Monday 10 AM
A strong cold front that caused cloudbursts of rain in the Ohio Valley yesterday is moving through the East today. At 10 a.m., the leading edge of the strongest thunderstorms extended from Elmira, N.Y., through Harrisburg, Pa., then on southwest through D.C.'s far western suburbs. A tornado watch was issued this morning in anticipation of these thunderstorms getting severe as they move through the very warm, humid air that has been in place recently. The watch was to be in effect until 5 p.m. for the area shown on this map.
The watch will be rescinded from west to east as the line of thunderstorms moves along. Keep in mind that a watch is an alert saying something could happen. Warnings, however, are focused on small areas based on reported tornadoes and on radar indications of one or more tornadoes. If a warning is issued for your neighborhood, please go the safest place you can find right away. Most places will have a period of very intense rainfall with quick street flooding along with strong gusty winds that do not last long.
Much cooler air follows the front, but the front will stall off the Southeast coast. Some computer models suggest that a low pressure area will form along the front and then fling rain at the Middle Atlantic coast. Meanwhile, milder air will start spreading back across the Midwest.
Erika's heavy rainfall separated into two areas yesterday. This is the Morehead City, North Carolina, radar, showing an area of heavy rain and thunderstorms that dumped more 4 inches of rain on parts of the coastal Carolinas this morning.
Tropical Storm Erika could eventually affect Florida and other sections of the Gulf Coast or Southeast, but for now it poses no threat for the Northeast. This map shows the storm as of early this morning.
The second concern is Erika. The map below shows what many different models area saying. While there is a good agreement in the short range, the longer-range spread is quite larger, with tracks ...
This picture shows where Erika is. The various models show a track toward Florida with a lot of uncertainty after that. If it does make it to land, then moves slowly (steering forces look weak), it could be a major rain producer.
It is way too early to be definitive about these storms, but the many models being used in predicting the track have closer agreement than many storms have at this point.
On this satellite picture, you can see a cold front approaching the Appalachians. That front helped produce thunderstorms in the Midwest yesterday, but that activity died out overnight. It is likely to reactivate today, with...