African tropical wave 99L has potential to develop

By: Dr. Jeff Masters , 3:10 PM GMT on July 30, 2012

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The first African tropical wave of 2012 with a potential to develop is Invest 99L, located in the Eastern Atlantic near 9°N 36°W, midway between the Lesser Antilles Islands and the coast of Africa. Visible satellite loops show a large area of the surrounding atmosphere has a pronounced counter-clockwise spin, though there is no surface circulation. The disturbance's heavy thunderstorm activity is pretty sparse, but appears to be slowly increasing. Water vapor satellite loops show that 99L has a reasonably moist environment, and the latest Saharan air layer analysis shows that the dry air from the Sahara lies well to the north of 99L. 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 for the next five days, and ocean temperatures will remain near 28°C, according to the 8 am EDT run of the SHIPS model. 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, with the storm reaching the Lesser Antilles Islands on Saturday, August 3. NHC gave 99L a 20% chance of developing into a tropical depression by Wednesday morning. I expect the storm will have trouble with dry air at times this week as it crosses the Atlantic, but I 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 night. The long-range fate of 99L is uncertain, but a trough of low pressure is expected to be present over the Eastern U.S. early next week, which would be capable of turning 99L more to the northwest.

Hot in the Central U.S.
The heat in America's heartland continued on Sunday, with Wichita, KS hitting 111°F, just 3° short of their all-time hottest temperature of 114° set on 8/12/1936. Other notable highs on Sunday:

111° Coffeyville, KS
111° Winfield, KS
110° Chanute, KS
110° Parsons, KS
109° Joplin, MO (all-time record is 115° on July 14, 1954)

The low temperature in Tulsa, Oklahoma this Monday morning dropped to only 88°F. This is the all-time warmest low temperature in the city since record keeping began in 1905. The previous record warmest minimum temperature was 87°F set on August 2, 2011 and July 16, 1980. The high in Tulsa Monday - Wednesday is expected to reach 110° - 111°, close to the city's all-time hottest temperature of 115° set on August 10, 1936.

Jeff Masters

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Quoting TropicalAnalystwx13:

The graveyard...scientifically called the John Hope rule...only applies to systems that have not developed. 99L should be a moderate to intense tropical storm by that time.



There is no guarantee 99L develops into a TS. The Atlantic is in the early stages of becoming favorable. I believe mid August is when the real fireworks should start and could end up being the most active month of hurricane season. September and October might be more quiet than usual.
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Quoting Bluestorm5:
Good night, y'all.
Quoting ProgressivePulse:
Night All!

nights both of you.
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1518. KEEPEROFTHEGATE (Mod)
nino/nina regions compare map jun july 2012



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1517. KEEPEROFTHEGATE (Mod)




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Quoting Bluestorm5:
Not really buying this NC blob getting stronger.
I at least hope an invest of it.
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Night All!

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Quoting Bluestorm5:
Good night, y'all.
good night
Member Since: March 16, 2012 Posts: 127 Comments: 7928
Good night, y'all.
Member Since: August 1, 2011 Posts: 28 Comments: 7912
1512. KEEPEROFTHEGATE (Mod)
Quoting ProgressivePulse:


What's the 18Z look like?
thats all i have access too we wait till the am after sunrise for new plots
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Quoting ncstorm:
the 00z nogaps is running..it actually strengthen the storm off of NC

48 hours


108 hours


120 hours
Not really buying this NC blob getting stronger.
Member Since: August 1, 2011 Posts: 28 Comments: 7912
Quoting allancalderini:
Maybe we will have Ernesto out of it and Florence for the system in the Caribbean or backwards.would be cool to track 2 systems at the start of August.
Imagine the Fujiwara effect!
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Quoting ncstorm:
the 00z nogaps is running..it actually strengthen the storm off of NC

48 hours


108 hours


120 hours



This looks like when debby,the majority of the models showed west and GFS showed east to florida....rigth now the majority of the models shows more west-northwest and the GFS is shows more to the west

