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Tropical Storm Bret


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Honestly though, this will go down as a rather poor genesis forecast... 40% at 2pm following TS at 5pm. The writing was on the wall this morning when WINDSAT had a well defined circulation.

Not to mention the LR radar signature at mid-levels, as well as an excellent sat. presentations, as far as invests go...

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Imagine your the TV met in Miami and you have to go on in an hour and tell your viewers that there is a TD/TS 90 miles off your coast and there will be TS watches in the next few hours.. and best of all.. You have little idea where its going because the models haven't handled it well.

Sucks to be that guy.

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Honestly though, this will go down as a rather poor genesis forecast... 40% at 2pm following TS at 5pm. The writing was on the wall this morning when WINDSAT had a well defined circulation.

The NHC is notoriously conservative. Maybe a little too conservative, but it's better to err on the side of caution rather than declaring something and then finding it's not really there, especially in a case like this where no immediate impacts are expected. Things get a little more tricky when land is in danger, such as during Humberto, but in this case there's nothing wrong with what they did imo.

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Honestly though, this will go down as a rather poor genesis forecast... 40% at 2pm following TS at 5pm. The writing was on the wall this morning when WINDSAT had a well defined circulation.

Hence the need for RECON data. Grand Bahama with 15 kt winds wouldn't pass the smell test. While convection has been rather impressive, it is not vertically stacked and with RECON so close, no real need to go any stronger with the TWO, IMO. We're not talking a disturbance to a 50 kt storm here.

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Honestly though, this will go down as a rather poor genesis forecast... 40% at 2pm following TS at 5pm. The writing was on the wall this morning when WINDSAT had a well defined circulation.

I bet they leave it as a TD..although its quite possible/likely its a 40 MPH min tropical storm

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Hence the need for RECON data. Grand Bahama with 15 kt winds wouldn't pass the smell test. While convection has been rather impressive, it is not vertically stacked and with RECON so close, no real need to go any stronger with the TWO, IMO. We're not talking a disturbance to a 50 kt storm here.

Agree pretty strongly with this. It clearly had a mid-level signature, but we had no idea what was happening at the surface except for some rain flagged WINDSAT obs.

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Agree pretty strongly with this. It clearly had a mid-level signature, but we had no idea what was happening at the surface except for some rain flagged WINDSAT obs.

Probably why the NHC decided to play conservative and only go with a 40% Chance of development- although 40% was really playing it very conservative. Are there any examples of a orange drop going directly do a TD?

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Agree pretty strongly with this. It clearly had a mid-level signature, but we had no idea what was happening at the surface except for some rain flagged WINDSAT obs.

I concur that the NHC shouldn't have classified this any earlier than a pass through. However, one could certainly quibble over the 40% TC genisis probs that were put out just a few hours ago. IMO, a 60-70% chance would have seemed more appropriate, but again, just friendly quibbling...

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Probably why the NHC decided to play conservative and only go with a 40% Chance of development- although 40% was really playing it very conservative. Are there any examples of a orange drop going directly do a TD?

I think they always play it conservatively with these near coastal developments. I can't think of any off the top of my head, but I'm sure it's happened. 40% was obviously conservative, but except to hurricane enthusiasts, does anyone actually care if they went 40% or 60% at 2pm? No decisions are being made off either forecast.

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I concur that the NHC shouldn't have classified this any earlier than a pass through. However, one could certainly quibble over the 40% TC genisis probs that were put out just a few hours ago. IMO, a 60-70% chance would have seemed more appropriate, but again, just friendly quibbling...

Yeah, I hear what you're saying. If I was the one on the desk, I probably would have went higher than 40% at 2pm, but I was still poo-pooing it when I put my forecast out at 8am this morning. I mean, it's still tilted and the convective pattern is only about T1.5 right now.

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Hence the need for RECON data. Grand Bahama with 15 kt winds wouldn't pass the smell test. While convection has been rather impressive, it is not vertically stacked and with RECON so close, no real need to go any stronger with the TWO, IMO. We're not talking a disturbance to a 50 kt storm here.

I agree that RECON data is by far the most important tool to determine genesis, but there were numerous other clues as well. The WINDSAT was the first to suggest a closed llc, but even surface obs around the circulation showed strong evidence of this. A buoy to the north of the circulation outside of the deep convection had sustained winds at 24 knots earlier today. The NHC does great work and they know exactly what they are doing waiting for recon to confirm the presence of a circulation. If it were me, I would have been more aggressive with the 2pm outlook for TCG. No bashing here, just my opinion.

