Archive for August, 2008

Gustav And Hanna Sunday Midday
August 31, 2008

Hurricane Gustav and Tropical Storm Hanna continue to churn in the Gulf of Mexico and the Atlantic Ocean.

Photo courtesy NOAA

Gustav weakened crossing Cuba late Saturday and has been unable to regain strength despite passing over very warm waters in the Gulf. Higher altitude winds may be partly to blame. At 11:00am EDT Sunday, Gustav’s winds were reported to be 120 mph, making the storm a category 3 hurricane. The storm is moving to the northwest, away from the warmest waters in the Gulf of Mexico.

An ensemble of computer models seems to indicate that Gustav’s winds could remain stable or may strengthen slightly. The official Hurricane Center forecast builds winds to 130-135 mph as the storm nears the north Gulf coast. This would put the storm right on the dividing line between a category 3 and category 4 hurricane.

“Plot provided courtesy of Jonathan Vigh, Colorado State University. For more information about this graphic, click here.” 

Computer model track ensembles are pretty unanimous in taking Gustav to around the Louisiana coast on Monday. After that the models diverge on the storm’s track.

“Plot provided courtesy of Jonathan Vigh, Colorado State University. For more information about this graphic, click here.” 

The final outcome of Gustav’s track and intensity are far from certain but it is evident that the storm has the potential to be very destructive to areas along the north Gulf coast.

Below is an updated, color enhanced close up satellite picture of Gustav, courtesy of StormCenter Communications.

The above image was taken by the GOES-East satellite at 12:33 pm CDT (17:33 UTC) on August 31, 2008.  It shows Hurricane Gustav in the Gulf of Mexico bearing down on the southern coast of the United States.

Tropical Storm Hanna is working its’ way toward the Bahamas. At 11:00am EDT Hanna’s winds were reported at 50 mph. Computer model ensembles lean toward a track that would take the storm close to the U.S. Atlantic coast by the end of the week but there is considerable disagreement as to a precise location.

“Plot provided courtesy of Jonathan Vigh, Colorado State University. For more information about this graphic, click here.” 

Computer model ensembles for Hanna’s intensity indicate the storm could likely reach category 1 hurricane strength by the end of the week.

“Plot provided courtesy of Jonathan Vigh, Colorado State University. For more information about this graphic, click here.” 

Once again though, computer models can contain many errors regarding track and intensity and the precise outcome of this storm is far from certain. Assuming the storm does get close to the Mid Atlantic region, we could receive some much needed rainfall by the end of the week or next weekend. August will end in Baltimore with a 2.26 inch deficit in precipitation and lawns, gardens and crops are beginning to show the effects.

Below is a chart from the morning run of the  of the National Weather Service “GFS” computer model. The chart depicts surface pressure and precipitation for Friday morning.

The bulls-eye on the east coast represents the remnant of Hanna moving into the Baltimore/Washington area. The model indicates that Hanna would still be a well defined storm, possibly a tropical depression strength. The rainfall would be welcome. Remember, this is but one of a number of computer models and does not necessarily reflect what will ultimately happen.

For the latest on the progress of Gustav and Hanna check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html

John Collins

Gustav Over Western Cuba
August 30, 2008

As of 5:00pm EDT Gustav was a strong category 4 hurricane with 150 mph winds. The NASA visible satellite picture below shows the impressive eye of the storm over western Cuba, roughly 65 miles west-southwest of Havana.

Hurricane force winds extend outward about 70 miles from the eye of the Gustav so Havana is right on the edge of the most powerful part of the storm.

The NOAA visible satellite picture below is a wider view of Gustav and the Gulf of Mexico.

The latest forecast track for Gustav has the storm moving pretty much in a straight line to the northern coast of the Gulf of Mexico by Monday afternoon or evening.

The water temperatures around western Cuba and the southern Gulf of Mexico are in the mid 80s based on NOAA weather satellite observations depicted on the picture below.

