Sources: ACIS GridData (grid 1, NRCC interpolated) for the divisional/statewide table; 1991–2020 normals computed in-run from grid 1; nClimGrid-Daily prelim (NJ divisions 2801/2802/2803) as cross-check; ACIS MultiStnData/StnData for Threadex airports (EWRthr, TTNthr, ACYthr, PHLthr, NYCthr) and the full NJ CoCoRaHS/mesonet network; IEM ASOS archive for dewpoint/MSLP; SPC storm reports; IEM VTEC event archive; IEM LSR archive; IEM AFOS archive for AFDPHI/AFDOKX. All seven climate-day labels (9/14–9/20) are populated. Narrative day-specific claims use calendar-day station data; the divisional table uses climate-day (7 AM–7 AM) grid labels — see Data Notes for the boundary effect this produces at the start of the week. Server cross-checks (SPC reports pages returning HTTP 200 through 260924; NCEI nClimGrid-Daily September prelim file stamped 2026-09-24 04:52 UTC) confirm the system date of September 24, 2026 is accurate; data pulled that date.
The report week — climate days Monday, September 14 through Sunday, September 20 — settled into a warm, mostly dry regime bracketed by two rain-producing frontal systems that largely missed the report window itself. Statewide mean temperature ran 69.4°F, 3.3°F above the 1991–2020 normal, with the anomaly skewed toward overnight lows and strongest along the coast (Coastal Division +4.1°F) versus the Highlands interior (Northern Division +2.5°F), where clear high-pressure nights allowed better radiational cooling. Statewide precipitation totaled only 0.67", 63% of normal, and nearly all of it traces to two narrow windows: a warm-frontal flash flood that struck Morris–Passaic–Bergen counties on Sunday, September 13 (which loads onto the Monday climate-day label under the 7 AM–7 AM convention) and a Saturday night–Sunday cold-frontal soaking that closed the week across the Mercer–Camden corridor. No SPC storm reports and no VTEC warnings were issued anywhere in New Jersey between Monday and Sunday — an otherwise quiet, non-convective seven days sandwiched between two frontal rainmakers.
Climate days 14–20 September (7 AM–7 AM). Normals computed from ACIS grid 1, 1991–2020, for the same calendar dates. The Monday (9/14) label's max-temp and precipitation contributions reflect the preceding Sunday afternoon/evening (9/13), not the calendar week itself — see Data Notes.
| Div | Mean Max | Mean Min | Mean Avg | Normal | Dep | Pcpn | Normal | Dep | % |
|---|---|---|---|---|---|---|---|---|---|
| Northern (NJ01) | 76.7 | 56.8 | 66.8 | 64.3 | +2.5 | 0.94 | 1.18 | −0.25 | 79% |
| Southern (NJ02) | 80.2 | 61.1 | 70.7 | 67.1 | +3.7 | 0.54 | 1.01 | −0.47 | 54% |
| Coastal (NJ03) | 79.8 | 63.9 | 71.9 | 67.8 | +4.1 | 0.29 | 0.91 | −0.63 | 31% |
| Statewide | 78.9 | 59.7 | 69.4 | 66.1 | +3.3 | 0.67 | 1.07 | −0.40 | 63% |
The temperature gradient across divisions is a minimum-temperature story, not a maximum-temperature one: mean-min departures (Northern +3.9°F, Southern +4.7°F, Coastal +5.5°F) run roughly double the mean-max departures (+1.2°F, +2.6°F, +2.7°F respectively) at every division. That pattern is consistent with a week where warm advection and elevated humidity — not clear-sky ridging — drove most of the anomaly, limiting nocturnal radiational cooling everywhere but especially along the coast, where the Atlantic's still-warm September water temperatures put a hard floor under overnight lows and compress the diurnal range (Coastal mean diurnal range 15.9°F versus 19.9°F Northern). The Highlands interior of the Northern Division retained enough capacity for radiational cooling on the two clear high-pressure nights (9/14–15, 9/18–19) to hold its warm departure to the smallest of the three divisions. The precipitation gradient is a rainfall-axis story: essentially the entire divisional pcpn total came from the Sunday, September 13 warm-frontal flood, which was centered over Morris/Passaic/Bergen (Northern Division) and decayed southward, leaving the Southern and especially Coastal divisions well below normal for the week.
Sunday, Sept. 13 (pre-period context for the Monday climate-day label): A weak wave of low pressure and an associated warm front lifted north across the Middle Atlantic overnight into Sunday morning, tapping a tropical airmass with precipitable water near 2.0–2.5" (KOKX AFD: "2.03" PWATs is the max moving average this time of year"). Rain rates to 2"/hr produced the flash flood detailed in Section 4. The system was progressive, clearing to Long Island by midday with a secondary cold front following overnight into Monday.
Mon. Sept. 14 – Tue. Sept. 15: Behind the departing low, high pressure built in quickly. The EWR dewpoint/MSLP ledger shows the exchange plainly: mean Td fell from 68.5°F (9/13) to 51.9°F (9/14) to 49.8°F (9/15) while mean MSLP rose from 1012.5 to 1017.5 to 1027.7 mb. Skies were mainly clear with light winds; highs settled into the mid-70s to near 80 south, lows dropped into the 50s with upper-40s in the Poconos/NW NJ fringe.
