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A Cape Verde Wave in the Central Atlantic

By: Bob Henson 3:41 PM GMT on July 17, 2015

The ferocious wind shear associated with El Niño has remained far enough west to give a tropical wave in the central Atlantic at least a slender chance of development. Invest 93L was located near 10.7°N and 38.4°W at 8:00 am EDT Friday, moving west at about 18 mph. Peak winds are close to 30 mph, with disorganized showers and thunderstorms evident on satellite imagery within a fairly large envelope of moisture. 93L has formed a bit early for systems in the Cape Verde region, which typically peaks in production during August and September. An upper-level anticyclone over 93L has resulted in low wind shear of 5 - 10 knots immediately over the circulation. Water temperatures are slightly below average across the deep tropical North Atlantic, but at around 26 - 27°C (79° - 81°F), they are just warm enough to support development along the track of 93L. Track models generally take 93L toward the northern Leeward Islands over the weekend before projecting a gradual recurvature. Statistical models bring AL93 up to minimal tropical storm strength, but the dynamical models most reliable for predicting tropical genesis are failing to develop AL93 substantially. Any embryonic system will soon ingest drier air toward the west, not to mention struggling against powerful wind shear that now tops 50 knots around the Leeward Islands. NHC gives the system 10 percent chance of tropical cyclone development in the next 48 hours and a 20 percent chance in the next five days. Given the currently favorable upper-level conditions and marginally warm water, I would give 93L a modest chance of becoming a minimal-strength named storm for a day or two.


Figure 1. An infrared satellite image from GOES-East of Invest 93L, taken at 1515 GMT (11:15 am EST) on Friday, July 17. Image credit: NOAA/NESDIS.


Pacific tropics calming down after a hectic few days
Tropical action in the hyperactive 2015 Pacific season looks set to take something of a breather over the next several days. Former Typhoon Nangka is now a weak tropical storm in the Sea of Japan after having swept over the Japanese islands of Shikoku and western Honshu. At least two deaths and 32 injuries have been reported. The nation’s rail lines and air traffic were seriously disrupted by Nangka, which came ashore as a minimal Category 1 typhoon around 11:00 am local time on Thursday. The remnants of Nangka are projected to arc eastward close to the north end of Japan’s Honshu island this weekend. To the southeast, Tropical Storm Halola is still fighting moderate to strong wind shear, but it should enter a more favorable environment over the next couple of days and gradually intensify to typhoon status. Halola could take a swipe at Japan next week before recurving.


Figure 2. Waves crash against the coast of Katsurahama on the island of Shikoku, western Japan, during the approach of Typhoon Nangka on July 16, 2015. Image credit: Kyodo News via AP.


Figure 3. A channel of upper-level moisture extended from Tropical Storm Dolores into Arizona and New Mexico on Friday morning. Image credit: Stu Ostro, The Weather Channel.

In the Northeast Pacific, Tropical Storm Dolores weakened below hurricane strength overnight, with colder waters and greater wind shear lying in wait on its northwestward path. The National Hurricane Center expects Dolores to weaken further over the next several days. Moisture associated with Dolores will continue to mix with monsoonal moisture moving toward the southwest U.S., bringing a threat of heavy showers and thunderstorms to Arizona on Friday and Saturday and a rare chance of July sprinkles over the Los Angeles area. Flash flood watches are in effect for much of Arizona and far southeast California. The remnant circulation of Dolores itself is predicted to stall early next week several hundred miles southwest of Los Angeles, but slugs of moisture from Dolores and the larger monsoonal pattern may get drawn as far north as central California, perhaps bringing an enhanced chance of thunderstorms there. Farther out to sea, weak Tropical Storm Enrique continue to spin harmlessly, while NHC is giving a tropical wave south of Mexico a 30 percent chance of development between Sunday and Wednesday.

I’ll have a post later today on the 2015 State of the Climate release, and a special report this weekend on progress in severe weather modeling and prediction. Jeff Masters and I will both be back on board next week.

Bob Henson

Hurricane

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Thanks for the update Mr.Henson....
Thanks for the new entry, Mr. Henson. 93L sure doesn't look all that impressive currently.

I also enjoyed your "PhD speech" for "man, it's gonna be hard to get a storm going in the MDR this year"....

