Warm Sierra Weather to give way to some cooling mid week…Then a Quick Warm Up for the Weekend Expected…..Mid Spring Thunderstorm Pattern may develop early the following week…..
Monday April 29, 2013
Posted at 10:28 am by Howard
Yes…..Temperature records were broken this past weekend and another day today of broken high temps are expected. However, Spring is a time of changing weather, and cooling is expected tomorrow.
A short wave now coming through the pacific northwest will drag a cool front through Eastern Ca and bring about 10 degrees of cooling Tuesday into Wednesday. There will be wind over the crest tomorrow as well as breezier weather in town. Our area lakes may have some white caps by mid to late PM Tuesday……Boaters take note!
High temps at 8000 feet will retreat back into the upper 50s by midweek and lows in the upper 20s by Wednesday AM. Upper ridging will return Thursday into the weekend. No precipitation is expected through the weekend.
Upper Air Pattern to change the following week for the possibility of Showers and Thunder.
A developing REX block is occurring out at 140W. The REX is highlighted by an upper level low below “latitude wise” an upper high to the north. This pattern, at this Longitude, this time of the year, keeps the westerly’s to our north and often times our weather fair. However, the block is expected to break down late next weekend with the upper cut-off drifting toward California. At the same time, a short wave dropping SE from the pacific north west may either diverge to the Rt, thereby coupling with it, or eject it through Southern Ca to our south. The position or exact track of the upper low will be important to the forecast for our weather next week.
At this time, confidence is low because of the distance in time. However, with antecedent warmth of the upcoming weekend and the possibility of increasing divergence and cooling aloft, an unstable atmosphere may very well develop over the elevated heat source of the Sierra. Showers and thunder for the high country is a good possibility beginning Sunday PM the 5th through the 7th or 8th of May.
Longer Range Thoughts:
The Dweebs note that the QBO is still very neutral in its index and as is often the case, blocking over near the Greenland area persists. The current forecasts of the more significant teleconnections of the AO and NAO are neutral to negative and the PNA index forecast is of a weakly positive sign into May. So more of the same weather is expected for some time to come. Warmer then normal over the Far west and southwest and Colder then normal over most areas of the Midwest and wetter then normal over parts of the east and southeast. Will the Midwest have a slower start to their growing season?
Dr Howard and the Dweebs……………………………….:-)