{ "number": 596, "headline": "May 4, 2025 Sunday Weather Update", "standfirst": "Boatloads of rainfall across southern U.S. next week", "desk": "notebook", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2025-05-05", "published": "2025-05-05T01:51:06.430000Z", "updated": null, "access": "free", "body_html": "

Quick late Sunday update while watching the NBA games \u2026

The great May 2025 Omega Block is underway with unusual weather in quite a few locations. The Southwest U.S. is cool and rainy as well as Indiana and the Ohio River Valley. Ridging in North Dakota and Canada lead to 80s for high temperatures.

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A mini-atmospheric river on the Atlantic side of the Indiana cut-off is bringing plenty of moisture and heavy rain into the Mid-Atlantic and Northeast.

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Sadly, NOAA GFS model skill has gone into the ditch. This chart compares 5-day NHEMI height forecasts for ECMWF, AIFS, and GFS (red line).

Drop-outs or \u201cpoor skill\u201d periods are NOT what we\u2019re looking for going into the Hurricane Season. Thankfully, we can use the A.I. models as well as ECMWF\u2019s ensemble system.

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Radar Simulation next 18-hours through Monday afternoon 1 PM ET

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Unusual to see this spinning storm over the U.S. southwest and all of the rainfall including Las Vegas, Phoenix, and storms in New Mexico \u2014 outside of monsoon season.

NWS WPC Precipitation | Next 7-days

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Big story this coming week is the enormous rainfall totals from Texas along the Gulf Coast into the Southeast.

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Zero rainfall across the Midwest!

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Up to 4\u201d around NYC and 1-2\u201d in New England, mainly in the next 48-hours.

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Sunday Evening Weather

Mixed precipitation tonight across the mountains in the Great Basin and Four Corners. A chilly rain in the Ohio River Valley continues!

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Frontal Boundaries this Evening 8 PM and Weather on Monday

Similar weather for Monday with little movement of the Omega Block.

But, add in some severe storm potential for west Texas!

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Massive hail and strong winds, maybe a tornado in ENHANCED risk counties of Texas.

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Temperature Analysis | 8:45 PM ET

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80s in North Dakota with 40s in Indiana \u2026 chilly air descending behind the trough into the Southeast.

Temperature Anomaly | 8:45 PM ET

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Overall the Lower 48 is -2.7\u00b0F below normal

Satellite Imagery this Morning

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Cool satellite image showing the two cut-off troughs \u2026 and the convection leading to hail in severe warned storms.

Opportunity to show the Arizona radar map

Phoenix Sky Harbor has dodged the rain so far \u2026 but storms to the west will moisten the metro.

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All new paid subscribers can use this coupon link to receive 20% off the Newsletter and receive all daily updates heading into hurricane season.

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Low Temperatures on Monday

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40s quite popular from the Plains to the Southeast!

High Temperatures on Monday

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High Temperatures Next 9-Days

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Slow warming day after day but only \u201cheat\u201d in the Southwest where it\u2019s quite typical. However, before we get to the 100s in Phoenix again, we\u2019ll see clouds and rain with highs in the 70s \u2014 maybe only the 60s in Vegas on Monday.

Then, by next weekend, coast to coast 70s and lower 80s as the Lower 48 warms into mid-May.

Precipitation and MSLP Next 6-Days | ECMWF 18z

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An omega block is typically very dry for the hump portion but the curly cut-off lows are slow moving, rain producers where an ocean can be tapped for moisture. That\u2019s the case for the mid-Atlantic and Northeast with a river of moisture off the Atlantic inland adding up to 2-3\u201d of total rain in just the next 3-days.

NWS Rainfall Next 72-Hours

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NOAA Blend of Models Precipitation Next 10-days

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Upper Level Weather Pattern | Height Anomaly next 10-days

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It\u2019s becoming difficult to ditch these upper-level troughs spinning out of Canada and the North Pacific. Unless you\u2019re lucky and underneath the ridge part of the block, it\u2019s gloomy and wet. AIFS forms another Omega block!

ECMWF EPS 12z | Weekly Temperature Anomaly

Week 1: May 4 - 10

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Significant negative temperature anomaly (-8\u00b0F) centered on North Texas extending to the Great Lakes.

Week 2: May 11 - 17

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Still below normal (slightly) across the Gulf Coast. Much warmer than normal across the Dakotas and northern Plains.

Maps sourced from weathermodels.com designed and innovated by yours truly! Please subscribe there for real-time access to the newest maps, charts from all of the weather models including ECMWF.

", "body_key": null, "teaser_html": "

Quick late Sunday update while watching the NBA games \u2026

The great May 2025 Omega Block is underway with unusual weather in quite a few locations. The Southwest U.S. is cool and rainy as well as Indiana and the Ohio River Valley. Ridging in North Dakota and Canada lead to 80s for high temperatures.

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