Tropical Depression Fifteen forms in the Caribbean
Tropical Depression Fifteen is here, and is destined to become Tropical Storm Matthew by late this afternoon or this evening. An Air Force hurricane hunter aircraft left the storm near 2pm EDT this afternoon, and on their final pass through the strong northeast quadrant of the storm, found a substantial area of surface winds of 40 - 45 mph with their SFMR instrument. Top flight level winds at 500 feet were 48 mph. These winds support upgrading TD 15 to Tropical Storm Matthew. Satellite loops show that TD 15's heavy thunderstorm activity continues to increase in intensity and areal coverage, with several respectable low-level spiral bands in evidence. There is some dry air to the northwest of TD 15, but it is currently not significantly affecting development.
Figure 1. TD 15 at 11:50am EDT 9/23/10, as seen by NASA's Terra satellite.
Forecast for TD 15
An upper-level high pressure system lies to the west of TD 15, near the coast of Nicaragua. The clockwise flow of air around this high will bring a moderate 10 - 20 knots of wind shear over TD 15 today and Friday. There is some dry continental air lying to the northwest of TD 15, and this shear may be able to drive dry air into the storm, slowing intensification and keeping TD 15 below hurricane strength through Saturday morning. By Saturday afternoon, TD 15 will move more underneath this upper-level high, causing the shear to decline. The SHIPS model forecasts that shear will fall to the low range, 5 - 10 knots, Saturday through Monday. This drop in shear should allow for intensification of TD 15 into a hurricane, if the center stays more than 50 miles offshore.
The future track and intensity of TD 15 depends critically upon the storm's interaction with land over the coming days. If TD 15 misses making landfall in Nicaragua and Honduras, and instead skirts the north coast of Honduras, the storm is likely to intensify into a hurricane by Sunday, as indicated in the official NHC forecast. However, if TD 15 spends significant time over or barely offshore of Honduras, the storm will likely stay below hurricane strength. TD 15 is being forced just north of due west by a strong ridge of high pressure. This ridge will keep the storm moving at 15 mph through Saturday. On Sunday, a trough of low pressure diving southwards over the Eastern U.S. will weaken the steering currents over the Western Caribbean and cause TD 15 to slow and turn more to the north. TD 15 will begin a period of slow and erratic movement on Sunday that may last many days, as the storm wanders in the Western Caribbean and over Belize, Honduras, and Mexico's Yucatan Peninsula. If the center of TD 15 spends significant time over water, the storm could easily develop into powerful and dangerous Hurricane Matthew. If the center remains mostly over land, TD 15 will still generate extremely heavy rains over Central America, but remain below hurricane strength. By late next week, the trough of low pressure over the Eastern U.S. may lift out, allowing a ridge of high pressure to build in and force TD 15 westwards across the Yucatan Peninsula and into the Gulf of Mexico's Bay of Campeche. Alternatively, the trough of low pressure over the Eastern U.S. may amplify, drawing TD 15 northwards across Western Cuba and into Florida. A complicating factor may be the development of a new tropical depression in the Central Caribbean 6 - 8 days from now, as predicted by both the GFS and NOGAPS models with their latest 12Z (8am EDT) runs. The uncertainties in the long-range fate of TD 15 are high, and depend strongly on slight variations in its track that determine how much time the storm spends over land. One thing that is virtually certain is that TD 15 will generate very heavy rains over Nicaragua, Honduras, Belize, and Mexico's Yucatan Peninsula Friday through Tuesday that will cause dangerous flooding rains and life-threatening mudslides.
Tropical Depression Lisa
Tropical Depression Lisa continues to churn the waters of the far Eastern Atlantic. By Saturday night, upper level winds out of the west are expected to increase, bringing high wind shear of 20 - 45 knots over Lisa. The high shear may be capable of destroying the storm by early next week. It appears unlikely that Lisa will affect any land areas.
Elsewhere in the tropics
The remnants of Hurricane Julia are still spinning over the far Eastern Atlantic, and are generating some sporadic heavy thunderstorm to the north of the center of circulation. Julia's remains are being given a 10% chance of re-developing by NHC.
Hurricane Karl's moisture causing flooding in Minnesota, Wisconsin
A plume of very moist air associated with what was Hurricane Karl last week has surged northwards over the Central U.S. over the past two days. This moisture is now being lifted over a warm front draped over Minnesota and Wisconsin, and has generated flooding rains in excess of six inches in southern Minnesota this afternoon. Flood warnings and flood watches are posted for a wide swath of the upper Midwest today, including most of southern Minnesota, northern Wisconsin, and Michigan's Upper Peninsula. These types of rain events are called Predecessor Rain Events (PREs), because they typically precede the actual arrival of the rain shield of a tropical storm.
