93L still disorganized; extreme heat wave hits the Middle East and Africa

The amount and intensity of heavy thunderstorm activity associated with the tropical wave (Invest 93L) located a few hundred miles south of Jamaica has increased over the past 24 hours, but the storm remains very disorganized and is not a threat to develop into a tropical depression today. The storm has not brought heavy rains to Haiti, fortunately, but heavy rains are expected today across Jamaica, where flash flood warnings have been posted. Satellite loops show a very disorganized system, with no low-level spiral bands and limited upper-level outflow. There are no signs of a surface circulation visible on satellite imagery. Pressures at the ground station nearest to the storm (Kingston) are beginning to fall, as are pressures at buoy 42057 a few hundred miles west of the storm, a sign that 93L is more organized than yesterday. Water vapor satellite loops show that moist air surrounds 93L, and there is less dry air to the storm's southwest than there was yesterday. There is an upper-level high pressure system a few hundred miles west of 93L, and the clockwise flow air around this high is bringing upper-level winds out of the northwest of about 10 knots over 93L, contributing to the 10 knots of wind shear observed in this morning's wind shear analysis from the University of Wisconsin's CIMSS group. Sea Surface Temperatures are plenty warm, a record 29 - 30°C. The Madden-Julian oscillation (MJO) currently favors upward motion over the Caribbean, which will act to increase the chances of tropical storm formation this week. The main negative for 93L continues to be the lack of spin. Last night's pass of the ASCAT satellite showed little in the way of a wind shift associated with 93L, though the pass did not completely capture the storm. The University of Wisconsin 850 mb relative vorticity analysis is showing that spin at 850 mb (roughly 5,000 feet in altitude) has increased over the past two days. The Hurricane Hunters are on call to investigate 93L Friday afternoon. Today's flight was canceled, due to 93L's lack of development.


Figure 1. Morning visible satellite image of the central Caribbean disturbance 93L.

Track forecast for 93L
I expect that by tomorrow, 93L should be closer to being directly underneath the upper level high pressure system to its west, which would act to lower wind shear and provide more favorable upper-level outflow. NHC is giving 93L a 40% chance of developing into a tropical depression by Saturday morning, which is a reasonable forecast. Given the storm's current lack of spin and relatively modest amount of heavy thunderstorms, the earliest I'd expect 93L to become a tropical depression would be Friday afternoon, with Friday night or Saturday morning more likely. Interaction with land will be a problem for 93L, as it will likely move over Mexico's Yucatan Peninsula or Western Cuba on Saturday. Expect 93L to bring flooding rains of 3 - 6 inches to Jamaica and eastern Cuba today through Friday. These rains will spread to the Cayman Islands, northern Honduras, and central Cuba Friday through Saturday, and western Cuba, Belize, and Mexico's Yucatan Peninsula on Saturday and Sunday. The current run of the SHIPS model has 93L slowing down late this week to a forward speed of just 7 knots (8 mph) from its current speed of about 10 mph, in response to a weakening in the steering currents. A trough of low pressure is expected to swing down over the Eastern U.S. on Monday. If this trough is strong enough and 93L develops significantly, the storm could get pulled northwards and make landfall along the northern Gulf of Mexico coast. This is the solution of the GFS, GFDL, and HWRF models. If 93L stays weak and/or the trough is not so strong, the storm would get pushed west-northwestwards across Mexico's Yucatan Peninsula and towards the Texas or Mexican coast south of Texas. This is the solution of the NOGAPS, ECMWF, and Canadian models. A likely landfall location is impossible to speculate on reliably at this point, and the storm could hit virtually anywhere along the Gulf of Mexico coast given the current uncertainty in its development. A key factor will be how far north the center of 93L eventually consolidates at.

Intensity forecast for 93L
The amount of wind shear in the Gulf of Mexico next week is highly uncertain. There is currently a band of high shear near 30 knots over the Gulf. The GFS model predicts that this band of high shear will lift northwards, keeping low wind shear over the Gulf next week. However, the ECMWF model keeps high shear entrenched over the Gulf of Mexico. I give 93L a 50% chance of eventually becoming Tropical Storm Alex, but the odds of it eventually becoming a hurricane have lessened to 10%. None of the computer models is calling for 93L to become a hurricane.

Elsewhere in the tropics
None of the reliable computer models is calling for tropical cyclone formation in the Atlantic over the next seven days.


Figure 2. Dust storm over Iraq on June 23, 2010. Image credit: NASA.

