Can Artificial Intelligence Outperform Professionals in Forecasting New Jersey's First Winter Storm?

Snowfall forecasts often shape how communities prepare for winter weather. I ran two AI models, Grok and ChatGPT 5.1 to see how their predictions for December 2nd compare with traditional meteorologists’ forecasts. Below are the forecasts from both models.

AI Models and Their Forecasts

Both Grok and ChatGPT 5.1 use advanced algorithms and large datasets to generate weather forecasts. However, their approaches and outputs vary in detail and focus.

Grok’s Forecast

As we wrap up a crisp December 1st with mostly cloudy skies and temps in the low 40s°F (per real-time observations from the latest weather API pull), the stage is set for our first true taste of winter tomorrow. I've crunched the freshest data: ECMWF/GFS 12Z ensembles (showing a deepening coastal low to ~1006 mb off DelMarVa), high-res HRRR/NAM for local bursts, current surface observations (cold front stalled near I-78 with 850mb temps at -6°C to -8°C), and historical analogs from similar early-Dec setups (e.g., 2018 and 2020 storms that delivered 3-6" north before mixing south). Climatology adds context—early December clipper/hybrids like this hit NJ ~50% of the time with 1-4" north, but today's warmer Atlantic blob (SSTs +1-2°F above normal) sharpens the rain-snow line along ~I-195.

The consensus? A potent but fast-moving system: snow-dominant northwest (thanks to orographic lift in the Skylands), quick mix-to-rain central/south. Total liquid equiv.: 0.8-1.3" statewide, but snow efficiency drops eastward (80% north, <20% coast). Confidence: 85% on precip timing, 70% on totals (GFS bullish north, ECMWF hedges on coastal stall). This isn't a nor'easter bomb, but it'll disrupt—think first-plow chaos and slushy Shore drives. Statewide snow avg.: 2-4", a solid kickoff to our mild-but-active winter (per my seasonal call).

What to Expect: Overview and Impacts

This hybrid coastal system dives from the Ohio Valley tonight, deepening offshore by midday Tuesday under a 120+ kt upper jet. Cold air locks in pre-dawn (surface temps 28-32°F), fueling fluffy snow north before warm advection (from a SW flow) flips the script south. Expect:

• Snow Quality: Dry/powdery northwest (ideal for building snowpeople), wet/slushy central (quick melt on roads).

• Winds: Gusts 30-45 mph (higher coast, 50+ in squalls)—could scatter flurries and down branches.

• Impacts:

  • Travel: Hazardous morning commute—slick I-80/I-78 bridges/overpasses; delays at EWR/PHL airports. Evening rush sloppier south with hydroplaning.

  • Power/Schools: Outages possible in rural Sussex (wet snow on lines); snow days likely northwest, delays statewide.

  • Other: Minor coastal flooding (tides +1-2 ft above normal); no major ice, but sleet pockets central could glaze untreated surfaces. Urban heat islands (NYC/Philly spillover) shave 0.5-1" off Essex/Camden totals.

• Wild Cards: 20% chance northern track adds 1-2" everywhere; 15% southern stall = all-rain south/central, trace north.

Timeline: Start, Peak, and End (All Times EST)

Fast mover—precip wraps in ~12 hours. Based on ensemble timing and current radar (light upstream bands approaching).

• Tonight (Dec 1, 8 PM-Midnight): Dry/cloudy buildup. Isolated flurries west ~10 PM (20% PoP). Lows 26-30°F.

• Tuesday, Dec 2 (Main Event):

  • Start: Light precip ~2-4 AM west (Sussex first), 4-6 AM statewide—initial snow or mix.

  • 6-10 AM: Steady snow ramps (rates 0.5-1.5"/hr north); transition sleet/rain central/south by 8 AM.

  • 10 AM-4 PM: Peak—heaviest bands northwest (1-2"/hr bursts); full rain south. Highs 32-38°F (colder north).

  • 4-8 PM: Tapers to flurries/showers; dry after 9 PM. Evening commute messy central.

  • End: Precip ends ~10 PM statewide; clear skies overnight.

NOTE: I had to prompt Grok to use SQL to give me a read-out for its snow map prediction, which I put together in QGIS. Generating its own snow map was a big failure but it does well with county recognition to allow QGIS to do the rest of the work

GROK used QGIS code to make a snow map.

