Tropical Cyclone Gombe to intensify over Mozambique Channel

TCf gombe

Satellite Image Tropical Cyclone Gombe via JTWC

Tropical Cyclone Gombe, currently located over the northern portion of Madagascar has been moving westward at about 10 knots with max winds of  around 30 knots.

 

 

 

 

 

 

Gombe will move out over the Mozambique Channel during the next 12-18 hours, then favorable conditions will allow for the system to  strengthen fairly rapidly to hurricane force winds prior to landfall over Mozambique south of Nacala about 1800 UTC on the 11th.

storm track

Tropical Cyclone Gombe Forecast Track via JTWC

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North Pacific Marine Weather Outlook

NOAA OPC 500 mb Forecast Chart

A blocking ridge has re-established itself over the eastern North Pacific, effectively shunting storm tracks from the western North Pacific northward towards the eastern Bering Sea. At the same time, a large semi stationary upper-level and surface level low prevail over the northwestern North Pacific which continues to depress the prevailing jet and storm tracks south of 40 N over the western North Pacific. 

NOAA OPC 48 hour Surface Forecast

 

The eastern ridge is expected to gradually weaken and drift southeastward later this week.

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New NOAA Sea Level Rise Estimate for St Petersburg, Florida 

New NOAA Sea Level Projection for St. Petersburg, Florida

A new Sea Level Rise report from NOAA has been issued to project sea level rise and coastal flood hazards for the United States out to 2150 for 5 sea level scenarios: low, intermediate-low, intermediate, intermediate-high and high.  The various scenarios are based on output directly from the United Nations Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report where global temperature projections are made based on various greenhouse gas emissions estimates.

There are 5 different Shared Socioeconomic Pathways (SSP) for CO2 emission scenarios (ie. SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). Many, if not most, of the high sea level projections reported by the media have been based on the SSP 8.5 scenario which has been described as the “business as usual” scenario. This scenario, far from being the “business as usual” scenario, can more accurately be labeled as the “extreme scenario” and not very likely, in my opinion.

What is Projected for Tampa Bay?

For Tampa Bay, the tide gauge with the longest record is located at St. Petersburg, Florida.  The new NOAA report projects sea level rise by 2050 of between 0.28 meters (0.9 feet) for the low estimate, 0.36 meters (1.2 feet)  intermediate estimate, and up to 0.49 meters (1.6 feet) for the high estimate relative to a baseline of year 2000.  Extending the projection out to 2100, the report projects a sea level rise at St. Petersburg from a low estimate of 0.48 meters (1.6 feet) to a high estimate of 2.15 meters (about 7 feet).  

If these projections are accurate, then there will be significant increases in the frequency of flooding events by mid-century and possibly catastrophic flooding by the end of this century in the Tampa Bay Region.

Just how much credibility should we place in these projections? 

For the Tampa Bay area, the actual tide gauge data at St. Petersburg shows an increase in sea level of about 150-170 mm over the past 50 years which equates to an average rate of 3 to 3.4 mm/year.  This rate is about the same as the satellite-based global sea level rise estimate between 1993 to 2020 of 3.4 mm/yr.

Actual Tide Gauge Data from St. Petersburg, Florida

In order to reach the report’s intermediate estimate for St Petersburg of 0.36 meters (1.2 feet) by 2050, a sea level rate increase from the present 3-3.4 mm/yr to an average rate of 12 mm/yr for the next 30 years is required.  Given the current rate of 3.4 mm/yr the rate would have to increase to something near 20 mm/yr by 2050 in order to achieve an average rate of 12 mm/yr for the 30 year period in question.  Even worse, in order to reach the high estimate of 0.49 meters (1.6 feet) by 2050, the sea level rise rate must average over 16 mm/yr over the next 30 years, requiring the rate to soar to over 25 mm/yr to get to the 16 mm/yr average!

Historically, global sea level rose by a total of about 120 meters over a period of about 8,000-9,000 years as the vast ice sheets of the last glaciation melted away. This equates to an average rate of sea-level rise during this period of roughly 1 meter (3.3 feet) per century or about 10 mm per year (some studies suggest the average rate was up to 13 mm per year). In order to achieve the NOAA projected intermediate to high sea level rises, rates must increase well beyond those experienced during most of the post glaciation period.

Post Glacial Sea Level Rise

 

Is Sea Level Rise Accelerating?

Various studies of the satellite altimeter data have shown that GMSL rise is accelerating somewhere between 0.015 mm/yr and about 0.10 mm/yr so there is still a considerable amount of uncertainty as to the actual rate.  Taking the high end projection of 0.1 mm/yr we should see the sea level rise rate increase from 3.4 to 6.4 mm/yr by 2050 which should result in a total rise of about 150 mm or 0.5 feet by 2050 (less than half of the NOAA intermediate estimate of  0.36 meters (1.2 feet).

How likely is this?

If you look at the sea level from actual tide gauge data vs. the projected sea levels made by the NOAA report,  you will see that the trend since 1996 indicates that the actual sea level at St Petersburg has been rising at rate equal to or below the  “Intermediate” projection and often even below the “low” projection (see below). 

NOAA Tide Gauge Data vs projections

 

In order to achieve these high sea level rise rates presented in the NOAA report, it would require rapid melting of portions of the Antarctic ice sheet.  Modeling suggests that a significant sea level rise is possible from Antarctica ice melt, however, the key assumption is that greenhouse gas emissions will boost the planet’s temperature by about 4 degrees C (7 degrees F).  This type of rapid collapse is highly uncertain as to timing and dependent on higher warming rates than currently projected for the end of this century.  

