Four invests in the Atlantic; fair weather in Arctic to drive rapid sea ice loss
It's a busy day in the tropical Atlantic, with the National Hurricane Center tracking four areas of interest (Invests.) None of these systems is a danger to any land areas over the next three days. The disturbance of most concern is the one farthest from land, a tropical wave that emerged from the coast of Africa two days ago. This wave, (Invest 93L), is located about 500 miles southwest of the Cape Verde Islands, and is moving westward at 15 - 20 mph. Recent visible satellite loops show that 93L has lost some of its heavy thunderstorms since yesterday, and the system is poorly organized, though there is a good deal of spin to the system. There is dry air to its north that is interfering with development. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing high wind shear in excess 20 knots affecting 93L, which has undoubtedly contributed to the storm's loss of organization. Sea surface temperatures are 27.5°C, which is one degree above the 26.5°C threshold usually needed to support a tropical storm.
Figure 1. Morning satellite photo of the four Invests in the Atlantic today.
Forecast for 93L
High wind shear above 20 knots is predicted along 93L's path through Saturday afternoon, followed by a drop to the moderate range, 10 - 20 knots, for the succeeding four days. This should allow the storm to organize over the weekend. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET), have only one model, the GFS, that is indicating significant development of 93L. This model brings 93L near the northern Lesser Antilles Islands by Wednesday. NHC gave 93L a 40% chance of developing into a tropical depression by Sunday morning in their 8am outlook. Given 93L's recent struggles, I'd put these odds at 30%.
92L
An African wave midway between the northern Lesser Antilles Islands and the coast of Africa, near 18°N 45°W, is moving west-northwest at 20 mph. This system, (Invest 92L), is being given a 40% chance of development by NHC. Recent visible satellite loops show a modest amount of heavy thunderstorm activity, but no signs of a surface circulation. A Windsat pass from 8:04 am EDT this morning also showed no surface circulation, and noted top winds of around 35 mph. Water vapor satellite loops show that a large area of dry air surrounds 92L, and this dry air is causing problems for the storm. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 20 knots affecting 92L. Sea surface temperatures are 27 - 27.5°C, which is a degree above the 26.5°C threshold usually needed to support a tropical storm.
Forecast for 92L
Moderate wind shear of 10 - 20 knots is predicted along 92L's path over the coming five days, which should allow the storm to organize if it can handle the dry air surrounding it. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show weak development or no development of 92L, and NHC gave 92L a 40% chance of developing into a tropical depression by Sunday morning in their 8am outlook. A steady west-northwest motion for 92L is predicted by all of the models, which should make the storm miss the Lesser Antilles by a comfortable margin. However, Bermuda may be at risk from 92L next week.
94L
A broad low pressure system about 700 miles northeast of the northern Lesser Antilles Islands has developed a small amount of heavy thunderstorm activity, and may be a threat to become a tropical depression early next week. This system, (Invest 94L), is currently headed west-southwest at 10 mph, but is expected to turn northwest later today. Recent visible satellite loops show some spin to the cloud pattern at middle levels of the atmosphere, but no signs of a surface circulation. This system is also battling dry air, which is keeping the its heavy thunderstorms relatively meager. The SHIPS model is showing moderate wind shear of 10 - 20 knots affecting 94L. Sea surface temperatures are 28°C.
Forecast for 94L
Moderate wind shear of 10 - 20 knots is predicted along 94L's path over the coming five days, which should allow slow development, if it can handle the dry air surrounding it. None of our reliable models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show no development of 94L, and NHC gave 94L just a 20% chance of developing into a tropical depression by Sunday morning in their 8am outlook. Bermuda is the only land area that needs to be concerned with 94L.
95L
The final invest out there is an area of disturbed weather along on old frontal boundary several hundred miles off the coast of North Carolina. This sytem, Invest 95L, is headed northeastwards out to sea, and is not a threat to any land areas.
Figure 2. Arctic sea ice extent on August 11, 2011, was the 2nd lowest on record for the date. The Northeast Passage and Northwest Passage (southern route) were both ice-free. Image credit: UIUC Cryosphere Today.