Statistical models bring AL93 up to minimal tropical storm strength, but the dynamical models most reliable for predicting tropical genesis are failing to develop AL93 substantially.
Thanks Dr. Masters. Great entry. Dr Masters, do you see any vorticity related to 93L, because it's hard for me to locate the COC. It seems as if the vorticity is weak, or there are multiple centers.


Thanks for the update Bob Henson.
93L:



Slowly but surely organising, despite recent collapse of its thunderstorms (although those are helping to moisten the environment). The 850 mb vorticity has become much better defined the last 15 hours or so:

Earlier:



Now:



Conditions should become more conducive over the next couple days as it moves into an area of lower shear:



It's currently under moderate wind shear. I wouldn't be surprised if it became a tropical depression or even a minimal tropical storm if it is able to keep up its current rate of organisation. With conditions becoming slightly more favourable, I would expect it to be able to organise quicker tomorrow & sunday than it has been today. Will be an interesting one to watch - a really good tropical wave for mid July!
Quoting 3. tiggerhurricanes2001:

Thanks Dr. Masters. Great entry. Dr Masters, do you see any vorticity related to 93L, because it's hard for me to locate the COC. It seems as if the vorticity is weak, or there are multiple centers.
There is no COC, just a small wind shift in a broad area.
Besides being remarkably persistent, the moist upper outflow of Enrique is flowing into a convergent belt around Dolores. While the belt looks dry on the vapor loop, this is deceptive in that it's only reflecting the subsidence of the upper convergence. The convergence may actually be contributing to an enhancement of the humidity of the mid and lower levels around Dolores which may prolong its existence. Meanwhile, a significant upper trough over western Canada is digging south over the Great Basin, with a strong offshore wind component coming off the associated jet. This is setting up an unusual easterly flow that might well keep Dolores from moving east as it moves over the coastal waters of California. On the wider view (no GIF available), you can also note the unusual (for July) southern dip of the jet over the Pacific northwest of Hawaii, probably driven by the recent spate of tropical activity in the Western Pacific.



I personally don't see much happening with this thing unless it has a flareup of convection like yesterday...
It needs to take advantage of the anticyclone and moist environment while it has it before gaining latitude..
That seems to be the story of most ATL storms these days.
It's apparently trying to form a circulation but it needs to do so pretty quickly if we want to see a minimal TS out of this..
Thank You Mr. Henson. I am not optimistic on development of 93L. It's a tough road ahead in terms of dry air issues as you have noted. The wave is very disorganized at present and any attempts at organization, even in the longer term, will result in substantial dry air entrainment unless it starts to build substantial convection and build a more substantial moisture envelope.

And one important point noted in the current speed of 18 mph; it is embedded in the trades at this speed and optimum speed for wave development (all other factors being equal) is in the slower 10-12 mph range which would allow a TD to stack up vertically. Potential development is not out of the question but it would have to make some real progress, on all relevant fronts/factors, over the next 5 days..................Gonna wait until Tuesday to see how it goes.
93L

Quoting 12. weathermanwannabe:

Thank You Mr. Henson. I am not optimistic on development of 93L. It's a tough road ahead in terms of dry air issues as you have noted. The wave is very disorganized at present and any attempts at organization, even in the longer term, will result in substantial dry air entrainment unless it starts to build substantial convection and build a more substantial moisture envelope.

And one important point noted in the current speed of 18 mph; it is embedded in the trades at this speed and optimum speed for wave development (all other factors being equal) is in the slower 10-12 mph range which would allow a TD to stack up vertically. Potential development is not out of the question but it would have to make some real progress, on all relevant fronts/factors, over the next 5 days..................Gonna wait until Tuesday to see how it goes.