Figure 2. Radar estimated rainfall over Minnesota.
Next post
I'll have an update on TD 15 Friday morning.
Jeff Masters
Neighbors help a driver to move his vehicle from the flood waters
Reader Comments
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nice
We’ve been following a tropical wave across the Atlantic for the past week. This wave, which we have identified as Tropical Disturbance 51, is now located in the eastern Caribbean Sea. On a side note, this wave appears to be the same one which spawned Hurricane Igor last week. Sometimes tropical waves can spawn several storms. Tropical Disturbance 51 appears to be getting better organized by the hour. A reconnaissance plane is scheduled to investigate it on Wednesday. I’m not sure if it will be strong enough to get upgraded to a tropical depression by then, but I think it may well be a depression or even a tropical storm by Thursday afternoon.
Although there was considerable disagreement among the various global models (U.S, Canadian and European) over the weekend as far as the potential track of the system, these models are coming into better agreement today. Such model agreement gives a forecaster more confidence in his or her forecast, but model agreement does not mean that the models are correct. In this case, the models indicate a general west to west-northwest track, taking the center near eastern Honduras on Saturday then northwestward toward the eastern Yucatan Peninsula on Sunday. That’s where the major uncertainty begins.
All of today’s runs bring the center near the eastern Yucatan Peninsula north of Belize on Sunday then move it very slowly northward for the next 2-3 days. By Wednesday, a cold front moving southward across the northern Gulf could pick up the storm and take it northeastward, possibly toward the Florida Peninsula, though the American model takes it across Cuba and south of the Florida Peninsula.
Where will it really go? That’s something I’m not at all sure of - yet. Any time steering currents get so weak such that a storm stalls makes for a very difficult forecast. The forecast track and setup sort of reminds me of Wilma in 2005. Wilma formed in the south-central Caribbean and tracked toward the northeast Yucatan Peninsula where it stalled for several days before being picked up by an approaching front and accelerating off to the northeast across south Florida. But the forecast also reminds me of another quite major hurricane from 1998 - Hurricane Mitch.
Initially, Mitch was forecast to get picked up by an approaching front and track northward into the Gulf. However, the front turned out being too weak and Mitch tracked westward into Nicaragua where it killed 10,000-20,000 people due to torrential rains. For now, my vote would be for the Wilma scenario, with a possible threat to Florida toward the middle to end of next week. That’s a long way out, though, to have much confidence.
One thing that does appear to be likely is that any storm moving into the northwest Caribbean will encounter extremely high oceanic heat content. The northwestern Caribbean Sea is dominated by a pocket of very warm water that is also quite deep. There is plenty enough energy there to support a Category 5 hurricane, not that any of the models is currently forecasting such intensity. But if the storm develops and stays over water, I think that there is certainly the potential that it could become a large and quite powerful Category 4-5 hurricane in the northwest Caribbean this weekend or early next week.
Beyond next week, I’m seeing signals which indicate additional development across the Caribbean Sea as we move into October. I don’t think that the 2010 hurricane season is going to be winding down until late October or November.
by Chris Hebert
Gonna make me do that calculation? ;)
He is hauling, though, for sure.
I agree that intensification should be slow over the next day or so.
My main thing right now is that land interaction. IMO, it is currently the most crucial aspect of the forecast, atm. And it's 50/50 at best, imo, whether there are any significant affects on Matthew.
Then explain how a miilion plus fish died lately with conexant blisters on them. The Gov will downplay this until some children get sick and die from eating seafood, Look at Valdez oil spill data, its all the same.
Mostly from lack of oxygen due to freshwater intrusion from the river. The dispersant you're refering too was called "corexit". not "conextant".
plenty of good REAL info out there, not hard to find either.
(More for us keith!)
The fish kills were due to the dead zones in the GOM that have been there for years. It has nothing to do with the oil spill. Those dead zones some 7000 miles worth have been caused by decades of chemicals from up north being dumped into the Mississippi River from industry and farming. Less than 1% of the seafood imported to the US is ever tested. Tens of thousands of tests have been run on the GOM seafood, you are safer eating that then anything imported from a foreign country.
Precisely my point.
You don't think those winds are from Matthew?
LOL
We need a poof-reader in here. Fix the Tropical Disturbance 51 thing too.
I agree that the winds at the buoy are associated with the wind field of Mathew, I just don't think it is likely to blow up into a cane overnight.
http://www.newscientist.com/blogs/shortsharpscience/2010/09/huge-fish-kill-a-common-sight.html
Can you post the steering maps? Or let me know where i can get htem .
