Over the weekend, the Climate Prediction Center released its revised December temperature outlook, which looks quite a bit different than the one they released back on November 20th. The old version had warmer than normal conditions predicted for an area centered on Oklahoma and Kansas, while the new one, as you can see below, says it’s going to be warm in the west and cold in the east:

The other possible bit of good news for rain-starved Georgia is that the precipitation outlook has changed as well, with what was a 33% chance of drier than normal weather in the state changing to equal chances of above or below normal rainfall.

The updated temperature outlook brings the Weather Service more in line with what other winter forecasts are saying, and with what the CPC’s 6-10 and 8-14 day outlooks call for, which is for a significant chance of below normal temperatures for most of the US and above normal precipitation for all but the desert southwest from the 7th through the 15th of December.

November certainly provided a good lead in to the cold weather, at least here in Georgia. At Atlanta’s Hartsfield Airport, the average temperature for the month was 50.5 degrees, 2.8 degrees below normal. It was a little cooler out here in the ‘burbs, with my thermometer recording an average temperature of 47.9 degrees. Despite around an inch and a half of rain throughout most of the Atlanta metro area from Friday through Sunday, we ended up with 2.64 inches of rain at Hartsfield, or 64% of normal. Here, I got even less, with 2.7 inches of rain, 1.5 of which we got over the weekend.

November 30th also marked the end of the 2008 hurricane season. It was an above average year, with 16 named storms, eight hurricanes, and five intense hurricanes. Hurricane Ike became the third most expensive hurricane to hit the US, after Katrina and Andrew. Tropical Storm Fay set a record, striking Florida four separate times back in August.

North Georgia has been blessed this year with a gorgeous few days of Indian Summer, traditionally defined as warm weather following a frost. Following a chilly end to October, November has been a delight, with temperatures more than five degrees above normal, which should be around 66. Of course, Indian Summer has its downside: a lack of rainfall. It’s been dry for the past two weeks, although that’s likely to change soon, as you’ll see below.

The dry weather hasn’t had much impact on the drought situation. The latest drought monitor doesn’t show much change from what we’ve seen since Labor Day. The latest drought outlook, released this morning, calls for some improvement in the short term, but paints a grimmer picture as winter settles in. The silver lining might be that the Lake Lanier drainage basin may get more precipitation than metro Atlanta proper.

As indicated by this post’s title, the mild weather we’ve had recently is going to come to an end, beginning tomorrow, when a cold front brings rain, and then cooler weather for the weekend. Following that, we’ve got a series of storms that are likely to bring rain several times over the next ten days or so. Temperatures are likely to seesaw during the period, with warmer weather during the week, and cooler weather on the weekends.

It’s all part of the battle between summer’s warmth and winter’s cold, with winter inevitably winning out as we move into December. The tropics are making a last stand as well. Hurricane Paloma has formed in the Gulf of Mexico, and appears to be heading towards Cuba as a category two storm, before recurving back out into the Atlantic, with no threat to the United States. Despite 17 Atlantic storms this year, Florida State University is reporting that overall, tropical activity in the Northern Hemisphere is down over the last two years, primarily due to a lack of storms in the Pacific. This is the lowest level of northern hemisphere storms seen in 30 years.

It’s been almost two weeks since I’ve posted… partially because of some well-deserved vacation, partially because, at least here in North Georgia, a fairly quiet weather pattern, and partially because of some other interesting events taking up my web time.

So, what did we miss. After a few weeks of quiet on the tropical front, last week brought Hurricane Kyle, which was notable in that in the first time in 17 years or so, a hurricane made landfall in Canada. Right now, Subtropical Storm Laura is on her way to England, apparently, bothering no one, really. And then there was the storm that didn’t get named despite showing some tropical characteristics—including an eye, but brought rain to the Carolinas and up into the Mid-Atlantic states.

During all this turmoil, weatherwise and otherwise, the Atlanta area stayed dry.  I’ve recorded less than 2/3 of an inch of rain this month, and the official rain gauge at Hartsfield airport shows 3/4 of an inch, with no meaningful precipitation since back on the 12th.  That’s about 3 inches less than a normal September, although one only has to go back to 2005 to find less, when we only had a quarter of an inch.  The final total could change, since there are some storms in the area tonight, but it’s highly likely that we’ll go through another month with below-normal rainfall.