Wed. Sept. 16 – Thu. Sept. 17: The high slid offshore and southwesterly return flow developed, driving a steady warm-advection climb: Td rebounded to 59.7°F (9/16) then 67.4°F (9/17) as MSLP eased to 1026.8 then 1021.7 mb. Highs reached the low-to-mid 80s (TTN 82–84°F) with rising humidity ahead of an approaching cold front out of the Ohio Valley.
Thu. night Sept. 17 – Fri. Sept. 18: The front crossed overnight, producing scattered showers and a few downpours (AFDPHI cited rates near 1"/hr) but with instability outrun by the front's forward speed — no severe weather resulted. Clearing followed by Friday.
Fri. Sept. 18 – Sat. morning Sept. 19: A second, reinforcing high built in from the north, again crashing the airmass: EWR mean Td fell from 62.0°F (9/18) to 50.8°F (9/19) as MSLP rose to 1021.3 mb, giving a notably cool, comfortable Saturday morning.
Sat. night Sept. 19 – Sun. Sept. 20: Low pressure organized over the Midwest with an attendant warm front lifting north through the region Sunday afternoon, quickly followed by a cold front Sunday evening. Easterly-to-southeasterly flow pulled PWATs back toward 2" (AFDPHI: "well above the 90th percentile"), but with limited instability the resulting rain was broadly stratiform rather than convective. Td at EWR jumped from 50.8°F to 62.5°F and MSLP fell from 1021.3 to 1015.6 mb across the transition, closing out the week.
Sept. 13 flash flood (Morris–Passaic–Bergen corridor — the event underlying the Monday climate-day label). Training showers and embedded storms along the lifting warm front concentrated over Morris, Passaic, and Bergen counties, with local mesonet totals of 4.32" (1 NW Florham Park), 4.28" (1 SW Towaco), 4.04" (Lincoln Park), and 3.96" (Whippany), and CoCoRaHS totals of 4.90" (Hawthorne, network maximum), 3.46" (Fair Lawn), 3.41" (Wayne Twp), and 3.25" (River Edge). Threadex airport totals for the same calendar day were far lower — EWR 0.48", TTN 0.98", PHL 1.47", ACY 0.28", NYC 0.96" — illustrating a sharp rainfall gradient between the sharply focused training band and the surrounding airport network. Fire Dept/Rescue-, Law Enforcement-, and NJDOT-sourced reports (strong tier) logged numerous water rescues and road closures: Paterson and Woodland Park businesses under 2 ft of water, NJ-208 northbound closed at Glen Rock, NJ-57 flooded near Pleasant Valley (Warren Co.), and street closures in Norwood, Haworth, Maywood, and Oradell. IEM VTEC logged a Flood Watch (issued 9/13 04:00Z, area-wide), four Flash Flood Warnings (Morris; Essex/Hudson/Bergen/Passaic; Mercer/Middlesex; Bergen), and a Flood Warning for the Passaic River basin in Bergen County (through 22:29Z). No SPC severe reports accompanied the event — this was purely a heavy-rain/QPF flood, not a convective-wind or hail event. The dominant rain event for the Northern Division's weekly total is this one, and per the ACIS-grid-1/normals-computation methodology used here, the smoothed nClimGrid product should be expected to show somewhat less; see Data Notes.
Thu. night Sept. 17 frontal passage. Fast-moving showers, locally to 1"/hr, produced only light general totals (0.1–0.3") with isolated readings near an inch; no severe reports.
Sat. night Sept. 19 – Sun. Sept. 20 frontal rain. With PWATs elevated but instability low, this event was steadier and less spatially discontinuous than the 9/13 flood. The heaviest totals fell along the Mercer–Camden–Burlington corridor: Pennsauken 1.46", Ewing 1.18" and 1.05" (two gauges), and Trenton 1.03" (both the CoCoRaHS Trenton-area gauge and Trenton-Mercer Airport agreed to the hundredth). North Jersey and coastal totals were lighter (EWR 0.26", NYC 0.28", ACY trace), a gradient roughly opposite the 9/13 event and consistent with the front's axis settling south through the day Sunday.
No tornado, wind, or hail reports were logged in New Jersey by SPC for any day in climate days 13–20, and no LSRs were filed for the calendar week of 9/14–9/20 itself — the only impactful reports of the period belong to the pre-period 9/13 flood.
Forward look (AFDPHI, 7:47 PM EDT Sun. Sept. 20): a cold front clears the region tonight; a frontal boundary stalling to the south keeps rain chances alive, especially across southern NJ, through midweek; a closed mid-level low ejecting from the Ohio Valley may spin up a new coastal surface low during the middle-to-latter part of the coming week, with the potential for increased rainfall depending on track; multiple rounds of tidal flooding are possible beginning as early as Tuesday evening, September 22.