The lack of strong, high altitude winds and the warm waters are the reason the storm strengthened so rapidly on Saturday. Gustav is expected to gain additional strength once the sorm clears Cuba and starts moving across the Gulf. Hurricane Center forecasts indicate that there will be a period when the storm will reach category 5 with winds around 160 mph. Slightly cooler water (low 80s) may contribute to a slight weakening of Gustav as it approaches the northern Gulf coast on Monday. At that time Gustav would still be extremely dangerous as a category 4 storm with 145 mph winds.

The area of highest danger from landfall is from the northeast Texas coast to the western tip of Florida. The Louisiana coast has the greatest odds for the passage of the eye of the Gustav. This would put New Orleans in the northeast quadrant of the storm where the heaviest rains and highest winds generally occur.

There is another storm worth watching.

The NOAA satellite picture above shows Tropical Storm Hanna in the Atlantic, west of the Bahamas. Hanna is expected to move much more slowly than Gustav. The forecast track has Hanna in the Bahamas on Thursday as a strong tropical storm and moving toward the northwest.

Longer range computer models take Hanna into the southeastern U.S. with either the storm core or the remnants of the storm moving into the Mid Atlantic states by next weekend. This is not totally bad news for Maryland. The area is running about 2 inches short of rain over the past 30 days and some generous rains would provide relief from the parched conditions.

For the latest on Gustav and Hanna check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html

John Collins

Gustav Strengthens Rapidly
August 30, 2008

Hurrican Gustav strengthened rapidly Saturday morning. At 5:00am winds were reported to be 110 mph. At 6:00am a hurricane hunter aircraft measured winds at 115 mph. By 8:00am winds were up to 120 mph. and by 11:00am winds were reported to be 125 mph.

The NASA visible satellite picture below shows the storm at 10:30am EDT.

The eye of the storm is clearly visible and started developing rapidly around sunrise, the same time that the wind speed of the storm was increasing.

Gustav is still on track to move over western Cuba and into the gulf of Mexico, possibly reaching category 4 strength for a period of time. Gustav is expected to lose some strength, but still be dangerous, as it makes landfall along the north Gulf coast late Monday or early Tuesday. The highest odds for landfall are along the Louisiana coast.

For more on Hurricane Gustav, as well as Tropical Storm Hanna, check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html

John Collins

Gustav and Hanna On Friday
August 29, 2008

Tropical storms Gustav and Hanna continue to move through the Caribbean and Atlantic. The enhanced NOAA satellite picture below shows their early Friday morning positions.

The box in the lower right shows the general direction the storms will be traveling over the next few days.

It appears Gustav is headed for the north Gulf coast around Louisiana, making landfall as a category 2 or 3 hurricane late Monday.

Hanna is expected to become a category 1 hurricane, traveling northwest for a while and then turning sharply to the southwest, eventually approaching the Bahamas as a tropical storm on Tuesday.

Check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html for the latest information.

Locally, the remnants of Fay are still moving across the area with clouds and periods of drizzle and light rain the dominant features. On Saturday a cool front will push all of the moisture eastward and it looks like rain will be out of the picture for Sunday and Monday.

John Collins

Tropics Getting Busy
August 29, 2008

There are now two tropical storms churning in the Atlantic Basin.

Gustav is moving across Jamaica as of Thursday evening with 70 mph winds. Hanna is the newest tropical storm located in the Atlantic, 260 miles northeast of the northern leeward islands.

Forecasts take Gustav to the north Gulf coast by Tuesday morning somewhere between northeast Texas and the western Florida panhandle. Gustav could be a category three hurricane by that time.

The forecast for Hanna keeps the storm north of the Caribbean islands, first travelling to the northwest and then turning to the west at about the same latitude as the northern Bahamas and still well offshore by Tuesday morning. Hanna could be a marginal hurricane by that time.

The NOAA map below shows the expected position of weather systems around North America on Monday morning.

Notice a large area of high pressure centering up over the northeast U.S. This feature will more than likely deflect all of the tropical activity away from the Mid Atlantic region, at least at the start of the week.

A similar ridge of high pressure kept the moisture from Fay away for most of this week. Thursday’s rains were from the remnants of Fay but were pretty well depleted by the time they reached Baltimore, which received only .22 inches of rain on Thursday compared to 3-5 inch rains measured earlier in the week in southern Virginia. Baltimore is 2.54 inches short of the average rainfall for August and area gardens and crops are beginning to show the effects.