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Fish

2100 UTC sun Jul 17 2011 changes in watches and warnings with this advisory... the government of the Bahamas has issued a tropical storm watch for Grand Bahama Island and the abaco islands in the northwest Bahamas. Summary of watches and warnings in effect... a tropical storm watch is in effect for... * Grand Bahama Island and the abaco islands in the northwest Bahamas

tropical depression center located near 27.5n 78.2w at 17/2100z position accurate within 30 nm present movement toward the south or 180 degrees at 2 kt estimated minimum central pressure 1010 mb Max sustained winds 30 kt with gusts to 40 kt. Winds and seas vary greatly in each quadrant.

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TROPICAL DEPRESSION TWO FORECAST/ADVISORY NUMBER 1

NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011

2100 UTC SUN JUL 17 2011

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A TROPICAL STORM WATCH FOR

GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST BAHAMAS.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WATCH IS IN EFFECT FOR...

* GRAND BAHAMA ISLAND AND THE ABACO ISLANDS IN THE NORTHWEST BAHAMAS

TROPICAL DEPRESSION CENTER LOCATED NEAR 27.5N 78.2W AT 17/2100Z

POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE SOUTH OR 180 DEGREES AT 2 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1010 MB

MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.

WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL

MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 27.5N 78.2W AT 17/2100Z

AT 17/1800Z CENTER WAS LOCATED NEAR 27.7N 78.2W

FORECAST VALID 18/0600Z 27.4N 78.2W

MAX WIND 40 KT...GUSTS 50 KT.

34 KT... 50NE 50SE 50SW 50NW.

FORECAST VALID 18/1800Z 28.2N 77.8W

MAX WIND 45 KT...GUSTS 55 KT.

34 KT... 60NE 60SE 60SW 60NW.

FORECAST VALID 19/0600Z 29.0N 77.3W

MAX WIND 50 KT...GUSTS 60 KT.

50 KT... 30NE 30SE 20SW 20NW.

34 KT... 75NE 75SE 75SW 75NW.

FORECAST VALID 19/1800Z 30.4N 76.5W

MAX WIND 50 KT...GUSTS 60 KT.

50 KT... 40NE 40SE 30SW 30NW.

34 KT... 90NE 90SE 90SW 90NW.

FORECAST VALID 20/1800Z 32.0N 73.5W

MAX WIND 50 KT...GUSTS 60 KT.

50 KT... 40NE 40SE 30SW 30NW.

34 KT... 90NE 90SE 90SW 90NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM

ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 21/1800Z 34.0N 67.0W

MAX WIND 45 KT...GUSTS 55 KT.

OUTLOOK VALID 22/1800Z 36.0N 60.0W

MAX WIND 40 KT...GUSTS 50 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 27.5N 78.2W

NEXT ADVISORY AT 18/0300Z

$$

FORECASTER PASCH/STEWART

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Product: Air Force Vortex Message (URNT12 KNHC)

Transmitted: 17th day of the month at 20:28Z

Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 304)

Mission Purpose: Investigate second suspect area (flight in the North Atlantic basin)

Mission Number: 1 seeall.png

Observation Number: 14

A. Time of Center Fix: 17th day of the month at 20:16:40Z

B. Center Fix Coordinates: 27°34'N 78°11'W (27.5667N 78.1833W) viewmap.png

B. Center Fix Location: 130 miles (209 km) to the ENE (63°) from West Palm Beach, FL, USA.

C. Minimum Height at Standard Level: Not Available

D. Estimated (by SFMR or visually) Maximum Surface Wind: 24kts (~ 27.6mph)

E. Location of the Estimated Maximum Surface Wind: 5 nautical miles (6 statute miles) to the NW (310°) of center fix

F. Maximum Flight Level Wind Inbound: From 60° at 25kts (From the ENE at ~ 28.8mph)

G. Location of Maximum Flight Level Wind Inbound: 2 nautical miles (2 statute miles) to the NW (320°) of center fix

H. Minimum Sea Level Pressure: 1010mb (29.83 inHg) - Extrapolated

I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 23°C (73°F) at a pressure alt. of 189m (620ft)