I haven’t said too much recently about Hurricane Ike, mainly because I’ve been busy this week with other projects, and because there has been plenty of coverage in the media. That being said, I think that after the storm passes through Texas, it will probably be recognized as the storm of the year, comparable to Katrina three years ago.

Take a look at the Houston weather forecast. For Saturday:

Saturday…Hurricane conditions expected. Showers and thunderstorms. Some thunderstorms may produce heavy rainfall. Highs in the mid 80s. Southwest winds 45 to 65 mph with gusts to around 90 mph in the morning Decreasing to 30 to 40 mph with gusts to around 65 mph in the afternoon. Chance of rain near 100 percent.

The real danger from Ike won’t be the amount of rain, nor will it be that the storm will remain over Harris County causing wet weather for days, as Fay did in north Florida. Instead, it’s going to be the storm surge across Galveston Bay and into the shipping canal that serves Houston. Surges of up to 20 feet are predicted, and the Weather Service is warning,

MANY RESIDENCES OF AVERAGE CONSTRUCTION DIRECTLY ON THE COAST WILL BE DESTROYED. WIDESPREAD AND DEVASTATING PERSONAL PROPERTY DAMAGE IS LIKELY. VEHICLES LEFT BEHIND WILL LIKELY BE SWEPT AWAY. NUMEROUS ROADS WILL BE SWAMPED… SOME MAY BE WASHED AWAY BY THE WATER. ENTIRE FLOOD PRONE COASTAL COMMUNITIES WILL BE CUTOFF. COASTAL RESIDENTS IN MULTI-STORY FACILITIES RISK BEING CUTOFF. CONDITIONS WILL BE WORSENED BY BATTERING WAVES CLOSER TO THE COAST. SUCH WAVES WILL EXACERBATE PROPERTY DAMAGE…WITH MASSIVE DESTRUCTION OF HOMES…INCLUDING THOSE OF BLOCK CONSTRUCTION. DAMAGE FROM BEACH EROSION COULD TAKE YEARS TO REPAIR.

VERY DANGEROUS WINDS WILL PRODUCE WIDESPREAD DAMAGE AND DESTRUCTION OF MOBILE HOMES IS LIKELY. STRUCTURAL DAMAGE WILL INCLUDE THE MAJORITY OF MOBILE HOMES BEING SEVERELY DAMAGED. THOSE THAT SURVIVE WILL BE UNINHABITABLE UNTIL REPAIRED. HOUSES OF POOR TO AVERAGE CONSTRUCTION WILL HAVE MAJOR DAMAGE…INCLUDING PARTIAL WALL COLLAPSE AND ROOFS BEING LIFTED OFF. MANY WILL BE UNINHABITABLE. WELL CONSTRUCTED HOUSES WILL INCUR MINOR DAMAGE TO SHINGLES…SIDING…GUTTERS…AS WELL AS BLOWN OUT WINDOWS. UP TO ONE QUARTER OF GABLED ROOFS WILL FAIL. PARTIAL ROOF FAILURE IS EXPECTED AT INDUSTRIAL PARKS…ESPECIALLY TO THOSE BUILDINGS WITH LIGHT WEIGHT STEEL AND ALUMINUM COVERINGS. OLDER LOW RISING APARTMENT ROOFS MAY ALSO BE TORN OFF…AS WELL AS RECEIVING SIDING AND SHINGLE DAMAGE. UP TO ONE QUARTER OF ALL GLASS IN HIGH RISE OFFICE BUILDINGS WILL BE BLOWN OUT. AIRBORNE DEBRIS WILL CAUSE DAMAGE…INJURY…AND POSSIBLE FATALITIES.

NATURAL DAMAGE WILL INCLUDE ALL TREES WITH ROTTING BASES BECOMING UPROOTED OR SNAPPED. NEARLY ALL LARGE BRANCHES WILL SNAP. BETWEEN ONE QUARTER AND ONE HALF OF HEALTHY SMALL TO MEDIUM SIZED TREES WILL BE SNAPPED OR UPROOTED…MOST COMMON WHERE THE GROUND IS SATURATED. UP TO THREE QUARTERS OF NEWLY PLANTED GROUND CROPS WILL BE DAMAGED.