Arctic sea ice poised to undergo record decline in mid-August
A strong high pressure system with a central pressure of 1035 mb has developed over the Arctic north of Alaska, and will bring clear skies and warm southerly winds to northeast Siberia and the Arctic during the coming week, accelerating Arctic sea ice loss. Widespread areas of northeastern Siberia are expected to see air temperatures 4 - 12°C (7 - 22°F) above average during the coming week, and the clockwise flow of air around the high pressure system centered north of Alaska will pump this warm air into the Arctic. Arctic sea ice extent, currently slightly higher than the record low values set in 2007, should fall to to its lowest extent for the date by the third week of August as the clear skies and warm southerly winds melt ice and push it away from the coast of Siberia. This weather pattern, known as the Arctic Dipole, was also responsible for the record sea ice loss in 2007, but was stronger that year. The weather conditions that led to the 2007 record were quite extreme--one 2008 study led by Jennifer Kay of the National Center for Atmospheric Research showed that 2007's combination of high pressure and sunny skies in the Arctic occur, on average, only once every 10 - 20 years. The 2011 summer weather pattern in the Arctic has not been nearly as extreme as in 2007, but the total sea ice volume has declined significantly since 2007, leading to much loss of old, thick, multi-year ice, making it easier to set a new low extent record with less extreme weather conditions. The GFS model is predicting that the Arctic Dipole will weaken by 8 - 15 days from now, with cloudier weather and weaker high pressure over the Arctic. This should slow down the rate of Arctic sea ice loss to very near the record low values observed in 2007. It remains to be seen if 2011 Arctic sea ice extent will surpass the all-time low set in September 2007; it will be close, and will depend on the weather conditions of late August and early September, which are not predictable at this time. It is already possible to sail completely around the North Pole in ice-free waters through the Northeast Passage and Northwest Passage, according to sea ice maps maintained by the UIUC Cryosphere Today website. This marks the fourth consecutive year--and the fourth time in recorded history--both of these Arctic shipping routes have melted free. Mariners have been attempting to sail these passages since 1497. This year, the Northeast Passage along the north coast of Russia melted free several weeks earlier than its previous record early opening.
Next post
I'll have a new post by 1pm Saturday.
Jeff Masters
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I have faith in 92L! It has spin, convection (be it off center East), and it is in 29 degree + waters. Just have no idea where it's going. NHC says W/NW, but I don't see how this doesn't pull a quick exit stage right eventually.
Nice pic, Nea.
93L has been the one that every expert was worried that this would become our first big hurricane. Looking at the visible this morning there is basically nothing left (hence the lowering to 10%). This is a very weird year so far. 7 storms, no hurricanes.
Ha, first post all year and I get my invests confused! Change that comment to 94L dang it. That's where I am putting my chips, 94L. Arrgghh!
...Franklin the storm
or
Franklin the forecaster?
lmao
Been watching that in Texas and praying that it will come my way ...that would totally make my weekend!
Where are you, txjac? This storm looks pretty all-inclusive, making blueberry french toast to celebrate.
I'm on the west side of Houston ...if you're close to me I'm on my way for the french toast!
Wow, this season keeps barfing out tropical storms.
Hopefully it holds together and we get rain ...I cant believe how excited I am just for rain and clouds ...hopefully thunder too ...love thunder
92 is lower right. 93L is off screen to the right.
3/6 of our named storms came from trough splits, those almost always go out to sea and very rarely become Hurricanes. Arlene, Don, and Emily all effected land however.. that should tell you something. Also, 2002 didn't see its first hurricane until the 'G' name AND they had to wait until September. The fact that we're already on our 6th storm is impressive as it is, and I suspect like 2002 and 2010 we'll be cranking out hurricanes very soon. In 2010 Alex was the offset, and we had to wait until late August for another hurricane.
WHXX01 KWBC 131301
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1301 UTC SAT AUG 13 2011
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
TROPICAL CYCLONE FRANKLIN (AL062011) 20110813 1200 UTC
...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
110813 1200 110814 0000 110814 1200 110815 0000
LAT LON LAT LON LAT LON LAT LON
BAMS 38.6N 58.9W 39.9N 55.6W 40.6N 51.6W 40.6N 47.8W
BAMD 38.6N 58.9W 40.8N 53.0W 41.8N 45.5W 42.0N 38.2W
BAMM 38.6N 58.9W 40.2N 54.2W 40.8N 48.5W 40.3N 43.1W
LBAR 38.6N 58.9W 40.8N 53.8W 42.9N 47.6W 44.2N 40.5W
SHIP 40KTS 49KTS 54KTS 55KTS
DSHP 40KTS 49KTS 54KTS 55KTS
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
110815 1200 110816 1200 110817 1200 110818 1200
LAT LON LAT LON LAT LON LAT LON
BAMS 39.9N 44.9W 38.1N 42.2W 36.4N 42.4W 36.2N 42.8W
BAMD 42.2N 32.7W 44.4N 22.0W 47.7N 8.1W 52.9N 3.9E
BAMM 39.2N 39.6W 37.6N 36.3W 36.3N 35.9W 36.5N 37.0W
LBAR 45.3N 33.2W .0N .0W .0N .0W .0N .0W
SHIP 53KTS 40KTS 19KTS 0KTS
DSHP 53KTS 40KTS 19KTS 0KTS
...INITIAL CONDITIONS...
