Sunday, October 23, 2011

Oct 22, 2011: Another Storm Mid-Late Next Week

With the cold air mass sticking over the region, today brought chilly temperatures once again. With more sunshine than yesterday, temperatures were slightly warmer across the area, reaching the upper 50s inland and the lower 60s across the rest of the area, which is about near to slightly below the average high temperature for this time of the year. The mainly dry conditions will last through Tuesday with warming temperatures, but stormy conditions will return again on Wednesday as several low pressures with a complicated set up will affect the region.


Tomorrow's Outlook:

With partly sunny skies expected for tomorrow again, conditions will once again be similar to those of today, but with slightly warmer temperatures. With 850 mb temperatures near 1-3 degrees celsius and a SW wind expected, high temperatures will reach the upper 50s to lower 60s inland and the lower to mid 60s across the rest of the area.


Monday - Tuesday: Slightly Warmer

Temperatures will slightly warm up on Monday as a weak low pressure in southern Canada pushes out the cold air, bringing high temperatures into the mid to upper 60s across the area, with parts of the immediate NYC area potentially reaching the 70 degree mark. Scattered showers are expected on Monday night as the cold front moves through, with slightly cooler temperatures for Tuesday, reaching the lower to mid 60s across the area.


Wednesday - Saturday: Rain Returns; So Does Uncertainty


Last night's update mentioned that the model guidance showed a cold rainstorm with some snow across the area, and that the models were expected to trend away from that direction. Today's models did trend away from that direction, and show a rainstorm for the area. While the precipitation type is not an issue for this storm, the scenario is still uncertain, as the models are still inconsistent with the scenario for this storm.

There is still high confidence with the first part of the storm through Wednesday night. A low pressure will move through the Great Lakes before reaching northern New York on Wednesday, bringing warmer temperatures into the area, reaching the mid to upper 60s. Meanwhile, a strong high pressure will dig into the central and southern US, which will push a piece of energy left over from the trough down into Texas. At the same time, the initial low pressure will bring its cold front through, bringing showers across the area for Wednesday and Wednesday night, and with the frost stalling just to the south of the area on Thursday, chilly temperatures are expected, likely peaking in the lower to upper 50s across the area, with occasional rain expected near and north of the front.

The uncertainty increases by Thursday night as the energy in Texas becomes another low pressure and starts to move into the southeastern US. The models show a wide range of solutions, ranging from a stronger low pressure near the Great Lakes on this morning's GFS run, to a relatively weak wave of low pressure moving through the southern Mid Atlantic. The uncertainty likely won't be resolved for a few days until the models get a better handle on the storm, but at this time, I am leaning towards a solution in between the two, with the storm moving towards the central/northern Mid Atlantic, bringing widespread moderate rain across the area with relatively chilly temperatures around Thursday night and Friday. Stay tuned for more information on this storm.


Brief Long Range Outlook: Beyond the storm, cooler temperatures are expected, with high temperatures likely staying in the 50s for next weekend and low temperatures potentially reaching their coldest point so far  this fall. Once again, however, the cold spell doesn't appear to be sustained, and while below average temperatures are likely, especially to the west of the area, an active storm track approaching Canada will likely weaken the cold air mass, with moderating temperatures likely towards Halloween and the start of November. Afterwards, however, the potential is there for colder temperatures to return across the region more frequently. The November outlook will be posted on October 31, discussing the potential for a colder pattern for November across the region.

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