African tropical wave 99L slowly organizing
A tropical wave (Invest 99L) near 9°N 41°W, halfway between the Lesser Antilles Islands and the coast of Africa, has the potential to develop into a tropical depression later this week as it moves westward at 10 - 15 mph. Visible satellite loops show that the disturbance now has a moderate amount of poorly-organized heavy thunderstorms that continue to slowly increase in intensity and areal coverage. There is no surface circulation, but some counter-clockwise rotation of the large-scale cloud pattern is evident. Water vapor satellite loops show that 99L has a reasonably moist environment. The latest Saharan air layer analysis shows that the dry air from the Sahara lies to the north of 99L and is currently not affecting the storm. WInd shear over the disturbance is a light 5 - 10 knots, and ocean temperatures are 28°C, (82°F) which is well above the 26.5°C (80°F) threshold typically needed to allow formation of a tropical depression.
Figure 1. Morning satellite image of Invest 99L.
Forecast for 99L
Wind shear is expected to remain light through Friday, and ocean temperatures will remain near 28°C, according to the 8 am EDT run of the SHIPS model. However, a band of high wind shear of 20 - 40 knots associated with the subtropical jet stream lies just to the north of 99L, and it would not be a surprise to see 99L experience some higher shear conditions than are currently forecast. The farther north 99L gets, the higher the shear it will experience, and the SHIPS model is predicting shear in the moderate range, 10 - 20 knots, for Saturday - Sunday, as the storm works its way to 15°N. The disturbance is at 9°N, which is close enough to the Equator that the storm will have some difficultly getting spinning. Most of the models are showing some slow development of 99L. There are some major differences in the predicted forward speed of 99L, with the ECMWF and UKMET models predicting the storm will reach the Lesser Antilles on Friday, and the GFS predicting a later arrival, on Saturday. At 8 am Tuesday, NHC gave 99L a 20% chance of developing into a tropical depression by Thursday morning. I expect the storm will begin having trouble with tendrils of dry air reaching down from the north at times this week, but give 99L a 50% chance of eventually developing into Tropical Storm Ernesto sometime in the next ten days. Residents and visitors to the Lesser Antilles Islands should anticipate heavy rains and strong winds from 99L beginning to affect the islands as early as Friday morning. The long-range fate of 99L next week is uncertain. A track west to west-northwest through the Caribbean, or to the northwest towards the U.S. East Coast are both possible. The storm is less likely to survive if it heads northwest towards the U.S.
Extreme heat in the Central U.S.
The withering heat in America's heartland continued on Monday, with high temperatures of 112° recorded in Winfield, Kansas and Searcy, Arkansas. Little Rock, Arkansas hit 111°, their 3rd hottest temperature ever record, behind the all time record of 114° set just last year on August 3, and the 112° reading of 7/31/1986. Wichita and Coffeyville in Kansas both hit 111° Monday, and in Oklahoma, Enid, Tulsa Jones Airport, and Chandler all topped out at 111°. Carr Creek, Missouri hit 110°, the hottest temperature measured in the state so far this year. Highs temperatures Tuesday and Wednesday in this region could reach 110° again, as the most extreme heat this week will stay focused over Oklahoma and surrounding states.
Jeff Masters
Reader Comments
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Some of that might be storm relative as well.
re Flood.... trapped in a car... electric windows... must break window to escape
Are you trying to ruin my chase, wash?
Geoff, that looks like it wants to go straight for the Cayman Islands. What do you think?
REally? I thought the main run was the average of the ensembles?
28kts shear isnt too helpful even for a good storm.
30kts is pretty deadly to a moderate TS
I was down in Gulfport not too long ago. There was still plenty of oil in the sand. Hate to see the subsurface.
Where can I find the link to this info?
You may be right. I'm really not sure.
Yep, you're right. I think in order to gain lat., it has to build intensity (high cloud towers) to get pulled towards the low. We shall see soon enough.
Trinidad may want to take cover. lol
AL 99 201207312345 920N 4300W SAB 1010 /////
AL 99 201208010000 970N 4280W TAFB 1515 /////
Link
I'm saying that the SHIPS/GFS sometimes think they see shear when it's really just being generated by a collocated anticyclone. Look around at the GFS wind shear forecasts on FSU's experimental genesis page, and you will sometimes notice 30 knots of shear directly ahead of a mature hurricane. That's usually not shear from external influences. Obviously 99L is not a mature hurricane, and may not ever be, but the general philosophy still stands.
LMAO!! Tell Romney to take out his money from here, it might get wet , J/K, personally this looks more like an Emily 05 or Felix 07 track to me!
WHXX01 KWBC 010041
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
0041 UTC WED AUG 1 2012
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
ATLANTIC OBJECTIVE AIDS FOR
DISTURBANCE INVEST (AL992012) 20120801 0000 UTC
...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
120801 0000 120801 1200 120802 0000 120802 1200
LAT LON LAT LON LAT LON LAT LON
BAMS 9.7N 43.0W 10.5N 46.4W 11.0N 49.7W 11.2N 53.2W
BAMD 9.7N 43.0W 10.2N 45.1W 10.6N 47.0W 10.8N 48.8W
BAMM 9.7N 43.0W 10.3N 45.4W 10.8N 47.6W 11.2N 49.7W
LBAR 9.7N 43.0W 10.2N 45.9W 10.8N 48.9W 11.2N 52.1W
SHIP 25KTS 32KTS 39KTS 45KTS
DSHP 25KTS 32KTS 39KTS 45KTS
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
120803 0000 120804 0000 120805 0000 120806 0000
LAT LON LAT LON LAT LON LAT LON
BAMS 11.1N 56.5W 10.7N 63.0W 11.5N 68.1W 13.6N 72.8W
BAMD 11.0N 50.6W 12.1N 54.6W 13.8N 58.7W 15.4N 62.0W
BAMM 11.7N 51.9W 13.3N 57.0W 15.5N 62.7W 17.4N 68.8W
LBAR 11.5N 55.2W 11.8N 61.4W 12.4N 66.5W .0N .0W
SHIP 50KTS 56KTS 55KTS 53KTS
DSHP 50KTS 56KTS 55KTS 53KTS
...INITIAL CONDITIONS...
LATCUR = 9.7N LONCUR = 43.0W DIRCUR = 280DEG SPDCUR = 17KT
LATM12 = 9.3N LONM12 = 39.6W DIRM12 = 277DEG SPDM12 = 16KT
LATM24 = 8.9N LONM24 = 36.6W
WNDCUR = 25KT RMAXWD = 50NM WNDM12 = 20KT
CENPRS = 1009MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
$$
NNNN
Just making sure that it doesn't look like I am copying anyone.
Link
Bad little storms, those!
No, the main run is at full resolution (for the GFS T574 ~27KM for the first 192 hours). The ensembles are run at a lower resolution (for the GEFS T254 ~55km for the first 192 hours).
00Z fix
AL, 99, 2012080100, , BEST, 0, 97N, 430W, 25, 1009, LO
lower pressure and tagged as LO not DB anymore
Respectfully disagree..HWRF is the worst by far. It over does intensity about as bad as the CMC.
Really??
Consolidating right around the center.
That's headed my way here in Nova Scotia. Looks like we'll get a nice soaker out of it. Then clear off for the weekend 'cause I'm going camping!
Agreed. And that will be the make it or break it point as far as potential for a strong system.
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