WxWatcher007

Meanwhile…Washington looks terrible too smh. I gotta stop picking them.

Really interesting discussion Hurricane Sam Discussion Number 14 NWS National Hurricane Center Miami FL AL182021 1100 PM AST Sat Sep 25 2021 It's been an interesting evening with regards to analyzing the various data from a NOAA Hurricane Hunter research flight into Hurricane Sam. Dropsonde data in both the southeast and northwest quadrants indicate that small eyewall mesovortices and possibly even tornado-scale vortices were present based on the wind profiles showing sharply opposite-direction winds from what would normally be expected in those regions of the hurricane. Some dropsonde surface winds have been as high as 162 kt, which is more representative of a gust, while SFMR surface winds have been as high as 133 kt. However, the strongest 700-mb flight-level winds have been 138-139 kt in the northeastern quadrant, which equates to about 125-kt tangential surface winds. Three dropsondes released in the eye indicate that the pressure had remained steady at 943-944 mb during the duration of the aircraft reconnoiter. That pressure equates to about 125 kt based on various pressure-wind relationships. Based on that estimate and the 700-mb flight-level to surface-wind conversion, the advisory intensity is 125 kt, which is representative of the mean tangential winds and no localized wind perturbations. The initial motion is toward the west-northwest, or 295/07 kt. Not to sound like a broken record, but no significant changes were made to the previous track forecast and reasoning. Sam is expected to move slowly west-northwestward and northwestward over the next few days around the southwestern periphery of a deep-layer subtropical ridge that is situated to the north and northeast of the small hurricane. On days 4 and 5, an upper-level trough/low is forecast to dig southward and amplify off the U.S. east coast and extend all the way to the Bahamas. This feature should act to lift Sam northward at a faster forward speed. The latest NHC model guidance based on 12Z and 18Z model runs has shifted noticeably to the east of the previous runs, and the new NHC track forecast has been nudged in that direction as well. However, since the NOAA G-IV jet aircraft has been out there sampling the environment around Sam, it's best to remain conservative and not shift the track any farther to the east until the new 00Z model runs with that new aircraft data come in for the next advisory package at 0600Z. The new NHC track forecast lies about halfway between the previous advisory track on the left and the tightly packed consensus track models on the right. The radar images from the reconnaissance aircraft indicated that the eyewall was thin in many locations due to dry-air intrusions, and the latest SHIPS intensity output indicates that Sam will remain within a fairly dry mid-level environment. Also, the depth of the warm water beneath the hurricane isn't overly deep, which could result in cold upwelling owing to Sam's slow forward motion of only 5-7 kt during the next couple of days. Eyewall replacement cycles are also likely now due to the hurricane's small size and strong intensity. Thus, fluctuations in intensity seem likely for the next couple of days even though the vertical wind shear is expected to remain quite low at only 5-10 kt. On days 3-5, however, the shear is forecast to increase to 15-20 kt from the southwest, which is expected to induce a slow weakening trend. However, it is likely that Sam will remain a major hurricane through 120 h, even on days 3-5 due to the cyclone moving over warmer and deeper water during that 3-day period. The new official intensity forecast is essentially the same as the previous advisory, and remains above the consensus model and is near the higher end of the intensity guidance. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 13.5N 49.0W 125 KT 145 MPH 12H 26/1200Z 14.0N 49.9W 130 KT 150 MPH 24H 27/0000Z 14.7N 51.0W 125 KT 145 MPH 36H 27/1200Z 15.4N 52.1W 120 KT 140 MPH 48H 28/0000Z 16.3N 53.2W 120 KT 140 MPH 60H 28/1200Z 17.1N 54.3W 115 KT 130 MPH 72H 29/0000Z 18.0N 55.6W 115 KT 130 MPH 96H 30/0000Z 20.1N 58.5W 110 KT 125 MPH 120H 01/0000Z 23.7N 61.4W 110 KT 125 MPH $$ Forecaster Stewart

Both recon flights have ended, so now we wait to see what the NHC does at 11.

It's awesome, and there are multiple dropsondes doing it. This has been a really cool recon flight to watch.

This is a full on five bun dropsonde.