The unspoken threat in the above is the possible damage to the energy refining and chemical production facilities along the coast. Some people are reporting gas stations already charging upwards of $4 per gallon. I noticed gas prices have risen by 10-15 cents since yesterday. We’ll know more by tomorrow evening, but this looks like one of the worst storms to hit Texas ever.

Here in North Georgia, we’ve been feeling the effects of the approaching Ike. While there hasn’t been a lot of rain, the tropical dew points have delayed the typical September days of lower humidity and lower temperatures at night. After a warm weekend, you can expect more seasonable weather by the middle of next week after Ike moves out. In the meantime, hope for the best for Houston.

Topical Storm Hanna ended up not causing as much damage as it could have, making landfall Saturday morning near the North Carolina/South Carolina border with winds bringing it close to but not quite hurricane strength. Over the course of Saturday, it moved rapidly north disrupting, among other things, the NASCAR night race at Richmond, Virginia and the US Tennis Open in New York. The storm has become extratopical, and is now heading east towards the United Kingdom.

Hanna’s rainfall will help ease drought conditions in North and South Carolina. Here are some rainfall totals from the storm:

Cape Fear, NC – 3.02 inches
Lumberton, NC – 5.0 inches
Whiteville, NC – 4.47 inches
Wilmington, NC – 2.33 inches
Darlington, SC – 3.1 inches
Myrtle Beach SC – 4.41 inches
Newark, DE – 3.69 inches
Atlantic City, NJ – 2.89 inches
East Brunswick, NJ – 5 inches
Ridgewood, NJ – 4.72 inches
Allentown, PA – 3.06 inches
Philadelphia, PA – 2.27 inches
Manhattan, NY – 3.54 inches
White Plains, NY – 4.42 inches
East Hartford, CT – 6.19 inches
New Canaan, CT – 6.45 inches
Warwick, RI – 4.07 inches
Boston, MA – 2.2 inches
Needham, MA 6.1 inches
North Grafton, MA – 6.41 inches
Nashua, NH – 6.56 inches
Kennebunkport, ME – 5.8 inches
Portland, ME – 5.52 inches

With Hanna (and Gustav) out of the way, the big concern now is Ike, which appears to be the last of this wave of storms that started back on August 15th with Fay. (Josephine faded away from shear a few days ago). Ike is a category 4 hurricane that pretty much demolished Grand Turk Island last night, and at 5 PM was 75 miles northeast of Guantanamo Bay, headed towards landfall on Cuba. The storm is moving west at 14 MPH with 120 MPH winds extending 60 miles from the storm’s center.

The major factor guiding Ike’s path is an upper level high pressure system over the North Atlantic ocean. Ike is underneath this system and is being prevented from moving north. After it crosses Cuba and emerges into the Gulf, Ike is expected to strengthen, and his path will be determined by what happens with the high. If it weakens, Ike may move towards the Florida panhandle. If it maintains its position, we could be seeing landfall somewhere in Louisiana. And, if it were to intensify westward, landfall might be in Texas. Whatever happens, landfall isn’t going to be until late next week or next weekend.

In the meantime, it looks like the Atlanta area may have its first real rain since Fay departed. We are also being affected by the ridge that’s controlling Ike, but it’s possible that a cold front or two may make it this far south midweek. The HPC is predicting up to an inch of rain by Friday. Then depending on where Ike makes landfall, he is expected to move northeast, and may affect our weather by the weekend, although it’s still too early to tell how much.

It’s beginning to look like the Georgia coast will be spared any significant effects from Tropical Storm Hanna. The storm’s forecast track has been moving steadily east, with landfall now predicted somewhere around Wilmington, North Carolina, then moving northeast along the coast past Wilmington, Delaware and Wilmington, Massachusetts, and then finally up through Nova Scotia by the end of the weekend.

The real question is how strong Hanna will get before it does make landfall. At this point, it is forecast by the Hurricane Center to be a category 1 hurricane with 80 MPH winds just before landfall. In comparison, Gustav had 115 MPH winds just before making landfall in Louisiana. The Hurricane Center is only calling for a 30% chance of tropical storm winds along the Georgia coast, although high tides and rip currents are definitely likely. Around an inch of rain is predicted along the coast, with far less called for in Georgia’s interior. Atlanta won’t see anything from the storm, and the Bulldogs should enjoy great weather this weekend in Athens.

