Hurricane Katrina Live Thread, Part III

Hurricane Katrina continues to strengthen in the Gulf of Mexico. Currently, the forecast models are converging upon New Orleans. However, all interests in the northern Gulf of Mexico should follow the path of this storm, and be prepared for a major hurricane landfall. Throughout Friday, the official track forecasts moved west, as Hurricane Katrina delayed making the anticipated northwest turn.

WFOR-TV Miami: http://dayport.wm.llnwd.net/dayport_0025_live
WWL-TV New Orleans: mms://beloint.wm.llnwd.net/beloint_wwltv
HurricaneCity.com: http://hurricanecity.com/live.ram
WTSP-TV Tampa: mms://wmbcast.gannett.speedera.net/wmbcast.gannett/wmbcast_gannett_jan032005_0856_78183
WKRG-TV Mobile mms://wmbcast.mgeneral.speedera.net/wmbcast.mgeneral/wmbcast_mgeneral_jul072005_1144_93320

Category	Wind Speed	Barometric Pressure	Storm Surge	Damage Potential
Tropical Depression	< 39 mph < 34 kts			Minimal
Tropical Storm	39 - 73 mph 34 - 63 kts			Minimal
Hurricane 1 (Weak)	74 - 95 mph 64 - 82 kts	28.94" or more 980.02 mb or more	4.0' - 5.0' 1.2 m - 1.5 m	Minimal damage to vegetation
Hurricane 2 (Moderate)	96 - 110 mph 83 - 95 kts	28.50" - 28.93" 965.12 mb - 979.68 mb	6.0' - 8.0' 1.8 m - 2.4 m	Moderate damage to houses
Hurricane 3 (Strong)	111 - 130 mph 96 - 112 kts	27.91" - 28.49" 945.14 mb - 964.78 mb	9.0' - 12.0' 2.7 m - 3.7 m	Extensive damage to small buildings
Hurricane 4 (Very strong)	131 - 155 mph 113 - 135 kts	27.17" - 27.90" 920.08 mb - 944.80 mb	13.0' - 18.0' 3.9 m - 5.5 m	Extreme structural damage
Hurricane 5 (Devastating)	Greater than 155 mph Greater than 135 kts	Less than 27.17" Less than 920.08 mb	Greater than 18.0' Greater than 5.5m	Catastrophic building failures possible

Here is a blogger who seems to know the jargon. He has that certain sang froid as he predicts the hammerstrike.

Observations:

1. Dry air is still entrained into Katrina, as seen on the water vapor satellite

2. Convection over Oklahoma is beginning to allow trough to deepen slightly faster than 12Z guidance suggested. Picked up on 18Z guidance.

3. Trough beginning to dig into Pacific Northwest.

4. There is a weak frontal boundary over the southern Mid Atlantic, which is causing scattered showers and thunderstorms from the Delmarva to Ohio Valley.

5. Deepening upper low moving towards western Great Lakes

6. Very warm water ahead of Katrina with very little shear.

Forecast:

This is still a very volital and difficult forecast, but since I'm going on my weekend I'll throw down this whole forecast as my last call. As I stated above the hurricane has a lot going for itself. There isn't much in the way of shear to inhibit the growth of the Katrina. I feel the dry air currently seen around the center of Katrina on the water vapor has slowed the strengthening of this system. However, given that the hurricane is moving into much warmer waters of 88 to 92 degrees, I have little doubt that this dry air will be eradicated. Further, given that the air is actually cooler than the water temperature in some places, strong heat transfer will be in play for the system. These combinations will produce rapid intensification of Katrina over the next 36 to 48 hours. I would not be surprised if Katrina maxes out around a Cat 5 hurricane. Now, let's look at other factors. For one, the track of this system. The key to this forecast can be seen in the water vapor satellite. The first factor is that the trough moving into the Northwest is beginning to build the ridge over the Rockies. This, in return, is allowing the trough over the Plains and Mississippi Valley to begin to deepen. The convection over the southern Plains also is producing an extra enhancement to the weakness developing over the Mississippi Valley. This weakness is what allowed Katrina to turn to more of a west and now west northwest track this evening. The next factor is the heat ridge building to the east of Florida, which will slow the the upper low as it moves into the Great Lakes. Now, let's put this all together. The trough builds into the Northwest, which builds the ridge over the Rockies, and allows the trough to dig over the Mississippi Valley. The heat ridge slows the upper low over the wester Great Lakes, which is "parent" of the trough over the Mississippi Valley. All of these factors will combine to draw a very powerful hurricane to the north and directly towards the southeastern LA coastline and New Orleans. I expect the Katrina to increase in speed as it approaches the coast line as steering winds increase slightly from the southwest.

