Karen Fizzles

Karen, the eleventh tropical storm of the season, dissipated along the central Gulf coast Sunday morning.  This was a relief to that area of the country, but was not expected from the forecast three days before.  The Federal Emergency Management Agency (FEMA) had already begun to recall personnel on furlough from the government shutdown.  Keep in mind that meteorologists at the National Weather Service (NWS) and National Hurricane Center (NHC) were already on the job, just not getting paid.

So what happened?

The tropical storm formed Thursday morning north of the Yucatan Peninsula and in my last post you can see what the track models were suggesting.  However, the storm was already being affected by a southwesterly shear aloft and dry air covered much of the western Gulf of Mexico.

The visible satellite picture of Karen for 21z Thursday, October 3. 2013.  The center of circulation is north of the Yucatan Peninsula.  Notice the asymmetry in the storm with all of the thunderstorms east of the center.  Dry air west of the center kept storms to a minimum.  Click on the image for a larger view.  Image Credit: UCAR.

Karen Will Affect South Carolina

Tropical Storm Karen formed just north of the Yucatan Peninsula Friday morning (correction: that should be Thursday morning).  The system had been moving northwest through the western Caribbean since early in the week.  Conditions were finally favorable for development.

Now Karen takes aim on the U.S.  It has been moving slowly through the southern Gulf of Mexico and toward the north-northwest.  Hurricane hunters found winds of near 60 mph this morning prompting the upgrade to tropical storm status.

As of 11 p.m. EDT, Thursday, Tropical Storm Karen was 340 miles south of the mouth of the Mississippi River moving north-northwest at 10 mph.  Maximum sustained winds were 65 mph in squalls to the northeast.

The wind field around Tropical Storm Karen as of 00z October 4, 2013.  Winds are measured in knots.  The Yucatan Peninsula can be seen in the lower part of the image.  Click on the image for a larger view.  Image Credit: NOAA/NHC.

Is Andrea About To Form?

Early Start

Hurricane season began June 1^st and by all accounts it is expected to be an active season.  Is the season about to get underway?  It seems the computers think so.  The vast majority of the computers have been indicating that something could form in the Gulf of Mexico this week.

There was an area of disturbed weather extending from the Yucatan Peninsula northeast into the Gulf of Mexico Monday evening.  Moisture was streaming north from the western Caribbean Sea.  No indications of development have been noted over the past 24 hours.

However, computer models suggest that thunderstorm activity will be on the increase today into Wednesday.  The latest Regional Precision Model (RPM) has a circulation forming in the Gulf north of Yucatan on Wednesday.  The system would then move north curving northeast into the Apalachee Bay on Thursday.

The 72-forecast valid Thursday evening at 00z June 7, 2013.  Click on the image for a larger view.  Image Credit: WSI.

The above model has the system coming onshore late Thursday afternoon and moving northeast toward coastal South Carolina.  That is where the heaviest rainfall would occur.  It could be breezy for the coastal sections, but the system is not expected to be very strong.

The Rise Of Extreme Weather

Extreme weather has always been with us, but the trend over the past few decades has been for it to increase in number.  The Climate Extremes Index (CEI) was developed by the National Climatic Data Center (NCDC) and goes back to 1910.  It looks at the number of events that occur.  The graph below compares the period of January through October so that data from this year can be included.

The CEI for the period of January - October 1910 - 2012.  Image Credit: NOAA/NCDC.

The CEI with the experimental tropical cyclone indicator included.  Image Credit: NOAA/NCDC.

A new report recently released (before Hurricane Sandy) by Munich Re, the world’s largest reinsurance company, re-enforces this observation.  The report is about the increase in extreme weather over North America.  The report states:

Sandy Update: Monday

Update: 10 p.m. EDT

Sandy made landfall about 5 miles southwest of Atlantic City, New Jersey around 8 p.m. EDT.  It came ashore as an extratropical cyclone as Sandy made a quick transition during the late afternoon.  The storm still had sustained winds up to 80 mph and was moving west-northwest at 21 mph.  Sandy slowed as it moved inland and may slow some more over the next few hours.

The windfield around Sandy as of 9 p.m. EDT, October 29, 2012.  Click on the image for a larger view.  Image Credit: NOAA.

Notice the area colored in yellow.  These are winds in the range of 45 to 60 mph.  This is a very large area of high winds and it is pushing water into New York harbor due to the southeast winds.  It produced a record flood for lower Manhattan.