The east coast could risk a second hit next week with Hurricane Ike, which will be a much more powerful storm than Hanna. By Monday, Ike will be a category 3 hurricane located just a little west of where Hanna is now. Models indicate that an upper level weather pattern may be in place that is similar to what we are going to see in the next day or two, meaning Ike could take a path similar to that of Hanna. But the weather can change, so we’ll have a better sense of what will happen with Ike by the end of the weekend.

The biggest problem in Louisiana, besides plenty of rain, is lack of power. Much of the electrical grid in the Pelican State is down, however the reverse diaspora has begun, and residents are beginning to pick up the pieces. Gustav hasn’t moved very far since arriving in Arkansas, although it will begin to travel north, bringing rain to Wilmington, Ohio and Wilmington, Illinois and should finally be gone by Friday. The HPC is reporting that New Orleans only received 3.1 inches of rain from Gustav–far less than further northwest. Jonesville, Louisiana is still having tornado warnings, and has recorded 17.7 inches of rain through this morning.

Vicksburg, Mississippi got almost 9 inches of rain, as did Hot Springs, Arkansas and Monroe, Louisiana. And, it is continuing to rain, so the final totals will be higher. And, if you want to stay out of the rain this weekend, avoid Wilmington.

Hurricane Gustav made landfall about 10 AM in Cocodrie, Louisiana, about 70 miles southwest of New Orleans. At this point, it looks like New Orleans will not face a repeat of the disaster brought about by Hurricane Katrina, although I suspect that we’ll know more in the morning. Here’s a satellite picture of Gustav taken about 9:45, just before landfall:

Gustav is expected to linger in the Arkansas/Texas/Oklahoma area for a few days dropping plenty of rain, possibly up to 20 inches in some areas. At some point, it’s going to get picked up by a low pressure system and taken northwest into Ohio. This means that except for the few showers Georgia is seeing today from extended hurricane bands, we aren’t likely to have any effects from Gustav.

Don’t worry though, because there is more where that came from. Hanna was upgraded to a hurricane this morning, about a day faster than what was previously forecast by the Tropical Prediction Center. The latest estimate is that Hanna will not change position much through Tuesday before becoming a category 2 hurricane early Thursday and beginning a northward trek that could lead to landfall in Georgia. The current estimate puts landfall near Savannah sometime on Friday, followed by a rapid move north into the Mid-Atlantic.

There is still some uncertainty over exactly where Hanna will make landfall and the exact strength of the storm when it does, but no matter whether it’s Brunswick, Savannah or Charleston, I wonder if the networks will pay as much attention to Hanna as they are to Gustav. In any case, as I heard Joe Bastardi say on the radio this afternoon, Atlanta and Macon are likely to get only a “glancing blow” from Hanna. Bastardi pointed to Hurricane Floyd back in 1999 as his guess of a comparable storm.

If Gustav and Hanna aren’t going to be drought-busters in Georgia, maybe the third time will be the charm. The Hurricane Center today identified Tropical Depression Eight, which by afternoon became Tropical Storm Ike. Ike has been brewing as a low pressure system off the coast of Africa for the past few days, and will move across the Atlantic fairly rapidly, probably turning into a hurricane by Wednesday. By Saturday, it will be in roughly the same location that Hanna is today.

While it’s too early to tell exactly what will happen to Ike once he approaches the Bahamas. It could follow Hanna north along the east coast, or move into the Gulf coast either through or south of Florida. The European model has Ike moving into the eastern Gulf and then recurving north through Alabama and Georgia sometime after September 10th.

And don’t look now, but there’s another strong tropical wave southeast of the Cape Verde Islands that the hurricane center says could develop into yet another tropical depression or storm in the next day or two. If it does, it will be named Josephine.

Not wanting to get caught like they did 3 years ago with Katrina, an estimated 90-95% of coastal Louisianans have left for locations north and west to get out of the way of Gustav, including an estimated 200,000 from New Orleans. Overall, things seem to be much better prepared than they were three years ago, although I wonder where Mayor Ray Nagin got this idea (via the New York Times):

The storm, he said, was now 900 miles wide, compared with 400 miles for Katrina. Even the capital of Baton Rouge, 80 miles inland from New Orleans, could experience hurricane force winds of up to 100 m.p.h., he said. But Dennis Feltgen, a spokesman for the National Hurricane Center, said he had no idea what the mayor meant by a 900-mile footprint, saying that hurricane force winds do not extend nearly that far.

