Monday, September 27, 2010

Not a Day for Flying

Last night when I toddled off to bed, I expected to be flying this morning. Really. The 00Z TAF for Bridgeport was calling for 4 miles visibility with a 900 foot overcast and wind favoring the ILS runway. But when I awoke this morning things had changed. This was the TAF on offer for KBDR at the time:

TAF KBDR 270522Z 2706/2806 06012G18KT P6SM VCSH OVC012
         FM270700 07012G18KT 5SM -DZ BR VCSH OVC008
         TEMPO 2709/2712 3SM -DZ OVC005 
         FM271200 09012KT 2SM -RA BR OVC005 
         FM271900 10010KT 1SM -RA BR OVC004=

So now we were looking at deteriorating conditions with a trend toward 500 foot ceilings and 1 to 3 mile visibility. A look at the NEXRAD radar seemed to indicate that large patches of heavier precipitation were headed toward Connecticut and could well be arriving about the same time that N631S and I would.

To complicate matters further, the conditions down in the DC area were poor. The METAR at Andrews AFB said:

SPECI KADW 271024Z AUTO 09004KT 9SM DZ OVC003 18/18 A2990
           RMK AO2 DZE0957B1024 SLP124=

And the TAF for Andrews was no more encouraging:

TAF KADW 2709/2809 05009KT 3200 -RA BR OVC003 QNH2983INS
         TEMPO 2712/2718 OVC005
         BECMG 2717/2718 15010G15KT 4800 RA BR OVC008 QNH2979INS
         BECMG 2723/2724 16009KT 4800 -RA BR OVC008 QNH2971INS
         T24/2720Z T15/2710Z LIMITED METWATCH 2709 TIL 2710=

We're looking at 300 foot ceilings and an expectation of falling visibility. Of course, I could take off, but there'd be no getting back into the departure airport, KVKX, if anything went wrong.

The low ceiling and visibility conditions were widespread, as well. There wasn't even a really good alternate.

Personal minima came into play here. I'll take off knowing that I might find 400-and-2 at the other end of the trip if I have a gold-plated alternate. That luxury was not available today. So, I opted to make the trip by train. As the wise man said, better to be on the ground wishing you were flying, than the other way around.

Sunday, September 26, 2010

"Some National Security Thing"

Apropos of nothing that this post will talk about, let me start with the pretty bird at left - a Globe Swift that seems to act as the mascot for Volo Aviation at KBDR. It nests there among the Gulfstreams and the Challengers and makes it a pleasure to walk past the open hangar door.

I snapped the Swift's picture on my way to N631S Friday afternoon. My flight plan called for a 2030Z departure toward KVKX and I was already anticipating a long-ish trip due to forecast headwinds in the range of 35 to 40 knots. FltPlan.com was telling me to expect 2:31 en route.

I pre-flighted N631S, picked up my clearance, started the engine and was cleared to taxi to Runway 24. By 2033Z I was at the hold short line and transmitted, "Bridgeport Tower, Skylane 631S ready for Runway 24 at Hotel." There was no immediate response.

Then, for something completely different, the tower controller said, "ATC has just informed us that it will be at least 20 minutes before they can issue any IFR releases. N631S, say intentions."

"N631S would like to make a 180 and return to parking to wait it out." No point in continuing to burn avgas. That was approved as requested and I went back and shut down.

For most of the week there'd been a TFR covering the maximum lateral area of the New York Class "B" airspace, from the surface to 18,000 feet, due to the United Nations General Assembly meeting. Now, that was ending and I inferred that assorted Presidents, Potentates and Supreme Leaders were getting out of town - which overloaded both ATC and the security apparatus.

I kept the hand-held radio tuned to KBDR's ground control frequency and after about 15 minutes heard, "631 Sierra, are you up?" I responded with, "31 Sierra is up," and got back, "31 Sierra, go ahead and start your engine. I believe we can get you out of here."

So N631S and I were back at the hold-short line at 2051Z and this time got an immediate release. But that doesn't mean the fun was over.

After takeoff from Runway 24, I contacted New York Approach and got the customary vector to the north. A couple miles later, I received a non-customary "Skylane 31 Sierra, turn right to a heading of 060, vector for spacing to Carmel - eventually. We'll try to get you headed back west in ten miles or so."