Sandy continues to move inland and was near Wilmington, Delaware as of 10 p.m. EDT.  Inland winds of 40 to 50 mph were common.  This heaviest rains were now south and west of the center.

The radar from Dover AFB as of 10 p.m. EDT, October 29, 2012.  Sandy was centered southwest of Wilmington, Delaware.  Image Credit: WLTX-TV.

Heavy snows are now falling in West Virginia and western Virginia.  The snow extends south into the mountains of North Carolina, but amounts have been generally light so far.  More snow is expected overnight and through the day on Tuesday.

Update: 6 p.m. EDT

Sandy is now extratropical.  However, that does not alter the overall pattern of the storm.  It has been making rapid transition during the past few hours.  The 5 p.m. analysis of the wind field is below with the radar composite from 5:48 p.m.  The storm is approaching Cape May, New Jersey and should make landfall in about an hour.

The wind field over the radar.  Click on the image for a larger view.  The storm is extratropical.  Image Credit: NOAA.

 

Update: 2 p.m. EDT

Hurricane Sandy is accelerating and turning to the west-northwest.  The storm has been moving northwest over the past three hours, but it is clearly turning.  Forward motion is now 28 mph and central pressure is 940 mb (27.76 in.).  Maximum sustained winds still at 90 mph, but it appears that an area of strongest winds are developing north of the center.

Windfall analysis as of 1 p.m. EDT October 29, 2012.  Image Credit: NOAA.

Radar image of Sandy as of 2 p.m. EDT October 29, 2012.  Image Credit: WLTX-TV.

The faster forward motion means that the center will cross the coast earlier than forecast.  In addition, it could move faster as it is affected by a strongly negatively tilted trough shown in this mornings upper-air analysis.  The jet stream may cause a further deepening of the pressure.

Analysis of the 250 mb level showing strong winds along the East Coast.  Image Credit: NCAR/RAP.

The Dance Begins

The upper-level trough that has been moving through the central part of the U.S. is beginning to affect Hurricane Sandy.  It is moving east and energy will be moving into the base of the trough that will cause to tilt negatively.  Initially this will push the hurricane to the northeast.  However, as the trough gets close and the upper-level winds back, Sandy will turn north and then westward moving inland in the Northeast.

The 500 mb analysis for Friday evening October 26, 2012.  Click on the image for a larger view.  Image Credit: WSI.

Wind shear has been increasing over the hurricane and it is beginning to resemble a hybrid system.  A warm core typical of the tropical cyclone is in place, but the center does not have a ring of thunderstorms surrounding it.  NASA imagery showed the thunderstorms displaced to the north Friday evening.

The Perfect Storm 2

In the previous post, which was written on Sunday, I described a scenario that would play out over the next 7 to 10 days.  The details often change significantly at those time frames.  However, the computer models have done a reasonably good job at the overall weather pattern.  The model which has performed the best in my opinion has been the European model at the medium-range.  Now most of the models are clustered toward a similar solution, although the American model (GFS) continues to show some strange results.

The overall pattern is a negatively tilted trough pushing into the eastern part of the country and picking up the northward moving hurricane.  As the two interact Sandy will transform from a tropical cyclone to a nor’easter.  The wind will greatly expand and the storm may become a monster worthy of a Halloween trick.  Sandy will weaken as a hurricane, but may strengthen as a nor’easter before moving into Northeast.

The 500mb forecast pattern by the ECMWF model.  The top chart is for Sunday evening while the bottom chart is for Tuesday morning.  Click on the image for a larger view.  Image Credit: WSI.

Coastal Storm Followed By Cold Weather?

The South Carolina State Fair was lucky and enjoyed great weather for its entire run which ended today.  Dry weather is expected to continue over the Midlands most of the coming week and it will be delightful fall weather.  However, the weather pattern will begin changing this week and the Midlands, as well as much of the East coast, will be challenged by the changing conditions next weekend.

All of the computer models, used for medium-range weather forecasts, are converging on a solution that changes the weather for much of North America.  The change is already underway.  It is happening in the middle troposphere (500 mb) over western Canada where a double-barrel low pressure system is pushing the polar jet stream south from Alaska to California.

The 500 mb chart for 00z, 22 Oct 2012.  Winds generally blow parallel to the contours lines.  Click on the image for a larger view.  Image Credit: WSI.

This will bring colder air south into the western U.S.  The low pressure system will slowly swing east and become an elongated trough of low pressure.  It will extend through the Plains states on Saturday intensifying a surface low pressure system and moving it north toward the Arctic.  At the same time a tropical system will be headed north from the Caribbean Sea into the Bahamas.

