WEATHERAmerica Newsletter, Saturday, April 21, 2026

[Larry Cosgrove]

TODAY'S FUN LINKS:

Traveling Tropical Disturbance Increases Rainfall across the Hawaiian Islands University of Hawai'i at Manoa - 8 April 2026 New research published in the Journal of Hydrometeorology reveals that the Madden–Julian Oscillation significantly influences climate conditions in Hawaiʻi. Getting to the Core of a Medicane European Space Agency - 27 March 2026 Researchers are gaining new insights into the formation and evolution of medicanes (which were defined in a recent BAMS article), and therefore, how their impacts can be predicted more accurately. Alaska's Wildfires Heat the Planet, but Canada's Cool It Eos - 9 April 2026 Researchers used satellite data to learn that wildfires in North America don’t follow the same script: In western Canada, snow reflectivity drives a cooling effect, whereas in drier Alaska, permafrost burning leads to net warming. 2026 Could See a Historic Super El Niño. Here’s Why. (may require subscription) Forbes - 7 April 2026 According to a recent NOAA briefing, conditions in the east-central Pacific Ocean are expected to transition to what could be a particularly strong El Niño by fall, with SST anomalies above 2.5°C. A Wisconsin-Sized Chunk of Alaskan Permafrost Is Thawing; Arctic and Global Climate May Never Be the Same University of Massachusetts at Amherst - 1 April 2026 A team of researchers has shown in fine-grained detail what happens when Arctic permafrost thaws. Super Typhoon Sinlaku, Earth's Strongest Tropical Cyclone of 2026, Hammering Saipan, Tinian, Guam Weather Underground - 14 April 2026 Sinlaku is the strongest typhoon to strike so close to Saipan and Tinian since Category 5 Super Typhoon Yutu did so in late October 2018. Scientists Mine Past Air Temperature Forecasts, Lower Cost with Greater Subseasonal Prediction Accuracy George Mason University - 9 April 2026 Researchers have developed a new method that improves air temperature forecasts one to five weeks in advance—without requiring additional model simulations. AI Supercharges Key NOAA Dataset, Ensuring Peak Accuracy NOAA - 13 April 2026 NOAAGlobalTemp, a dataset that combines long-term sea surface and land surface temperature datasets, has gotten an AI upgrade, ensuring that it is more complete and accurate than ever before. In New England, Catching Climate Data Along With Fish (may require subscription) The New York Times - 1 April 2026 Commercial vessels are deploying high-tech sensors to map a shifting sea, providing critical data for scientists and some help for the industry. Tiny Particles in Arctic Ponds May Play Role in Cloud Formation, Climate Change Colorado State University - 13 April 2026 New evidence shows melt ponds in the northern parts of the Arctic may be biological sources of ice-nucleating particles, key ingredients for cloud formation that have been largely overlooked.

 

WEATHER HAZARDS (During The Next 24 Hours)

 

SEVERE WEATHER OUTLOOK
(potential for tornadoes, damaging winds, and large hail within the next 24 hours)

 

ISOLATED Severe Thunderstorms

(Microbursts, Large Hail, Isolated Tornadoes)

E NC....E VA....DC....C, E MD....DE....SE PA....NJ....NYC/LI NY....CT....RI....E MA

 

HEAVY RAINFALL OUTLOOK
(potential for an inch or more total rainfall within the next 24 hours)

 

Isolated Locations In

E NC....E VA....DC....C, E MD....DE....SE PA....NJ....NYC/LI NY....CT....RI....E MA

(QPF 1 - 2")

 

WINTER WEATHER POTENTIAL

(potential for Moderate Icing, Snow 2 - 4" or more, and/or temperatures below 10 deg F)

 

Isolated Locations In

N, C ON....N, C QC

(Intense Cold, Wind Chill)

Isolated Locations In

N NY....W MA....VT....NH....QC Eastern Townships....N ME

(Wet Snow; Higher Elevations; 4 - 8")