The green track shown above (courtesy of the useful folks at FlightAware.com) shows my peripatetic departure. During this tour, I heard a helicopter inbound from the north calling New York Approach:

[345AB]: "New York, Helicopter 345AB. We had a flight plan filed for pickup to get into the Bravo, but Bradley just dumped us."

[Approach]: "Helicopter 345AB, say destination."

[345AB]: "5AB is headed to Newark."

[Approach]: "Helicopter 5AB, yeah, they've got some national security thing down there. We've been advised absolutely no more helicopters into the airspace. Say intentions." (I'm starting to think that "Say intentions" may be one of the most unwelcome phrases in the language.)

[345AB]: "OK, I guess 5AB will land at White Plains."

After that, Approach issued them an appropriate vector and frequency change. And, they finally got N631S headed west, slowly. I was getting ground speeds of 95 to 100 knots which implies a headwind component of about 40 knots. Considering the delays so far, it was becoming clear that I'd get to enter the first time of this season in the Night column of my log.

Plodding along near Carmel (CMK), this exchange got a smile from me:

[804L]: "Approach, Baron 804L, request."

[Approach]: "Zero four Lima, say request."

[804L]: "They've got us way up here by Barrington, way out of our way...any chance of direct BREZY from here?"

[Approach]: (without any hesitation) "No!"

[804L]: "Okaaayyy..."

After entering Allentown's airspace I requested and got a descent from 8,000 to 6,000 feet that got me about 5 more knots of groundspeed. Also, the wind out of the southwest eased a bit (to a mere 30 knots or so) so by the time Baltimore was coming into view the Garmin 530W was telling me I was up to 112 knots or so. And the sun had set.

The first night landing of the season was uneventful. I picked up the airport beacon about 10 miles from the field, reported the field in sight and got, "Skylane 31 Sierra, cleared for the visual approach, proceed directly to VKX, frequency change is approved." I cancelled IFR, made my traffic calls, and entered the right downwind for 24. The runway was right where it was supposed to be, and I had wheels on pavement at 2346Z. 2 hours + 55 minutes airport-to-airport, 3.2 tach hours with all of the thrashing around. It was nice to have that one in the can.

Here's the track for the whole trip:

Tuesday, September 21, 2010


The second most intense event in aviation, short of having an emergency develop on your own aircraft, may be to hear another pilot on the frequency dealing with an emergency of his or her own. It certainly concentrates one's attention.

This morning, not very long after departing KVKX and climbing to 7,000 feet MSL, we (that's me and N631S) were crossing Delaware and doing business with Dover Approach.

As is common, I listened as the Dover controller cleared a departing flight - REACH 7045 - to climb on course. He called the departure as traffic for a northbound Beech Baron, saying, "Traffic is a C-5, Heavy, climbing to 11,000." Soon thereafter, Dover Approach transmitted, "REACH 7045, contact Washington Center on..." and gave them a frequency. The big Lockheed transport was gone on its way.

About ten minutes later, an unexpected call: "Dover Approach, REACH 7045, at 5,000, we need a straight-in visual to Runway 32." I took note - wasn't that the call sign of the C-5 that just departed?

The controller responded calmly, saying, "REACH 7045, I understand you have an IFE. You are cleared for the visual, Runway 32."

IFE? In Flight Emergency? The C-5 must have reported an emergency to Washington Center and turned back to Dover. Center had undoubtedly called Dover Approach with a "heads up."

The C-5 Galaxy responded with, "Understand cleared visual Runway 32. We'll be on the ground in ten minutes. We'd like a truck standing by."

From Approach, "REACH 7045, are you declaring an emergency? If we need to roll the equipment, that's the only way they'll respond."

"OK, yes, we are declaring an emergency," said the Galaxy pilot, and Approach asked, "What is the nature of your emergency."

"We have smoke and fumes in the aircraft."

Approach asked, as they must, "Say souls on board and fuel on board in time," which elicited "10...no, 11 souls on board and three hours of fuel."

