NHC weakening Cindy too fast: Obs Refute 5AM Advisory

[drezee]

Why are they saying it is weaker DPIA1 reported 59 knots sustained (1-min) last hour (9.3M height on anenometer). Buoy pressure is at least 996mb.

06/10 42007 30.1 -88.8 25.1 24.5 170 43 G 52 170 52 996.4 -9.0 26.9 5.5 10 * 42007

[drezee]

Wow! this is the one hour totals!!



Max 6.5 inches!!!!!!!

[baygirl_1]

okay... i haven't had much sleep (that's my disclaimer), so someone plese help me with radar. it looked like the center made 2nd landfall about an hour ago, but what is thay circle/semi circle still off ms coast? dry slot? or is tat the center?? if it's still over water, it will stay stronger, right?
http://www.srh.noaa.gov/radar/loop/DS.p19r0/si.kmob.shtm

p.s. that red is right over me! whole lotta rain...

[drezee]

these are the 1 hour rain totals at 0918Z. Not live radar

[senorpepr]

Why are they saying it is weaker DPIA1 reported 59 knots sustained (1-min) last hour (9.3M height on anenometer). Buoy pressure is at least 996mb.

06/10 42007 30.1 -88.8 25.1 24.5 170 43 G 52 170 52 996.4 -9.0 26.9 5.5 10 * 42007

Hmmm... I'm beyond confused. DPIA1 is Dauphin Island, AL. Cindy is 25 mi ENE of New Orleans. Furthermore, the highest winds at DPIA1 has been 48kt. As for the observation you posted (42007 or 22SSE Biloxi) They are reporting 43kt. I'm not sure where you are getting 59kt from.

[drezee]

Pressure still at least: 996mb

06/11 42007 30.1 -88.8 24.8 24.4 190 39 G 47 170 52 996.2 -7.6 26.8 4.5 10 * 42007

DPIA:

06/09 DPIA1 30.3 -88.0 25.3 25.1 150 48 G 59
06/10 DPIA1 30.3 -88.0 27.3 24.5 150 38 G 46 G 130 64
Recored are 10-min / 1-minute / 5 sec peak gust

For other buoys:

http://www.aoml.noaa.gov/hrd/tcfaq/D4.html
FROM NHC:
While one can utilize a simple ratio to convert from peak 10 min wind to peak 1 min wind (roughly 12% higher for the latter)

[senorpepr]

Pressure still at least: 996mb

06/11 42007 30.1 -88.8 24.8 24.4 190 39 G 47 170 52 996.2 -7.6 26.8 4.5 10 * 42007

DPIA:

06/09 DPIA1 30.3 -88.0 25.3 25.1 150 48 G 59
06/10 DPIA1 30.3 -88.0 27.3 24.5 150 38 G 46 G 130 64
Recored are 10-min / 1-minute / 5 sec peak gust

For other buoys:

http://www.aoml.noaa.gov/hrd/tcfaq/D4.html
FROM NHC:
While one can utilize a simple ratio to convert from peak 10 min wind to peak 1 min wind (roughly 12% higher for the latter)

I'm still not seeing why NHC is "too low." The highest wind speed you've show was 48KT. That 48KT is a one-minute average (it's a US Buoy), which translates to 55 mph.

[drezee]

Pressure still at least: 996mb

06/11 42007 30.1 -88.8 24.8 24.4 190 39 G 47 170 52 996.2 -7.6 26.8 4.5 10 * 42007

DPIA:

06/09 DPIA1 30.3 -88.0 25.3 25.1 150 48 G 59
06/10 DPIA1 30.3 -88.0 27.3 24.5 150 38 G 46 G 130 64
Recored are 10-min / 1-minute / 5 sec peak gust

For other buoys:

http://www.aoml.noaa.gov/hrd/tcfaq/D4.html
FROM NHC:
While one can utilize a simple ratio to convert from peak 10 min wind to peak 1 min wind (roughly 12% higher for the latter)

I'm still not seeing why NHC is "too low." The highest wind speed you've show was 48KT. That 48KT is a one-minute average (it's a US Buoy), which translates to 55 mph.

The NHC advisory is 998 mb 60 mph right....three hours ago

The CURRENT PRESSURE in BILOXI , MS is 995.9 MB! Three hours later!!

The 10 minute 48kts * 1.12 *1.154 = 62mph (1-minute sustained winds) Well removed from the center!! (like you said)

On the point of 1-min winds: excerpt from NDBC (like I said 10-minute avg. on DPIA1)

Continuous wind measurements are six 10-minute average values of wind speed (in m/s) and direction (in degrees clockwise from North) reported each hour. These measurements provide wind data for those users who need better temporal resolution in wind data, such as for micro-scale studies of air quality and sea breeze effects. Note that NDBC uses two types of payload-dependent wind averaging methods. Not all NDBC stations report continuous winds. These measurements are usually associated with C-MAN sites along the south Atlantic and in the Gulf of Mexico and at most deep-water moored buoys of the Gulf of Mexico, the Pacific, and the northern Atlantic.

The acquisition interval of the continuous wind measurements depends on the end-of-acquisition minute. For example, let's examine a buoy reporting continuous wind speed and direction measurements reported for hour 12 which has the end-of- acquisition minute set at minute 50. The first average speed (WS1) and direction (WD1) measurements will be the average of the speed and direction data, respectively, collected from 1140 to 1150. The second average speed and direction measurements will be the average of the speed and direction data, respectively, collected from 1130 to 1140. The sixth and final average speed (WS1) and direction (WD6) measurements will be the average of the speed and direction data, respectively, collected from 1050 to 1100.

[drezee]

Thanks NHC...lowered the pressure on the 8am advisory

ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB...29.29 INCHES.

Advisory also mentioned recent 46 mph wind gust: 12z measurement from DPIA

7:00 am S ( 183 deg ) 35 kts

35kts *1.154mph/kts * 1.125 (10-min wind) =.........drum roll please....................... ~46 mph!!!!

[drezee]

1135Z from MOB: Cindy is still kicking

Wind from the SE (140 degrees) at 30 MPH (26 KT) gusting to 49 MPH (43 KT)

1228Z:
8:28 AM 73.4 °F / 23.0 °C 69.8 °F / 21.0 °C 88% 29.64 in / 1003.6 hPa 2.0 miles / 3.2 kilometers SSE 35.7 mph / 57.4 km/h 51.8 mph / 83.3 km/h 0.29 in / 0.7 cm Rain Heavy Rain