LATCUR = 38.6N LONCUR = 58.9W DIRCUR = 55DEG SPDCUR = 19KT
LATM12 = 36.2N LONM12 = 62.6W DIRM12 = 58DEG SPDM12 = 18KT
LATM24 = 34.7N LONM24 = 66.7W
WNDCUR = 40KT RMAXWD = 30NM WNDM12 = 30KT
CENPRS = 1004MB OUTPRS = 1013MB OUTRAD = 150NM SDEPTH = D
RD34NE = 45NM RD34SE = 60NM RD34SW = 0NM RD34NW = 0NM
$$
NNNN
375
WHXX01 KWBC 131304
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1304 UTC SAT AUG 13 2011
DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.
ATLANTIC OBJECTIVE AIDS FOR
DISTURBANCE INVEST (AL942011) 20110813 1200 UTC
...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
110813 1200 110814 0000 110814 1200 110815 0000
LAT LON LAT LON LAT LON LAT LON
BAMS 27.1N 59.4W 28.1N 61.0W 29.1N 62.4W 30.5N 63.4W
BAMD 27.1N 59.4W 27.6N 60.8W 28.2N 62.1W 28.9N 63.4W
BAMM 27.1N 59.4W 27.9N 60.9W 28.6N 62.2W 29.7N 63.4W
LBAR 27.1N 59.4W 28.4N 60.7W 29.6N 61.7W 31.2N 62.2W
SHIP 25KTS 28KTS 32KTS 37KTS
DSHP 25KTS 28KTS 32KTS 37KTS
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
110815 1200 110816 1200 110817 1200 110818 1200
LAT LON LAT LON LAT LON LAT LON
BAMS 32.5N 63.7W 38.2N 59.9W 42.3N 50.8W 45.4N 40.5W
BAMD 30.1N 64.7W 35.3N 66.4W 42.6N 62.2W 48.6N 40.1W
BAMM 31.2N 64.3W 37.0N 63.3W 43.3N 55.3W 48.6N 37.7W
LBAR 32.7N 61.9W 36.6N 58.8W 40.2N 52.7W 42.5N 41.4W
SHIP 41KTS 51KTS 55KTS 52KTS
DSHP 41KTS 51KTS 55KTS 52KTS
...INITIAL CONDITIONS...
LATCUR = 27.1N LONCUR = 59.4W DIRCUR = 300DEG SPDCUR = 11KT
LATM12 = 25.8N LONM12 = 57.2W DIRM12 = 298DEG SPDM12 = 11KT
LATM24 = 25.0N LONM24 = 55.4W
WNDCUR = 25KT RMAXWD = 40NM WNDM12 = 25KT
CENPRS = 1012MB OUTPRS = 1016MB OUTRAD = 150NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
$$
NNNN
Development is not expected until the Caribbean, 10% makes sense at this time.
XD Sorry, lol Fixed it.
Well, that explains it.
Does your forecast also say 0% chance of rain with a sunny 103o high?
How do ya make french toast? How hot does the fire have to be and how long does a french-man take to cook?
LOL! Let me check...nope...103 with 10%...hahaha 10%
I've just had half a block of chocolate, a handful of gummy bears and now having a soothing cuppa tea.
Currently
53.8°F heading for a low of 46°F.
Could be worse, could be in New Zealand going by this.
New Zealand braces for an intense winter storm.
A powerful winter storm that is barreling towards New Zealand will bring a gale force and bitterly cold southwest change that will drop snowfalls to sea-level.
A low is sitting just to the north of the country, but as it continues its track to the east it will send the first round of cold air in today. Showers and brisk southwest winds will spread into the south and snow levels will drop to around 300 metres tonight.
The low will intensify to the southeast of New Zealand over the next few days, dragging a polar airmass far north. Sunday through Tuesday is when the coldest of this wintry blast will engulf the country.
Snow will fall to near sea level in eastern and southern parts of the South Island and to low levels across the North Island. The gale force winds combined with heavy snow could create blizzard conditions over parts of the south.
This unusually cold polar blast will cause travel headaches as snow falls in areas that are not prone to the wintry weather. Major centres that are likely to be affected by the low level snow include, Dunedin, Christchurch and Wellington.
The wintry blast will batter New Zealand until Wednesday, before conditions finally ease.
- Weatherzone
Same for me.....have always enjoyed his sharp wit , and he certainly comes across with an honest common sense syle :)
I don't think so going by this.
Yup...exit..stage right..
From the 12z satellite classification.
TS BUSTED FORECAST ALIBI
Viewing: 1501 - 1551
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