Isaac's Biggest Threat: Water

Update: 1:35 a.m. EDT August 29,

The eye seems to have stalled off the coast of Grande Isle, LA.  It seems to be doing a loop on radar and this will delay landfall.  Much of southeastern Louisiana will be pounded by high winds, heavy rains, and storm surge for much of Wednesday.

The radar view from Slidell, LA at 1:05 a.m. EDT, August 29, 2012.

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As Isaac makes landfall in southeastern Louisiana it is likely to be a category 1 hurricane.  This may not sound like much, but the winds are still a danger and shelter will be needed.  However, it is the water, both surge and rain, that are the biggest threat.  The storm is expected to slow down as it moves through southeastern Louisiana and could produce rain through Wednesday night.

The forecast for Isaac as of 11 a.m. EDT, August 28, 2012.  Click on the images for a larger view.  Image Credit: NOAA/NHC.

At 11 a.m., Tuesday, Isaac was still a tropical storm; however it was close to becoming a hurricane with maximum sustained winds of 70 mph.  This is strong enough to take out trees and power lines with some minor structural damage to buildings.  The satellite picture below showed the storm getting better organized, but the bulk of the rain was east and south of the center.

Isaac Is Now In The Gulf

Key West is normally a festive place particularly leading up to Labor Day.  Tonight it is a different place.  Webcams show only a few cars on the road on only a few brave souls on the streets.  Any partying is being done indoors.  It has been a rainy and windy day in Key West with gusts frequently up to 40 mph.  Peak gust occurred at 1:22 p.m. with winds to 47 mph.

Image from a webcam in Key West, FL.  Image Credit: WebcamViews.com

Isaac took a turn to the west-northwest for much of the day taking it through the Florida Straits.  It passed south of Key West late this afternoon instead of going through the Keys.  At 8 p.m. EDT on Sunday, the storm was located about 60 miles southwest of Key West moving west-northwest at 15 mph.  Maximum sustained winds were about 65 mph making it a tropical storm.

Isaac Heads For The Gulf

Last night Isaac moved across Haiti dumping torrential rains on the poorest country in this hemisphere.  High winds and flooding rains pounded the country into the morning hours.  The center of Isaac moved across the southern mountains of Haiti, but then turned northward through the Windward Passage to reach the eastern tip of Cuba by midday.

Click on image to enlarge.  Image Credit: NOAA/NHC.

This is the latest plot of the path of Isaac with the associated wind field.  Notice how erratic the path has been since moving into the Caribbean.  This is due to the complex weather pattern over the region playing a tug-of-war with the storm and it is still happening.

Isaac Is A Difficult Call

Tropical Storm Isaac moved into the eastern Caribbean Tuesday afternoon and was moving westward during the evening.  The storm was getting better organized late in the evening, but the winds were not much different from earlier in the day.  It is only a matter of time before the winds respond to the drop in pressure.

Tropical Storm Isaac at 0215z August 23, 2012.  This is an enhanced infrared picture of the storm.  The dark areas represent the colder cloud tops meaning that they are higher in the atmosphere.  Image Credit: NESDIS.

There has been considerable concern about the future of this storm due to the impact it could have on Florida and the Republican National Convention in Tampa next week.  Any evacuation would greatly alter the plans for the convention.  A general idea of where the storm is going can be gleaned from the models.  However, the devil is in the details.  It is far too uncertain at this time frame to pin down where the storm will strike land.

Ernesto Approaches Barbados

Tropical Storm Ernesto formed in the tropical Atlantic east of the Windward Islands Wednesday afternoon.  Hurricane hunter aircraft found tropical storm force winds even though satellite pictures did not indicate as much organization.  Ernesto was nearing the island of Barbados just after midnight on Thursday morning.  The storm had maximum sustained winds of 50 mph and was moving west at 22 mph.  The latest National Hurricane Center advisory can be found here.

Tropical Storm Ernesto approaching Barbados.  Click on the image for a larger view. Image Credit: NOAA/NHC.

Ernesto will pass through the Windward Islands this morning and head into the Caribbean Sea.  Conditions do not favor significant strengthening over the next few days and the computer models are tightly clustered around a westward path.

Computer model forecasts of the center of the storm.  Image Credit: NCAR.

Drought Relief For Some Areas

Conditions were looking bleak at the beginning of May.  Only four months of above normal rainfall had occurred in the previous 28 months.  The details can be found in a previous blog post (here).  Much of the state was in a drought and the situation was getting worse.

