approaches the region late today, crossing tonight. High pressure builds over the northeast Sunday into Monday. A frontal system then moves across the region Monday night into Tuesday. High pressure returns for Wednesday and Thursday with potential of another frontal system for the end of next week. && .NEAR TERM /THROUGH TONIGHT/... Key Messages: * Unseasonably warm temperatures (15 to 20 degrees above normal) areawide today, particularly away from southern and eastern coast, with highs in the upper 70s to mid 80s. * Isolated late day thunderstorms with strong wind gusts possible, mainly N&W of NYC/NJ metro. * Cold water submersion dangers for recreational boaters, canoers or kayakers this weekend with warm air temperatures, but water temps remaining in the 40s. Some adjustments to clouds and thus hourly temperatures were needed with this update as thick canopy of high clouds is pushing through the forecast area. This has led to lower than forecast temperatures in many spots. There is clearing to the west, and once this moves over the region, temperatures are expected to warm into the 70s away from the coast later this morning (where skies are clearer over portions of PA, temperatures are in the lower to middle 70s), and 80s later this afternoon. Some weak returns over Long Island, NYC, and portions of northeast NJ and southern CT have prompted the addition of sprinkles for the next couple of hours. East coast upper ridging holds strong today, giving way to an amplifying northern stream shortwave/closed low tracking east from eastern Ontario into Quebec tonight. At the surface, a developing low pressure system takes a similar track today, intensifying under the upper low tonight, while high pressure remains anchored off the SE US coast. In between, a deep SW flow of subtropical origin air continues to stream into the NE US today, with strong SW surface flow (15-25g25- 35mph) developing later this morning into afternoon as area is squeezed between SE Canadian low pressure and elongated Atlantic high pressure to the south. High-res guidance indicating flow backing more to the WSW away from southern and eastern coastal areas. Potential for a few peak winds gusts to 40 mph in the warmest areas in the late afternoon as llj strengthens ahead of approaching cold front. 850 mb temps have trended a degree or so slightly warmer than 24 hrs ago. With WSW flow and mixing towards 850mb away from southern and eastern coasts, and unseasonably warm temps aloft (+1-2 STD 850mb temps), have continued to lean to NBM 50-75th percentile and HRRR. With temps already starting near seasonable highs this morning, widespread high temps in the upper 70s to mid 80s are expected away from southern and eastern coastal areas (greater maritime influence). This will result in temps approaching records for the date for a few spots. NBM deterministic is still generally running in the lower 25th quartile of guidance for max temps today, which appears to be low based on the anomalously warm airmass. A few high based sprinkles early this morning, otherwise high- res guidance signaling the weakening remnants of MCS activity over the Ohio Valley early this morning potentially bringing a few showers to far NW portions of the Tri- State late morning/early afternoon along with approaching/developing pre- frontal trough. Strong shear profiles and some weak elevated instability warrant slight chance pops. More likely is this activity weakening, but bringing an increase in convective debris to filter sunshine this afternoon, which could limit max heating potential. A distinct but inconsistent signal for a line of broken convection developing along/ahead of approaching cold front over western/central NY/PA this afternoon, and/or a series of convective line segments developing out ahead off previous MCS activity, moving into the region this late today/this evening. With weak and waning instability over the coastal plain this evening, and best forcing still well to the N&W, this convection will likely be weakening as it enters the region. But with strong deep layer shear, and relatively steep mid-level lapse rates realizing weak elevated CAPE, this will bring potential for scattered shra/tsra late today/this evening for areas well N&W of NYC, likely weakening to isolated activity as it slide to the coast. Severe weather is not expected, but any thunderstorms could produce strong wind gusts based on strong low-level winds and steep low-level lapse rates. Cold front pushes south of the entire region by midnight, with a windshift to the NW advecting in a much cooler and drier airmass. Temps will remain unseasonably mild for this time of year with mixed low-levels (mid to upper 40s interior to lower to mid 50s coast) && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Key Messages: * Much cooler but still above normal temps on Sunday (High is the lower to upper 60s). * Below seasonable temperatures on Monday. Vigorous northern stream closed low slides east through the Canadian Maritimes on Sunday into Sunday Night, with southern upper ridging building back towards the region Sunday Night into Monday. At the surface, a cold front pushes well south of the region by Sunday AM, with weak Canadian high pressure building in Sunday Night and sliding east on Monday. Overall gusty NW winds 10-20G20-30mph, drier and much cooler conds expected Sunday. Temps will still run several degrees above normal with unseasonably mild start to the day and deep mixing and plenty of sunshine in a gradual caa regime. Have stayed close to NBM 50th for temps based on the above, which has a better representation of warmer temps along the coast in NW flow than the NBM deterministic. Temps in the lower to mid 60s interior and mid to upper 60s for city/coast. Canadian high pressure noses in Sunday Night with potential for good radiational cooling conds for pine barrens of LI and interior Tri-State with temps dropping into the lower to mid 30s and bringing frost conditions. 