TD 14 likely to become Maria; new Gulf of Mexico system brewing
Tropical Depression Fourteen formed yesterday from a strong tropical wave that moved off the coast of Africa early this week, and is headed west-northwest towards an encounter with the Northern Lesser Antilles Islands. Satellite loops show a large a steadily organizing system with plenty of heavy thunderstorm activity, good upper-level outflow to the north and west, and some respectable low-level spiral bands beginning to form. TD 14 is probably a tropical storm now, and is very likely to be named Tropical Storm Maria later today. Water vapor satellite images show that 95L is embedded in a very moist environment. Ocean temperatures are near 28.5°C, which is 2°C above the 26.5°C threshold usually needed to sustain a tropical storm. With wind shear predicted to remain low to moderate the next five days, the atmosphere expected to stay moist, and ocean temperatures predicted to gradually warm, TD 14 should generally show a strengthening trend. Curiously, most of the intensity forecast models show little strengthening of TD 14, so NHC is keeping their intensity forecast lower than is typical for a storm in these conditions at this time of year.
The track forecasts for TD 14 from the various models agree that the storm will affect the Northern Lesser Antilles Islands, though there are some differences in forward speed, resulting in some uncertainty whether the storm will arrive at the islands as early as Friday night, or as late as Saturday afternoon. After it passes the Lesser Antilles, TD 14 has the usual amount of high uncertainty in its 5 - 7 day track forecast. The models are split on how strong the steering influence a trough of low pressure along the U.S. East Coast will have. The ECMWF and UKMET models prefer a more southerly track for TD 14 through the Bahamas towards the U.S. East Coast, while the GFS, NOGAPS, and HWRF models predict a more northwesterly track, with a potential threat to Bermuda. It's too early to guess which track the models will eventually converge on. Climatology favors a track that would miss land, with Dr. Bob Hart's track history pages suggesting TD 14 has a 22% chance of hitting Canada, 19% chance of hitting Bermuda, and an 11% chance of hitting North Carolina.

Figure 1. Morning satellite image of TD 14.
Gulf of Mexico disturbance 96L
A cold front swept into the Gulf of Mexico off the coast of Texas behind Tropical Storm Lee on Monday, and has stalled out along a line from Tampa, Florida to Mexico's Bay of Campeche in the southern Gulf of Mexico. Heavy thunderstorms have begun to build along the tail end of this front in the Bay of Campeche, and this disturbance has been designated Invest 96L by NHC. Latest visible satellite loops do not show that 96L has a closed surface circulation yet, but buoy and surface observations along the coast of Mexico suggest that there may be a large-scale counter-clockwise circulation present over the Bay of Campeche. Sustained winds at Buoy 42055, about 100 miles to the northwest of the suspected center of 96L, were northeast at 27 mph at 6:50 am CDT this morning. Water vapor satellite loops show that here is a large area of very dry air from Texas to the north of 96L, and this dry air may interfere with 96L's development. A hurricane hunter mission is scheduled for this afternoon into 96L.
Most of the computer models develop 96L into a tropical depression in the next 1 - 2 days, and these same models did very well at anticipating the formation of Tropical Storm Lee in the Gulf of Mexico last week. Given the moderate wind shear, warm waters, and presence of an old cold front to serve as a nucleus for development, I give 96L an 80% chance of becoming a tropical depression over the next tow days, a bit higher than the 60% probability NHC is going with. Steering currents are weak in the Bay of Campeche, making for a lot of uncertainty in where 96L might go. The only model predicting a U.S. landfall is the ECMWF, which predicts 96L might hit between Louisiana and the Florida Panhandle on Monday. A more popular solution is for the storm to meander in the Bay of Campeche for many days, and eventually make landfall on the coast of Mexico between Veracruz and Tampico. None of the models is hinting at a track towards Texas, and the intense dome of high pressure associated with their record drought and heat wave will tend to discourage any tropical cyclones from making a Texas landfall over the coming seven days.
Hurricane Katia
Hurricane Katia continues to the northwest as a Category 1 hurricane with 90 mph winds. Latest satellite loops show that dry air has eaten into the southwest side of the storm. The computer models continue to agree that a low pressure system over the Eastern U.S. associated with the remnants of Tropical Storm Lee will turn Katia to the north. As the storm moves northwards past North Carolina, Katia will get caught up in west-to-east moving winds associated with the jet stream, and taken northeastwards out to sea. No land areas are in Katia's cone of uncertainty, and Katia's outer rainbands should remain just offshore from North Carolina, New England, and the Canadian Maritime provinces at the point of closest approach. Bermuda may see a few rain showers from Katia, but the storm will not cause hazardous weather there. The main impact of Katia will be a multi-day period of high surf leading to beach erosion and dangerous rip currents. The East Coast is lucky that Tropical Storm Lee came along, since Lee helped to create the steering pattern that will keep Katia from hitting the U.S.

