Bizarre Storms Overnight in PA
We had a really unusual night of storms last night here in Central Pennsylvania. Storms were breaking out near the back-door cold front and morphing westward overnight, then outflow boundaries from those storms sparked other storms which formed suddenly here in Centre County around 1 a.m. (Outflow boundaries occur when the thunderstorm's downdraft hits the ground and spreads out, often sparking new storms far from the parent).
Near 11 p.m. a TVS (Tornadic Vortex Signature) showed up on the radar as a supercell headed towards Williamsport (thanks to officemate Carl for the screen capture of the TVS, I was oblivious and fast asleep). A closeup radar shot from AccuWeather.com RadarPlus is shown below.
SUPERCELL APPROACHES WILLIAMSPORT
When it was all said and done, a maximum of 11.5" of rain fell near Bloomsburg, according to the Doppler-estimated precipitation (whole state | zoomed). Of course, actual amounts might be lower, as sometimes hail in thunderstorms fools the radar. Surprisingly, no storm or flooding reports for the overnight storms have been issued yet by the State College National Weather Service Office, as of this writing. 1-inch diameter hail was reported in Williamsport yesterday evening.
Click here for a large Quicktime movie (see also clutter-free version*) to see the strangest behavior of precipitation that you'll ever see in Central PA. Watch the storms blow up after the outflow boundaries move westward. We are used to precip moving eastward and dying as it comes down the mountains, but last night a storm formed right over the top of AccuWeather HQ. Storms were moving east, west and south; it was a crazy night.
Elliot Abrams (PREMIUM | PRO) will also have (later today) a webcam movie of the clouds blossoming in our area yesterday afternoon. There was a lot of rapid vertical development (also unusual around here) with the extreme heat we have been suffering through.
ZOOM OF HEAVY RAINFALL AREA
*The clutter-free version shows the main storms better but obscures the outflow boundaries.
Report a Typo
