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Nerd mode: every forecast, readouts, filters and range & bearing for weather enthusiasts

HurricaneEast Pacific

Hurricane Polo will slowly weaken as it heads northeast

San Diego — Could pass near San Diego Wed morning; 2 in 10 forecasts bring it within 100 mi.

Updated Mon., Sept. 28, 5:47 p.m. PDT · 169 forecast tracks from NOAA, ECMWF and Environment Canada: low

San Diego — Could pass near San Diego Wed morning; 2 in 10 forecasts bring it within 100 mi.

Quick answers

As of the Mon 28 Sep 12Z–18Z model runs · updated Mon., Sept. 28, 5:47 p.m. PDT

Where is Hurricane Polo going?
The centre is about 250 miles northwest of Cabo San Lucas, moving northeast at about 10 mph. The most likely path takes it about 280 miles east of San Diego by Tuesday night.
When will Hurricane Polo be closest to San Diego?
Most likely Wednesday, Sept. 30, around 5 a.m. PDT. Across the forecasts the comes between Tue 7 p.m. and Wed 5 p.m. PDT. Most forecasts pass the centre 90–550 miles northeast of San Diego.
What is the chance it passes within 100 miles of San Diego?
16%: 2 in 10 forecasts bring the storm’s centre within 100 miles of San Diego. Elsewhere: Los Angeles 10%. Rain, wind and coastal flooding can reach well beyond 100 miles from the centre.
How much rain could San Diego get while Hurricane Polo passes?
From Mon 5 p.m. (when the forecast’s rain totals start) to Wed 5 p.m. PDT, the end of the window when its centre is closest to San Diego, the middle of NOAA’s 31 GEFS forecasts brings almost no rain or melted snow to San Diego; fewer than 1 in 10 bring 0.5 in. By Tue 5 p.m., when that window opens, the middle forecast has almost none yet. That is all the rain in that time, not only Hurricane Polo’s, from one model (GEFS) on a coarse grid; local official forecasts can differ. San Diego: rain and wind this week →
How sure is the forecast?
Path certainty: low. 169 of 185 show the storm, and they on where it goes. Little has changed since the previous run.
Do the AI and physics models agree?
Largely, yes. Chance within 100 miles of San Diego: AI ensembles (AIFS ENS, AIGEFS) 15%, physics ensembles (GEFS, ECMWF ENS, GEPS) 18%. By model: GEFS 6%, ECMWF ENS 27%, AIFS ENS 14%, AIGEFS 16%, GEPS 14%. By Tuesday night the AI ensembles’ middle track is about 30 miles west of the physics ensembles’. At its deepest, the AI ensembles take it to about 982 and the physics ensembles to about 980 mb.

New to these maps? Read how to read a spaghetti map, or see the week’s rain and wind around the world on the globe.

What we know

Where it is. At 6 p.m. Monday, the centre was about 250 miles northwest of Cabo San Lucas, with a central pressure near 985 .

How sure. 169 of 185 show the storm, and they on where it goes. Little has changed since the previous run.1

How strong. Forecasts have it filling steadily, to about 1,003 by Tuesday.

What’s uncertain

How close it comes. For San Diego, most forecasts put the between 90 and 550 miles away, most likely Wednesday 5 a.m.

Later on. The forecasts fan out after Tuesday. By Tuesday night, the is about 1,150 miles across.2

When it arrives

When the centre passes closest to each place, earliest to latest across the forecasts. Places are ordered by the most likely time.

Window of Most likely timeNight
is the share of forecasts that bring the centre within 100 miles. Shaded columns are night; times are in your time zone.

Rain and wind this week in San Diego, Los Angeles, San Francisco and Sacramento.

What the forecasts said vs what happened

Collecting: so far at most 3 runs of any one model made 1 day ahead can be checked. We show how the forecasts did once a model has 4. How good are the forecasts this season?

DetailsStrength, sources and the fine print

How strong it gets

Central pressure over time. The line is the middle forecast; the band holds 8 in 10 of them.

(lower is stronger)

Times are shown in

Where the forecasts come from

ModelTracksStatus
NOAA
31 of 3118Z
arrived 1 h 23 min ago
Latest run
ECMWF
48 of 5112Z
arrived 3 h 58 min ago
Latest run
ECMWF
42 of 5118Z
arrived 13 min ago
Latest run
NOAA
28 of 3112Z
arrived 5 h 40 min ago
Latest run
Environment Canada
20 of 2112Z
arrived 7 h 28 min ago
Latest run

Also tracking

  1. Southern Ocean lowVery deep low in the Southern Hemisphere, near 936 mb now and filling; all 185 forecasts show it
  2. Amundsen Sea lowVery deep low bottoming out near 956 mb Tue night, in the Southern Hemisphere; all 185 forecasts show it
  3. Southern Ocean lowVery deep low bottoming out near 953 mb Thu morning, in the Southern Hemisphere; nearly all forecasts show it
  4. Southern Ocean low south of New ZealandVery deep low near 922 mb now, in the Southern Hemisphere; 9 in 10 forecasts show it
  5. Southern Ocean low south of New ZealandVery deep low in the Southern Hemisphere, near 939 mb now and filling; 9 in 10 forecasts show it
  6. See all 27 storms →

Notes

  1. Forecast tracks from the 18Z model run: GEFS (31), ECMWF ENS (51), AIFS ENS (51), AIGEFS (31), GEPS (21). A single run is one high-resolution forecast; ensemble forecasts are the same model run many times with small changes.
  2. The cone encloses where the centre is expected to be about two times in three at each hour, from the spread of the forecasts, widened by 20 percent; not yet calibrated against past storms. It shows uncertainty in the track, not the size of the storm.
  3. Shading shows the share of forecasts that bring the centre within 100 miles of a spot at any time in the next 6 days. Rain, wind and surge can reach much farther.
  4. Times are in your time zone. Arrival windows run from the earliest to the latest closest approach across forecasts that bring the centre within about 300 miles (500 km).
  5. NOAA/NCEP.
  6. Data Source: Environment and Climate Change Canada.
  7. This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). Source: www.ecmwf.int. Licence: CC BY 4.0.
  8. Cyclone tracks computed by Stormlines from the model fields.
  9. Reading these maps: , or the illustrated guide to spaghetti models. The week’s rain, wind and temperature everywhere: the Stormlines globe.
  10. How often these forecasts turn out right: the season’s forecast check, AI vs physics.
  11. Stormlines storm ID: L-2026-0056.

Stormlines draws every storm the world’s ensemble forecasts can see: tracks from NOAA (GEFS and the AI ensemble AIGEFS), ECMWF (ENS and the AI ensemble AIFS) and Environment Canada (GEPS), updated as each model run lands. Coastlines and place names from Natural Earth; sea areas from IHO Sea Areas, version 3 (Flanders Marine Institute, marineregions.org, CC BY 4.0; modified: simplified, some islands removed, names edited).

Not an official forecast. For warnings and decisions, follow your national weather service.

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Stormlines Tracks: NOAA, ECMWF, Environment Canada

Full forecast
Through Tue 11 p.m. PDT