OK, deep breath. Remember Swissair 111. Remember the recent UPS crash in the Middle East. This is as serious as a heart attack. This can turn completely to...well, you know...in a matter of minutes. At this point, I'm rooting for the C-5 crew. The guy handling the radios sounds cool and calm. They have many more options than the crew of the UPS flight that augured in recently; they have access to the cargo deck and they have troops ("11 souls on board") that can try to attack the problem. Still...get it on the ground!

"REACH 7045, contact tower on 126.35."

"Tower on 26.35...REACH 7045." I reached toward my Number 2 Comm radio to dial in the Tower frequency but heard on Comm #1, "Skylane 31 Sierra, contact Atlantic City Approach on 126.4." Damn! "31 Sierra, A.C. Approach 26.4, thanks and so long," and a quick switch. "Good morning, Atlantic City Approach, Skylane 631 Sierra level 7,000." As I waited for Atlantic City to respond to my check-in I dialed up Dover Tower on #2.

"Skylane 631 Sierra, good morning, Atlantic City altimeter is 30.22." I no sooner said, "30.22 for 31 Sierra" when I heard over the Dover frequency, "Tower, REACH 7045 will clear the runway and then stop to meet the trucks." They had to be getting close. From Tower, "REACH 7045, will you clear at Charlie or at Golf?" Good for the Tower controller! He's getting the information he needs to direct the emergency equipment to the correct taxiway. These guys are well trained! "We'll clear at Charlie," was the answer.

Perhaps a minute later, "REACH 7045 is clear of the runway." From Tower, "REACH 7045, the equipment is with you, contact ground on 118.87."

And that was that! An Air Force crew had a really interesting morning, and I got to listen in. Everyone involved sounded sharp and in control. And luck was with them today. This was a live, in-the-moment reminder that there is only one acceptable response to smoke in the aircraft - land, NOW! We fly and we learn.

Saturday, September 18, 2010

Nothing to Report

"An uneventful journey is a good journey for the technician."
-- N.S. Norway (a.k.a. Nevil Shute)

Last evening's flight from KBDR to KVKX was exceptional only by virtue of its exceptionally unexceptional nature. After most flights I can (and do) look back and reflect on lessons learned, errors of omission or commission to be avoided in the future, and points of interest to be shared. It's a rarity to be unable to fill any of these categories.

Preflight, startup and takeoff were uneventful, climb-out was more efficient that usual (with a minimum of vectors from ATC for sequencing at Sparta) and soon N631S and I were on top in the sunshine.

The winds aloft had only a modest effect on progress, with ground-speed for most of the trip close to 130 knots - that's pretty good for the westbound portions. Controllers offered up several small but helpful shortcuts. After Lancaster (LRP) we descended to 6,000 feet and that had us beneath the broken ceiling as far as Baltimore (BAL); after that, clear skies.

Arriving in the DC environs, the visibility was very good and it was easy to pick up the home 'drome (KVKX) visually. And the landing was great (i.e., I get to use the airplane again).

So I got to log 2.3 hours of pleasant aviating and wound up with little to talk about. In short, the best kind of flight.

An administrative note: For some time I've been bothered by the long, narrow strip of blog-space in the lower reaches of the sidebar. So I've done some housekeeping; it's now occupied by an entirely idiosyncratic list of aviators and aircraft designers whom I have long admired. Most of the photos link to something interesting. I hope you'll have a look around down there. Comments always welcome. (Hat tip to Captain Dave of Flight Level 390, whose similar feature inspired this one.)

Wednesday, September 15, 2010

Mid-Air Over the Hudson - Probable Cause

The National Transportation Safety Board (NTSB) met a couple of days ago in Washington to approve the final report on the "Hudson River Mid-Air." Just over a year ago (9 Aug 2009) a transient Piper Lance and a sight-seeing helicopter collided over the river. The mishap was fatal for all nine occupants of the two aircraft.