J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 24°C (75°F) at a pressure alt. of 188m (617ft)

K. Dewpoint Temp (collected at same location as temp inside eye): 21°C (70°F)

K. Sea Surface Temp (collected at same location as temp inside eye): Not Available

L. Eye Character: Not Available

M. Eye Shape: Not Available

N. Fix Determined By: Penetration, Radar, Wind and Pressure

N. Fix Levels (sfc and flt lvl centers are within 5nm of each other): Surface and 1,500 feet

O. Navigation Fix Accuracy: 0.02 nautical miles

O. Meteorological Accuracy: 1 nautical mile

Remarks Section:

Maximum Flight Level Wind: 25kts (~ 28.8mph) in the northwest quadrant at 20:16:00Z

Sea Level Pressure Extrapolation From: Below 1,500 feet

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I think they always play it conservatively with these near coastal developments. I can't think of any off the top of my head, but I'm sure it's happened. 40% was obviously conservative, but except to hurricane enthusiasts, does anyone actually care if they went 40% or 60% at 2pm? No decisions are being made off either forecast.

From a scientific standpoint, it will hurt their genesis forecasts verification they have been producing in the year end reports. This storm will have a poor POD (.26), and I'd argue that its more important to be able to identify systems developing over occasionally producing a false alarms as long as the system out in open waters.

Obviously its not a big deal though, ultimately.

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00

WTNT42 KNHC 172042

TCDAT2

TROPICAL DEPRESSION TWO DISCUSSION NUMBER 1

NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011

500 PM EDT SUN JUL 17 2011

AN AIR FORCE HURRICANE HUNTER PLANE INVESTIGATING THE LOW PRESSURE

AREA JUST NORTH OF THE NORTHWEST BAHAMAS FOUND A WELL-DEFINED

LOW-LEVEL CENTER OF CIRCULATION...AND THE SYSTEM IS BEING

DESIGNATED AS A TROPICAL CYCLONE AT THIS TIME. ALTHOUGH WINDS OF

TROPICAL STORM FORCE WERE MEASURED BY THE SFMR INSTRUMENT ON BOARD

THE PLANE...THESE OBSERVATIONS WERE FLAGGED AS QUESTIONABLE. PEAK

FLIGHT-LEVEL WINDS REPORTED BY THE AIRCRAFT WERE 44 KT WHICH WOULD

NORMALLY INDICATE A SYSTEM OF TROPICAL STORM STRENGTH. HOWEVER...

THE CONVECTION NEAR THE CENTER IS RELATIVELY WEAK...AND IN THIS

CASE THE STRONGEST WINDS ARE LIKELY NOT MIXING DOWN TO THE SURFACE

AS MUCH AS TYPICALLY OCCURS. THE CURRENT INTENSITY ESTIMATE IS 30

KT. THE ATMOSPHERIC ENVIRONMENT IS NOT IDEAL FOR STRENGTHENING

WITH SOME DRIER AIR JUST TO THE NORTH AND NORTHWEST OF THE CYCLONE.

THE OFFICIAL INTENSITY FORECAST CLOSELY FOLLOWS THE LGEM AND

INTENSITY CONSENSUS GUIDANCE. NONE OF THE CURRENT MODEL RUNS SHOW

THE SYSTEM STRENGTHENING INTO A HURRICANE.

INITIAL MOTION IS A SOUTHWARD DRIFT. STEERING CURRENTS ARE LIKELY

TO REMAIN QUITE WEAK OVER THE NEXT DAY OR SO...AS THE SYSTEM IS

SITUATED IN A WEAKNESS IN THE SUBTROPICAL RIDGE. IN A COUPLE

OF DAYS...THE MID-LEVEL RIDGE TO THE SOUTHEAST OF THE TROPICAL

CYCLONE IS FORECAST TO STRENGTHEN SLIGHTLY AND THIS...ALONG WITH A

WEAK TROUGH PASSING NORTH OF THE CYCLONE...SHOULD INDUCE A GENERAL

NORTHEASTWARD MOTION. LATER IN THE FORECAST PERIOD...THE TRACK

GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON AN EAST-NORTHEASTWARD

MOTION AT AN INCREASING FORWARD SPEED. THE OFFICIAL FORECAST IS

RATHER CLOSE TO THE MODEL CONSENSUS AND TO THE LATEST ECMWF TRACK.

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