Here's the visual. Again, for posterity

I'm a little leary of >140 kt SFMR readings without similiar flight level readings as well. But Sam is no doubt an intense hurricane. Especially in this region of the MDR. It's in rare company. Think Hugo and Irma. I'd be comfortable with 135 kts / 155 mph on the next advisory. Agree. Also, here's a great dropsonde for posterity. It went for one hell of a ride Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)Transmitted: 26th day of the month at 0:12ZAgency: National Oceanic and Atmospheric Administration (NOAA)Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)Storm Name: SamStorm Number: 18 (flight in the North Atlantic basin)Mission: Second flight of a sequence of non-tasked research missions into this systemObservation Number: 27 ( See all messages of this type for this mission. )Part A... Date: Near the closest hour of 0Z on the 26th day of the month Highest Mandatory Level For Which Wind Was Reported: 700mb Coordinates: 13.3N 48.7W Location: 734 statute miles (1,181 km) to the E (89°) from Bridgetown, Barbados. Marsden Square: 041 ( About ) Surface and Standard Isobaric Surfaces Level Geo. Height Air Temp. Dew Point Wind Direction Wind Speed 1000mb -400m (-1,312 ft) This level does not exist in this area of the storm above the surface level. 956mb (28.23 inHg) Surface (Sea Level) 24.0°C (75.2°F) 23.3°C (74°F) 110° (from the ESE) 162 knots (186 mph) 925mb 285m (935 ft) 22.2°C (72.0°F) 22.1°C (72°F) 125° (from the SE) 174 knots (200 mph) 850mb 1,022m (3,353 ft) 20.2°C (68.4°F) 20.0°C (68°F) 165° (from the SSE) 115 knots (132 mph) 700mb 2,687m (8,816 ft) 14.0°C (57.2°F) 12.8°C (55°F) 220° (from the SW) 96 knots (110 mph) Information About Radiosonde: - Launch Time: 23:56Z - About Sonde: A descending radiosonde tracked automatically by satellite navigation with no solar or infrared correction. Remarks Section... Dropsonde Location: Dropped in eyewall 135° (SE) from the eye center. Highest altitude where wind was reported: - Location: 13.35N 48.70W - Time: 23:56:15Z Lowest altitude where wind was reported: - Location: 13.49N 48.73W - Time: 0:00:53Z Mean Boundary Level Wind (mean wind in the lowest 500 geopotential meters of the sounding): - Wind Direction: 130° (from the SE) - Wind Speed: 158 knots (182 mph) Deep Layer Mean Wind (average wind over the depth of the sounding): - Wind Direction: 165° (from the SSE) - Wind Speed: 105 knots (121 mph) - Depth of Sounding: From 699mb to 955mb Average Wind Over Lowest Available 150 geopotential meters (gpm) of the sounding: - Lowest 150m: 157 gpm - 7 gpm (515 geo. feet - 23 geo. feet) - Wind Direction: 115° (from the ESE) - Wind Speed: 161 knots (185 mph) Sounding Software Version: AEV 30406 Part B: Data for Significant Levels... Significant Temperature And Relative Humidity Levels Level Air Temperature Dew Point 956mb (Surface) 24.0°C (75.2°F) 23.3°C (74°F) 850mb 20.2°C (68.4°F) 20.0°C (68°F) 719mb 14.4°C (57.9°F) 14.2°C (58°F) 692mb 14.6°C (58.3°F) 12.1°C (54°F) Significant Wind Levels Level Wind Direction Wind Speed 956mb (Surface) 110° (from the ESE) 162 knots (186 mph) 954mb 110° (from the ESE) 161 knots (185 mph) 953mb 110° (from the ESE) 167 knots (192 mph) 951mb 115° (from the ESE) 168 knots (193 mph) 936mb 125° (from the SE) 147 knots (169 mph) 925mb 125° (from the SE) 174 knots (200 mph) 921mb 130° (from the SE) 169 knots (194 mph) 916mb 140° (from the SE) 171 knots (197 mph) 910mb 140° (from the SE) 162 knots (186 mph) 905mb 140° (from the SE) 144 knots (166 mph) 903mb 140° (from the SE) 139 knots (160 mph) 894mb 145° (from the SE) 144 knots (166 mph) 889mb 155° (from the SSE) 132 knots (152 mph) 879mb 160° (from the SSE) 122 knots (140 mph) 871mb 155° (from the SSE) 124 knots (143 mph) 866mb 155° (from the SSE) 113 knots (130 mph) 862mb 160° (from the SSE) 121 knots (139 mph) 856mb 160° (from the SSE) 113 knots (130 mph) 850mb 165° (from the SSE) 115 knots (132 mph) 699mb 220° (from the SW) 96 knots (110 mph)

...and in the next set of data we see FL winds of 130, 132kts and another SFMR of 144kts. Could be a gust and biased high, but clearly a high end Atlantic hurricane. Quite impressive.

Don't see the FL winds to support it in this set of data, but there's an unflagged 141kt SFMR on this latest pass (SE to NW).