Check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html for more on Gustav and Hanna.

John Collins

Gustav Ready To Strengthen
August 27, 2008

Tropical Storm Gustav continues to churn in the Caribbean over the southwest tip of Haiti. The NOAA satellite picture below shows the storm’s position mid afternoon Wednesday.

Gustav’s interaction with land has prevented it from becoming better organized. The forecast track for the storm will keep it over water just south of Cuba into Saturday and this is one of the key factors in Gustav’s becoming a dangerous storm. Gustav will be moving over some very warm water. The NOAA satellite picture below shows sea surface temperatures. The red shading around Cuba indicates water temperatures around 86 degrees.

Readings this warm are perfect for storm strengthening, assuming that the upper winds remain favorable.

Gustav’s forecast track ultimately takes the storm over the western tip of Cuba and into the Gulf of Mexico, in the general direction of the north Gulf coast. Water temperatures in the Gulf are in the 80-85 degree range, plenty warm to allow for strengthening into a major storm. For more on Gustav, check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html .

Closer to home, the moisture from the remnants of Fay is moving very slowly northward. High pressure has held the rain just south of the Baltimore-Washington area through Wednesday afternoon but rain chances will increase across the area and be with us until a cold front moves through on Saturday.

John Collins

Gustav Gets Stronger
August 26, 2008

Hurricane Gustav continues to gain strength near the south coast of Haiti with winds clocked at 90mph Tuesday morning. The NOAA satellite picture below shows that the storm, has yet to take on the classic form of a hurricane with a clearly defined eye.

Gustave started as a tropical wave in the central Atlantic but didn’t build in strength and organization until the storm reached the warm waters of the Caribbean and upper winds subsided. Tuesday morning winds in the storm are sustained at 90 mph.

Forecast models have recently leaned toward a more westerly track for Gustav which would favor keeping the storm over water just south of Cuba. By the time the storm is forecast to cross the western tip of Cuba winds may be up to 115 mph. If upper winds remain favorable the storm could further strengthen over the warm, open waters of the Gulf.

Hurricane forecasters are monitoring additional activity as indicated on the NOAA satellite picture below.

The tropical waves labeled 1 and 2 have a medium probability of further development and tropical wave three has a low probability based on current forecast parameters. The “L” over the state of Mississippi is the remnant of Fay. For more on developments in the tropics, check out our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html .

The satellite picture also shows all of the tropical moisture bottled up over the southeastern U.S. with drier air to the north holding it in place. The Mid Atlantic region is right at the dividing line. As the week wears on, advancing weather systems from the west should help to draw more moisture up from the south and increase rain chances in the area. BWI-Marshall has recorded only .60 inches of rain so far this month, 2.40 inches below the 30 year average. We could use the rain.

John Collins

Record Rainfall
August 24, 2008

This weekend the Mid Atlantic region is sitting high and dry while Tropical Storm Fay continues to dump buckets of rain on Florida. Back in 1933 the situation was reversed as the “Chesapeake-Potomac Hurricane moved across the area.

Tropical systems were not named in those days and this storm is on the record books as Hurricane #8. It was what would now be considered a category three storm and the eye passed directly over Norfolk, VA as it moved inland. The storm proceeded to move northward along the western shore of the Chesapeake Bay at Tropical Storm strength. The storm caused millions of dollars in damage to buildings and crops across the region as well as 30 fatalities.

In Baltimore, 7.62 inches of rain was recorded on August 23 as the storm approached the Chesapeake Bay. That is the all-time record rainfall in Baltimore for a 24 hour period.

This is the same storm that opened the Ocean City Inlet between the resort town and Assateague Island.

The National Weather Service map below compiled by Paul Kocin shows the regional rainfall totals from the storm.

 

So far this Hurricane season the Mid Atlantic region has avoided tropical downpours. Tropical Storm Fay has been traversing Florida this past week with rains in the 10-20+ inch range. Moisture from Fay may eventuall reach Maryland by the end of the coming week but it should not be nearly as extreme as the rains of the past week or the rains back in 1933.

