Upper Level Block Over NW Territories Has Forced Upper Jet South…..Resulting In Cooler Temps For The High Country Through Wednesday…Warmer Weather is Expected For The Holiday Weekend….Monsoon Moisture Lurking To The South Over The Holiday
Friday June 24, 2011
Posted at 10:09 am by Howard
Looking at the HT 500MB means for the 3, 5, 8 and 11 day period, it is clear that the current pattern will continue through Wednesday with a significant warm up there after.
The GFS day+ 3 means (through Sunday) shows the main height anomaly over British Columbia stretched NW well up into the Arctic near 140west, this block is having the effect of suppressing the upper jet into Northern Ca, with the mean negitive height anomaly just off the Northern Ca coast. This is the reason for the cooling overthe past 24 to 36 hours. Little change in temps for the high country is expected through Sunday with highs in the low 70s.
The Day+ 5 shows the block weakening…however, heights build north of Hawaii about the latitude of Washington State, keeping long wave troffing in the same areas as it is now. However, with that said, a short wave ridge will move into California Monday for a quick bump up in temps followed by the actual long wave trof progressing inland mid week. This should result in a significant cool down and breeze-up Tuesday into Wednesday next week. There is a chance of showers anytime between Tuesday night and Wednesday night. Highs will cool to the lower 60s Wednesday. With early am temps in the low 30s.
Day+8 of the Multi-Day Ensemble Means show a strong core of positive height anomalies just south of the Western Aleutions which teleconnects to a mean trof along 160west and weak upper flow along the US Canadian border. It has been suggested that after the main long wave moves through California Wednesday/Wednesday Night, that Significant Ht 500 height rises will occur Day+ 8 into day+ 11 (July 4th) over the west coast,. A strong positive height anomaly is indicated to develop just west of Seattle.
This all adds up to a strong subtropical east-west upper ridge stretched from the Hawaiian islands north east into the desert southwest Via California. Ht 500 Heights will probably rise into the low 590s across the golden state for a perfect Holiday Weekend for the high Country. High temps will probably be back up into the low 80s at 8000 feet. This looks like a dry pattern with only a few isolated TSRWs until about the 4th when Monsoon Moisture makes a run north out of Mexico.
Dr Howard and the Dweebs……………………………….:-)
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Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.