Latest VDM Product: NOAA Vortex Message (URNT12 KWBC)Transmitted: 25th day of the month at 23:21ZAgency: National Oceanic and Atmospheric Administration (NOAA)Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)Storm Name: SamStorm Number & Year: 18 in 2021 (flight in the North Atlantic basin)Mission: Second flight of a sequence of non-tasked research missions into this systemObservation Number: 17 ( See all messages of this type for this mission. )A. Time of Center Fix: 25th day of the month at 22:59:16ZB. Center Fix Coordinates: 13.34N 48.64WB. Center Fix Location: 738 statute miles (1,188 km) to the E (89°) from Bridgetown, Barbados.C. Minimum Height at Standard Level: 2,638m (8,655ft) at 700mbD. Minimum Sea Level Pressure: 946mb (27.94 inHg)E. Dropsonde Surface Wind at Center: From 200° at 16kts (From the SSW at 18mph)F. Eye Character: ClosedG. Eye Shape & Diameter: Circular with a diameter of 13 nautical miles (15 statute miles)H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 136kts (156.5mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 6 nautical miles to the NNE (31°) of center fix at 22:57:47ZJ. Maximum Flight Level Wind Inbound: From 123° at 139kts (From the ESE at 160.0mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 8 nautical miles to the NNE (31°) of center fix at 22:57:16ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 103kts (118.5mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 6 nautical miles to the SSW/SW (214°) of center fix at 23:00:53ZN. Maximum Flight Level Wind Outbound: From 287° at 103kts (From the WNW at 118.5mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 6 nautical miles to the SSW/SW (214°) of center fix at 23:00:46ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 10°C (50°F) at a pressure alt. of 3,068m (10,066ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 20°C (68°F) at a pressure alt. of 3,057m (10,030ft)R. Dewpoint Temp (collected at same location as temp inside eye): 6°C (43°F)R. Sea Surface Temp (collected at same location as temp inside eye): Not AvailableS. Fix Determined By: Penetration, Radar, Pressure and TemperatureS. Fix Level: 700mbT. Navigational Fix Accuracy: 0.01 nautical milesT. Meteorological Accuracy: 1 nautical mileRemarks Section: Maximum Flight Level Wind: 139kts (~ 160.0mph) which was observed 8 nautical miles to the NNE (31°) from the flight level center at 22:57:16Z

Probably? Over the last few years there has been an apparent high bias with SFMR in very intense hurricanes. https://twitter.com/AndrewHagen/status/1441893019435872267?s=20

Just shy of Category 5 based on the data so far.

Recon doing NE to SW pass right now. Finding 138, 139kt FL winds and a 134, 136kt SFMR.

First VDM Product: NOAA Vortex Message (URNT12 KWBC)Transmitted: 25th day of the month at 22:34ZAgency: National Oceanic and Atmospheric Administration (NOAA)Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)Storm Name: SamStorm Number & Year: 18 in 2021 (flight in the North Atlantic basin)Mission: Second flight of a sequence of non-tasked research missions into this systemObservation Number: 08 ( See all messages of this type for this mission. )A. Time of Center Fix: 25th day of the month at 22:07:46ZB. Center Fix Coordinates: 13.29N 48.58WB. Center Fix Location: 742 statute miles (1,194 km) to the E (89°) from Bridgetown, Barbados.C. Minimum Height at Standard Level: 2,627m (8,619ft) at 700mbD. Minimum Sea Level Pressure: 945mb (27.91 inHg)E. Dropsonde Surface Wind at Center: From 120° at 9kts (From the ESE at 10mph)F. Eye Character: ClosedG. Eye Shape & Diameter: Circular with a diameter of 9 nautical milesH. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 111kts (127.7mph)I. Location & Time of the Estimated Maximum Surface Wind Inbound: 4 nautical miles to the W (273°) of center fix at 22:06:44ZJ. Maximum Flight Level Wind Inbound: From 358° at 106kts (From the N at 122.0mph)K. Location & Time of the Maximum Flight Level Wind Inbound: 4 nautical miles to the W (273°) of center fix at 22:06:49ZL. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 133kts (153.1mph)M. Location & Time of the Estimated Maximum Surface Wind Outbound: 7 nautical miles to the E (95°) of center fix at 22:09:26ZN. Maximum Flight Level Wind Outbound: From 177° at 127kts (From the S at 146.1mph)O. Location & Time of the Maximum Flight Level Wind Outbound: 9 nautical miles to the E (94°) of center fix at 22:09:53ZP. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 10°C (50°F) at a pressure alt. of 3,055m (10,023ft)Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 27°C (81°F) at a pressure alt. of 3,050m (10,007ft)R. Dewpoint Temp (collected at same location as temp inside eye): 4°C (39°F)R. Sea Surface Temp (collected at same location as temp inside eye): Not AvailableS. Fix Determined By: Penetration, Radar, Wind, Pressure and TemperatureS. Fix Level: 700mbT. Navigational Fix Accuracy: 0.01 nautical milesT. Meteorological Accuracy: 1 nautical mileRemarks Section: Maximum Flight Level Wind: 127kts (~ 146.1mph) which was observed 9 nautical miles to the E (94°) from the flight level center at 22:09:53Z

Western eyewall dropsonde.

East side has the goods. 942.2 extrapolated with a peak FL wind of 127kts and peak SFMR of 133kts. Hell of a compact wind field.

Looks like a west to east pass from recon. Peak FL wind of 106kts and SFMR of 111kts. Extrapolated pressure of 942.1 at about 9,000ft. Might be just shy of the center though.

My goodness.

That's just how it goes. MDR stuff is always high risk high reward if you're looking for US impacts.

That's the flight to sample the environment, while NOAA2 will sample the center. Not sure how many passes they will get given the distance from their takeoff location.

I'm pumped to see what recon finds.