WEATHERAmerica Newsletter, Saturday, November 15, 2025

[Larry Cosgrove]

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)

CA....NV....AZ....W NM

STRONG WINDS

(Pressure Gradient Derived)

NS....NB....PEI....Newfoundland

 

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

 

Isolated Locations In

CA

(QPF 1 - 3")

Scattered Locations In

NS....S Newfoundland

(QPF 1 - 3")

 

WINTER WEATHER POTENTIAL

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

 

Isolated Locations In

Coastal BC....WA....OR....CA High Sierra....NV....W CO....W NM....AZ

(Snow; Above 4000 Feet; 4 - 12")

Isolated Locations In

S ON....QC....NW PA....W, C NY....VT....NH....ME

(Snow; In Squalls; 4 - 8")

GLOBAL WEATHER SUMMARY

(a review of important weather features around the world)

 

IODC

ECMWF; METEOBLUE; EUMETSAT

 

Let there be storms! For a short while, at least....

Two disturbances with frontal structure are passing through southwestern Asia, replete with showers, thunderstorms and some cases of higher elevation snowfall. The second impulse should reach Afghanistan on Monday or Tuesday, opening the scene for some nice weather across the Levant and Persia through the end of the month. A shortwave ridge will take shape across Mesopotamia and later between the Alborz and Zagros Ranges, with dryness and a mostly mild temperature pattern. Keep in mind that a southern branch storm track is likely to return at some point in December, with better chances for meaningful cold intrusions.

 

HIMAWARI 8

METEOBLUE; Kochi University

 

Colder air continues a slow build over Eurasia, but impacts along the populated Pacific shoreline will be minimal through the remainder of the month (although the cPk and cA realms will prove to be an issue in December and later winter 2026). Tropical Cyclone potential has lessened as the Madden-Julian Oscillation has congealed in a sort of "phalanx" stretching from Phase 2 (Bay of Bengal) to Phase 4 Philippines, New Guinea northern/eastern Australia. Note that the MJO convective array (tropical forcing) is feeding a very vibrant southern branch that runs below Hawaii into western Mexico. Heat will start to build through the Australian subcontinent and later New Zealand. A southern storm track will soon be evident across the lower 48 states of the USA from this formation.

 

GOES WEST

NOAA/NESDIS

 

A La Nina can sometimes have a vigorous southern branch storm track (often thought to be a characteristic of an El Nino episode). You can see the prominent subtropical jet stream that has origins in the MJO convective plumes across Indonesia, This is a formula for future "Miller A" coastal storms as well as "Galveston Bay Spin-Up" cyclones, both of which can be heavy precipitation producers across the eastern half of the lower 48 states. This situation is concurrent with eastward-progression Sub-Aleutian and Gulf of Alaska vortices, which also implies chances for prominent ice and snow events in the U.S. with cold snaps.

 

GOES EAST

NOAA/NESDIS

 

A strong low pressure is taking shape in Quebec, and will likely track through the Maritime Provinces into Newfoundland on Sunday with inland and lake-effect snow, with heavy rain and wind along the coastline. Much of the USA is mild or warm, waiting on an eastward translation to the Gulf of Alaska vortex and a southern branch storm moving into California to possibly alter the pattern.

Note the elongated convective arc from Colombia into southern Brazil. Temperatures are hot to the right of the thunderstorms, merely warm to cool in Argentina and Chile. Shearing wind profiles have eliminated most chances for tropical cyclone formation.

 

METEOSAT

ECMWF; METEOBLUE; EUMETSAT

 

The formation of a cA vortex across the northern Atlantic Ocean, British Isles and Scandinavia could be signaling the start of a colder pattern for the northern half of Europe. A large storm off of the coast of France and the Iberian Peninsula will be forced on a due-eastward track, eventually reaching Poland and western Russia with significant higher elevation snows and heavy rain below the Danube Valley. The Mediterranean countries should stay warm, under the influence of a still-extant Saharan heat ridge.

The ridge complex covering the northern half of Africa is so strong it has crushed the ITCZ, compacting thunderstorm threats below the Congo River on into South Africa. Risks for severe weather are high across interior southern sections of the continent as cold fronts in the southern Atlantic Ocean are filled with impulses.