Monsoon Update 17 July 2026 — Break Monsoon Ending, Bay Low Develops ~19–20 July; Bihar and Jharkhand Revival Underway; Near-Nationwide Active Monsoon Likely 22–26 July

The VayuMet model's 17 July 2026 run confirms that the break monsoon episode, active since 11 July, is in its final stage. While the monsoon has now advanced spatially to cover the entire country as of 09 July, it has been in a weak phase over much of the covered region — that phase is now ending. A low-pressure area is developing over the north Bay of Bengal around 19–20 July, slightly earlier than the 16–20 July window indicated in the 11 July run, and its moisture is already reaching Bihar, Jharkhand, and the eastern Gangetic belt. Very Heavy Rain alerts are active for Bihar on 19–20 July. Looking further ahead, 22–26 July is shaping up as a near-nationwide active monsoon period — widespread positive rainfall anomalies cover the Gangetic plains, central India, northeast India, and the foothills simultaneously. Northwest India heat stress, still intense today, is likely to ease progressively from around 21 July as the monsoon reactivates across the plains.

Chart Analysis — VayuMet Model 17 July 2026 00Z

VayuMet Model · Mean Sea Level Pressure · 17–21 July (left) and 22–26 July (right) · Contours at 2 hPa · Anomaly vs 1981–2010 NCEP R2

Mean Sea Level Pressure — Break Monsoon Signature Weakening; Broad Revival 22–26 July

The 17–21 July panel shows a positive MSLP anomaly of +3 to +6 hPa still in place over Rajasthan and the northwest plains — the residual fingerprint of the break monsoon — but this anomaly is considerably weaker than what the 11 July run showed for this period, indicating the break is dissolving faster than anticipated. A low-pressure signal is developing over the northeast Bay of Bengal, consistent with the ~19–20 July formation timing. The 22–26 July panel shows a dramatically different picture: the positive anomaly over northwest India shrinks to near zero, and a broad negative anomaly covers the Gangetic belt and Bay of Bengal, confirming a full transition to an active monsoon pattern by the third week of July.

VayuMet Model · 5-day Cumulative Rainfall and Anomaly vs 1991–2020 Long Term Mean · 17–21 July (left) and 22–26 July (right)

Precipitation — Bay Low Moisture Reaching Eastern India; Near-Nationwide Revival 22–26 July

The 17–21 July rainfall panel shows the monsoon recovery already underway in the east: strongly positive anomalies cover northeast India, the sub-Himalayan foothills, Bihar, Jharkhand, and the eastern Gangetic belt as the Bay low feeds moisture northward. Maharashtra, Gujarat, and the central Deccan remain in deficit, with negative anomalies persisting through 21 July. The 22–26 July panel marks a decisive shift — positive anomalies spread across the Gangetic plains (Uttar Pradesh, Bihar, Madhya Pradesh), central India (Chhattisgarh, Jharkhand), and the west coast simultaneously, while the northeast and foothills remain continuously active. This is a near-nationwide monsoon revival signal.

VayuMet Model · 2 m Temperature Anomaly vs June Long Term Mean (1991–2020) · 17–21 July (left) and 22–26 July (right)

Temperature — Heat Stress Still Intense Over Northwest India; Progressive Easing From ~21 July

The 17–21 July temperature anomaly panel shows persistent and severe heat stress over Rajasthan, Punjab, and Haryana, with anomalies exceeding >8°C above normal and mean temperatures above 34°C. Central India also remains warmer than normal under the influence of suppressed cloud cover. The 22–26 July panel shows a marked improvement: the intense heat anomaly retreats progressively as monsoon cloud cover and rainfall spread northward and westward. The cooling is most pronounced over the eastern plains and central India, while far western Rajasthan retains some residual warmth through the period.

VayuMet Model · 850 hPa Wind Speed and Anomaly vs 1991–2020 Long Term Mean · 17–21 July (left) and 22–26 July (right)

850 hPa Wind — Bay Cyclonic Circulation Developing; Arabian Sea Low-Level Jet Strengthening 22–26 July

The 17–21 July low-level wind anomaly shows positive anomalies along the foothills and northeast India, with a cyclonic wind anomaly beginning to organise over the north Bay of Bengal — the low-level signature of the developing low-pressure area. The Arabian Sea Low-Level Jet (LLJ) is near-normal during this period. The 22–26 July panel shows a decisive strengthening: the Bay cyclonic circulation is well-established, the LLJ intensifies (positive anomaly +4 to +6 m/s over the Arabian Sea), and broad enhanced flow covers the Gangetic plains from west to east. This is the lower-tropospheric wind configuration that drives widespread active monsoon rainfall across the country.

