Archive for September, 2008

Soggy September
September 29, 2008

After a two to five inch drenching from last Thursday through the weekend, the monthly rainfall total at BWI-Marshall has reached 6.73″.  This is in stark contrast to last September, which came in as the 4th driest September on record for Baltimore, with just 0.35″ of rain at BWI-Marshall airport.  But wet Septembers have been more common over the past decade.  From 1999 through 2008, five of the last ten Septembers in Baltimore have had at least 5″ of rain.  With more showers possible on Tuesday, the last day of the month, the average September precipitation for the past decade already comes in at 4.84″, almost an inch above the 30 year average of 3.98″.  It will be interesting to see if the rainy pattern transitions into a snowy pattern as we head into the cold weather months.

Tom Tasselmyer

Tropical Storm Wannabe
September 24, 2008


Low pressure off the Carolina coast is looking more and more like a tropical storm, but as of late Wednesday afternoon the National Hurricane Center has not classified this as “Kyle”, the next name on the tropical storm list.  To be officially classified as a “tropical storm”, the cyclone would need sustained winds of at least 40 mph and meet these criteria:

Tropical Cyclone:
A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).

This low developed on an old cold front and originally sustained itself and strengthened due to a temperature contrast across the front. Since its initial development, the old cold front has dissipated and the storm has continued to strengthen, partly in response to the warm ocean waters off the coast of South Carolina. If it continues to strengthen by taking heat energy from the ocean and a well defined circulation develops near the center of the storm, this could become “Kyle” before it makes landfall Thursday night. Either way, the storm will bring heavy rain, strong winds, heavy surf and coastal flooding to parts of Virginia, North Carolina and possibly Maryland from Thursday afternoon into Friday.

Tom Tasselmyer

Autumn Startup
September 23, 2008

Autumn has started appropriately with pleasantly cool temperatures. It has remained dry with ten consecutive rain free days. It looks like that will be changing.

It appears a coastal storm will be developing and there is a fairly decent chance that the end of the week will be a little wet and windy.

NOAA Surface Forecast Map for Thursday Morning, September 25

Added to the mix is action in the tropics.

National Hurricane Center Enhanced Satellite Image

The red circled area labeled “1” is a low pressure system that has been drifting in the Caribbean since the weekend. It is moving toward an area that may allow for further development and it could be declared a tropical depression at any time. If it were to reach tropical storm or hurricane strength the next name on the list is Kyle.

John Collins

End Of Summer Ramblings
September 22, 2008

Autumn begins on Monday so I thought I’d take a look back at the basic statistics of the “astronomical summer” of 2008.

Temperatures (June 20-September 21) were far from extreme this year. Only 20 days were 90 degrees or warmer:

  • June (20th-30th) – 3 days
  • July – 10 days
  • August – 4 days
  • September (1st-21st) – 3 days

Precipitation (June 20 – September 21) totaled 10.39 inches. Once again, nothing extreme except for July.

  • June (20th-30th) – 1.03 inches
  • July – 5.47 inches
  • August – 1.48 inches
  • September (1st-21st) – 2.41 inches

As the region moves into the autumn months precipitation is running ahead of the annual average to date with a surplus of 1.91 inches. If it weren’t for the month of July though, the area would probably be in deficit territory.

The past eight days have been rain free so a little precipitation wouldn’t hurt. A fix for that may be on the way. Computer models indicate that a coastal weather feature may crank up off the Carolinas by the end of the week. The models do not have a good handle on the details though so beneficial rains may or may not fall. Our forecast allows for a rain chance beginning late Thursday but the timing and strength of the storm are far from certain. A best guess right now would place the highest rain and wind chances east of the Bay. The NOAA computer model chart (below) for Thursday evening shows the developing storm off shore.

This is but one of several models and there is no firm agreement among them on the timing and extent of this weather feature.

Note that there is a more significant “storm” on the chart southwest of the coastal feature. This is where this computer model positions what is now a low pressure system near Puerto Rico. Forecasters are monitoring this storm for further tropical development. An Air Force plane surveyed the storm Sunday and could not find sufficient organization to label the storm a tropical depression.  Conditions are favorable for further development and the storm could become a depression at any time. Kyle is the next name on the list if the storm reaches tropical storm strength.

This week could become interesting.

John Collins

Hurricane Ike Damage … A Picture Comparison
September 19, 2008

The following series of pictures and text were provided courtesy of StormCenter Communications. The pictures clearly demonstrate the degree of destruction hurricane winds and storm surge can cause to developed coastal areas.

John Collins

———

The images were taken by aircraft on September 9 and September 15, 2008,provided by the United States Geological Survey (USGS), and enhanced by StormCenter Communications.  It shows the coastal destruction caused by Hurricane Ike at Crystal Beach on the Bolivar Peninsula in Texas.

