Dr. Jeff Masters' WunderBlog

Invest 91L reorganizing; The heat is on (again)
Posted by: Dr. Jeff Masters, 4:16 PM GMT en Agosto 01, 2011 +21
Invest 91L, which is located near 14°N, 57°W, is showing signs of reorganization after a pretty rough weekend. On Saturday, the wave looked ripe to develop with organized convection and the hint of a surface circulation. On Sunday a Hurricane Hunter and NOAA G9 flew into the system only to find it disorganized and negatively influenced by the burst of convection that sprouted on its western edge. Since then, low-level circulation has at least strengthened, if not consolidated, and residents of the Lesser Antilles should be prepared for tropical storm advisories to be posted on short notice. Satellite loops show decent thunderstorm activity and some mid-level circulation, and continued bursts of thunderstorms to the southwest of the invest region. The wave is surrounded by moderately strong wind shear (30-40 knots) on both the north and the south sides, which could delay development. Also, a large mass of dry, Saharan air continues to linger to 91L's north. In a mission this morning, Hurricane Hunters found winds close to tropical storm strength, but no signs of a closed surface circulation—just plenty of winds from the east or southeast. The next mission is scheduled for 2pm EDT, and they will continue every six hours if the system remains a threat.


Figure 1. Visible satellite of Invest 91L at 10:30am EDT as it moves west toward the Lesser Antilles.

Forecast For 91L
Development will probably occur in the next day or two, and the National Hurricane Center is giving the wave a 90% chance in the next 48 hours. The question now is where will it go, and how long will it remain a tropical cyclone. Models are split today, although still leaning toward an Atlantic recurving solution. In the camp of a Gulf of Mexico track are the CMC and the UKMET models. The GFS and the ECMWF are still in favor of the system tracking northwest toward Florida (and coming close) before taking a turn to the northeast. The NOGAPS model is resolving a Florida landfall in this morning's run, and the HWRF hints that it might like that solution, as well, at the end of its run. The GFDL remains conservative and forecasts that the system will turn north and northeast well before making any connection with the U.S. coast. It is notable that although there is still much disagreement on where this system will go, the models have been trending west in their tracks over the past few days. However, it is extremely difficult to nail down a track before a cyclone has even developed. Something we know for sure is that 91L is a threat to the Lesser Antilles and the Caribbean islands including Puerto Rico, Hispaniola, and the Bahamas.

In terms of intensity, both the GFDL and the HWRF are thinking this will eventually get to hurricane strength once it develops, although neither are forecasting it to become stronger than a category 1. SHIPS (which tracks 91L into the far eastern Gulf of Mexico) brings the system up to a category 1 hurricane, and the LGEM does as well, but is slower in its intensification. General consensus this morning is that 91L will max out somewhere between a moderate tropical cyclone and a moderate category 1 hurricane. Again, this is something that is difficult to predict before development itself occurs.

The Heat Is On (Again)

Someone turned the furnace on again in the central U.S., although many would argue that it was never actually turned off after the last heat wave. Heat advisories have been issued from southern Louisiana to North Dakota. Temperatures are expected to climb to 115°F in the central Plains through Wednesday, and heat index values will soar again. Oklahoma has now seen over a month of high temperatures hitting at least 100°. Some reprieve could come later this week.


Figure 2. Weather advisories issued by the National Weather Service. Heat-related advisories are pink.

Angela
Categories: Heat Hurricane
  Permalink | A A A
Reader Comments
Display: 0, 50, 100, 200 Sort: Newest First - Order Posted
Viewing: 1701 - 1751

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53Blog Index

1701. MississippiWx 10:12 PM GMT en Agosto 01, 2011    
Shear should begin to lessen over 91L tonight with the development of a pretty strong upper level anticyclone. I would imagine that the low will stay heavily weighted to the east, however, because of the speed it is moving. We may not see much shear show up in the CIMSS maps, but speed shear will probably effect it somewhat until the trades slow down.

Member Since: Julio 15, 2006 Posts: 14 Comments: 8925
1703. Torgen 10:13 PM GMT en Agosto 01, 2011    
Try as I might, all I see with these loops is 91L getting a circulation going for half the series, then spazzing out. I just can't see what everyone else is seeing. :(
Member Since: Junio 3, 2010 Posts: 0 Comments: 321
1704. Seflhurricane 10:13 PM GMT en Agosto 01, 2011    
Quoting wunderkidcayman:
why is the HH going that far south near St Lucia
there were west winds all the way down there, so i imagine the NHC wants a complete sample of the whole area
Member Since: Julio 14, 2009 Posts: 0 Comments: 2910
1705. ackee 10:13 PM GMT en Agosto 01, 2011    
what do u make NHC percent when 91L was at 100 or 90 it did not devlop not its been down to 80 it devlop into EMILY
Member Since: Julio 15, 2008 Posts: 0 Comments: 1196
1706. weatherguy03 10:13 PM GMT en Agosto 01, 2011    
Quoting beell:


True enough. Would not have bet you 50 cents on that area this morning!