The GFS will win the second round ?
Member Since: June 20, 2012 Posts: 0 Comments: 2150
99L has all the makings of a hurricane to be, in my opinion. It has outflow, a clear spin, blowups of convection near a giant center. This is such a massive system. Maybe similar to the Great Atlantic Hurricane of 1944?
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Quoting ncstorm:
the 00z nogaps is running..it actually strengthen the storm off of NC

48 hours


108 hours


120 hours
Maybe we will have Ernesto out of it and Florence for the system in the Caribbean or backwards.would be cool to track 2 systems at the start of August.
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1505. Skyepony (Mod)
Quoting CaribBoy:
Bored with the GFS! I hope it's wrong lol


You're in luck, average model error (in nm) from the first run on 99L is in.. Out of the box GFDL (6) & HWRF (8) takes the lead.. GFS is best of the rest with 46, AVNO, NGP & CMC are even further off.
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At least imo 99L will cross a little bit of the Caribbean it will cross PR or pass near it.
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Quoting KEEPEROFTHEGATE:






What's the 18Z look like?
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1502. ncstorm
the 00z nogaps is running..it actually strengthen the storm off of NC

48 hours


108 hours


120 hours
Member Since: August 19, 2006 Posts: 13 Comments: 14615
1501. KEEPEROFTHEGATE (Mod)




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starts to come apart at 162

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1499. Skyepony (Mod)
Atleast 7 dead in Philippines from SAOLA & 97W.

The wild weather whipped up by Typhoon Saola as it roared off the country's northeast was compounded by a separate low-pressure area that lashed the capital with tornado-like winds and powerful thunderstorms late Sunday and early Monday. Many parts of Manila and outlying provinces were without power and low-lying areas were flooded. Initially a tropical storm, Saola strengthened late Monday into a typhoon with sustained winds of 120 kilometers (74 miles) per hour and gusts of 150 kph (93 mph). The howler is expected to blow toward Taiwan later this week, according to Manila's weather bureau.
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I think 99L will be further N near like 13N/15N and stronger when its in the E and Central caribbean
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Bored with the GFS! I hope it's wrong lol
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There's a problem when it's July 31 and there are TCHP values in excess of 140 kJ/cm^2 in the northwest Caribbean.

Trade winds may help prevent something bad later in the season though.

Member Since: July 6, 2010 Posts: 113 Comments: 31554
I know we're used to re-curves and such but, the high is back with a vengeance this year.
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1494. HadesGodWyvern (Mod)
Philippines Atmospheric Geophysical Astronomical Services and Administration
Tropical Cyclone Bulletin #13
TYPHOON GENER (SAOLA)
11:00 AM PhST July 31 2012
================================

Typhoon "GENER" has made a loop and is now moving in a north northwest direction

At 10:00 AM PhST, Typhoon Gener (Saola) located at 21.1°N 124.1°E or 210 km east northeast of Basco, Batanes has 10 minute sustained winds of 65 knots with gusts up to 80 knots. The cyclone is reported as moving north northwest at 4 knots.

Signal Warnings
================

Signal Warning #3
------------------

Luzon Region
------------

1. Batanes Group of Islands

Signal Warning #2
-----------------

Luzon Region
------------

1. Cagayan
2. Calayan Group of Islands
3. Babuyan Group of Islands

Signal Warning #1
----------------

Luzon Region
============
1. Isabela
2. Kalinga
3 .Apayao

Additional Information
=========================

Typhoon "GENER" is expected to enhance the southwest monsoon that will bring rains and moderate to strong winds over Luzon and Visayas especially the western section.

Residents living in low lying and mountainous areas are alerted against possible flash floods and landslides. Likewise, those living in coastal areas under Public Storm Warning Signal #3 and #2 are alerted against big waves or storm surges generated by this tropical cyclone.