The Board has made a synopsis of the final report available on its web site. (The report itself is in final editing and won't be posted for a couple of weeks.) The synopsis contains recommendations, conclusions and a statement of Probable Cause:

"The National Transportation Safety Board determines that the probable cause of this accident was (1) the inherent limitations of the see-and-avoid concept, which made it difficult for the airplane pilot to see the helicopter until the final seconds before the collision, and (2) the Teterboro Airport local controller’s nonpertinent telephone conversation, which distracted him from his air traffic control duties, including correcting the airplane pilot’s read back of the Newark Liberty International Airport (EWR) tower frequency and the timely transfer of communications for the accident airplane to the EWR tower. Contributing to this accident were (1) both pilots’ ineffective use of available information from their aircraft’s electronic traffic advisory system to maintain awareness of nearby aircraft, (2) inadequate Federal Aviation Administration (FAA) procedures for transfer of communication among air traffic control facilities near the Hudson River class B exclusion area; and (3) FAA regulations that did not provide adequate vertical separation for aircraft operating in the Hudson River class B exclusion area." (emphasis added)

Several of the Board's conclusions, as contained in the synopsis, relate to the inadequacy of "see-and-avoid" as a strategy for avoiding mishaps like this one (in each case, emphasis added):

  • "The airplane pilot may have believed that no other potential traffic conflicts existed because he had not received additional traffic advisories, but the pilot was still responsible for seeing and avoiding other traffic."
  • "The helicopter would not have been obscured from the airplane pilot’s view but would likely have been difficult for him to detect until the final seconds before the collision because, before that time, the helicopter would have appeared as a relatively small and stationary object against a complex background of buildings."
  • "The airplane would likely have been in the helicopter pilot’s field of view until 32 seconds before the collision, after which time the airplane was above and behind the helicopter and was outside the pilot’s field of view."
  • "The guidance in Advisory Circular (AC) 90-48C, “Pilots’ Role in Collision Avoidance,” could better assist pilots’ efforts to establish effective see-and-avoid skills if the AC were to recognize current challenges that pilots encounter in managing their see-and-avoid responsibilities, including complex, high-density airspace and the increasing presence of technology in the cockpit."
So, in sum, the airplane pilot was responsible for seeing and avoiding conflicting traffic; it was difficult (maybe impossible) for him to detect the conflicting aircraft before it was too late to avoid a collision; the helicopter pilot was completely unable to see the fixed-wing aircraft; and the FAA's existing guidance on "see-and-avoid" (AC 90-48C), is obsolete (having been issued on 18 March 1983) and not comprehensive.

None of this comes as news. I've written about this event and its aftermath in six previous posts ( 1 - 2 - 3 - 4 - 5 - 6 ). In the first of these posts, written about a week after the mishap, I linked to a 1991 report published by the Australian Transport Safety Bureau (ATSB) titled Limitations of the See and Avoid Principle. This very well written report effectively demolishes the notion that unalerted "see-and-avoid" can be an effective strategy for collision avoidance.

In that post a year ago, I wondered if "...a technological aid like the TIS system shown above, could be required for commercial operators and strongly urged for non-commercial users of the Hudson airspace." I claim no prescience, but in its recommendations, the NTSB has netted out to the same place. Here (among other recommendations) is what they are proposing (again, emphasis added):

  • "Update Advisory Circular 90-48C to reflect current-day operations, including (1) a description of the current National Airspace System and airspace classifications, (2) references to air tour operational areas as high-volume traffic environments, and (3) guidance on the use of electronic traffic advisory systems for pilots operating under the see-and-avoid concept."
  • "Develop standards for helicopter cockpit electronic traffic advisory systems that (1) address, among other flight characteristics, the capability of helicopters to hover and to fly near other aircraft at lower altitudes, slower airspeeds, and different attitudes than fixed-wing airplanes; (2) reduce nuisance alerts when nearby aircraft enter the systems’ alerting envelope; and (3) consider the different types of operations conducted by helicopters, including those in congested airspace."
  • "Once standards for helicopter electronic traffic advisory systems are developed, as requested in Safety Recommendation [4], require electronic news gathering operators, air tour operators, and other operators of helicopters used for passenger revenue flight to install this equipment on their aircraft."

"See-and-avoid" has been a cherished part of the freedom to fly as it's practiced in the US. And it can continue to be so, but the time has come to acknowledge that for high traffic areas "see-and-avoid" must be augmented with effective alerting technology.