Yesterday morning I thought we would see Emily by the end of the day. This morning I said no..LOL
Member Since: Julio 5, 2005 Posts: 581 Comments: 29681
1708. FLWeatherFreak91 10:13 PM GMT en Agosto 01, 2011    
.
Member Since: Diciembre 1, 2006 Posts: 2 Comments: 3516
1709. IceCoast 10:13 PM GMT en Agosto 01, 2011    
96 Hrs GFS
Member Since: Octubre 17, 2010 Posts: 0 Comments: 1260
1710. chevycanes 10:13 PM GMT en Agosto 01, 2011    
gfs well east of FL this time.

Member Since: Agosto 6, 2007 Posts: 0 Comments: 687
1712. RitaEvac 10:14 PM GMT en Agosto 01, 2011    
GFS should be thrown out
Member Since: Julio 14, 2008 Posts: 1 Comments: 8953
1713. weatherguy03 10:14 PM GMT en Agosto 01, 2011    
Quoting scott39:
When is the trough forecasted to pull 91L N... if it does?



Good question. If Emily ramps up quickly we could see it turn NW near the D.R.. If it stays weak(TS 40 to 50mph this turn may not occur until it gets closer to Haiti or Cuba.
Member Since: Julio 5, 2005 Posts: 581 Comments: 29681
1714. stormpetrol 10:14 PM GMT en Agosto 01, 2011    
Quoting ackee:
what do u make NHC percent when 91L was at 100 or 90 it did not devlop not its been down to 80 it devlop into EMILY

That's why they always say "unpredictable as the weather"
Member Since: Abril 29, 2007 Posts: 0 Comments: 6498
1715. FLWeatherFreak91 10:14 PM GMT en Agosto 01, 2011    
Quoting RitaEvac:
GFS should be thrown out
Why is that?
Member Since: Diciembre 1, 2006 Posts: 2 Comments: 3516
1717. scott39 10:14 PM GMT en Agosto 01, 2011    
There is a no posting of models ban for 1 hour!
Member Since: Junio 13, 2009 Posts: 0 Comments: 6221
1718. CybrTeddy 10:15 PM GMT en Agosto 01, 2011    
Member Since: Julio 8, 2005 Posts: 255 Comments: 20658
1719. barbamz 10:15 PM GMT en Agosto 01, 2011    
Second COC? Or did the other one move to the southeast in the meantime?

Time: 22:01:00Z
Coordinates: 13.65N 61.35W
Acft. Static Air Press: 976.4 mb (~ 28.83 inHg)
Acft. Geopotential Hgt: 276 meters (~ 906 feet)
Extrap. Sfc. Press: 1007.5 mb (~ 29.75 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 192° at 2 knots (From the SSW at ~ 2.3 mph)
Air Temp: 24.1°C (~ 75.4°F)
Dew Pt: 22.2°C (~ 72.0°F)
Peak (10s) Flt. Lvl. Wind: 4 knots (~ 4.6 mph)
SFMR Peak (10s) Sfc. Wind: 22 knots* (~ 25.3 mph*)
SFMR Rain Rate: 1 mm/hr* (~ 0.04 in/hr*)
Member Since: Octubre 25, 2008 Posts: 25 Comments: 1908
1720. weatherguy03 10:15 PM GMT en Agosto 01, 2011    
Quoting MeterologyStudent56:
1590. weatherguy03 9:54 PM GMT on August 01, 2011

Do you still think this will affect Florida?


Million dollar question!..LOL I can say this much right now, its gonna come close! I have said that all along.
Member Since: Julio 5, 2005 Posts: 581 Comments: 29681
1722. HuracanTaino 10:15 PM GMT en Agosto 01, 2011    
Quoting cat5hurricane:
18Z GFS developing and taking 91L a little further to the north over Hispaniola this time around...
Hortense did something like that on Sept.10,1996, I believe, made landfall on SW PR, and headed NW towards the valleys of Punta Cana, very flat terrain there towards the NW.
Member Since: Mayo 31, 2011 Posts: 0 Comments: 536
1723. chevycanes 10:15 PM GMT en Agosto 01, 2011    
Quoting FLWeatherFreak91:
Why is that?

because he's been saying its going to TX.
Member Since: Agosto 6, 2007 Posts: 0 Comments: 687
1724. beell 10:15 PM GMT en Agosto 01, 2011    
Quoting scott39:
Love your art work!! LOL


Artwork compliments of a friend. I'll pass it on. Thanks.
Member Since: Septiembre 11, 2007 Posts: 126 Comments: 13072
1725. Grothar 10:15 PM GMT en Agosto 01, 2011    
Blob behind 91L

Member Since: Julio 17, 2009 Posts: 58 Comments: 19682
1728. HurricaneSwirl 10:16 PM GMT en Agosto 01, 2011    
58 of the last 60 obs have had a westerly component in them.
Member Since: Julio 7, 2008 Posts: 2 Comments: 3237
1732. RitaEvac 10:16 PM GMT en Agosto 01, 2011    
Quoting FLWeatherFreak91:
Why is that?