ChatGPT 5.1’s Forecast

A coastal low approaching from the south will spread precipitation into New Jersey Tuesday morning. Cold air in the lower levels is limited, especially away from the northwest hills, meaning this storm will feature a snow-to-rain transition for much of the state. Areas in far northwest New Jersey will hold onto cold air longer and see the bulk of accumulating snow.

This will not be a widespread shovel event statewide, but parts of Sussex and Warren Counties may receive plowable snowfall before mixing and changing to rain.

Snowfall Forecast for New Jersey

Northwest Hills (Sussex, Warren, higher terrain of Passaic)

Expected Snow: 3–6 inches

Cold air hangs on the longest here, allowing several hours of accumulating snow Tuesday morning. The snow will be wet and heavy, with a mix or change to rain after midday. Road conditions will be most problematic in this region during the morning commute.

Interior North & Central (Morris, Hunterdon, Somerset, parts of Mercer/Middlesex/Monmouth)

Expected Snow: 1–3 inches

These areas will start as snow or a snow/sleet mix but will transition to rain by late morning or early afternoon. Accumulations will be highest on grassy and elevated surfaces, with roads generally turning wet as temperatures rise.

I-95 Urban Corridor (Bergen, Essex, Union, Hudson)

Expected Snow: Coating to 1 inch

A brief burst of snow is possible at the onset, but surface temperatures and warm air aloft will quickly lead to a changeover to rain. Travel impacts here will be low.

Southern NJ & Coast (Ocean, Burlington south of I-195, Camden, Gloucester, Salem, Cumberland, Atlantic, Cape May)

Expected Snow: Trace to 0.5 inches – mostly rain

South and coastal areas may see a few flakes or sleet pellets early, but the storm is primarily a cold rain event. Little to no accumulation is expected.

🕒 Storm Timing

• 5–7 AM: Snow begins in far NW NJ

• 6–9 AM: Precipitation expands through central NJ and the I-95 corridor

• 7–10 AM: Reaches the south and coast, mainly as rain

• 10 AM–2 PM: Snow changes to rain statewide except NW hills

• 2–5 PM: Precipitation tapers off from southwest to northeast

🚦 Travel & Impact Assessment

• Northwest NJ: Slushy to snow-covered roads early; wet, heavy snow may cause isolated tree or power issues.

• Interior NJ: Some slick spots early; roads turn wet as rain takes over.

• Urban corridor: Mainly wet roads; minimal snow impacts.

• Coast & South: Raw, rainy, breezy conditions with no meaningful snow.

Final AI Forecast Verdict

This system will deliver the most snow to far northern and northwestern New Jersey, where 3–6 inches of wet, heavy snow is expected.Most of the state will see 1–3 inches or less, with a quick transition to rain cutting down on accumulations.South and coastal New Jersey remain primarily a rain event.

ChatGPT 5.1 used QGIS code to make a snow map

NOTE: I had to prompt ChatGPT to use SQL to give me a read-out for its snow map prediction, which I put together in QGIS. Generating its own snow map was a big failure but it does well with county recognition to allow QGIS to do the rest of the work.

After Action Report

I used this prompt for both Grok and ChatGPT 5.1:

I want your final snow forecast for December 2nd snow event in New Jersey. Use the latest tools available to you like weather models, real-time weather data and observations, current climate and climatology, etc. Give me a breakdown of snow totals by county in New Jersey.

As I advance, I will refine my prompts to be clearer and more specific. Both models provided very similar analyses, as shown above. Grok offered more detailed explanations regarding its thoughts on the low-pressure system and highlighted the differences between the ECMWF and GFS models.

ChatGPT presented a cleaner and more user-friendly version for the average reader. Although it wasn't as detailed as Grok, it produced a very similar f

orecast.

Creating two forecasts using different AI platforms took less than 2 minutes. Including an additional 5-10 minutes to set up QGIS for the snow map, the entire forecast was completed in under 15 minutes. We will evaluate after this snowstorm passes if the AI platforms can match the accuracy of professional meteorologists. I believe that combining AI with a professional background in meteorology could be transformative, as the AI's effectiveness depends on the input, and a professional can ensure the inputted formula is logical and meaningful.

Stay tuned for the results after the storm!