In any case, at 5 PM, Gustav was a category 3 hurricane, with winds of 115 MPH, located 215 miles southeast of the Mississippi River. Satellite images show banding reaching up into South Georgia. The latest pressure reading was 957 millibars. The storm has not strengthened as much as was expected previously, which is good, with the storm expected to make landfall west of New Orleans sometime early Monday afternoon.

Comparing Gustav with Katrina, shortly before landfall, Katrina had winds of 166 MPH, with a minimum pressure of 902 MB: a much stronger storm. However, the Weather Service has issued a strong warning:

IN THE AREA NEAR LANDFALL OF THE EYE…EXTREMELY DANGEROUS WINDS WILL CAUSE EXTENSIVE DAMAGE…AND ALL MOBILE HOMES WILL BE DESTROYED. HOUSES OF POOR TO AVERAGE CONSTRUCTION MAY BE SEVERELY DAMAGED OR DESTROYED. MODERATE TO MAJOR DAMAGE COULD OCCUR TO WELL CONSTRUCTED HOMES. MANY GABLED ROOFS MAY FAIL ALONG WITH SOME EXTERIOR WALLS. ALUMINUM AND LIGHT STEEL ROOFS WILL BE TORN OFF BUILDINGS AT INDUSTRIAL PARKS. PARTIAL ROOF AND EXTERIOR WALL FAILURES ARE LIKELY AT LOW RISE APARTMENT BUILDINGS…ESPECIALLY THOSE OF POOR TO AVERAGE CONSTRUCTION. SOME WINDOWS IN HIGH RISE OFFICE BUILDINGS WILL BE BLOWN OUT. AIRBORNE DEBRIS HAS THE POTENTIAL TO CAUSE ADDITIONAL MAJOR DAMAGE…AS WELL AS INJURIES AND A FEW FATALITIES. NEAR TOTAL POWER LOSS IS EXPECTED WITH NUMEROUS LINES AND POWER POLES KNOCKED DOWN. THE AVAILABILITY OF POTABLE WATER WILL BE DIMINISHED AS FILTRATION SYSTEMS BEGIN TO FAIL. NUMEROUS TREES…ESPECIALLY SMALL TO MEDIUM TREES…WILL BE DOWNED…SNAPPED OR UPROOTED.

MANY RESIDENCES OF AVERAGE CONSTRUCTION IMPACTED BY THE STORM SURGE MAY BE HEAVILY DAMAGED OR DESTROYED. NUMEROUS ROADS WILL BE SWAMPED. ENTIRE FLOOD PRONE COASTAL COMMUNITIES WILL BE CUTOFF BY STORM SURGE FLOODING. SIGNIFICANT STORM SURGE FLOODING WILL MOVE WELL INLAND ESPECIALLY ALONG BAYS AND BAYOUS. A STORM SURGE OF THIS MAGNITUDE COULD RESULT IN EXTENSIVE FLOODING AND POSE A THREAT TO LIFE AND PROPERTY.

The threat of the storm caused the Republican National Committee to hold activities at their St. Paul convention to a minimum on Monday. About all we can do now is wait and hope for the best. If you want to get a sense of what’s going on from the New Orleans perspective, visit the New Orleans Times Picayune website. You can also stream New Orleans’ TV stations here.

The next question is what is going to happen to Gustav after landfall. Some models indicate that the storm will linger in the Louisiana/Texas area and eventually peter out, while others show the remnants of Gustav being picked up by a low pressure system, and dragged east, which could affect North Georgia and Atlanta’s weather by next weekend.

Also, Tropical Storm Hanna has been chugging along slowly in the Atlantic. The latest projected track has Hanna making landfall somewhere near Savannah, Georgia as a Category 1 hurricane on Friday. Some models show landfall further north in North or South Carolina, while others pull the storm southwest towards Florida. Landfall to the north would minimize the storm’s effect on the Atlanta area, while a more southerly track could bring Hanna’s presence known here.