In her opening statement for the meeting, NTSB Chairman Deborah Hersman made these observations (emphasis added):

"What I find so striking about this accident is that the airplane pilot was simply following his directions. And although the helicopter’s conspicuity was improved by anticollison lights and a high-visibility paint scheme on the blades – these enhancements didn’t help. Both aircraft were equipped with radios and traffic information systems, yet they didn’t hear or see each other, and the technology did not prevent the accident, and the air traffic system neither separated them nor alerted them that they were about to collide.


I might add that the ability to avoid future accidents like this one is dependent on a fully implemented ADS-B (automatic dependence surveillance-broadcast) program. The FAA has taken the initial steps to move towards an ADS-B-based ATC environment, but that is an expensive proposition. If we are serious about changing the paradigm and moving forward, then it’s critical that ADS-B, both in and out, be a part of this next phase of safety for collision avoidance."

The last part of this statement is quite controversial, as ADS-B (especially the "in" part) has no shortage of detractors. But some enhancing technology is needed and ADS-B is on the program.

There's a lot more that's of interest in the Board's synopsis (including some fairly severe criticism of ATC's involvement in the mishap). I urge you to read it, along with the final report when it issues.

Monday, September 13, 2010

Fog to Start the Week

Fair is foul, and foul is fair:
Hover through the fog and filthy air.

-- Macbeth, Act 1, Scene i
That may be a bit harsh. But there seemed something of the heath in the fog at KVKX when I arrived this morning. The airport is nestled in a valley and the occasional dense fog is the price we pay for the protection afforded by the surrounding higher terrain.

That's N631S in the distance, at left, waiting in front of the hangar for the fog to lift enough to make an IFR departure sensible. The photo was taken at 0745 local time, about when I'd normally be departing. As it was, I had another half hour to wait.

After departure, most of the trip to Connecticut was on top in clear conditions. The cloud layer that we flew over was, however, widespread and quite low. Ceilings at many stations were under 1,000 feet.

The METAR for conditions at KBDR on arrival had this to say:

KBDR 131352Z 36004KT 5SM BR BKN006 OVC023 16/14 A3001 
RMK AO2 RAB12E43 SLP161 P0000 T01610144

Just a breath of a breeze from the north, five miles visibility in mist, and broken clouds at 600 feet, overcast above at 2,300. The ILS approach to Runway 6 was on offer.

In the event, N631S and I broke out of the cloud bases at about 450 feet, a mile and a half from the runway threshold. Below, the track for the trip from the nice folks at FlightAware.com.

Saturday, September 11, 2010


The flight down to the DC area from Connecticut on Friday evening was quick and uneventful. Most of the trip was in visual conditions (VMC) on top of a widespread overcast layer that mostly topped out just below N631S's cruising altitude of 8,000 feet MSL.

The few seconds of video above show the cloud tops going by at about 140 knots true airspeed.
One other thing. The photo at left shows the outside air temperature in the cloud layer, at 8,000 feet over Reading, PA (KRDG).

Summer is over, my friends, and it's time to start paying close attention to where the freezing level is. Cold weather IFR is upon us.

Sunday, September 5, 2010

Earl Went Thataway!

After all of the Thinking of Great Thoughts about Hurricane Earl (discussed earlier at (1), (2), and (3)), it turned out to be pretty much of a non-event.

The METAR in effect at the time N631S and I departed KBDR on Friday afternoon looked like this:

KBDR 031930Z 05007KT 10SM SCT021 27/23 A2961 RMK AO2 RAE01 PRESFR P0000
The strong, gusty winds from the northeast had not yet materialized, visibility was unrestricted, there was no precipitation and the overcast was quite high.

The weather "snapshot" in the FlightAware track above reflects conditions when N631S and I were between Allentown and Lancaster. As you can see, the echoes from precipitation associated with Earl hadn't yet reached Bridgeport.

As I noted in the previous post (linked as #3, above), one New York-based forecaster remarked (in the TAF Discussion) that the winds then being forecast "may end up being too high depending on the strength and position of Earl." Full points to that forecaster - he got it right!

