S Plains Weather

[jeff]

Last week bone cold with snow, this week 15 degrees above normal.

Large upper air pattern change from eastern US trough to western US trough and SE US ridge has occurred. Powerful storm system pounding away at CA currently with warming over the eastern 2/3rds of the nation.

Moisture continues to increase over TX and the southern plains on increasing SE winds. However the Gulf has had a good working over in the last week from the deep arctic intrusion and the air is circulating around the SE US ridge, so dewpoints in the low 60's is about all we can get right now. Showers have been developing under a capping inversion around 800mb and this inversion should hold through Friday. The active sub-tropical jet is just to our west and is forecast to move over the region in the next 36 hours. Rain chances will remain limited to scattered showers below the cap and mainly during the day.

Changes happen by the weekend as weak disturbances eject ENE across TX from the slow moving low in the SW US. Most of the energy will be aimed at the central plains, however enough moisture and instability should return to TX by that time to produce showers and thunderstorms. The GFS is very impressive with its QPF Sat. through Sun over the state, while the ETA is much drier. Will go with the GFS solution for now as it has preformed much better with the events of the past 2 weeks and did very good with the snow event last week.

Strong upper low moves east across the state early next week with widespread rain and thunder likely. PWS increase to near 1.5 inches and a 45kt low level jet supplies increasing deeper and richer moisture. Stage may be set for a heavy rainfall event by Monday with severe weather also a threat given the shear profiles and low level jet expected. Upper low heads for the Great Lakes bringing only a weak wind shift into the area by Wed. Doubt we will clear much and not much cooling either as cold arctic air remains bottled up in Canada and the N plains.

Pattern change looms around the middle of the month and very cold arctic air may begin moving south again. Undercutting sub-tropical jet will keep things active rain wise at least for the next week or so.

Asian tsunami:

As I am sure many have heard, an incredible 8.9 magnitude (5th strongest on record, 9.5 in Chile is the strongest on record) seaquake occurred Sunday AM in the eastern Indian Ocean off the west coast of Indonesia. Satellite images and GPS data have noted that the tectonic activity with the quake has displaced many of the islands in the Indian Ocean by as much as 15-20 feet. The plates slipped along a 620 mile interface which is extremely large in tectonic terms. In addition a 35ft bulge developed in the ocean floor near the epicenter of the quake. The quake was so powerful that the earth's rotation was briefly disrupted and it has changed the length of a day by -2.676 microseconds.

The quake generated a tremendous tsunami which impacted 11 nations surrounding the Indian Ocean. The wave was moving upwards of 300 mph and crossed the entire ocean in less than 2 hours after the earthquake It's height increased to near 25-30 ft as the energy ran aground in the shallow waters off many of the islands. The wave (in a much weaker state) was detected along the west coast of N and S America after crossing the entire Pacific Ocean. As can be expected with no warning, the death toll has risen to extreme numbers (80,000)

In the US, NOAA and the NWS are responsible for the US and Pacific tsunami warning system which covers Hawaii, Alaska, and the US west coast.Warnings and Watches are broadcast via NWS warning methods to local media and then to the public through TV, radio, and in some places outdoor siren systems. There is very little time between the time of an earthquake and the time a tsunami reaches the coast especially if the quake is close to shore.