Oh how I despised Chantal

Atlantic Tropical Weather Discussion


000
AXNT20 KNHC 171039
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI JUL 17 2015


BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE WAS RE-INTRODUCED TO THE ANALYSIS THIS MORNING.
THIS WAVE HAS AN AXIS THAT EXTENDS FROM 17N37W TO A 1011 MB LOW
CENTERED NEAR 10N37W. THESE FEATURES ARE INTERACTING WITH EACH
OTHER AND CURRENT GUIDANCE SHOW THE LOW DISSIPATING WITHIN THE
NEXT 48 HOURS LEAVING THE WAVE MOVING BY ITSELF ACROSS THE
CENTRAL ATLANTIC AND E CARIBBEAN. TPW IMAGERY DEPICTS A HIGH
MOISTURE CONTENT MAINLY E OF THE WAVE AXIS BETWEEN 03N-16N.
SCATTERED MODERATE CONVECTION IS OBSERVED FROM 03N-15N BETWEEN
29W-39W.
thanxs
At this point, with what appears to be a relatively healthy wave train off of Africa, we will have to watch all the waves for potential development between now and the end of September but one of the important factors, which also helps lower pressures, is sustained and "persistent" convection over a period of several days. I will also note, per NOAA stats, that about 60 African waves cross the Atlantic from Africa during any given Atlantic hurricane season. However, only a very few out of this ball park ever go on to make it to TD or storm status. These early ones however, will contribute more and more moisture along the ITCZ that will help pave the way for the more robust waves coming in mid to late August.




SYNOPSIS 2015071700

93L .. P07L (NHC: 10% 2-day / 20% 5-day)
11N, 35W
925 hPa

Interestingly, 700 hPa had the best depiction of v700 in the Hovmoller diagram (especially for ECMWF), but the best depiction of a circulation was down at 925 hPa.


ECMWF: Just a trough with unorganized OW up at 700 hPa. Down at 925 hPa, P07L is the easternmost of at least three tiny OW maxima in the analysis. By 12 hours, P07L has grown a little, has a CL-trough intersection, and a circulation. However, as much larger P06L moves in from the east, 93L/P07L quickly dissipates.

GFS: With a faster phase speed than in ECMWF, 93L is able to outpace the approaching P06L. Tracks to the WNW. Pouch TPW decreases after 36 hours, and deep vertical shear increases after 72 hours as 93L approaches the Caribbean. Dissipates south of Puerto Rico after 108 hours.

UKMET:

NAVGEM:

HWRF-GEN:


ECMWF -5.6 0.0 v700 36h
GFS -8.0 1.2 v700 108h
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
1125 AM EDT FRI JUL 17 2015

.UPDATE...
LATEST SURFACE ANALYSIS SHOWS WEAK FRONTAL BOUNDARY WITH LOW LEVEL
CONVERGENCE BOUNDARY FURTHER SOUTH ACROSS EAST CENTRAL GULF UNDERNEATH
AREA OF UPPER LEVEL DIFLUENCE AND HIGHER PRECIPITABLE WATER VALUES
FUELING CONVECTION ACROSS THAT REGION AT THIS TIME. 12Z SNDG PARAMETERS
REVEAL MID LEVELS SLIGHTLY WARMER THAN NORMAL ACROSS SOUTH FLORIDA,
WITH 700-500MB LAPSE RATES OF AROUND 6.2 C/KM WITH A VERY UNIMPRESSIVE
THERMAL PROFILE BELOW 650 MB OR SO. MICROBURST INDICES INDICATE
ONLY MARGINAL POTENTIAL FOR TODAY WITH EVEN LESS FOR HAIL. PWAT
VALUES HAVE FALLEN SINCE YESTERDAY TO NEAR NORMAL LEVELS PER
BLENDED AMSU/SSMI/GPSMET SATELLITE PRODUCT WITH SLIGHTLY DRIER AIR
COLUMN. ON THE OTHER HAND, PLENTY OF HEATING TODAY VERSUS
YESTERDAY YET BECAUSE OF UNIMPRESSIVE THERMAL PROFILES MODIFIED
SOUNDING STILL YIELDED 2700 J/KG CAPE. ALL IN ALL THIS MEANS
MOSTLY GARDEN VARIETY STORMS TODAY WITH MAIN CONCERNS BEING
FREQUENT LIGHTNING WITH THE STRONGEST STORMS AND MAY BE WIND GUSTS
IN EXCESS OF 40 MPH.

ENSEMBLE OF HIGH RESOLUTION MODELS BETWEEN HRRR AND TWO OTHER LOCAL
CONFIGURATIONS STILL INDICATE AREA MOST FAVORED FOR CONVECTION TODAY
WILL BE INTERIOR AND EASTERN HALF OF SOUTH FLORIDA WITH BEST CHANCES
UP THE EAST COAST TOWARDS WEST PALM BEACH. THERE IS STILL A LESSER
CHANCE FOR THE WEST COAST FROM ACTIVITY TO THE NORTH/NORTHWEST
PROPAGATING SOUTH AND/OR DIURNAL CONVECTION ACROSS THE INTERIOR
IMPACTING NAPLES AREA ON ITS WESTERN PERIPHERY.

