Where's Earl?

Well, here, actually:

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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).

BRIDGEPORT      
 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 
 CLD  CL CL CL CL CL CL CL CL CL CL CL CL CL CL FW FW OV OV OV OV SC 
 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 
 CLD  FW FW CL CL CL CL CL CL FW SC SC FW BK BK BK SC FW FW BK SC SC 
 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:

BRIDGEPORT     
 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 
 CLD  FW FW CL FW CL CL CL CL CL CL CL CL CL FW SC BK OV OV OV OV SC 
 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 
 CLD  CL CL CL CL CL CL CL CL FW FW CL CL CL CL CL CL FW SC BK BK SC 
 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.