40s elsewhere for the city/coast.. Meanwhile, a vigorous closed upper low over the SW US lifts through the central plains on Sunday and into the upper Great Lakes on Monday, with a resultant low pressure system taking a similar track, and associated warn front approaching Monday Night. A strengthening return SE flow develops Monday as high pressure slides offshore. Maritime flow off mid 40 degree waters, and developing/ne advecting stratus under a strong low-level inversion, will likely result in temps running a few degrees below seasonable across the region on Monday, from mid 50s along southern and eastern coasts to around 60 interior. LLJ will strengthen ahead of approaching trailing cold/occluded front Monday Night, with warm front approaching and entering the region just ahead of it. Modest theta-e advection and lift over this boundary will bring potential for scattered showers Monday Night. Limited forcing and moisture will keep QPF light. && .LONG TERM /TUESDAY THROUGH FRIDAY/... There has been little change to the overall forecast thinking in the long term and have stuck close to the previous forecast/NBM. The long term period starts off with a chance of showers on Tuesday, mainly in the morning with as a cold front approaches and move across the region during the afternoon/evening hours. Thereafter, weak high pressure remains over the region Wednesday and Thursday. The high moves east on Friday, with another shortwave/low pressure system approaching for late Friday into the weekend. Mainly looking at just chance POPs (30-35 percent) late Friday into the weekend for now. The warmest day of the week will be Tuesday with highs in the NYC/NJ metro area reaching the upper 70s. The remainder of the region will see highs in the 60s and lower to middle 70s. Mid 60s to mid 70s can be expected Wednesday and Thursday, and 60s and lower 70s for Friday and Saturday. Locations right along the immediate coast will likely see slightly cooler temperatures. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... A cold front approaches from the west today, and moves across the area this evening and overnight. VFR through at least 19-20Z. MVFR possible in any isolated to scattered showers and/or thunderstorms. Best chance for any showers or thunder after 21Z. PROB30 was used to highlight this chance for SWF/HPN with TSRA. SHRA elsewhere. WSW-SW winds will increase to 12-20kt G22-30kt into early afternoon. Winds shift to the W then NW with the cold frontal passage. Gust end for a period overnight, but pick up once again between 10z-12z Sunday morning with gusts into the mid 20kt range. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Can not rule out a peak gust above 30kt. Chance of an isolated thunderstorm Saturday evening especially EWR/TEB. .OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY... Sunday: VFR. NW wind gusts around 20kt possible. Monday: VFR, then sub VFR possible at night with a chance of showers. Tuesday: Becoming VFR with W winds. Wednesday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... After a brief lull in SCA winds early this morning, SCA wind gusts expected to develop on all water this morning and continue through this afternoon. Ocean seas build to 5 to 8 ft today. Nearshore winds should subside below SCA this evening, with potential for a brief burst of marginal SCA gusts in wake of cold front between 03z and 08z tonight. Otherwise winds should subside below SCA on the ocean late in the evening (after 03z). Sub SCA winds then expected on all waters Sunday through Monday as high pressure moves across the waters, but southerly SCA ocean swells may take until Sunday afternoon to fall below 5ft. Marginal SCA conditions possible on the ocean waters Monday Night into Tuesday morning ahead of cold frontal passage. Otherwise, conditions will remain below SCA levels Tuesday afternoon through Friday with a relatively weak pressure gradient over the waters. && .FIRE WEATHER... Marginally elevated wildfire spread threat today and Monday. Dry conditions remain. There is potential for scattered showers N&W of NYC this evening, and isolated showers elsewhere. A widespread wetting rain is not expected. Highs in the upper 70s to mid 80s, with southwest winds of 15 to 25 mph with gusts 25 to 35 mph and min RH values in the 35 to 45 percent range. Highs in the 60s on Sunday, with northwest winds of 10 to 20 mph with gusts 20 to 30 mph and min RH values in the mid 20 percent range. && .HYDROLOGY... There are no hydrologic issues through next week. && .CLIMATE... Record high temps for Today April 19th. Temps will approach records at BDR, LGA, JFK, ISP. EWR...92 BDR...82 NYC...92 LGA...85 JFK...84 ISP...82 && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ331- 332-335-338-340-345. Small Craft Advisory until 2 PM EDT Sunday for ANZ350-353. Small Craft Advisory until 11 AM EDT Sunday for ANZ355. && $$ SYNOPSIS...BC/NV NEAR TERM...JP/NV SHORT TERM...NV LONG TERM...BC AVIATION...DBR MARINE...BC/NV FIRE WEATHER... HYDROLOGY...BC/NV CLIMATE...