Keeping his eye on the weather during his stay in Easton, Dudley had watched a developing upper low pressure area make its way eastward. The latest web forecast (Figure 1) showed a low pressure area over the mid-upper Mississippi valley. A warm front curved to the south through southern Ohio, West Virginia, and just south of Maryland, with a swath of precipitation around it. Dudley figured that the large scale counter-clockwise circulation about that low probably would give him a tailwind, but it might be a wet one. He was hoping, somewhat boldly, to fly higher than usual, maybe at 11,500 feet, to take advantage of the tailwind.
Up before six the next morning, Dudley connected his computer to DUATS. Both the textual synopsis and the weather depiction chart's synoptic picture (Figure 2) showed that the warm front had indeed moved north. It was forecast to move farther into southern New Jersey and Pennsylvania by 11 p.m. Up in New England it was VFR, but was forecast to change to marginal VFR (MVFR) with a 5,000 foot ceiling and light rain showers. The forecast predicted the same thing around the halfway point, in southeast New York. So much for a high cruising altitude and that tailwind.
Closer to Easton the present weather didn't look so good. New Jersey and eastern Pennsylvania had scattered to broken clouds at 5,000 feet, and the forecasts said by noon the ceilings could drop to 3,000 feet with scattered light rain showers and widely scattered thunderstorms. On the home front (the Boston area), the ceiling was reported at 10,000 feet but the forecast said between 9 a.m. and noon the ceiling was expected to lower to between 3,000 and 5,000 feet with scattered rain and thunderstorms. This flight was quickly moving to the maybe range of the go/no-go decision scale.
There was a convective SIGMET covering an area west of his route, and an AIRMET Sierra for mountain obscuration in Pennsylvania and Maryland between 10 a.m. and 4 p.m., but Dudley planned to be north of the area by then.
However, he winced when he read AIRMET Zulu, which called for moderate mixed rime/mixed icing in clouds and precipitation until 10 a.m. from 8,000 feet to flight level (FL) 200 (20,000 feet) for southern New York, all of Pennsylvania and New Jersey, and Maryland as far as Baltimore. To avoid the possibility of encountering precipitation that could cause airframe icing he could delay his departure, avoid the precipitation, or fly below 8,000 feet. But with the lowering ceilings, staying below 8,000 was pretty much a given.
What was happening right now? Generally, the METARs reported scattered areas of light rain near the start of his route. The ceilings were good - up around 10,000 feet, but the narrow temperature/dewpoint spreads, which could mean fog, bore watching. The visibility was generally greater than seven statute miles. In the northern half of his route ceilings were higher and the air was drier; but still, one "caution" area south of Boston put Dudley in alert mode.
Boston Logan International Airport reported 10 miles visibility, a few clouds at 25,000 feet, and a 10 degree temperature/dewpoint spread. Just 30 miles due south of Boston, however, Taunton had a rapid-fire sequence of special observations. Taunton's temperature/dewpoint spread went from 0.5 to zero in three minutes, and along with that the visibility dropped from four miles to between one and two miles, and the ceiling went from 12,000 feet down to 100 feet indefinite in mist, up again to 4,700 feet broken, then 100 feet scattered - all in just over 20 minutes. None of the airports nearby reported similar conditions, so he'd keep an eye on it.
To "see" the areas of rain, Dudley turned the cryptic radar summaries into a visual picture by using the identifiers on his sectional chart and drawing the appropriate lines. When he finished he saw several overlapping polygons of rain showers covering northern Maryland, Delaware, eastern Pennsylvania, all of New Jersey, and southern New York.
Looking for information that would move the "maybe" back toward "go," Dudley read the TAFs, which are more precise than the area synopses. The TAFs brought some good news - forecast visibility of more than six miles - but also some disappointing news regarding ceilings - they might be down to around 5,000 feet during the earlier part of the trip, up to Philadelphia. But the ceilings and visibilities met his personal VFR weather minimums, so the flight was leaning toward a go.
He decided to start out cruising no higher than 3,500 feet, which meant he would need clearances through some Class B airspace. He also might encounter some light rain, but as long as he remained in VFR conditions - and below 8,000 feet to avoid any chance of ice, he was good to go. From Philadelphia on, however, the skies brightened - literally as well as figuratively. The winds aloft showed that he might have that tailwind after all! The winds along his route were westerly at about 15 knots at 6,000 feet, and more than 20 knots at 9,000 feet.
Dudley decided to go. If things started downhill, he'd land en route. Plenty of airports lay along his way, so he wouldn't have to double back.
After filing his VFR flight plan via DUATS, Dudley beat feet to the airport. He found no preflight surprises and took off on time. Not a cloud anywhere, and though it was hazy, the flight visibility looked to be about eight miles. Half an hour later, and clocking 140 knots ground speed over Cedar Lake VORTAC at 5,500 feet, same story - the weather was better than the forecast.
Twenty minutes later, he passed east of New Jersey's McGuire AFB. The ATIS there reported five to seven miles visibility and broken clouds at 12,000 feet, which was better than the 3,000 to 5000 foot ceilings detailed in the TAF Dudley read earlier.
Talking to Millville (New Jersey) Flight Watch, Dudley got a weather advisory for thunderstorms and moderate rain showers moving east at 28 knots, about 30 miles north-northeast of Atlantic City. That area was behind him now, and sure enough, when he looked back that way, there it was. The weather apparently was moving slower than forecast and that probably accounted for the good weather on the trip so far.
Passing by New York at 9:30 a.m., JFK's ATIS reported 10 miles visibility and few clouds at 6,000 feet. JFK's TAF had predicted 10,000 broken for this time. En route to Bridgeport, Connecticut, over Long Island Sound, the visibility was better than eight miles with clear skies, but between Bridgeport and Hartford, 40 miles to the northeast, he saw overcast skies well above him (Bridgeport's TAF predicted 10,000 broken).
The flight visibility was improving. Pulling in a very scratchy ATIS from Boston, Dudley listened to information Yankee, which reported 10 miles visibility and few clouds at 20,000. Nearing Boston, he saw few cirrus clouds, no turbulence, and a good 30 miles visibility. This agreed with the Boston TAF, which predicted more than six miles visibility.
Arriving in Boston well under two and a half hours later, Dudley was quite pleased with the outcome of this flight - and his decision. The area synopsis wasn't sunny and cheerful, but as he worked through the layers of weather information and predictions he decided that a safe flight was possible - and he had options if the weather didn't happen as predicted.
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