What happens with both Gustav and Hanna will be determined by three upper level features: a strong ridge of high pressure that will move from the Midwest to the Mid-Atlantic in the next day or so, a closed low pressure system that will develop off the New England coast and the aforementioned low pressure trough in the Northwest. Until we know the exact effects of these systems, North Georgia will actually be in for some good weather, with lower humidity for midweek, courtesy of the ridge.

The twin threats of Hurricane Gustav and Tropical Storm Hanna almost guarantee that tropical weather will be in the news for the next week to ten days. Gustav is just about to make landfall as a powerful category 4 hurricane over western Cuba, while Hanna is becoming slightly more organized as a tropical storm about 250 miles east of the Bahamas.

Gustav is expected to strengthen into a category 5 hurricane after it passes over Cuba, and all models have it making landfall somewhere on the Louisiana coast sometime Monday afternoon. The intensity is expected to drop to category 4 by the time he makes landfall, and the storm is likely to move northwest through Louisiana and Texas in the two or three days after landfall. After the devastation caused by Katrina three years ago, officials are taking no chances, but if the storm follows the NHC path, while New Orleans will get a lot of rain, there is less risk to the levees if the storm follows its current projected path. Evacuation efforts have begun, and FEMA is assembling materials needed should disaster strike.

In any case, Gustav isn’t likely to have too much effect on Atlanta or North Georgia’s weather if it follows its expected path–certainly nothing like we saw with Fay. Hanna, however may well turn out to be a different story. Although initial projections had Hanna petering out somewhere north of Cuba, models are now telling a different story, with more of a northwest movement after a few days that could lead to landfall anywhere between northern Florida and South Carolina.

High pressure over the mid-Atlantic is currently helping to steer both Gustav and Hanna, and by midweek, the ridge is expected to weaken. While Gustav will have already made landfall by that point, Hanna will react, and will likely make landfall somewhere in an area that will affect our weather by late week. Meanwhile, the Hurricane Center is taking a long look at a tropical wave coming off of the African coast that could turn into a third Atlantic storm before you’re done with your Labor Day picnic.

The two maps below show the tremendous difference a tropical system can make in dampening the effects of a drought. The map at left shows drought conditions in Georgia as of Tuesday, August 19th, when almost ten percent of the state was in exceptional drought conditions and only two percent was drought free. The right hand map shows conditions as of Tuesday morning the 26th at 7 AM. Now, none of the state is in exceptional drought, and 16% is drought free.

Remember, the cutoff for the drought maps was 7 AM Tuesday, which was before a good bit of the rain hit North Georgia, so I expect to see continued improvement with next week’s drought monitor as well. Lake Lanier has also risen just over two feet from the rainfall brought on by Fay.

The weather service has investigated the severe weather brought about by Fay, and has issued a report saying that there were six tornadoes in Georgia brought on by the storm. Most of the damage was in Hall and Jackson counties. Three EF1 tornadoes with 90 MPH winds were verified in Hall, where trees were knocked down and damage was reported to an elementary school.

Another tornado with 100 MPH winds touched down near Commerce in Jackson County, while two additional EF0 tornadoes with 70 MPH winds were reported in Monroe and Wilkes counties.

We may have some more opportunities for drought relief in the next week to 10 days. Gustav was a hurricane, and then was downgraded to a tropical storm when it made landfall in Haiti. It has moved a bit south, and is expected to increase in intensity to at least a category 3 hurricane. The media is comparing Gustav to Katrina, which hit New Orleans three years ago today. Despite the timing coincidence and the likelihood that Gustav will become an intense hurricane before it makes landfall sometime on Monday, it’s still too early to know exactly where the storm will make landfall. Recent updates to the forecast track have moved landfall west of New Orleans, and the further west it is, the less likely it will have any effect on the Atlanta area. A track further east, as some models are suggesting would make the storm more like Ivan in 2004, which brought intense rainfall to North Georgia.

And if Gustav isn’t enough, the Hurricane Center is now tracking Tropical Depression 8, located to the east of Puerto Rico. Later this afternoon, the storm will gain enough intensity to be named Hanna. Instead of moving south of Cuba as Fay and Gustav are doing, Hanna is likely to become a category 1 hurricane by Labor Day, moving north of the Dominican Republic and the Bahamas and heading west towards the Florida coast.

I suspect we’ll have a better idea of what both these storms will do as the weekend unfolds.