Way. At least a week.
I don't think it can either... I think this is going to be like everything else in this area and the GOM this year.... its gonna be huge. Maybe not really strong unless it has lots of time... but physically HUGE.
I totally agree, if you really want to scare yourself check out the contaminants that come in our food from other countries and how little our country regulates and checks it.
Won't "sling" anything, I don't think.
Would disperse more, which would be a good thing, letting nature take its course. Not a big fan of the chemical method of doing that.
I expect strengthening too, but it just doesn't look organized enough to make the jump past the 64 kt threshold tonight:
If it is we have a miniature cane on our hands shortly
And, I stand by my assertion that it has never undergone as much scrutiny as it's getting now.
You guys do realize that there are natural crude seeps out there, too, right?
Great post XCOOL!!
+++
Evening SJ.
That would be the one. Sheared a bit tonight, that microwave pass shows it nicely, thanks for that.
even if Gulf shrimp are every bit as polluted as some say....and I'm not sayin' they are...but even if they are.....it's minute compared to the crap in foreign shrimp....look for 'Wild American Shrimp' on menus, etx.
WTNT25 KNHC 240248
TCMAT5
TROPICAL STORM MATTHEW FORECAST/ADVISORY NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL152010
0300 UTC FRI SEP 24 2010
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...
THE GOVERNMENTS OF NICARAGUA AND HONDURAS HAVE CHANGED THE TROPICAL
STORM WARNING TO A HURRICANE WARNING FROM PUERTO CABEZAS NICARAGUA
TO LIMON HONDURAS.
THE GOVERNMENT OF HONDURAS HAS ISSUED A TROPICAL STORM WARNING FROM
WEST OF LIMON WESTWARD TO THE GUATEMALA BORDER.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT...
A HURRICANE WARNING IS IN EFFECT FOR...
* PUERTO CABEZAS NICARAGUA TO LIMON HONDURAS...INCLUDING THE
OFFSHORE ISLANDS
A TROPICAL STORM WARNING IS IN EFFECT FOR...
* LIMON HONDURAS WESTWARD TO THE GUATEMALA BORDER
WATCHES OR WARNINGS COULD BE REQUIRED FOR THE COASTS OF
GUATEMALA AND BELIZE ON FRIDAY.
A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED
SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN 24 TO 36
HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED
TO COMPLETION.
A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.
TROPICAL STORM CENTER LOCATED NEAR 14.0N 78.4W AT 24/0300Z
POSITION ACCURATE WITHIN 25 NM
PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 15 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 40NE 0SE 0SW 40NW.
12 FT SEAS.. 30NE 0SE 0SW 30NW.
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 14.0N 78.4W AT 24/0300Z
AT 24/0000Z CENTER WAS LOCATED NEAR 13.9N 77.7W
FORECAST VALID 24/1200Z 14.5N 80.5W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 0SE 0SW 20NW.
34 KT... 50NE 25SE 25SW 50NW.
FORECAST VALID 25/0000Z 15.1N 82.9W
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 25NE 10SE 0SW 25NW.
34 KT... 70NE 50SE 45SW 70NW.
FORECAST VALID 25/1200Z 15.9N 85.1W...INLAND
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 25SE 0SW 25NW.
34 KT... 75NE 50SE 30SW 75NW.
FORECAST VALID 26/0000Z 16.6N 87.1W...OVER WATER
MAX WIND 65 KT...GUSTS 80 KT.
50 KT... 30NE 25SE 0SW 25NW.
34 KT... 75NE 50SE 30SW 75NW.
FORECAST VALID 27/0000Z 17.9N 89.2W...INLAND
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 20SE 0SW 0NW.
34 KT... 75NE 60SE 30SW 45NW.
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 200 NM
ON DAY 4 AND 250 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY
OUTLOOK VALID 28/0000Z 18.5N 89.5W...INLAND
MAX WIND 40 KT...GUSTS 50 KT.
OUTLOOK VALID 29/0000Z 19.0N 89.5W...INLAND
MAX WIND 35 KT...GUSTS 45 KT.
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 14.0N 78.4W
NEXT ADVISORY AT 24/0900Z
$$
FORECASTER BROWN
Julia - NFI Model...
Lisa - Appears well organized... but still on the NFI Model (with friends coming off of Africa)
Matthew - Track is still questionable as well as landfall. Intensity is no longer in the OMG range, but it does look like the rainfall will be measured in FEET not inches.
AOI
TS BUSTED FORECAST ALIBI
Viewing: 1751 - 1801
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