TAF KDCA 041726Z 0418/0518 00000KT P6SM SCT045 SCT100 OVC140 FM042300 28006KT P6SM VCTS BKN050CB BKN150 FM050100 31006KT P6SM BKN050 BKN150 FM050900 35007KT P6SM SCT050 BKN150 FM051600 02009KT P6SM OVC050=The "VCTS" means "thundershowers in the vicinity" normally, within five to ten miles of the field. I expected to get to Potomac Airfield (KVKX) about 2230Z (i.e., before the thundershowers were forecast) but the destination weather would bear watching.
And in fact, there was no weather worth mentioning for the first 90 minutes or so. That's about when N631S and I were passing Lancaster, PA and entering Potomac Approach airspace. Looking at the NEXRAD weather depiction down the road, I saw that a cell was working over KDCA and heading eastward toward KVKX. I hoped it would move on to the east fast enough to be a non-factor for my arrival.
Passing Baltimore, I picked up the METAR for KDCA to see what conditions were like:
METAR KDCA 042152Z 18012KT 10SM FEW040 BKN110 BKN200 26/16 A2990 RMK AO2 WSHFT 2121 TSB10E30RAB13E32 SLP125 VCSH S CB DSNT S MOV E P0000 T02560156=The METAR indicated that the big airport was having good weather, but that a thunderstorm had begun at 2110Z and lasted until 2130Z. The associated precipitation had begun at 2113Z and lasted until 2132Z.
As I pressed on I could see the cell clearly to the south. (I wish I had a photo for you, but I was a little busy...) I didn't want to dive into the cell and try to find KVKX visually...and I wasn't thrilled with the prospect of the RNAV Rwy 6 instrument procedure either, as it would involve passing through the cell to approach the field from the southwest. Of course, I had lots of fuel so I could just ask ATC to send me somewhere to hold for 45 minutes or so while the weather cleared the area. But...looking over to the west, I could see that Andrews AFB (KADW) was in the clear. And knowing where KVKX was relative to Andrews, I could see that it was emerging from the rain. So I keyed the mike:
N631S: "Approach, Skylane 31 Sierra, request."Not more than two minutes later, the controller came back with:
PCT: "31 Sierra, go ahead."
31S: "Can you turn me west right along the south boundary of Andrews? That's in the clear and I can make a left-base visual approach to VKX."
PCT: "OK, I have your request."
"Skylane 31 Sierra, steer heading 195. I have to keep you going south a little further, but the supervisor is talking to Andrews about your request. I think we can work this out for you. Meanwhile, descend and maintain 3,000."
I descended to 1,500 feet and as N631S and I were crossing just south of the arrival ends of Runways 1R and 1L at KADW I said to the controller, "Please pass my thanks along to Andrews Tower. I appreciate their doing this for me." At that point, all that was left was a 30° turn to the left and a three mile straight in visual to a dry Runway 24.
Just for fun, here's the track of the last few minutes of the flight, courtesy of FlightAware.com. The weather depiction in this image is from 2130Z, about 50 minutes before N631S and I landed.