FORECAST GRIDS ARE BEING AMENDED ACCORDINGLY ALONG WITH HWO.

turning off the sprinklers for delores, a bit unusual in OC, CA in the summer we r in a gorgeous weather pattern highs in the 80s lows around 60 perfect for the whole house fan.
Good afternoon, and thanks for the update on 93L. Hope it'll make it to a tropical storm as I need a boost of numbers to meet my bet on named systems this year ;-)

In Europe quite interesting things with soon to be warm cored "Xaver" north of Ireland are going on:


Source.

ESTOFEX-SYNOPSIS, Issued: Thu 16 Jul 2015 23:04
A very complex forecast evolves with lots of dephasing in respect of ingredients and an abnormally developing synoptic-scale vortex just west of Ireland.
All models agree in track and strength of that vortex, which features a tight pressure gradient in the lowest 2 km AGL. Phase diagrams show a distinct warm-core signature as influx of modified subtropical air continues towards its center. This is an unusual strong vortex for that time of year e.g. with core pressure approaching 990 hPa in some model runs. As often seen with such features, a steady motion exists, increasing overall confidence in the forecast of numerical models, which indicate peak strength NW of Ireland during the day. Increasing strength of that vortex towards lower levels also means strong gradient flow in the lower to mid troposphere (up to 5 km AGL), which spreads northeast and affects N-France, NW-Germany, the North Sea and UK during the forecast. ...

Read the whole in depth discussion with forecast of severe storms by link above.


Source for updates.



Current temps at my place mid Germany 35C/95F - well, we're getting used to it; next week should be even hotter. Some severe weather south of me this afternoon, and maybe some storms will visit my area tonight and tomorrow as well. At least some rain would be very nice. The drought in central Germany is further deepening these hot weeks.

Bad outlook for the harvest of maize and wheat:
Strategie Grains cuts EU grain hopes again, with more hot weather coming
Meanwhile, that complex in the Gulf off of Florida (left-over from the stationary front) is tying desperately to get somebody's attention and struggling with the moderate shear:





Posted by Jim Cantore, TWC

Belle Chasse Navy fighter pilot awarded medal for 'heroic' flight after being struck by lightning.


Emergency responders at the Naval Air Station-Joint Reserve Base in Belle Chasse rush to help Cmdr. Abaxes "Chili" Williams, who slumped out of the cockpit of a F/A-18C Hornet after it was struck by lightning during a training exercise over the Gulf of Mexico on July 18, 2014. (Courtesy of Cmdr. Abaxes Williams)
Paul Purpura, NOLA.com

Belle Chasse Navy fighter pilot awarded medal for heroic flight

The first sign that something was wrong was the static on his radio. Then as he was about to speak to his wingman, Navy Cmdr. Abaxes "Chili" Williams, flying a F/A-18 Hornet over the Gulf of Mexico east of St. Bernard Parish, felt a warm sensation in his fingertips on the radio trigger.

"And then, white," Williams said. "A pretty, magnificent, bright, almost shiny white."

Williams already knew peril in the air. Before he joined the Navy Reserve's Strike Fighter Squadron 204, known as the River Rattlers, he was a Marine Corps fighter pilot who flew combat missions over Afghanistan and patrolled the no-fly zone over southern Iraq. He had been flying airplanes that were struck by lightning, too, both in Hornets and the Boeing 737 commercial airliners he flies for Continental in his civilian job.

But this time, the lightning strike was different. This time, he felt it.

The electrical charge from the radio trigger seemed to fry his neurological network, just like it did to the soup can-sized fuse plugs in the Hornet's wings. The jolt he received, 23,000 feet in the air, set in motion a 25-minute struggle to sync his body and mind and to control the jet until he could return to the Naval Air Station-Joint Reserve Base.