Two events happened to change the course of the drought.  First, Tropical Depression Beryl brought much needed rain to parts of the drought-stricken Midlands.  However, there were still areas that received little rain.  This was soon followed by an upper-level pattern that brought copious amounts of rain to the Southeast, especially along parts of the central Gulf coast.  It eventually made its way to South Carolina bringing an abundance of rain.  More than 8 inches of rain fell in just four weeks in the Columbia area.  The result has been flooding of some of the creeks in the area.

Flooding of the Rocky Branch Creek closed the intersection of Main St. and Whaley St. on Monday, June 11.  Click on any of the images for a larger view.  Image Credit: USGS.

The 2012 Hurricane Outlook

The Atlantic Basin has the most variable hurricane activity in the world and thus has become a challenge for meteorologists.  There seems to be a fascination with knowing what the season will be like, even if you can’t forecast where they may strike.

The Tropical Meteorology Project at Colorado State University has been making forecasts of the Atlantic hurricane seasons for the past 29 years.  It explains the need to forecast hurricane seasons this way:

“We issue these forecasts to satisfy the curiosity of the general public and to bring attention to the hurricane problem. There is a general interest in knowing what the odds are for an active or inactive season. One must remember that our forecasts are based on the premise that those global oceanic and atmospheric conditions which preceded comparatively active or inactive hurricane seasons in the past provide meaningful information about similar trends in future seasons. This is not always true for individual seasons. It is also important that the reader appreciate that these seasonal forecasts are based on statistical schemes which, owing to their intrinsically probabilistic nature, will fail in some years. Moreover, these forecasts do not specifically predict where within the Atlantic basin these storms will strike. The probability of landfall for any one location along the coast is very low and reflects the fact that, in any one season, most U.S. coastal areas will not feel the effects of a hurricane no matter how active the individual season is.”

Image Credit: SCMED Operations Center.

Every year South Carolina gears up for the expectation of hurricanes.  The state has a state-of-the-art facility to monitor hurricanes and emergency events.  Plans are reviewed and renewed.  Everyone is encouraged to become aware of their local situation and if need be know what routes are to be used for evacuations.  It is important to have hurricane kits and to update them each year.  This is also important for land-lovers since the effects of hurricanes can extend far inland.

A Beryl of Trouble

Yes, this is a play on words, but I think you will understand as the story unfolds.  This is not just about the current tropical storm, but also about one of its past lives.  What?  You see, there are six lists of names for hurricanes and so the list are rotated every six years.  The only way that a name leaves the list is for it to be retired, like Hugo, Andrew, Katrina, and Irene.

Visible image at 6:45 p.m. EDT on May 27.  Image Credit: NEDIS.

Beryl transformed from a subtropical storm to a tropical storm Sunday afternoon.  By late afternoon the storm was getting better organized and strengthening.  It made landfall near Jacksonville Beach, FL, just after midnight (12:10 a.m. Monday).  Highest sustained winds were estimated at about 70 mph mainly in squalls over the open water.  This highest wind gust on land occurred at Mayport, FL, with a gust of 73 mph late in the evening.

The system is now a tropical depression and is likely to make a very slow turn to the northeast over southern Georgia.  This will likely take 12 to 24 hours which means that there will be a great deal of rain for some areas.  Rains are already causing some flood issues for northeast Florida.

Wake-Up! It's Hurricane Season

The official start of the 2012 hurricane season is not until June 1, but Mother Nature decided to start it a little early.  Tropical Storm Alberto formed Saturday afternoon off the coast of South Carolina.  It was centered at that time about 140 miles east-southeast of Charleston, South Carolina with maximum sustained winds of 45 mph.  A ship report indicated that it was a little stronger shortly after the official release and it was bumped up to 60 mph.

Image Credit: NEXSA

Satellite photos showed a tight circulation yesterday morning with convection west of the center.  It stated that way much of the day and the photo to the left shows the storm as of early afternoon before the first advisory was released.  The center of the storm was just under the high clouds with good convection near the center.  Click on the image to see an enlarged view.

The system was drifting to the southwest at about 3 mph, but it began moving west-southwest at about 5 mph overnight.  The movement was largely the result of a high pressure system over the eastern U.S.

Most of the rain and higher winds were well offshore, but a Tropical Storm Watch was issued for the low country of South Carolina as a precaution due to the closeness of the storm.  There is some concern that the immediate coast could see tropical storm force winds.