Estimated rainfall amount is from heavy to torrential (10-35mm per hour) within the 700 km diameter of the typhoon.

Fishing boats and other small seacrafts are advised not to venture out into the Seaboard of Luzon and Visayas due to the combined effect of Typhoon "GENER" and the southwest monsoon.

The public and the disaster coordinating councils concerned are advised to take appropriate actions and watch for the next bulletin to be issued at 5 PM today.
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Now do I believe the gfs here, no. Should be farther north and stronger.
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1492. ncstorm
150 hours
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Quoting ProgressivePulse:
I would forgo any commitments in either direction till 99L gets out of the ITCZ. Noticing the high stronger in the latest GFS which may not allow it to move N much.


That's what I was noticing too.
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1489. Gearsts
Quoting wxchaser97:
The gfs kills 99L right around the southern islands.
Takes it too south
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I would forgo any commitments in either direction till 99L gets out of the ITCZ. Noticing the high stronger in the latest GFS which may not allow it to move N much.
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Quoting robert88:
GFS sees the graveyard...bet the 00Z ECMWF will too

The graveyard...scientifically called the John Hope rule...only applies to systems that have not developed. 99L should be a moderate to intense tropical storm by that time.
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1486. ncstorm
138 hours..still there ..
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1485. KEEPEROFTHEGATE (Mod)
POSS T.C.F.A.
XX/INV/99L
MARK
9.91N/38.01W


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GFS sees the graveyard...bet the 00Z ECMWF will too
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Quoting DDR:
What is the strenght of 99L over the Windward islands?

I say moderate TS
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The gfs kills 99L right around the southern islands.
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Quoting wxchaser97:
114 hours, why is the gfs now killing 99L before it reaches the islands?


Looking at the isobars Ernesto was dragged down into the gallows to continue the curse.
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Quoting TropicalAnalystwx13:
24 hours ago:



Now:



Deserving of much more than 20% IMO.
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plus even if we have a weak el nino the conditions won't really change much well atleast till around mid-late AUG or early SEPT
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1478. DDR
What is the strenght of 99L over the Windward islands?
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24 hours ago:



Now:

Member Since: July 6, 2010 Posts: 113 Comments: 31554
Quoting TropicalAnalystwx13:

If anything enters the central Caribbean it will be ripped to shreds. That's all there is to it.

I'd show you guys how strong the trade winds in that region are, but the ASCAT site is not cooperating all with me today.


The GFS is cooperating with you, for the moment, the GFS is predicting strond wind shear and CMC don't show the same shear
GFS 18z

CMC 12z

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Quoting KoritheMan:


A buoy in the central Caribbean only had northeast winds of 15 kt. Unfortunately NDBC doesn't want to work now, but I would consider that comparably weak relative to other Caribbean trackers we've seen (i.e. Chantal in 2001).

thank you
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Quoting JLPR2:


Nah, that's just convection probably being sheared away from the wave.

As you can see its spin is moving west in the Caribbean.


Also to note: 99L's spin is slowly getting stronger and rounder.
I'm just a little off-put at the thought of an East Coast hurricane. Seaside Heights, New Jersey is long overdue for their 1 in 200 year, 1 in 100 year, and 1 in 50 year hurricanes.
They seem to come in pairs (Connie and Diane) or within a few years of each other: 1815 & 1821, 1938 & 1944, 1954 & 1955. I fear Irene was a taste of things to come.
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99L is toast if it goes into the Caribbean. Trade winds are not going to slack off with a weak El Nino developing. They stay steady or most likely get worse here on out.
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1472. Patrap
Stage fright from all the FRAME watching?
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Quoting HurrikanEB:
just out of curiosity, is this 99L from the first round of invests? If i remember correctly it goes invest 90L to 99L and then back to 90L. Were all of the named systems so far this year from the same round, and is this the end of that round?



..if that makes sense.


This is the finale of the first round.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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