For the latest on Fay check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html

John Collins

Rain Would Be Helpful
August 22, 2008

It is certainly hard to complain about the weather we have had recently. August temperatures have been anything but extreme with only four days hitting 90 degrees or higher so far. Rainwise, unlike July, August has been dry.

A quick check of the record books at BWI-Marshall show that the last measurable rain was on August 14. It wasn’t much, only .07 inches. The last significant rain was August 2 with only .53 inches. Rain has fallen on a few other days elsewhere around the state but it has been scattered in nature and the BWI-Marshall readings pretty well represents what has happened across the region.

The August rain total at BWI-Marshall is only .60 inches, 2.04 inches below the 30 year average. We would be in much worse shape if were not for the excessive rains we received in July when 5.47 inches fell. Vegetation in the region is beginning to show the stress of this short term rain shortage and it would be nice to see a good rain at this stage of the game.

Several hundred miles to the south it is a totally different situation. Tropical Storm Fay has been meandering from south to north across Florida this past week, producing some amazing rain totals in the range of 10-20 inches. The storm has now made a turn to the west and is about to move over the Florida panhandle. The NOAA satellite picture below shows the storm’s position as of Friday afternoon.

For the latest on Tropical Storm Fay’s progress, check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html

Fay’s slow movement is the major reason why the rain totals have been so high. The storm will continue to move slowly to the west and then northwest over the next five days. The map below shows a National Weather Service model forecast for rain totals across the nation for the next five days. It is easy to spot the bullseye for the rain from Fay.

You might notice that there is some shading over the mid Atlantic region. There is an increasing chance for rain early next week in Maryland but, as the shading indicates, it appears that it will be relatively minor with less than .25 inches likely.

John Collins

Fay Wednesday
August 20, 2008

Tropical Storm Fay continues to wander around Florida. The colorized NOAA satellite picture below shows the storm position late Wednesday morning.

Fay is expected to turn back to a northwesterly track and head toward the Florida panhandle and Alabama.

Below is a National Weather Service Doppler Radar image showing the rain estimates over central Florida.
Notice how the rain totals sharply drop off around Orlando

It is interesting to note that Fay was able to gain strength for a period of time while passing over the south Florida land mass. An ample supply of warm water may have been the reason, as explained in the following, courtesy of StormCenter Communications,

—————
•      Fay surprisingly intensified after making landfall on mainland Florida on the morning of August 19, 2008 with winds increasing from 50 mph to 65 mph.

Dr. Jeff Halverson, a hurricane researcher at NASA, surmises that given the swampy and lake-strewn nature of the Florida landscape, and the abundance of water vapor streaming in off both sides of the Florida peninsula, there may have been sufficient fuel to maintain Fay’s intensity while over land.  The accompanying image, derived from NASA’s MODIS sensor and courtesy of Scott Bachmeier at SSEC/UWISC, shows that the surface waters of Lake Okeechobee were well in excess of 80 degrees Fahrenheit.  The lake may have provided a potent source of water vapor, fueling the storm as it approached Okeechobee’s southwest shore.

•     Fay is not the first time a storm failed to weaken appreciably while crossing southern Florida.  Hurricane Andrew in 1992 maintained maximum sustained winds of 130 mph across the state, partly because the swampy Everglades contained enough heat and moisture which slowed the decay.
•      Fay is interesting because of its slow movement across the Florida peninsula and its unwillingness to weaken quickly while over land.

——————

Below is a late Wednesday afternoon NOAA visible satellite picture of a wide view of of the eastern U.S.

Notice the clear air covering Maryland, Pennsylvania and much of the northeast U.S. This is the high pressure ridge that is expected to deflect Fay toward the west and keep the storm away from the Mid Atlantic region. Rain from the remnants of Fay would be beneficial in the Baltimore area. At the end of the day Wednesday the monthly rain total at BWI-Marshall will be 1.81 inches below average for August and it doesn’t look like Fay will be helping to make up the deficit

For more on Fay check our Hurricane Tracker at …… http://www.wbaltv.com/hurricanes/index.html

John Collins