More storms to chase soon?

Here at the height of the summer doldrums it's hard to scare up a storm or two to chase. Recent activity has stayed well to the south across central and southern Virginia as the racetrack around the heat dome over much of the country has steered storms away from the Fredericksburg region. None of the recent setups have had enough severe potential to provide the incentive to travel several hours in the heat and humidity to intercept ordinary storms. However with a couple of weak fronts on the way hopes are rising for local convection both Monday and Wednesday of this week. The overall setup doesn't look promising for severe storms either day but anything that provides rain at this point is of interest.

Meanwhile the tropics are becoming more active so that too is an area to keep an eye on for severity. Not wishing severe weather on anyone, but it is true that some of the best chasing in the past few years has been during the passage of tropical storm remnants through the area.

July 25 Heat wave breaker

Today's storms formed along a pre-frontal trough early in the afternoon, meaning I needed to get out earlier than normal to chase.  Unfortunately all the NWS radars in Virginia - and possibly the nation - stopped providing internet access for roughly 90 minutes during the time I really needed situational awareness.  In desperation I rolled out the driveway with my chase gear in a mobile reconnaissance, using the MK 1 eyeball to determine what storms may be worth chasing.  Fortunately I guessed right and headed east into King George county where I set up shop at a favored vantage point to observe oncoming cells. 

I got out of the car to take a few still photos after I'd set up my dash video, and was immediately chased back inside the vehicle by this:

It's been a long time since I was outside and had a CG hit that close, and I just about had to go home and change pants.  There had been no CG's visible prior to this one, but they certainly rained down with vigor after this.

At this point the radars were back up so I noted that the cell I was watching exhibited some rotation on it.  That rotation was literally right above my head as the scud gathered and rose into the updraft.  I watched carefully until the rain set in but never could identify a wall cloud.   Given that the only direction I could go to keep up with the storm was south - the Rappahannock River prevented that option -  I plowed thru the heavy rain westward to reposition in a small break in the line for the next cell and took a few pictures but didn't see much else.  I still have that video to review but there were no more close CG's.

Cheering on the outflow boundary

The white arrow points to a southward moving outflow boundary laid down by earlier storms northwest of DC. As this image shows the boundary has already fired storms (cell just north of the center of the line) and the hope is that it will continue down this way and fire up cells around here. Anything to beat the heat!!!

7:07 pm UPDATE: Alas, the boundary died out as it reached the Stafford Courthouse area, along with the updrafts it was creating. Storms tomorrow?

Virginia Tech meteorology program approved

I posted this article over at the Fredericksburg Weather blog and decided it was important enough to post here as well. Kudos to the new Virginia Tech meteorology program!!!

Meanwhile, even tho' the NWS Sterling radar is off line today I've been keeping an eye on the Wakefield radar in case some decent - and reachable - convection fired. So far nothing has gone up where I could get to it, but we could still see a storm or two before dark.

July 13 cold front approach

Given that today's cold front passage is supposed to ease back the heat and humidity I was anxious to chase the storms associated with it, so I motored up to Bealeton on Route 17 and stopped there at 3:00 pm to monitor the situation. The frontal storms lined up west to east with individual cells moving to the southeast, and I sat there almost 45 minutes for them to get close enough to see details. The best two cells were traversing the DC suburbs so I regretfully ignored them as I waited for a chaseable storm to distinguish itself.

One finally did become severe-warned as it crossed the Blue Ridge southwest of me so I dropped down to Culpeper on Route 29 and checked radar again. That cell was still the best available so I continued south on Route 15 to Orange, parking on a hill just north of town to watch the approach. It was outflow dominant and pushed out a shelf cloud:
When the rain shaft got too close I moved south through town as a very bright CG struck somewhere close with ear-pounding thunder.

As I struggled to stay ahead of the line I was able to snap a photo from underneath the shelf cloud:
I dove southeast down Route 33 from Gordonsville to stay ahead of the rain and the very strong outflow. Doing so took me to Louisa before I could find a spot to pull off the road and conduct a "static core punch" as I let the line overtake me. Even tho' the core of the cell just north of me had a hail marker on it all I witnessed was rain and wind. A chase, but nothing severe.

July 8th chase: Part 2

After I pulled off the storms east of Fredericksburg I dove south to Thornburg to intercept the tornado-warned cell that continued to show rotation on radar in Orange county. This cell was moving to the east as part of the frontal line scouring out the tropical air mass. Unfortunately for me I was cut off from a clear shot at this storm by another storm ahead of the front that was scooting to the northeast. I relied heavily on my GR3 display plus GPS to put me in a position to rescue something worthwhile out of what was becoming a royal rainy mess.

I finally wound up near the intersection of Gordon and Brock Roads in western Spotsylvania county to watch the approach of the area of interest in the approaching line. The cloud deck ahead of the line looked like cold air had already partially stabilized the air mass:
Since radar still showed some rotation in the line I stuck with it and wound up watching an area of scud building into what may have become a wall cloud if conditions had been a bit riper.
And here's a video of the gathering scud (again sped up 4x):


I still have a bit more video to review in hopes that I caught a CG or two, but the chase was over by 5:30 after the frontal passage. Some July fun!

July 8th chase: Part 1

Given an SPC Slight Risk and an increase in overall shear over yesterday's model runs I awaited convection to fire today with great anticipation...and was not disappointed. When several cells approached the Stafford / King George county line from the southwest early in the afternoon I positioned myself along Route 3 east of Fredericksburg to observe. The northernmost cells were already crossing the Potomac River to my north when I arrived at my first site, where I finally coaxed my laptop to boot up so I could look at GR3 radar. When I noticed some good-looking storms crossing the Blue Ridge mountains I decided to head west in their general direction but yet another updraft entering the "magical" Rappahannock River valley caught my eye.
It was obviously sheared toward the northeast so I watched it until rain obscured my view. Moving a half mile to the west I caught this view:
The entire updraft was definitely rotating and I was able to catch it on my dashboard video and speed it up a bit:


I watched it for several minutes until the cell weakened. At that point I succumbed to the siren call of the storms now across the Blue Ridge since one of them was already tornado-warned. Part two to follow..,

Blurry vidcaps from 3 July "chase" and probable Friday July 8th chase

These two vidcaps are from Sunday July 3rd's storm system that rolled through the Fredericksburg area. It provided some great CG's and strong winds, but the worst of the storm scooted by just north of us. This "chase" was notable in that my daughter and her husband accompanied me...it was his first chase!!

Tomorrow the setup looks better for severe storms given that the upper level winds look to be a bit stronger as an upper trough approaches from the west. The complicating factor will be exactly where the weak surface front sets up. Areas to the north of said front will likely not see much sun. Thus if we can stay south of the front and allow the sun to peek through enough to destabilize things there will be storms worth chasing.

Chesapeake Bay Breeze

One of the factors in Mid-Atlantic storm chasing is the presence of the Chesapeake Bay.  It affects both storm access - bridges are few and far between - and storm initiation and intensification.   The latter two are a direct result of the "Bay breeze", a localized phenomenon that occurs when the overall wind field is light and a circulation develops between the water and the land.  The air over the warmer land rises and is replaced at the surface by cooler air from atop the Bay waters.  The result is a mini-cold front that can both create storms and intensify existing ones.  Here is a radar depiction of today's Bay breeze:

The weak radar return inside the yellow oval is the Bay breeze.  It is advancing toward the northwest and will likely meet the storms heading southeast from Pennsylvania.  The result could be an intensification of said storms, possibly resulting in low level rotation.  I'm sure the NWS Sterling mets are keeping their eyes on this.