There was one item of interest, unrelated to Earl, on this flight. When I flipped the avionics master to "ON", the Garmin GPSmap 396 did not wake up in the usual manner. It was unable to link with any satellites and after a minute or so it gave up trying. If the weather had been as predicted (i.e., rather nasty) then this would have been quite distressing. Without the GPSmap 396 I was deprived of the XM Weather product. But conditions were not bad at all so I decided to shut it down and troubleshoot the problem en-route.

After departing and getting up to cruising altitude, I turned the 396 back on. It still could not find satellites and offered up a dialog box with several choices for me, such as "Start Simulation Mode", "Continue Acquiring", and "Auto-Locate Mode". The "fine print" under the last said "Choose this option if today is not Sep 2, 2010".

Well, it certainly was not Sept 2nd, so I chose that option and the unit began to laboriously scan the sky for satellites. And that, of course, is when the little light bulb went on for me. Dead battery.

The 396 normally operates on ship's power. But when everything is powered down it uses its internal Li-ion battery to remember the data it needs to reestablish a picture of the GPS satellite constellation. If the Li-ion battery pack dies, the unit forgets where (and when) it is.

After a number of minutes of heavy lifting in Auto-Locate mode the 396 was back to normal...and I need to order it a new battery pack (for about $40).

Incidentally, this is Post Number 200. May I express my great appreciation to all of you for stopping by to read and occasionally comment. I hope that you'll continue to find these posts enjoyable and, perhaps, useful.

Friday, September 3, 2010

Where's Earl? (for the Last Time)

At left, Earl's 1145Z portrait for this morning. Overnight, the storm was downgraded to Category 2 and shifted its track a bit to the east. That's all good news. The result is that the forecast for time of departure from KBDR is looking a bit less challenging than it did last evening.
Here's the 12Z TAF:

KBDR 031125Z 0312/0412 VRB03KT 6SM HZ SCT015 BKN150 
     FM031700 06012G17KT 5SM -SHRA BR BKN015 OVC150 
     FM032000 05020G30KT 5SM -SHRA BR SCT015 OVC035 
     FM040200 35020G30KT 5SM -SHRA BR SCT035 BKN150 
     FM040500 30012KT P6SM SCT150 
     FM040800 29005KT P6SM SCT150

For the time of interest (around 21Z) that's calling for 20 knot winds from 050 with gusts to 30 knots, and five mile visibility in mist and light rain showers. There should be scattered clouds at 1,500 feet and an overcast at 3,500 feet.

That's a fairly sporty wind forecast, but the direction is fortunate as it will be almost straight down Runway 6. Last evening's TAF had the same wind strength but a forecast direction of 010. That would have been a more challenging situation for takeoff as it would have offered a sizable crosswind component. So I'm happy with the change.

In the Terminal Area Forecast Discussion, the forecaster offers this:



So at least one forecaster thinks conditions may be less severe than currently predicted. I could live with that.

Thursday, September 2, 2010

Where's Earl? (cont'd)

Earl is moving right along. Here is an 1145Z Thursday satellite image showing the storm off the Florida coast.

And, at left, an enlarged view of the track forecast from the National Hurricane Center. The two marked points on the track denote 02Z Friday and 02Z Saturday, and the green coastal outline denotes the Tropical Storm Warning area.

It's late enough in the week to start looking at some Terminal Area Forecasts (TAF's) to get an idea of what to expect for the flight south. Here are the pertinent forecasts for major terminals that provide a 30 hour forecast horizon:

KJFK 021123Z 0212/0318 23006KT P6SM FEW080 
     FM021600 20010KT P6SM FEW060 
     FM021900 19016KT P6SM FEW050 SCT250 
     FM030100 18008KT P6SM BKN250 
     FM031000 08008KT P6SM OVC150 
     FM031700 04015G22KT 5SM -SHRA BR OVC015
KPHL 021120Z 0212/0318 20006KT P6SM SKC 
     FM021600 20011KT P6SM FEW070 
     FM022300 17007KT P6SM SCT280 
     FM030500 08006KT P6SM OVC200 
     FM031200 04012KT P6SM OVC090
KBWI 021135Z 0212/0318 VRB03KT 6SM HZ SCT110 SCT250 
     FM021300 VRB04KT P6SM SCT250 
     FM021600 18006KT P6SM SCT250 
     FM022200 16008KT P6SM BKN250 
     FM030300 VRB05KT P6SM SCT200 BKN250 
     FM030800 03005KT P6SM SCT080 BKN200 BKN250 
     FM031400 36009KT P6SM SCT120 BKN200
KIAD 021135Z 0212/0318 VRB03KT P6SM FEW120 
     FM021600 17006KT P6SM FEW250 
     FM022200 15004KT P6SM SCT250 
     FM030200 VRB03KT P6SM SCT250 
     FM030800 35003KT P6SM FEW080 BKN200 BKN250 
     FM031400 32006KT P6SM SCT250