It's basing on an entity that has yet to materialize into a well defined system
Member Since: Julio 14, 2008 Posts: 1 Comments: 8953
1735. chevycanes 10:17 PM GMT en Agosto 01, 2011    
Quoting barbamz:
Second COC? Or did the other one move to the southeast in the meantime?

Time: 22:01:00Z
Coordinates: 13.65N 61.35W
Acft. Static Air Press: 976.4 mb (~ 28.83 inHg)
Acft. Geopotential Hgt: 276 meters (~ 906 feet)
Extrap. Sfc. Press: 1007.5 mb (~ 29.75 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 192° at 2 knots (From the SSW at ~ 2.3 mph)
Air Temp: 24.1°C (~ 75.4°F)
Dew Pt: 22.2°C (~ 72.0°F)
Peak (10s) Flt. Lvl. Wind: 4 knots (~ 4.6 mph)
SFMR Peak (10s) Sfc. Wind: 22 knots* (~ 25.3 mph*)
SFMR Rain Rate: 1 mm/hr* (~ 0.04 in/hr*)

they should have a SSW wind there if it has a good LLC around 15.3
Member Since: Agosto 6, 2007 Posts: 0 Comments: 687
1736. Bubu77 10:17 PM GMT en Agosto 01, 2011    
Ca commence a se dégrader très très nettement chez moi en Martinique !!
On est en alerte orange pour risque d'inondations

Entre 100 et 150 mm de précipitation Prévue !!

Member Since: Mayo 6, 2009 Posts: 0 Comments: 11
1738. FLWeatherFreak91 10:18 PM GMT en Agosto 01, 2011    
Quoting RitaEvac:


It's basing on an entity that has yet to materialize into a well defined system
But you were all over the models from earlier today trending westward... why is this run any less credible to you?
Member Since: Diciembre 1, 2006 Posts: 2 Comments: 3516
1741. TomTaylor 10:18 PM GMT en Agosto 01, 2011    
Recon's checking out our other circulation to the SW


Member Since: Agosto 24, 2010 Posts: 18 Comments: 4053
1742. SLU 10:18 PM GMT en Agosto 01, 2011    
YAYYYY! the radar is back up Link

Meanwhile gusts to 37mph in Dominica
Member Since: Julio 13, 2006 Posts: 11 Comments: 3058
1743. HurricaneSwirl 10:18 PM GMT en Agosto 01, 2011    
Yeah.. when the GFS forecasts a FL strike it's accurate and should be believed, but when it forecasts a recurvature it should be immediately thrown out and disregarded.. There is some unconscious wishcasting going on here.
Member Since: Julio 7, 2008 Posts: 2 Comments: 3237
1744. seflagamma 10:18 PM GMT en Agosto 01, 2011    
Quoting tiggeriffic:


hey gamma...OMG...the blog is unreal tonight


Hey, I know, when we really need to be here to get good information have to wade thru the junk.

But I am drawn to this blog when there is a system out there like a Moth to a flame! LOL

Pass the popcorn because if it is upgraded to a TS and the models get updated.. going to get crazy!


Aqua! LOL Love #1866!

Quoting aquak9:
Member Since: Agosto 29, 2005 Posts: 287 Comments: 40512
1745. Autistic2 10:18 PM GMT en Agosto 01, 2011    
Ok.
Me don’t understand,
We had 20% then 30% then 50% then 90% then 100% then 100% then 90% now 80%.

Is this thing falling apart?

Did Levi post another video?

Will something entirely different spin up to become Emily?

Is there a law that reads something like If the NHC calls it 100% for two or more TWU and it does not develop then it will never will? Sort of a reverse take off of those two 350 mile boxes?
Member Since: Agosto 29, 2008 Posts: 0 Comments: 307
1746. Seflhurricane 10:18 PM GMT en Agosto 01, 2011    
reviewing all the HH info so far they can upgrade at anytime all the winds and directions confirm a closed circulation and TS force winds are near dominica and to its NE so buckle down and get ready for real bad weather shortly
Member Since: Julio 14, 2009 Posts: 0 Comments: 2910
1749. JupiterFL 10:18 PM GMT en Agosto 01, 2011    
Quoting aquak9:


Don't pull other people's quotes from other people's websites and claim them as your own!!!


Keep em in check Aquak9!
Member Since: Agosto 10, 2005 Posts: 0 Comments: 2146

Viewing: 1701 - 1751

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53Blog Index

New Comment
Community Standards Policy Comments will take a few seconds to appear.
Post Your Comments
Please sign in to post comments.
Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.
About JeffMasters
Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather
Clear
48 ° F
Despejado
Community Activity