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Saturday, October 29, 2011

Artifact

The terminal area forecast for KDCA that issued at 18Z yesterday (recovered from the marvelous OgiMet site) had me motivated to get N631S and myself airborne and headed toward the DC area without undue delay. The lines for "FM2100Z" and "FM2300Z" are relevent:
 
TAF KDCA 281740Z 2818/2918 06005KT P6SM SCT140 SCT170 BKN250 
FM282100 08004KT P6SM VCSH BKN060 OVC090 
FM282300 10004KT P6SM -RA FEW020 SCT040 OVC080 
FM290300 07005KT 6SM -RA BR SCT020 OVC030 
FM290600 03006KT 5SM -RA BR SCT015 OVC025
FM290900 01007KT 6SM -RA BR FEW007 OVC011 
FM291100 36009KT 4SM -RASN BR SCT008 OVC012 
FM291500 35011G18KT 3SM -RASN BR FEW005 BKN008 OVC011 
FM291700 35015G24KT 1SM -SN BR BKN004 OVC007=
The 21Z line in the TAF for KBWI was about the same. I could get past Baltimore with a broken ceiling at 6,000 feet (BKN060) and for arrival I could work around "showers in the vicinity" (VCSH). But the freezing level was going to be somewhere around 3,000 feet which made the forecast for 23Z, calling for light rain (-RA) and an overcast at 3,000 (OVC030) a "no-go" condition. My conclusion was that I'd better be on the ground at Potomac Airfield (KVKX) well before 23Z (7:00 PM EDT).

Conditions were quite good departing KBDR and stayed that way until I reached the Allentown Approach airspace. From that point onward the overcast was solid and at 8,000 feet it looked like I could reach up and touch it. On the positive side of the ledger, winds aloft were light and I was making good speed over the ground (mostly between 130 and 140 knots).

I had to smile looking at the screen showing the NEXRAD returns when N631S and I were abeam of Allentown. The Outside Air Temperature was 27 degrees, and to look at the green area ahead, you might think that there was a problem in the making. NEXRAD was indicating lots of moisture, and that added to sub-freezing OAT's can mean ice! But, if you go ahead and click on that screen shot, you'll see a picture taken seconds later that shows what I was seeing straight ahead through the windshield.

The hint is in the color of the triangles next to the ABE and RDG airport symbols. Blue means good VFR weather, and that held up all the way across Baltimore and into KVKX. This was the METAR in effect as I crossed the BAL VOR:

 
KBWI 282054Z 11005KT 10SM FEW060 BKN110 OVC150 09/M02 A3021 RMK AO2 SLP231 T00891022 53001\
And this was the one for Andrews AFB (KADW) as I was landing a couple of miles away at KVKX:
 
METAR KADW 282055Z AUTO 11003KT 10SM FEW075 SCT090 08/M01 A3022 RMK AO2 SLP236 T00791007 53002 $=
N631S was snug in its hangar well before the rain began, about an hour after the TAF had forecast:
 
KADW 290016Z AUTO 07003KT 10SM -DZ FEW024 BKN044 OVC055 07/00 A3021 RMK AO2 DZB0016 SLP235 $

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