Friday 9 a.m.
Rain is advancing through the Northeast this morning, with heavy rain at times during the midday hours from Philadelphia through New York City... and from this afternoon into tonight in Providence and Boston. Interior sections of northern New England will have a nasty assortment of snow, sleet and freezing rain. Snow has been common across the upper Great Lakes, and some snow showers can occur in Chicago and Detroit tonight intro tomorrow, then in Buffalo, Rochester and Syracuse tomorrow night into Sunday.
Away from the Great Lakes and Appalachians, the weekend looks pretty good for the Northeast. There should be some sunshine with afternoon temperatures well up in the 50s in Boston and Providence, with slightly higher temperatures toward Philadelphia and D.C.
As a new cold shot comes into the northern Rockies and northern Plains (where it is the year without a spring so far) and a new storm takes shape in the central Plains, there will be a big warmup in the I95 corridor early next week. The upper-air steering winds will become southwesterly in the East, as shown on this forecast map:
Boston should have temperatures reaching the 60s Monday and Tuesday before a back door cold front spoils the fun. In Philadelphia, Baltimore and D.C., temperatures will climb well into the 60s to near 70 on Monday, then soar to the 70s again Tuesday, Wednesday and Thursday. I wouldn't be surprised if some 80 plus readings occur as well.
This video has more:
Thunderstorms will continue to erupt near the northern edge of the heatwave, enhanced by a series of disturbances rippling along in the upper air flow. This is the NWS Storm Prediction Center's severe thunderstorm outlook for today
... the main upper air steering current moves eastward across the northern Plains, then dives southeastward toward the Middle Atlantic states. The core of this current defines the rim of the hottest weather and serves as a conduit for clusters of thunderstorms.
3. Hot air will be moving east from the Plains, reaching the major East Coast cities Friday and Saturday. This map shows the upper-air flow that will make this happen.
This map shows lightning strikes from 8 a.m. EDT yesterday until 7:20 a.m. EDT today. A concentration of thunderstorms can be seen in the Midwest ahead of the cold front.
At 10 a.m., it was already 85 in Boston and 90 in Newark, N.J. The afternoon will be quite hot as weak cold front approaches. It should become a <u>little</u> more more comfortable this weekend.
Subtle and sometimes hard-to-detect boundaries within the heated air mass help with shower and thunderstorm development and organization. There is no one well-defined cold front.