VayuMet Model · 200 hPa Wind Speed and Anomaly vs 1991–2020 Long Term Mean · 17–21 July (left) and 22–26 July (right)

200 hPa Wind — Upper-Level Break Signature Dissolving; Tropical Easterly Jet Recovering

The 17–21 July upper-level anomaly shows a negative signal over the Indian subcontinent — the strong upper westerly jet that characterised the break monsoon episode is retreating northward. The Tropical Easterly Jet (TEJ) remains below normal over peninsular India but shows signs of recovery compared to the 11 July run. The 22–26 July panel shows the upper-tropospheric pattern reorganising in favour of active monsoon: the Tibetan High is well-maintained, TEJ strengthens over the Bay of Bengal, and upper-level divergence over the Gangetic belt improves, providing the ventilation needed to sustain deep convection across a broad swath of central and northern India.

Heavy Rain Alert Districts — 17–23 July 2026 (Model Guidance)

Date	State	Key Districts	Alert Level
19 Jul	Bihar	Arwal, Bhagalpur, Bhojpur, Jehanabad	Very Heavy
19 Jul	Bihar	Aurangabad, Banka, Buxar, Gaya, Khagaria, Lakhisarai, Munger, Nalanda, Nawada, Patna, Sheikhpura	Heavy
19 Jul	Jharkhand	Deoghar, Dumka, Giridih, Godda, Kodarma	Heavy
19 Jul	Uttar Pradesh	Ballia, Jaunpur, Varanasi	Heavy
19 Jul	West Bengal	Darjiling, Jalpaiguri, Paschim Bardhaman	Heavy
19 Jul	Madhya Pradesh	Damoh	Heavy
19 Jul	Nagaland	Tuensang	Heavy
20 Jul	Bihar	Jamui	Very Heavy
20 Jul	Jharkhand	Jamtara	Very Heavy
20 Jul	Himachal Pradesh	Sirmaur	Very Heavy
20 Jul	Jharkhand	Deoghar, Dhanbad, Dumka, Kodarma	Heavy
20 Jul	Uttarakhand	Dehradun, Tehri Garhwal	Heavy
20 Jul	Uttar Pradesh	Saharanpur	Heavy
20 Jul	Haryana	Yamunanagar	Heavy
21 Jul	Himachal Pradesh	Una	Heavy
21 Jul	Uttar Pradesh	Bulandshahr	Heavy
22–23 Jul	West Bengal	Jhargram, Medinipur West, South 24 Parganas	Heavy
22–23 Jul	Uttar Pradesh	Hapur, Meerut	Heavy
22–23 Jul	Jharkhand	Purbi Singhbhum	Heavy
23 Jul	Haryana / Delhi	Gurugram, South Delhi	Heavy

Model guidance only — verify against latest IMD district bulletins.

VayuMet Outlook — 17–26 July (Break Ending, Near-Nationwide Revival)

17–21 July:

• Break monsoon episode in its final stage — residual dry conditions over Maharashtra, Gujarat, and central Deccan through ~20 July.
• Bay low-pressure area developing ~19–20 July over north Bay of Bengal, activating Bihar and Jharkhand; Very Heavy Rain likely over Arwal, Bhagalpur, Bhojpur, Jehanabad (Bihar) on 19 July and Jamui (Bihar), Jamtara (Jharkhand) on 20 July.
• Eastern Gangetic plains (Varanasi, Jaunpur, Ballia, Saharanpur belt) seeing Heavy Rain by 19–20 July.
• Himalayan foothills (Uttarakhand, Himachal Pradesh) remain active; Sirmaur (HP) flagged for Very Heavy Rain on 20 July.
• Northwest India (Rajasthan, Punjab, Haryana) still under heat stress >8°C above normal through ~20 July; gradual easing begins from 21 July.

22–26 July:

• Near-nationwide active monsoon: Gangetic plains, central India (Madhya Pradesh, Chhattisgarh), Jharkhand, Bihar, West Bengal all seeing above-normal to strongly above-normal rainfall.
• Arabian Sea Low-Level Jet reactivates — west coast and western Ghats rainfall likely recovering.
• Northwest India heat stress easing progressively as cloud cover and rainfall spread; Delhi, Haryana, western UP seeing Heavy Rain signals by 22–23 July.
• Northeast India remains continuously active throughout both periods.
• The upper-tropospheric pattern — Tibetan High maintained, Tropical Easterly Jet recovering — supports sustained active monsoon into late July.

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