Extreme heat wave sets all-time high temperature records in Africa and Middle East
A withering heat wave of unprecedented intensity and areal covered has smashed all-time high temperatures in five nations in the Middle East and Africa over the past week. Saudi Arabia, Iraq, Chad, Kuwait, and Niger all set new records for their hottest temperatures of all time, and two other Middle East nations came within a degree of their hottest temperatures ever. The heat was the most intense in Kuwait, which recorded its hottest temperature in history on June 15 in Abdaly, according to information I received from the Kuwait Met office. The mercury hit 52.6°C (126.7°F). Kuwait's previous all-time hottest temperature was 51.9°C (125.4°F), on July 27,2007, at Abdaly. Temperatures reached 51°C (123.8°F) in the capital of Kuwait City on June 15, 2010.

Iraq had its hottest day in history on June 14, 2010, when the mercury hit 52.0°C (125.6°F) in Basra. Iraq's previous record was 51.7°C (125.1°F) set August 8, 1937, in Ash Shu'aybah.

It was also incredibly hot in Saudi Arabia, which had its hottest temperature ever on Tuesday (June 22): 52.0°C (125.6°F), measured in Jeddah, the second largest city in Saudi Arabia. The previous record was 51.7°C (125.1°F), at Abqaiq, date unknown. The record heat was accompanied by a sandstorm, which caused eight power plants to go offline, resulting in blackouts to several Saudi cities.

In Africa, Chad had its hottest day in history on Tuesday (June 22), when the temperature reached 47.6°C (117.7°F) at Faya. The previous record was 47.4°C (117.3°F) at Faya on June 3 and June 9, 1961.

Niger tied its record for hottest day in history on Tuesday (June 22), when the temperature reached 47.1°C (116.8°F) at Bilma. That record stood for just one day, as Bilma broke the record again on Wednesday (June 23), when the mercury topped out at 48.2°C (118.8°F). The previous record was 47.1°C on May 24, 1998, also at Bilma.

Two other countries came within a degree of their all time hottest temperature on record during the heat wave. Bahrain had its hottest June temperature ever, 46.9°C, on June 20, missing the all-time record of 47.5°C (117.5°F), set July 14, 2000. Temperatures in Quatar reached 48.8°C (119.8°F) on June 20. Quatar's all-time record hottest temperature was 49.6°C (121.3°F) set on July 9, 2000.

According to Essa Ramadan, a Kuwaiti meteorologist from Civil Aviation, Matrabah, Kuwait smashed this record and had Asia's hottest temperature in history on June 15 this year, when the mercury hit 54.0°C (129.2°F). However, data from this station is notoriously bad, and each year bogus record highs have to be corrected, according to an email I received from weather record researcher Maximiliano Herrera. Asia's hottest temperature in history will very likely remain the 53.5°C (128.3°F) recorded at MohenjuDaro, Pakistan on May 26 this year.

Commentary
We've now had seven countries in Asia and Africa that have beaten their all-time hottest temperature record during the past two months. As I discussed in my blog about Pakistan's May 26 record, Southeast Asia also had its all-time hottest temperature in May, when the mercury hit 47°C (116.6°F) in Myinmu, Myanmar on May 12. All of these records are unofficial, and will need to be certified by the World Meteorological Organization (WMO). According to Chris Burt, author of Extreme Weather, setting five national heat records in one month is not unprecedented--in August 2003, six countries (the UK, France, Portugal, Germany, Switzerland, and Liechtenstein) all broke their all-time heat records during that year's notorious summer heat wave. Fortunately, the residents of the countries affected by this week's heat wave are more adapted to extreme high temperatures, and we are not seeing the kind of death tolls experienced during the 2003 European heat wave (30,000 killed.) This week's heat wave in Africa and the Middle East is partially a consequence of the fact that Earth has now seen three straight months with its warmest temperatures on record, according to NOAA's National Climatic Data Center. It will be interesting to see if the demise of El Niño in May will keep June from becoming the globe's fourth straight warmest month on record.


Figure 3. Approximate oil spill location on June 23, 2010, and estimated by NOAA using visible satellite imagery from NASA's MODIS instrument, and Synthetic Aperture Radar (SAR) imagery from polar-orbiting satellites. Image credit: NOAA Satellite Services Division.

Wind and ocean current forecast for the BP oil disaster
East to southeast winds of 5 - 15 knots will blow in the northern Gulf of Mexico today through Monday, according to the latest marine forecast from NOAA. The resulting weak ocean currents should push the oil to the west and northwest onto portions of the Louisiana and Alabama coasts, according to the latest trajectory forecasts from NOAA and the State of Louisiana. I would expect Mississippi to have its most serious threat of oil yet early next week as these winds continue. The longer range outlook is uncertain, and will depend upon what 93L does.

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Jeff Masters