Feb 19, 2013: Next Storm Expected This Weekend

Forecast Highlights:

A weak storm affected the area today, producing rain for most with totals generally up to 1/4 inch. Interior western parts of the area, however, started out with a period of moderate snow with minor accumulations, especially in the higher elevations. Temperatures briefly warmed into the upper 30s to mid 40s, although a cold air mass will return for Wednesday and Thursday with windy conditions expected again. The stormier pattern is expected to continue afterwards with a storm for the weekend and another towards February 26-27.

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Tonight - Friday: Colder, Windy

Behind today's storm, a cold air mass will return into the region, lasting through Thursday, along with stronger wind expected resulting in wind chills in the 10s and single digits again. Temperatures on Wednesday are not expected to rise much from the morning lows, peaking in the upper 20s to low 30s inland and low to possibly mid 30s for the rest of the area, along with WNW winds of 15-25 mph and gusts up to 30-40 mph. Low temperatures are expected to drop into the low to mid 10s inland and mid 10s to low 20s across the rest of the area, with breezy conditions resulting in wind chills in the single digits.

Thursday will be similar to Wednesday with temperatures about the same, if not slightly warmer, along with a breezy NW wind. The cold air mass will weaken overnight into Friday, however, with increasing clouds expected for Friday with highs in the upper 30s to low 40s as the next storm approaches.


Friday Night - Weekend: Rain, Snow Expected

The next storm to affect the region over the weekend has its origins as a significant snowstorm in the Plains late in the week, with the weakening low pressure then tracking into the Great Lakes as light precipitation spreads into the area late on Friday into the overnight hours. This initial round of light precipitation is expected to be snow inland with rain or a rain/snow mix further south and east, with minor accumulations possible inland. The main event, however, is expected to be late on Saturday into Saturday night, as a coastal low pressure develops near the coast.

As with yesterday, the model guidance has yet to reach an agreement regarding the specifics of this storm, with a lack of consistency considering this is still 4 days away; most of today's models, specifically the GFS, ECM and CMC, have alternated between a significant rain/snow event and a light rain event with some snow inland. Precipitation type is an issue with all of today's runs, however, as the primary low pressure initially tracks into the Great Lakes, resulting in a warmer air mass over the region, with the coastal low in its development stage, which would be on Saturday into Saturday evening, ending up as a mostly rain producer for the area, even if it takes a track that would typically support a snowstorm for the whole area. After this point, specifically for Saturday night, the forecast depends on the outcome of the coastal low, whether it tracks close to the coast and significantly intensifies, or stays weak and more suppressed. Should the former scenario happen, moderate-heavy precipitation would spread into the region with the rain gradually changing over into a snowstorm, especially inland, as temperatures cool down and the coastal low becomes dominant. Should the latter scenario happen, most of the area would see light rain showers, aside from northern areas which would see some snow.

At the very least, should the significant storm fail to materialize, some impact is expected from the coastal low in the form of light rain/snow, although a minor event is unlikely based on the latest indications. At this time, I am siding towards a moderate impact storm in the area with rain changing over to a rain/snow mix for the coast and a snowstorm in New England away from the coast, with the higher risk of precipitation towards Saturday evening into the overnight hours and parts of Sunday, although the potential remains for a stronger and colder storm, in which case parts of the area could see a more significant snowstorm especially towards Connecticut. It is important to note, however, that this is still several days away, at a range where the model guidance has not performed strongly with recent storms, and additional changes are likely with the forecast. Stay tuned for more information over the next few days as details become clearer.



Longer Range Update:

The next storm to affect the region is expected next Tuesday and Wednesday, around February 26-27, currently shown to be a significant rain storm on the model guidance but still subject to change. After this potential, however, a blocking pattern over Canada with above normal 500mb heights is likely to develop and continue through the medium and long range; along with temporary ridging in the western US, the potential is there for a colder pattern to continue into early March. There have been hints of a possible storm around the beginning of March, and along with the upcoming pattern, this possibility will continue to be watched. The longer range model pattern outlooks still need to be taken with caution, however, considering the time range and how the long range guidance has frequently exaggerated blocking this winter, and the possibility is there that the magnitude of the cold pattern shown on the long range models, such as the GFS, fails to materialize. Stay tuned for more information on the longer range.