Starting at 17Z Friday afternoon KJFK is anticipating wind from 040 at 15 knots with gusts to 22 knots, five miles visibility in mist under a 1,500 foot overcast and light rain showers.

The real point of interest is four hours later and 50 miles northeast - KBDR at 21Z, when I expect to be departing. But given Earl's expected track and weakening trend, weather on departure should not be much more severe, and that would be good enough.

And, N631S and I will be headed in the right direction. The TAF's for KPHL, KBWI and KIAD suggest that by mid-afternoon Friday conditions will be quite benign.

So far, so good.

Wednesday, September 1, 2010

Where's Earl?

Well, here, actually:

The more pertinent question is, "Where will Earl be from 21Z to 23Z Friday, and how will that effect me and N631S on our trip from Connecticut to DC?" We need a forecast or two, and the NWS is happy to oblige.

The latest track projection from the Hurricane Center has the storm offshore Cape Hatteras at 12Z Friday morning. Interpolating between the Friday and Saturday morning locations, one can infer that Earl will be at or near the 40N 70W "benchmark" at 00Z Saturday. If the track forecast verifies, we can hope that most of the mess will be well to the east and the afternoon and evening will be flyable.

Here's a graphic depicting the probability of winds of tropical storm strength (i.e., 39 mph) through 00Z Saturday. The probability for the DC area is about 10%; that for Bridgeport, CT is about 30%.

One more chart. This is the forecast from NCEP for 12Z Friday showing Earl churning up the Atlantic off Hatteras. Look at how tightly the isobars around the eye of the storm are spaced. This implies that the storm effects will drop off quickly with distance. Plan to give Earl a decently wide berth and he may not be too bad.

Let's take a look at what the models are actually saying for departure (KBDR) and destination (KVKX).

 KBDR   GFS MOS GUIDANCE    9/01/2010  0600 UTC                      
 DT /SEPT  1      /SEPT  2                /SEPT  3             /     
 HR   12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 00 06 
 TMP  77 83 88 89 83 77 73 71 74 80 84 86 81 75 72 71 72 75 78 73 69 
 DPT  64 64 63 63 65 66 65 64 64 64 62 64 66 68 68 68 68 69 69 67 62 
 WDR  34 22 22 22 23 24 26 27 29 22 22 21 22 23 21 18 10 11 09 03 31 
 WSP  02 06 07 08 06 05 03 03 04 07 09 10 07 05 04 04 05 08 10 12 08 
 P06         1     0     3     4     1     4     7    20    37 53 52 
 Q06         0     0     0     0     0     0     0     0     1  4  2 
 T06      0/ 2  0/ 5  0/ 0  0/ 1  0/ 5  0/12  0/ 4  0/ 1  8/ 5  9/ 6 
 CIG   8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  7  5  4  4  8 
 VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  5  5  5  5  5  7 
 OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N BR BR HZ BR BR  N

For Bridgeport (KBDR), for the six hours leading up to 00Z Saturday the GFS model predicts wind from 030 at 12 knots, 53% probability of precipitation with 1/4" to 1/2" of rain, ceiling between 1000 and 1900 feet, and 3 to 5 miles visibility. Not pretty, but flyable.

