ATL: BRET - Remnants - Discussion

[AdamFirst]

[ronjon]

Really beginning to wrap up now on VIS SAT. Movement appears nil at the moment. Probably a TD by later this afternoon. Where to? Climatology suggests NE or N-NE out to sea. Steering winds extremely weak. Models diverge on W-SW motion across S FL or staying offshore. None of this mornings global models initialized the system well.

http://weather.rap.ucar.edu/satellite/displaySat.php?region=TPA&itype=vis&size=large&endDate=20100612&endTime=-1&duration=3

[Aric Dunn]

Latest shear analysis has 10kts or less over the system.. so shear is not as big of a factor now..

[jinftl]

To the untrained eye, it does appear that some fanning of the cloud patten is being to take place - isn't that usually a sign that conditions are becoming more favorable for development (i.e., shear is lessening)? This appears to be the case on the southern half of the system in particular.

[wxman57]

With the exception of the two worst tropical models (NAM and NOGAPS), 12Z models are unanimous in taking the system slowly southward for a day or two then off to the NNE-NE. If it does develop further, then it may be less likely that it crosses Florida into the Gulf.

[Hybridstorm_November2001]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org For Official Information please refer to the NHC and NWS products.

This puppy is looking good the past few hours. If the tend continues we might have a depression on our hands by late tonight or early tomorrow. It certainly has my interesting going forward.

[abacorun]

Not much wind just solid overcast, a lot of thunder and occasional rain, not heavy, in Marsh Harbour, Abaco. I guess we will see more later.

[gatorcane]

With the exception of the two worst tropical models (NAM and NOGAPS), 12Z models are unanimous in taking the system slowly southward for a day or two then off to the NNE-NE. If it does develop further, then it may be less likely that it crosses Florida into the Gulf.

The 12Z NAM looks to move it slowly NNE as well though over a 5-day period. Seems it keeps it around a bit too long maybe. Yesterday the BAMs were showing a path WSW and West into the Gulf.

But as you said, the more quickly it deepens means the more quickly it should feel the weakness off to the north-northeast of it and gradually get pulled out to sea.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

I will lean more with the N/NE solution at this time and probably will not move over Florida and get into the GOM (thankfully).

[cycloneye]

Officially,this afternoon's mission is going ahead. Here is today's TCPOD.

Code: Select all

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1215 PM EDT SUN 17 JULY 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
         VALID 18/1100Z TO 19/1100Z JULY 2011
         TCPOD NUMBER.....11-047

I.  ATLANTIC REQUIREMENTS
    1. SUSPECT AREA
       FLIGHT ONE -- TEAL 72
       A. 18/1800Z
       B. AFXXX 0302A CYCLONE
       C. 18/1500Z
       D. 28.0N 79.5W
       E. 18/1700Z TO 18/2300Z
       F. SFC TO 10,000 FT

       FLIGHT TWO -- TEAL 73
       A. 19/0600Z
       B. AFXXX 0402A CYCLONE
       C. 19/0300Z
       D. 28.5N 79.5W
       E. 19/0500Z TO 19/1100Z
       F. SFC TO 10,000 FT

    2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 12-HRLY
       FIXES WHILE SYSTEM REMAINS A THREAT.
    3. REMARK: FLIGHT SCHEDULED FOR 18/1800Z WILL CONVERT TO AN
         LOW-LEVEL INVEST MISSION IF THE FLIGHT SCHEDULED FOR
17/0600Z         IS CANCELLED.



http://www.nhc.noaa.gov/text/MIAREPRPD.shtml?

[northjaxpro]

To the untrained eye, it does appear that some fanning of the cloud patten is being to take place - isn't that usually a sign that conditions are becoming more favorable for development (i.e., shear is lessening)? This appears to be the case on the southern half of the system in particular.

I agree jinftl. The "fanning" of the upper level cloud pattern indicates that 98L is ventilating and the upper level environment is beginning to get more conducive for 98L to organize into a tropical cyclone. It is improving more and more with time.

[jinftl]

Update this morning from Dr. Jeff Masters - he is thinking more like a 50% chance of development at this time...