BEFORE

AFTER

BEFORE

AFTER

BEFORE

AFTER

 

The above aerial images were taken on September 9 and September 15, 2008.  They show the coastal destruction caused by winds and storm surge in Hurricane Ike at Crystal Beach on the Bolivar Peninsula.

 

Additional Information:

 

  • Hurricane Ike made U.S. landfall at Galveston, TX at 2:10 am CDT (07:10 UTC) on September 13, 2008 as a Category 2 hurricane.

 

  • Ike and its remnants have been blamed for 63 deaths in the U.S. and 145 deaths overall.

  • Estimated damage is $27 billion, making Ike the third costliest U.S. hurricane behind Katrina and Andrew.

 

Quiet Weather on A Global Scale Today But Not In Years Past
September 17, 2008

Mid Atlantic weather has been quiet and cool for the past couple of days and it looks like it will stay that way in the near future. Some shower activity is concentrated around a stalled front along the southeast coast and a weak cool front coming out of the Great Lakes has very little moisture to work with. Most of the U.S. is cloud free.

On a more global scale, the NOAA full disk satellite image of the western hemisphere shows very little organized storm activity.

Most of the tropical Atlantic is storm free except for showers and thunderstorms associated with a wave approaching the Caribbean. The eastern Pacific is also quiet except for a disorganized area of showers and thunderstorms off the Central American coast. This area may become more organized over the next day or two.

Yesterday was the anniversary of Hurricane Floyd’s visit to Maryland. The category 4 storm dumped a record 5.02″ of rain on Baltimore on September 16, 1999.

NOAA/National Hurricane Center Map

NOAA Satellite Image

Today is the anniversary of Hurricane #2’s passage over the Mid Atlantic region. This category 3 storm produced a record 3.94 inches of rain in Baltimore in 1876. The map below shows all of the recorded hurricanes and tropical storms from that year.

NOAA/National Hurricane Center Map

 

John Collins

Hurricane Ike Pictorial Review
September 17, 2008

The images below are from NOAA. They review the development of Ike on its’ path to the Texas and Louisiana coast.

John Collins

Monday’s Record Rainfall
September 15, 2008

The record rainfall in Baltimore on September 15 is 3.20 inches. On that date a tropical storm passed to the south and east of Baltimore. Names were not assigned to storms in those days. This storm made landfall in South Carolina as a hurricane and then turned to the northeast, crossing southeast Virginia, the Chesapeake Bay and the DELMARVA Peninsula as a tropical storm. It weakened to a tropical depression as it moved across the New Jersey shore.

Graphic from the NOAA Coastal Services Center

For more information on tropical weather, check our Hurricane Tracker at http://www.wbaltv.com/hurricanes/index.html

John Collins

Ike Aftermath
September 15, 2008

What was Hurricane Ike has cut a long swath across the central U.S., leaving behind considerable damage from wind and rain.

Ike came on shore at Galveston, Texas with 110 mph winds. Winds were still in excess of 100 mph as the storm moved inland to Houston. The storm then turned northward, generating winds into the 60s and 70s all the way up to Missouri.

Ike was exceptionally large and carried a huge amount of tropical moisture with it. A sampling of rain totals follows:

  • Pease River, near Vernon, TX  18.09″
  • Houston, TX  15.75″
  • Pasadena, TX  8.35″
  • Calcasieu River near Glenmora, LA  7.62″
  • Udall, KS  11.02″
  • Kirksville, MO  8.14″
  • Oakland M ills, IA  7.60″
  • Kewanee, IL  7.59″
  • Davenport, IA  5.12″

The Chicago metropolitan area (including northern Indiana cities near Lake Michigan) was hit by two distinct storm systems over the weekend. One of those was the remnant of Ike. Rain totals from the combined events ranged from 7 inches to over 11 inches and serious flooding resulted.

To view a more detailed list of National Weather Service wind and rain reports related to Hurricane Ike, go to  http://www.hpc.ncep.noaa.gov/discussions/tcpat4.html

John Collins

Ike On Shore
September 13, 2008

Hurricane Ike made landfall at Galveston, Texas at 3:10am EDT with 110 mph winds, making it a strong category 2 hurricane, one mile per hour short of category 3. Ike’s hurricane force winds extended 125 miles out from the center of the storm. Tropical storm force winds extended 260 miles out from the eye.

Below is the Galveston National Weather Service radar image at roughly the time of landfall.

Note that the eye of the storm was moving directly over Galveston and would proceed to move over Houston as well.

By 11:00am EDT Ike was about 65 miles north-northwest of Houston. Ike was still a hurricane but winds had diminished to 80 mph. Hurricane force winds extended 45 miles out from the center of the storm. Friction with land and the lack of warm Gulf water to fuel the storm were starting to take its’ toll.

The visible NASA satellite image below shows the storm’s position at about 10:30am EDT.

Ike is expected to continue to turn in a gentle arc toward the Great Lakes over the next two days.

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

John Collins