Conclusion

Sea level is rising and the evidence suggests that the rate of rise has increased.  There remains, however, a significant amount of uncertainty regarding predicting future warming rates and thus sea level estimates for the next 30-80 years are problematic. Based on observed sea level trends since 1996, the best estimate for sea level rise in Tampa Bay by 2050 is more likely to be near 150 mm (about 6 inches) and by 2100 roughly 1.5 to 2 feet.

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Tropical Cyclone Vernon Forms over South Indian Ocean

Satellite Image TC Vernon via JTWC

Tropical Cyclone Vernon has formed over the South Indian Ocean southwest of Cocos Islands and was moving west-southwest at 8 knots with max winds of 45 knots.  Vernon is expected to reach hurricane strength later today.

There is also another disturbance about 300 nm to the northwest and the two systems may interact and may begin a Fuiwara loop around each other over the next couple of days.

 

Eventually, Vernon should turn southward.

Tropical Cyclone Vernon Forecast Track via JTWC

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North Pacific Marine Weather Outlook.

NOAA OPC North Pacific surface Analysis

A huge complex low pressure system dominates the North Pacific this morning.

 

 

 

 

 

The upper-level jet remains displaced south of 40-45 N latitude and will spread eastward into the eastern North Pacific as the blocking ridge over the easternmost North Pacific weakens and moves southeastward. 

NOAA OPC 72 hour 500 mb Forecast

 

This will set-up a primary storm track from east of Japan to near 40N/175W then northeastward over the eastern Gulf of Mexico.

72 hr surface foercast

NOAA OPC 72 hour Surface Forecast

 

Frequent gale to storm conditions are likely near and south of the storm tracks for the next several days. 

 

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Tropical Cyclone Emnati Nears Madagascar East Coast

Tropical Cyclone Emnati

Satellite Image Tropical Cyclone Emnati via JU\TWC

Tropical Cyclone Emnati, currently located north-northwest of La Réunion Island in the South Indian Ocean and was moving west-southwestward at 6 knots with maximum winds to 100 knots and significant wave heights up to 32 feet (9.8 meters). 

Emnati is forecast to turn more towards the southwest and some additional strengthening is possible during the next 24 hours followed by some weakening as the system nears the east coast of Madagascar making landfall about 1800 UTC on the 22nd with max winds of  about 100 knots. 

Emnati will weaken rapidly over the mountainous terrain of Madagascar passing off the southwest coast of Madagascar about 0000 UTC on the 24th as a tropical storm. Earlier this month, Intense Tropical Cyclone Batsirai impacted the same area on February 5th.

Tropical Cyclone Emnati Forecast Track

Tropical Cyclone Emnati Forecast Track via JTWC

 

 

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North Pacific Marine Weather Outlook

NOAA OPC 500 mb Analysis

A large and deep upper-level low over the western North Pacific is reflected at the surface by an intense 952 low with storm to hurricane force winds west and south of the center with significant wave heights up to 13 meters (43 feet).  This system will slowly weaken as it moves east-north east towards the Bering Sea over the next few days. 

Over the eastern North Pacific a high-pressure Omega Block prevails between 130W and 160W which will prevent storms from entering the Gulf of Alaska.  Low pressure over the US West combined with the high over the eastern North Pacific will produce strong to near gale N-NW winds along the US West Coast. 

NOAA OPc Surface Analysis

 

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Intensifying Tropical Cyclone Emnati bears down on Madagascar

 

Tropical Cyclone Emnati Satellite Image

Tropical Cyclone Emnati continues to strengthen over the South Indian Ocean north-northwest of Mauritius as it moves west at 7 knots with max winds about 105 knots and max significant wave height about 9 meters (near 30 feet). 

 

 

 

 

 

Emnati is forecast to turn more towards the southwest today reaching a peak intensity of 110-120 knots during the next 24-36 hours making landfall along the east-central coast of Madagascar around 1200-1500 UTC on the 22nd. Thereafter Emnati will weaken rapidly over land then turn more towards the south after passing out over the Mozambique Channel. 

Earlier this month, Intense Tropical Cyclone Batsirai impacted the same area on February 5th.

Forecast Track

Tropical Cyclone Emnati Forecast Track via JTWC

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Tropical Cyclone Emnati to threaten Madagascar

Tropical Cyclone Emnati Meteosat-8 IR image

Tropical Cyclone Emnati over the South Indian Ocean northeast of Mauritius currently with max winds of about 55 knots is moving west at 16 knots.

Emnati is forecast to continue to deepen, reaching hurricane-force in about 12 hours.  Thereafter, Emnati will turn more towards the west-southwest reaching max winds of 90-100 knots in about 48 hours then making landfall over central Madagascar about 1800 UTC on the 22nd.  Some weakening is expected prior to landfall. 

JTWC Forecast Track

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North Pacific Marine Weather Outlook

NOAA OPC 500 mb Forecast chart

Active weather system will continue over the western and central North Pacific this week.

The upper-level jet remains depressed south of 35 N latitude over the western-most North Pacific but then turns northeastward towards Alaska as a blocking ridge continues to remain over the eastern North Pacific.

NOAA OPC Surface Forecast chart

The primary storm tracks will be from Japan northeastward over the eastern Bering Sea and over Alaska.  Frequent gale to storm force to occasionally hurricane force winds are likely near and south of low pressure centers.

 

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