WEATHERAmerica Newsletter, Saturday, July 13, 2024; WEATHER HAZARDS And GLOBAL SATELLITE IMAGERY

[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)

 

Some Thunderstorms May APPROACH Severe Limits

CA....NV....AZ....NM....W, C CO....W WY....UT....S ID

ISOLATED Severe Thunderstorms

(Microbursts, Large Hail, Isolated Tornadoes)

AB....C, S SK....SW MB....ND....SD....E WY....NE Panhandle

ISOLATED Severe Thunderstorms

(Microbursts, Large Hail, Isolated Tornadoes)

Far W QC....ON....MI....S WI....N IL....N IN....N, C OH....NW PA

Some Thunderstorms May APPROACH Severe Limits

FL....GA....AL....MS....LA....SE AR....TN....KY....VA....DC....MD....DE....C, E PA....NJ....NYC, LI NY

 

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

 

Scattered Locations In

Far W QC....ON....MI....S WI....N IL....N IN....N, C OH....NW PA

(QPF 1 - 3")

 

EXCESSIVE HEAT RISK

(Potential For Temperature To Exceed 95 deg F)

 

Scattered Locations In

S BC....WA....OR....CA....NV....ID....UT....AZ....NM....CO....WY....MT....W, C ND....SD....NE....KS....OK....TX....LA....AR....MO....IA....C, S MN....C, S WI

IL....IN....KY....TN....MS....AL....FL....GA....SC....NC....VA....DC....DE....NJ....C, S PA....WV....OH....S Lower MI

GLOBAL WEATHER SUMMARY

(a review of important weather features around the world)

 

IODC

ECMWF; METEOBLUE; EUMETSAT

 

Wait! What? The Monsoon trough has lost ground? Does that mean...????

Yes, it means that the ongoing heat and drought over Iran and the Middle East is sticking around and that even Afghanistan and Pakistan will be involved in soaring temperatures with little or no chance for rain through at least July 23, if not longer. Part of the issue is that the broad upper low has flattened across India, rather than retrogress and expand north and west. As a result, the numerical models have wiped out any and all chances for rain in most of the Levant (even Turkey and the Caucasus look drier) and may well deny the Indus River watershed additional moisture well into August. This trend goes against model guidance and analogs, and implies dangerous heat will not relent anytime soon (the traditional end of the monsoonal moisture is around September 9, not that far away.

The core of the subtropical high will continue to straddle the Arabian Peninsula and Persia, linked to the Saharan heat ridge which may attempt to bulge northward into the Mediterranean countries next week. A low pressure area and frontal structure in the Central Asian Republics may cool sections of Russia while drawing in the fire-like atmosphere into the Taklamakan and Gobi Deserts. This is going to be a long-lived and brutal heatwave.

 

HIMAWARI 8

METEOBLUE; Kochi University

 

The monsoonal moisture fetch is larger but has shifted east somewhat, linked partially to a Madden-Julian Oscillation Phases 2 through 4 convective array to its south and the polar westerlies from the Pacific shoreline into the Gulf of Alaska. This alignment removes the deep tropical rainfall cases from the Indus Valley and points west, while promoting historic rainfall in Southeast Asia. There remains some chance for tropical cyclone development across the South China Sea, while the PRC and Russia west of the Pacific shoreline communities will likely encounter extreme heat and dryness.

Note the strong frontal structure moving toward New Zealand. The air mass covering Australia is largely very warm and dry, with precipitation likely only over Tasmania and also the southwestern corner of the subcontinent. The next polar front will likely arrive in the middle of the new week.

 

GOES WEST

NOAA/NESDIS

 

The surprise player so far in July is the Sonoran heat ridge, which is extremely amplified and largely separate form its Bermuda High counterpart over the eastern USA and western Atlantic Ocean. This development was not expected, as a Gulf of Alaska Low (sometimes retrogressive to the Aleutian Islands and mainland Alaska) normally sets up linkage between the two subtropical highs. The condition is forecast to last through the near term, then correct to the Sonoran+Bermudan conjoined ridge formation. That would allow for a more vigorous monsoonal moisture pulse into the American West, which has been lacking so far for July.

 

GOES EAST

NOAA/NESDIS

 

Along with low pressure and a cold front in the Upper Midwest, you can make out a weakness at 500MB southward into Texas and Louisiana. This gap between heat ridges may weaken in early week, allowing for a cooler pattern in the Corn Belt, Great Lakes and the Northeast. The moisture axis along the Gulf Coast and into Mexico may finally begin to edge north and westward, assuming a monsoonal axis position that is normal for the second half of July and August. The frontal structure along the Eastern Seaboard should wash out on Sunday night and Monday, with heat and humidity returning along the Interstate 95 corridor.

A frontal structure in northern Argentina has slowed markedly, returning that area into southern Brazil to yet another round of heavy rain and thunderstorms. Clear, dry and cooler air stretches westward to Chile. Hot and dry weather remains across most of the northern two-thirds of South America, but convection in a moist ITCZ transport from Africa dominates Colombia and the Caribbean nations.

 

METEOSAT

ECMWF; METEOBLUE; EUMETSAT

 

I am watching the intense Saharan heat ridge make a northward lurch into the Italian Peninsula from Morocco and Algeria. This could be the hot weather building into Europe, when the subtropical high covers the Mediterranean Sea and western portions of the subcontinent finally are overtaken by the ridge complex. Another cold front and trough will move from the British Isles into France and Germany in the new week, so thunderstorms risks in the subcontinent will continue above the Alps.

The most interesting feature in Africa is the ITCZ, which continues to flare strongly across the central third of the continent. The dominance of the Sahra and Kalahari heat ridges keeps the tropical waves moving westward into the equatorial Atlantic Ocean, which is still infested with the hot, dry, dusty Sakaran Air Layer. The SAL kills off impulses, but at some point over the next few weeks the ridge will shift northward, and allow full-bloom "Cape Verde" disturbances a chance to grow and deepen, making for better chances for hurricanes in the major islands and North America.