Now, after landfall Katrina will be a significantly destructive storm even inland. Those of you in western MS are not out of the woods and may be inline for some extensive wind damage, tornados, and flooding conditions. By Monday morning, the following upper level features will be in place. First, the heat ridge will be developing along the East coast and force the upper low over the Great Lakes to slow down. This will keep the boundary over the Mid Atlantic in place and ready for a certain tropical low to develop along it. Katrina will push into MS with declining hurricane force winds and very heavy rains. Now, as Katrina moves north, expect some significant heavy rain over MS, western KY, western TN, and WV. I highlight these areas because significant orographic lifting will be present in these locations due to the Appilachains. Also, the cyclonic flow associated with the remnants of Katrina will further enhance orographic liftings as winds move up over the western sides of the mountains. The saving grace here will be the speed of the remnants as the system gets phased into the departing trough. The lack of support for the heat ridge will begin to allow the ridge to break down. This will allow the upper low to move into Ontario and Quebec by Wednesday morning. The remnant low of Katrina will become extratropical by Tuesday night/ Wednesday morning and begin to redevelop along the previously stationary front over the Mid Atlantic and the cold front stalling over the eastern Great Lakes. With the remnant low moving into the Ohio Valley on Wednesday, I believe the Northeast will NOT see flooding rains. It is my observation over the past few years that the majority of the heavy precipitation occurs on the northern and western side of the remnant low. In this case, the heaviest rains will be focused over Ohio, western PA, and western NY. NOT over NJ, NYC metro area, or in the Hudson Valley. Further the speed of the system at this time will be too fast to support significant flooding criteria. In fact, the heavy rain will give great relief to the drought stricken areas of parts of the Ohio Valley. Notice at this point that the GFS and Euro bring some strong (for this time of year) CAA into the equation from western Ontario. This factor, the combination of the warm, humid tropical air mass with the cool Canadian air mass, will allow for some heavy strato type precipitation over western NY, Ohio, and northwestern PA on Wednesday night. The entire system will basically be done with on Thursday afternoon with much drier air building into much of the East and a nice quiet weekend (well earned too) as well.

Found this at the weather forum:

http://www.easternuswx.com/bb/index.php?s=9221bffaa1b733e26d7872790f79046c&showtopic=47482

My Forecast for Hurricane Katrina, and possible effects on the NE

Observations:

1. Dry air is still entrained into Katrina, as seen on the water vapor satellite

2. Convection over Oklahoma is beginning to allow trough to deepen slightly faster than 12Z guidance suggested. Picked up on 18Z guidance.

3. Trough beginning to dig into Pacific Northwest.

4. There is a weak frontal boundary over the southern Mid Atlantic, which is causing scattered showers and thunderstorms from the Delmarva to Ohio Valley.

5. Deepening upper low moving towards western Great Lakes

6. Very warm water ahead of Katrina with very little shear.

Forecast:

This is still a very volital and difficult forecast, but since I'm going on my weekend I'll throw down this whole forecast as my last call. As I stated above the hurricane has a lot going for itself. There isn't much in the way of shear to inhibit the growth of the Katrina. I feel the dry air currently seen around the center of Katrina on the water vapor has slowed the strengthening of this system. However, given that the hurricane is moving into much warmer waters of 88 to 92 degrees, I have little doubt that this dry air will be eradicated. Further, given that the air is actually cooler than the water temperature in some places, strong heat transfer will be in play for the system. These combinations will produce rapid intensification of Katrina over the next 36 to 48 hours. I would not be surprised if Katrina maxes out around a Cat 5 hurricane. Now, let's look at other factors. For one, the track of this system. The key to this forecast can be seen in the water vapor satellite. The first factor is that the trough moving into the Northwest is beginning to build the ridge over the Rockies. This, in return, is allowing the trough over the Plains and Mississippi Valley to begin to deepen. The convection over the southern Plains also is producing an extra enhancement to the weakness developing over the Mississippi Valley. This weakness is what allowed Katrina to turn to more of a west and now west northwest track this evening. The next factor is the heat ridge building to the east of Florida, which will slow the the upper low as it moves into the Great Lakes. Now, let's put this all together. The trough builds into the Northwest, which builds the ridge over the Rockies, and allows the trough to dig over the Mississippi Valley. The heat ridge slows the upper low over the wester Great Lakes, which is "parent" of the trough over the Mississippi Valley. All of these factors will combine to draw a very powerful hurricane to the north and directly towards the southeastern LA coastline and New Orleans. I expect the Katrina to increase in speed as it approaches the coast line as steering winds increase slightly from the southwest.

Now, after landfall Katrina will be a significantly destructive storm even inland. Those of you in western MS are not out of the woods and may be inline for some extensive wind damage, tornados, and flooding conditions. By Monday morning, the following upper level features will be in place. First, the heat ridge will be developing along the East coast and force the upper low over the Great Lakes to slow down. This will keep the boundary over the Mid Atlantic in place and ready for a certain tropical low to develop along it. Katrina will push into MS with declining hurricane force winds and very heavy rains. Now, as Katrina moves north, expect some significant heavy rain over MS, western KY, western TN, and WV. I highlight these areas because significant orographic lifting will be present in these locations due to the Appilachains. Also, the cyclonic flow associated with the remnants of Katrina will further enhance orographic liftings as winds move up over the western sides of the mountains. The saving grace here will be the speed of the remnants as the system gets phased into the departing trough. The lack of support for the heat ridge will begin to allow the ridge to break down. This will allow the upper low to move into Ontario and Quebec by Wednesday morning. The remnant low of Katrina will become extratropical by Tuesday night/ Wednesday morning and begin to redevelop along the previously stationary front over the Mid Atlantic and the cold front stalling over the eastern Great Lakes. With the remnant low moving into the Ohio Valley on Wednesday, I believe the Northeast will NOT see flooding rains. It is my observation over the past few years that the majority of the heavy precipitation occurs on the northern and western side of the remnant low. In this case, the heaviest rains will be focused over Ohio, western PA, and western NY. NOT over NJ, NYC metro area, or in the Hudson Valley. Further the speed of the system at this time will be too fast to support significant flooding criteria. In fact, the heavy rain will give great relief to the drought stricken areas of parts of the Ohio Valley. Notice at this point that the GFS and Euro bring some strong (for this time of year) CAA into the equation from western Ontario. This factor, the combination of the warm, humid tropical air mass with the cool Canadian air mass, will allow for some heavy strato type precipitation over western NY, Ohio, and northwestern PA on Wednesday night. The entire system will basically be done with on Thursday afternoon with much drier air building into much of the East and a nice quiet weekend (well earned too) as well.

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