Figure 2. GOES-13 image of Hurricane Katia and the remains of Tropical Storm Lee, taken at 11:45 am EDT Tuesday September 6, 2011. At the time, Katia was a Category 3 hurricane with 120 mph winds. Image credit: NOAA Visualization Laboratory.
Heavy rains from Lee create significant flooding, tornadoes
Tropical Storm Lee is no more, but its remnants are marching slowly northeastwards along a stalled cold front, bringing torrential rains. Fortunately, the dry soils that were present before the event started have helped keep river flooding in the minor to moderate range. No river is currently at major flood stage as a result of rains from Tropical Storm Lee. Soils are at near-average moisture levels in Central Pennsylvania, where Lee's remnants are expected to drop 3 - 5 inches of rain over the next two days. These rains should cause moderate but not major flooding in Pennsylvania. Also of concern is the potential for tornadoes today. NOAA's Storm Prediction Center (SPC) has logged 40 tornado reports over the past four days from Lee, including two in North Carolina yesterday. Most of these tornadoes have been weak EF-0 and EF-1 twisters. A tornado that hit Cana, Virginia at Sunday night ripped the roof off of a gas station and injured two people. More tornadoes are likely today over coastal Virginia, Maryland, Delaware, and Southern New Jersey, where SPC is predicting a "Slight Risk" of severe weather.
Lee's heaviest rain amounts, by state, as of 4 am CDT today:
Holden, LA: 15.43"
Waveland, MS: 14.11"
Fyffe, AL: 12.94"
Cleveland, TN: 12.22"
Rome, GA: 11.01"
Milton, FL: 10.03"
Blowing Rock, NC: 7.18"
Fancy Gap, VA: 6.77"
Cranks Creek Reservoir, KY: 5.49"
Andover, NJ: 5.06"
Montgomery, NY: 4.23"
Pittsfield, MA: 3.90"
Bluefield, WV: 3.76"
Bridge City, TX: 3.12"
Keene, NH: 3.64"
Hagerstown, MD: 3.60"
Norwalk, CT: 3.20"
Wilmington, DE: 2.63"
Woodford, VT: 2.63"
Washington, DC: 2.42"
Jeff Masters
Reader Comments
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I figure even if Nate were to go into Mexico, the deeper canadian trough should in theory recurve Maria further east
.
Grothar is back and doing well.
Welcome back Gro!
Yeah, but the center might be too broad. Of course, it was fairly broad with Lee on the first advisory.
I have ArcMap, and you cant add GIFs or animations. Maybe in ArcScene?
If memory serves, the west winds in Lee when it initially developed were very weak, 2-3 mph winds lol. We have 10 kt winds in 96L.
Can only add the static visible satellite view with obs from the NOAA site, that's it. Don't have ArcScene license
Maria is already in the Eastern Atlantic.
Now you've done it...
lol yes. Satellite imagery shows 96L is steadily becoming better organized with a good curved band south of the LLC and one developing to the west.
191700 1936N 09257W 9875 00162 //// +215 //// 269051 053 045 001 05
191730 1934N 09257W 9893 00146 //// +222 //// 269049 051 042 003 05
191800 1932N 09257W 9896 00142 //// +220 //// 269047 050 041 006 01
But that countermands several of the earlier guidance models.
Will have to see as it builds, but i think the guidance models taking it north, at least initially are proving to be correct.
Link
Time: 19:17:00Z
Coordinates: 19.6N 92.95W
Acft. Static Air Press: 987.5 mb (~ 29.16 inHg)
Acft. Geopotential Hgt: 162 meters (~ 531 feet)
Extrap. Sfc. Press: -
D-value: -
Flt. Lvl. Wind (30s): From 269 at 51 knots (From the W at ~ 58.6 mph)
Air Temp: 21.5C* (~ 70.7F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 53 knots (~ 60.9 mph)
SFMR Peak (10s) Sfc. Wind: 45 knots* (~ 51.7 mph*)
SFMR Rain Rate: 1 mm/hr* (~ 0.04 in/hr*)
(*) Denotes suspect data
7:29 PM GMT en Septiembre 07, 2011
Jeff Masters
EMILY too ....
As for Maria, her 20 knot forward speed might be the reason why the models are hesitant on intensifying her too quickly.
AL, 15, 2011090718, , BEST, 0, 202N, 925W, 40, 1004, TS, 34, NEQ, 0, 0, 75, 60, 1009, 150, 45, 0, 0, L, 0, , 0, 0, NATE, M,
And they're coming from the west???? Gosh! Strongest west winds I have seen!
Well here we go LOL
Might go straight to a 50mph Nate.45mph:
AL, 15, 2011090718, , BEST, 0, 202N, 925W, 40, 1004, TS,
Link
Yup, cat's out of the bag now!
Thank you Dr. Masters!
at last 96L gets its turn
Yeah, but the big Lone star himself is too stubborn to give y'all any rain, and plus we need to blame the people who threw the cigarettes out for all that dry air in the GOM.
We knew it would happen in that location...crazy.
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