Tuesday 10 a.m.
It remains chilly in central and northern New England this morning. Farther south in New York City and Philadelphia, yesterday's snow has been replaced by temperatures in the 40s under cloudy skies. Meanwhile, it feels like May in parts of the Midwest. Just after daybreak, the Chicago temperature hit 60 degrees, breaking a record that had been in place for 99 years. The warmth was advancing on the strength of gusty southwest winds. Yesterday, the temperature soared to 77 in Topeka, Kan., burning the previous record of 74 for the warmest January reading in their history of record keeping.
A strong upper-air trough over New Mexico will move out over the Plains today, sponsoring development of a strong low pressure area at ground level. As that storm moves northeast and its attendant cold front whips around its south side, violent thunderstorms and potentially deadly tornadoes will be unleashed. The following map shows today's severe weather threat.
The storm system has already tapped into moisture streaming northward from the Gulf of Mexico. This will cause a period of torrential rain from the mid-Mississippi Valley into the Great Lakes. Virtually that entire needs rain, but the intensity will lead to local flooding. North of the path of the storm, there will be wind-whipped snow. This video has more:
By Thursday, the cold front will be off the East coast, and wintry winds will be generating snow showers from the Great Lakes into the Appalachians. Just a few flurries are likely east of the mountains Thursday night and Friday. Models have not come into agreement on this, but a patch of mostly light snow may moves from the southern Great Lakes and Ohio Valley regions to the Middle Atlantic coast during the coming weekend.
If correct, cooler, drier and more comfortable weather will take over in the Northeast as we go into the holiday weekend, then warmth and humidity would increase as we go through next week. This map matches that scenario.
that short wave is what the models latch onto in bringing a cold front through the Northeast Wednesday night and Thursday. This would bring noticeable cooling to the Northeast late in the week.
Labor Day is a week from Monday. The computer model used here, the GFS ensemble mean, suggests the weather will favor outdoor late summer activities across the Great Lakes and Northeast:
In response to heating at ground level and a weak cold front approaching from the west, showers and locally strong thunderstorms should develop across northern Ohio this afternoon.
... much greater interest is being generated on threats and rumors about tropical storms. It is worthwhile to read Dan Kottlowski's authoritative reports on this. Here is a copy of his map from this morning:
The tropical Atlantic shows signs of life in the storm development department. Dan Kottlowski's expert discussion suggests the third storm (which could be Hermine) of current concern is one that could head to the Bahamas, Florida, the Gulf or ???