Reported by Don Thompson at location in Belmopan 17'15" N, 88'47" W
Friday, February 27, 2015
Its the last day of February and North America is still dominated by Arctic Air. The polar and jet stream pattern has remained virtually unchanged over the entire month. The Caribbean as shown in the water vapour remains extremely dry. The lower images show a cold front as of last night and on the right the same cold front today which has not moved and will now likely just disappear or retreat back to the north as a warm front. Seems like the Earth's weather systems get locked into a pattern and just sit in one place for extended periods of time. This is not a good sign. The planet's atmosphere needs to be dynamic to be healthy.
The images show the upper air at 10 mb pressure level. The red arrow is the boundary between the North and South hemispheres. The green arrow in the south is the direction of the circulation. The upper right is South pole where there is very light winds. The lower left is the north pole where the circulation has changed very little during the month of February. The large CCW center is at 81.2 N / 7.3 W and the small CW circulation on the west coast of NA is now at 56.4 N / 134.3 W . The pattern has resulted in continuous record breaking cold in the east and above normal temperature in the west. The Caribbean in now getting warmer and continues to be very dry. The trade winds are beginning the get stronger.
The cold front passed through Belize overnight with just a trace of light rain. This morning is cool and cloudy. The red line shows the final position of the front where it will dissipate on Friday. Eastern North America is experiencing record cold. The cold CCW polar circulation has been expanding and is now at 77.7 N / 68.6 E and elongated while the warmer High cell has weakened and moved back more towards Alaska at 49.4 N / 160.7 W this is allowing the cold arctic air to invade far to the south and spread further west.
The Cold Front is shown by the yellow line. There is a minor wind shift line as show by the red line. The cold front will bring a sharp drop in temperature beginning on Thursday. The night may remain cloudy so the nighttime temperature may not be too cold. The polar circulation has changed very little so eastern North Am remains extremely cold, even record cold in some places.
A new Cold front has just entered the Gulf of Mexico. The front is suppose to reach Belize sometime Wednesday night. We should be getting some hot daytime temperature before the front arrives then much cooler the following day.
The upper air polar circulation is pretty much in the same position as before the large CCW is now at 79.1 N / 53.7 E and the smaller CW has moved NW slightly to 52.0 N / 137.0 W. The strength of the polar Low Pressure is keeping the east part of North America in the deep freeze (almost record cold). Belize is still under the influence of a cold High Pressure which is centered at 27.2 N / 91.3 W this is producing warm sunny days and very cool nights ( 16 to 18 C). The temperature is forecast to increase briefly ahead of a new Cold front due mid week.
The Water Vapour image shows that the Caribbean is extremely dry. Any significant rainfall may be 10 days away. The clear sky over Belize has brought bright sunny warm days and very cool nights. The lower image shows that the polar CCW circulation has shifted more towards the north pole from the previous location closer to Siberia. It now centered at 82.5 N and 25.4 E. Meanwhile the CW circulation has shifted to the south and east and is now over British Columbia at 58.5 N and 128.8 W.
Here is the latest image of the Upper Air polar circulation at 10 mb. The center of the larger CCW circulation is at 74 N / 71 E and the smaller CW circulation is at 62 N / 147 W. What I think is going to happen from now on is that the CCW system will slowly become smaller and the CW system will grow larger and eventually dominate as the summer season approaches. In the southern hemisphere, the opposite should take place.
The red arrow points to the wind shear line which is actually a trough of lower pressure. The High is south and west of Belize and this is what is producing the cold air flow. The trough is rotating CCW slightly so tonight will be very cool since the cold High will dominate.
The red line in the image is the wind shear line. West of the line is the cool air mass and the east side of the line is the warmer air mass. The line is forecast to gradually weaken allowing the warmer air to extend further to the west. Belize should be in warmer air tomorrow. The line is actually a ridge of high pressure. Cold air is flowing down on the west side.
There is a wind shift front at the tip of the red arrow but the wind is very light here in Belmopan so the shift is not very noticeable, just a sight drop in temperature and a few drops of rain. Not as much rain around Belize as I expected. The white areas in the right image show where there is some rain. Maybe we could get some rain after midnight.
A wind shift line passed through Belize sometime before sunrise and now lies out in the Gulf of Honduras. The associated cold front is still north of Belize. The shift line was clear this morning but this afternoon the line is beginning to break apart. Have been hoping for some rain from this system but no rain is in sight at this time. There is not even any convection. Maybe there will be some rain tonight.
High Pressure in Caribbean centered at position of 20.5 N and 80.9 W or just south of Cuba. Belize is in an area of low water vapour. The upper air polar low pressure is centered at 78.7 N / 63.1 E, A high pressure cell is forming near Alaska. North America is experiencing very cold temperatures. A Cold front is expected to cross Belize this coming Wednesday night.