Weekly Storage and S/D Brief - week ending 8/21/2026

Week Ending August 21, 2026

SynMax Analytics | Published August 26, 2026

Headline

SynMax models a +16 Bcf injection for the week ending August 21, unchanged from the prior week's EIA-reported +16 Bcf build. The story this week is one of persistent but rotating heat: national population-weighted CDDs eased to 12.7 (from 13.6), yet power burn still climbed +0.90 Bcf/d WoW to 50.72 Bcf/d as the heat dome slid off the East and parked over the South Central region. That gain was largely offset on the demand side by softer residential/commercial load and a dip in LNG feedgas, leaving the daily surplus roughly flat at 2.30 Bcf/d. If confirmed, working gas storage would stand at approximately 3,185 Bcf, about 32 Bcf below last year's pace but a comfortable +172 Bcf (+5.7%) above the five-year average.

Review the full analysis on the dashboard.

Storage Summary

Working gas in underground storage stood at 3,169 Bcf for the week ending August 14 (EIA-reported, +16 Bcf), with the SynMax model projecting 3,185 Bcf for the week ending August 21 — a modeled injection of +16.1 Bcf. This marks a second consecutive sub-20 Bcf build, cementing the sharp deceleration from the +28-to-+33 Bcf pace that prevailed through late July and early August.

The year-over-year position holds a modest deficit: at ~3,185 Bcf, storage sits roughly 32 Bcf below the comparable 2025 level of ~3,217 Bcf. Against the five-year average of ~3,013 Bcf, however, inventories remain a healthy +172 Bcf (+5.7%) ahead, preserving a solid cushion as we transition into the shoulder season.

Against last week's EIA print, the SynMax storage-number model called +12.5 Bcf for the week ending August 14 versus the EIA-reported +16 Bcf — a -3.5 Bcf miss on the low side, consistent with the model's slight under-injection bias over the summer. The back-to-back lean builds are a weather signature, not a supply shift: production continues to grind higher while cooling demand, though still elevated, is no longer accelerating.

Model accuracy: Across the full scored window since July 3 (seven weeks, CONUS), the SynMax storage-number model has averaged a mean absolute error (MAE) of 3.6 Bcf, a slight negative (under-injection) bias of -1.1 Bcf, and a 0.96 correlation with EIA-reported changes.

The accuracy table reflects SynMax's official weekly storage-number call, the figure scored directly against EIA releases. This may differ modestly from the supply/demand-decomposition modeled change shown in the linked dashboard, which reflects the latest updates to SynMax’s S&D models.

Primary Driver: Power Burn Rotates South

The defining feature of the week ending August 21 was a regional rotation in power burn rather than a national surge. CONUS electric power demand rose +0.90 Bcf/d WoW to 50.72 Bcf/d — the summer's second-highest weekly average and +2.59 Bcf/d above the year-ago 48.13 Bcf/d — even as national CDDs fell by nearly one degree-day. The apparent contradiction resolves at the regional level: the mid-August heat dome that had concentrated over the East relaxed there and reformed over the South Central.

The South Central region drove the entire increase, with power burn jumping +1.92 Bcf/d WoW to 15.97 Bcf/d (+1.23 Bcf/d YoY) as Texas and the Gulf Coast baked. The East eased in the opposite direction, falling -0.56 Bcf/d to 20.70 Bcf/d as the Mid-Atlantic and Northeast cooled. The Midwest (-0.26 to 6.50 Bcf/d), Mountain (-0.14 to 4.38 Bcf/d), and Pacific (-0.06 to 3.17 Bcf/d) all softened modestly.

On the supply side, dry gas production firmed +0.35 Bcf/d to 111.97 Bcf/d — still robust and running well above year-ago levels — while Canadian pipeline imports slipped -0.43 Bcf/d to 8.04 Bcf/d. Net supply was essentially flat. With power burn gains neutralized by softer Res/Com and LNG feedgas demand (see below), the weekly balance barely moved.

Weather Context

National population-weighted CDDs averaged 12.7 for the week ending August 21, down from 13.6 the prior week but still well above the year-ago 11.5:

• The week opened warm (CDDs of 12.4-13.2 through August 15-18) before easing to 11.7 by August 21 as the dome broke down
• The national average masks the regional rotation — the South Central ran hotter week-over-week while the East cooled, a redistribution that lifted aggregate power burn despite the lower national CDD count
• Year-over-year, the +1.2 CDD gap (12.7 vs 11.5) is consistent with the +2.59 Bcf/d YoY increase in power burn, confirming that demand strength remains predominantly weather-driven

Supply & Demand Factor Changes (WoW)

Note: Canadian pipeline imports are treated as a supply source; Canadian pipeline exports are treated as demand (gas leaving the domestic market). The Balancing Factor captures the residual between independently modeled supply and demand components and is reported below the totals — it is folded into the implied change but excluded from Total Supply and Total Demand.

Secondary Factors

LNG Feedgas: Eases to 18.20 Bcf/d

Total LNG feedgas averaged 18.20 Bcf/d for the week, down -0.40 Bcf/d from the prior week's 18.60 Bcf/d after touching the summer high. The pullback reflects routine variability across the Gulf Coast fleet rather than any structural change, with Plaquemines and Sabine Pass holding near capacity. Lower feedgas is a bearish (loosening) factor for storage, returning roughly 3 Bcf of supply to the domestic balance over the week and offsetting much of the power-burn increase.

Mexico Exports: Higher

Pipeline exports to Mexico rose +0.30 Bcf/d to 7.62 Bcf/d, a bullish factor pulling additional gas off the domestic market — consistent with elevated cross-border cooling demand as the heat concentrated along the Texas–Mexico corridor.

Residential/Commercial: Softer

Combined Res/Com demand eased -0.40 Bcf/d to 8.57 Bcf/d, a bearish factor as the marginal cooling-related commercial load pulled back with the national CDD decline. Industrial demand was flat at 21.75 Bcf/d (-0.03 WoW), a non-factor in the weekly balance.

Regional Power Burn

The South Central region alone contributed the entire week-over-week increase in national power burn — more than offsetting declines in every other region — while all five regions ran above year-ago levels for a +2.59 Bcf/d CONUS YoY gain.

Methodology & Data Sources

Storage change is modeled as Total Supply (Dry Gas Production + Canadian Pipeline Imports + LNG Imports) minus Total Demand (all consumption sectors + LNG feedgas exports + pipeline exports), with the Balancing Factor added as a calibration residual, multiplied by seven days. The EIA storage week runs Saturday through Friday (the week ending August 21 covers Saturday August 15 through Friday August 21). Canadian pipeline imports are treated as a supply source supplementing domestic production; Canadian pipeline exports are treated as demand. The Balancing Factor (+0.51 Bcf/d this week) represents the residual between independently modeled supply and demand components and calibrates the injection estimate against EIA actuals.

Data sources: SynMax storage-number model calls (storage.v_storage_number_calls, CONUS), SynMax daily production model (hdl.daily_production), SynMax demand model (hdl.gas_demand, baseline scenarios), SynMax LNG feedgas model (hdl.lng_feed_gas), EIA Weekly Natural Gas Storage Report, NOAA GFS/HRRR weather data (via local PostgreSQL temperature_conus).

Disclaimer: This report is produced by SynMax Analytics for informational purposes only. Modeled figures are estimates and may differ from official EIA releases. Past model accuracy does not guarantee future performance.