WEATHERAmerica Newsletter, WEATHER EXTREMES, GLOBAL SATELLITE DISCUSSION, Saturday, October 21, 2023

[Larry Cosgrove]

TODAY'S FUN LINKS:

National Operational Hydrologic Remote Sensing Center

-EPO, -AO, +PNA And -NAO Blocking Signatures Affecting North America

Air Mass Designations And Terms Used In WEATHERAmerica Discussions

A GUIDE TO BAROCLINIC DISTURBANCES AFFECTING NORTH AMERICA, Parts 1a - 3

 

WEATHER HAZARDS (During The Next 24 Hours)

 

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

 

Some Thunderstorms May APPROACH Severe Limits

NS....NL (Newfoundland)

 

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

 

Scattered Locations In

N NY....N VT....N NH....QC Eastern Townships....ME....NS....NL (Newfoundland)

QPF 1 - 3")

Isolated Locations In

Coastal N CA, OR

(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

Mountains Of SE BC, SW AB

(Snow; 3 - 6")

Scattered Locations In

NE BC....N AB

(Snow, 3 - 6")

Isolated Locations In

Coastal Ranges Of N CA....W OR

(Snow; 4 - 8")

Scattered Locations In

N BC....N AB....N SK....N MB

(Intense Cold)

GLOBAL WEATHER SUMMARY

(a review of important weather features around the world)

 

IODC

ECMWF; METEOBLUE; EUMETSAT

 

Your eyes are not deceiving you. That really is a major cyclone, Tej, that is aimed at the central coast of Yemen, likely to make landfall in about 72 hours. While dry air inclusion will weaken this system after the circulation reaches the coast, the arid character of the region will have surge, wind, and severe weather issues before Tej dissipates below Riyadh SA around October 26. See also the formative tropical depression nearing the Ganges Delta, with torrential rain threats.

Successive shortwaves and cold fronts have pushed the hottest air below the Tigris/Euphrates watershed and the Persian Gulf. A shortwave entering the Levant from the eastern Mediterranean Sea will renew thunderstorm threats across Iraq and Iran, and a stronger trough will push across the Middle East and Persia around Halloween with the potential for widespread thunderstorms, and a big drop in temperature that may bring the freeze line as low as 35 N Latitude in early November.

 

HIMAWARI 8

METEOBLUE; Kochi University

 

With the formation of two new tropical cyclones (92B and 90P), the Madden-Julian Oscillation is incoherent and badly fragmented. Remember that in order for the MJO to impact theaters in the Northern Hemisphere, the convective array must be well-organized, attached to the polar westerlies, and not scattered around the Equator. For this reason, the cold intrusion and Alaskan ridge sequence coming up next weekend will be transient and likely not establish an ongoing weather trend.

90P will progress west-southwest through some of the islands in Oceania, but should not involve New Zealand. But Australia could see effects from a full-blown storm. Surface cold fronts are making a comeback of sorts through the southern half of the subcontinent.

Colder air is building through Russia, and some polar intrusions could pass through China into Japan, Taiwan and the Philippines.

 

GOES WEST

METEOBLUE; NOAA/NESDIS

 

Hurricane Norma has weakened in the process of moving through the Los Cabos vicinity of Baja California. Rainfall from Norma will be a major problem for the interior of Mexico as the circulation breaks up on a northeastward path.

Another vigorous impulse ejected from the Gulf of Alaska Low is trying to approach the Pacific Northwest. But look for the storm to break up over Oregon and Northern California on Sunday. The trend of ridging over western North America continues with mostly warm and dry conditions. Subtropical jet stream formation below Hawaii almost certainly will take aim at Mexico, and may interact with convection below Central America by the start of November.

 

GOES EAST

METEOBLUE; NOAA/NESDIS

 

Tammy does not look like a hurricane in terms of its satellite cloud presentation, and its small core of strong winds is offshore of the Leeward Islands. The tropical cyclone and its follow-up wave will be pulled northward into a trough and cold front, with the moisture and energy form both systems recurving just east of Bermuda.

The "almost Nor'easter" off of Cape Cod is generating strong winds and heavy rain as far west as the St. Lawrence Valley. Even with this feature weakening on Sunday, rainfall and chilly air will still be an issue across New England and the Maritime Provinces.

A lack of rainfall and extremely hot weather persists over much of northern South America. Orographic and wave convection is seen across portions of Colombia, Venezuela and northwestern Brazil. Note the cold fronts that are moving from the eastern Pacific Ocean through Chile and Argentina. After a very warm winter, those nations are seeing chances for showers and briefly cool temperatures.

 

METEOSAT

ECMWF; METEOBLUE; EUMETSAT

 

The polar westerlies are quite strong, and laden with impressive shortwaves in a progressive flow. Later in the new week, these disturbances will knock out strong ridging in the Balkan Peninsula and Asia Minor. Mountain snows are possible in parts of the United Kingdom, Scandinavia and western Russia.

The ITCZ has fallen apart, and likely will not regroup above the Equator. Convection has fragmented, and is now limited to the Atlantic shoreline of Africa and the Nile headwaters. The Saharan heat ridge covers much of the Mediterranean Sea (for now). A late season cold front is triggering intense thunderstorms in South Africa. Another frontal structure is scheduled to arrive from Antarctic waters by Thursday.