A tropical disturbance (Invest 98L) has formed off the east coast of Florida, along the tail end of a cold front that pushed off the coast late last week. This disturbance has the potential to develop into a tropical depression that will bring heavy rains to the northern Bahamas and east coast of Florida today through Tuesday. Satellite imagery shows that the disturbance has become more organized this morning, with an expanding area of intense thunderstorms, the beginnings of a surface circulation, and upper-level outflow on the east and north sides of the storm. Some rotation of 98L is also evident on long-range radar out of Melbourne, Florida, but the rain showers are poorly organized and there is little evidence of low-level spiral banding. Wind shear is a moderate 10 - 20 knots, and sea surface temperatures are 27 - 28°C, which is plenty warm enough to support a tropical storm. There is dry, continental air over North Florida, and upper level winds out of the northwest are driving this dry air into the center of 98L, retarding development.


Forecast for 98L
The models are shy about developing 98L; only the HWRF model shows a tropical depression developing. The SHIPS model predicts that wind shear will be in the low to moderate range, 5 - 15 knots, over the next five days. NHC is giving 98L a 30% chance of developing into a tropical depression by Wednesday. Given the recent satellite and radar presentation of the storm, I'd put those odds higher, at 50%. A hurricane hunter aircraft is scheduled to investigate 98L this afternoon.

Steering currents are weak off the coast of Florida, and 98L can be expected to move slowly at less than 5 mph over the next two days. The HWRF and GFDL models predict 98L will execute a clockwise loop, heading towards the coast of Florida on Monday, then looping northeastwards towards South Carolina later in the week. The track of 98L will depend strongly on how intense the storm gets; a weak system is likely to stay farther to the south, while a stronger system will "feel" upper level winds with a west-to-east component, and tend to move to the northeast, parallel to the coast.
http://www.wunderground.com/blog/JeffMa ... rynum=1847

[shortwave]

bit confused on the weakness..to the north. only seeing 1025mb highs .. anyone have an in-depth map?

[gatorcane]

Only thing to watch is the big 500MB ridge currently in the center of the United States. That ridge is bringing the big heat wave that we are hearing about.

That looks like it is sliding to the east. I wonder if 98L meanders enought it will get blocked as the ridge shifts over to the MidAtlantic. Thoughts?

WV loop:
http://www.ssd.noaa.gov/goes/east/eaus/loop-wv.html

500MB heights from 06Z GFS:

[cycloneye]

Product: Air Force Tropical RECCO Message (URNT11 KNHC)
Transmitted: 17th day of the month at 16:37Z
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
Observation Number: 01

Observation Time: Sunday, 16:30Z
Radar Capability: Yes
Aircraft Altitude: Below 10,000 meters
Coordinates: 28.7N 88.1W
Location: 132 miles (212 km) to the SSE (153°) from Gulfport, MS, USA.
Turbulence: None
Conditions Along Flight Route: In the clear
Pressure Altitude: 7,310 meters
Flight Level Wind: From 80° at 15 knots (From the E at ~ 17.2 mph)
- The above is a spot wind.
- Winds were obtained using doppler radar or inertial systems.
Flight Level Temperature: -17°C
Flight Level Dew Point: -18°C
Weather (within 30 nautical miles): Overcast / Undercast
400 mb Surface Altitude: 7,630 geopotential meters

[Aric Dunn]

Only thing to watch is the big 500MB ridge currently in the center of the United States. That ridge is bringing the big heat wave that we are hearing about.

That looks like it is sliding to the east. I wonder if 98L meanders enought it will get blocked as the ridge shifts over to the MidAtlantic. Thoughts?

WV loop:
http://www.ssd.noaa.gov/goes/east/eaus/loop-wv.html

That is for sure a possibility... especially if it keeps sliding southerly over the next 24 hours.. it would then get shoved into FL

[senorpepr]

You can get recon notifications as they come in by following @storm2k_recon on Twitter.

[Ivanhater]

It's a tough call with it being stuck in between the upper air features. The further south and west it moves in the short term could have big track implications in the long term....this is an interesting one

[mvtrucking]

Didn't Katrina come out of this general area?

[gatorcane]

Here we are 5 days from now. The 06Z GFS actually keeps the ridge centered over the central U.S. and does not move it eastward right away.

It actually weakens by days 3-5 and slides east but is still there (over the Carolinas), flow becomes zonal across the CONUS.

[plasticup]

Didn't Katrina come out of this general area?

Eh, kinda. Katrina passed a little south of where 98L is now, but coming from the southeast not the northwest. Not a lot of similarities here.