ANDREWS AFB         
 KADW   GFS MOS GUIDANCE    9/01/2010  1200 UTC                      
 DT /SEPT  1/SEPT  2                /SEPT  3                /SEPT  4 
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 
 TMP  92 92 82 74 70 67 72 86 89 88 79 71 69 68 71 81 89 91 82 69 67 
 DPT  63 59 62 61 61 61 63 62 59 60 65 66 65 65 66 65 61 58 59 60 55 
 WDR  24 21 17 18 20 20 22 18 16 15 14 14 08 03 35 34 32 28 25 29 29 
 WSP  06 07 06 05 05 03 03 05 08 08 05 04 04 05 08 12 14 12 09 07 09 
 P06         0     6     6     1     2    16    31    15     8 10  2 
 Q06         0     0     0     0     0     0     0     0     0  0  0 
 T06      0/ 4  0/ 1  0/ 0  0/ 1  1/ 5 10/ 1  5/ 0  2/ 3  5/19  4/ 3 
 CIG   8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8 
 VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  6  7  7  7  7  7  7  7 
 OBV   N  N  N  N  N  N  N  N  N  N  N  N  N BR HZ  N  N  N  N  N  N 

For the same period at Andrews AFB (just down the road from KVKX) the model predicts wind from 250 at 9 knots, 8% probability of precipitation, ceiling greater than 12,000 feet, and more than 6 miles visibility. In short, benign conditions.

For comparison let's look at the NAM model output:

 KBDR   NAM MOS GUIDANCE    9/01/2010  1200 UTC                      
 DT /SEPT  1/SEPT  2                /SEPT  3                /SEPT  4 
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 
 TMP  90 91 85 79 75 72 76 83 88 89 83 77 74 73 72 75 78 78 76 70 70 
 DPT  62 61 63 65 64 63 64 64 64 63 64 65 66 67 67 69 70 70 69 62 57 
 WDR  23 22 23 24 26 26 26 22 22 21 22 22 22 17 15 12 13 10 01 30 31 
 WSP  07 08 06 05 04 03 04 08 10 12 08 07 05 05 04 07 09 04 04 05 07 
 P06         2     2     4     3     2     6     5    23    24 20  7 
 Q06         0     0     0     0     0     0     0     0     0  0  0 
 T06      0/ 3  0/ 0  0/ 0  2/ 9  0/14  0/ 1  0/ 1  3/ 1 17/ 9  5/ 2 
 CIG   8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  4  4  6  6  8 
 VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  6  6  6  7 
 OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N HZ BR  N  N 

For the period of interest at Bridgeport (KBDR), the NAM model predicts wind from 010 at 4 knots, 24% probability of precipitation, ceiling between 3000 and 6500 feet, and 6 miles visibility. Not bad at all; in fact lots better than the GFS forecast.

ANDREWS AFB         
 KADW   NAM MOS GUIDANCE    9/01/2010  1200 UTC                      
 DT /SEPT  1/SEPT  2                /SEPT  3                /SEPT  4 
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 
 TMP  91 92 84 77 73 71 74 84 89 89 80 72 69 67 71 79 83 85 78 69 68 
 DPT  62 60 63 63 62 62 63 62 58 59 63 64 64 64 66 65 62 61 64 60 55 
 WDR  22 20 19 19 21 21 22 21 21 19 18 18 18 36 33 33 32 26 29 30 30 
 WSP  06 08 05 07 07 04 05 06 09 08 05 04 02 02 04 06 06 08 04 11 13 
 P06         2     2     4     3     2     4     5    14     1 11  0 
 Q06         0     0     0     0     0     0     0     0     0  0  0 
 CIG   8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8 
 VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7 
 OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N 

Finally, the NAM output for Andrews AFB calls for 00Z Saturday calls for wind from 290 at 4 knots, a 1% probability of precipitation, ceiling above 12,000 feet and better than 6 miles visibility.

So to sum up, Earl is a tightly wound, fast moving hurricane that the models predict will stay pretty far offshore. The current state of the forecast leads me to think that a departure from Bridgeport around 21Z Friday may be unpleasant but not dangerous, that in any event N631S and I will be out of most of the weather effects by the time our normal routing takes us to eastern Pennsylvania, and the arrival at KVKX ought to be routine.

Hurricanes are, of course, notoriously fickle beasts and Earl will bear continuous watching...but for now it looks like AMTRAK will have to go without me this weekend.