For his "heroic achievement in aerial flight" on July 18, 2014, the New Orleans resident has been awarded the Air Medal. He was cited for saving the $70 million jet, his own life and potentially those of people on the ground had he crashed in a populated area. Rear Adm. Mark Leavitt, commander of Naval Air Force Reserve, approved the award in April, and Cmdr. Mark "Sheryl" Crowe, who at the time commanded the River Rattlers, presented it to Williams on July 1.

"By his skillful airmanship, steadfast aggressiveness and exemplary devotion to duty in the face of hazardous flying conditions, Commander Williams reflected great credit upon himself and upheld the highest traditions of United States Naval Service," according to the citation.
Quoting 8. LargoFl:



Now if those showers and discrete thunderstorm cells can fill in to the north over the next few hours, we may be in business for some rain today (as forecast).

93L not looking terribly healthy on the visible, but at least it is a CV wave to track.
One dead as forest fires rage across Greece
Towns, villages evacuated as series of wildfires are fanned by high winds
17 July 2015 18:36 (Last updated 17 July 2015 19:13), By Magda Panoutsopoulou, ATHENS

(BTW, the outbreak of 34 fires at different places across the country triggered investigations of possible arson, according to Greek media.)
It was a cool/cold week and now it's quite warm here in Berlin. Sun is out, I'm grilling burgers on the terrace(shhhhh...don't tell the hausmeister) and enjoying a cold Krombacher. Life is good!

Quoting 25. barbamz:

Good afternoon, and thanks for the update on 93L. Hope it'll make it to a tropical storm as I need a boost of numbers to meet my bet on named systems this year ;-)

In Europe quite interesting things with soon to be warm cored "Xaver" north of Ireland are going on:


Source.

ESTOFEX-SYNOPSIS, Issued: Thu 16 Jul 2015 23:04
A very complex forecast evolves with lots of dephasing in respect of ingredients and an abnormally developing synoptic-scale vortex just west of Ireland.
All models agree in track and strength of that vortex, which features a tight pressure gradient in the lowest 2 km AGL. Phase diagrams show a distinct warm-core signature as influx of modified subtropical air continues towards its center. This is an unusual strong vortex for that time of year e.g. with core pressure approaching 990 hPa in some model runs. As often seen with such features, a steady motion exists, increasing overall confidence in the forecast of numerical models, which indicate peak strength NW of Ireland during the day. Increasing strength of that vortex towards lower levels also means strong gradient flow in the lower to mid troposphere (up to 5 km AGL), which spreads northeast and affects N-France, NW-Germany, the North Sea and UK during the forecast. ...

Read the whole in depth discussion with forecast of severe storms by link above.


Source for updates.



Current temps at my place mid Germany 35C/95F - well, we're getting used to it; next week should be even hotter. Some severe weather south of me this afternoon, and maybe some storms will visit my area tonight and tomorrow as well. At least some rain would be very nice. The drought in central Germany is further deepening these hot weeks.

Bad outlook for the harvest of maize and wheat:
Strategie Grains cuts EU grain hopes again, with more hot weather coming



Guys it's the middle of July in a lot stronger than usual El Nino.
I'd say what I said yesterday...Under the circumstances, this wave is pretty impressive.

But it won't make it IMO...NHC don't think so either so it seems...


But I'd even give this thing a shot. It's on the tail end of a front and been firing convection regularly today. Moist environment and under moderate to low wind shear.

And after the rain it dumped on me yesterday, I sensed a bit of tropicalness in the air :P
Something I haven't sensed since Andrea.
I have only picked up 0.31” today, while areas less than 10 miles from me (as the crow flies) were flooded with 6 to 8 inches. Summer rainfall in Florida is truly an amazing thing.
Addition to post #25 about this warm cored "Xaver"-system, at present west of Scotland onto which it has dumped a lot of water:


VIDEO: Incredible scenes as homes and businesses are flooded in Alyth
By Jamie Buchan, 17 July 2015 3.00pm.
Torrential downpours caused widespread devastation in Alyth this morning.
Rescue crews used inflatable boats to free people trapped in their homes and businesses in the flood-hit town centre.
Alyth Burn, which runs through the community, overflowed after debris and fallen trees blocked a series of bridges.
Locals told The Courier a large section of the town centre was under water within minutes. ...


And more rain is falling:

Source.
Current rainfall in Scotland.


Xaver.

Have a nice evening and weekend everybody!
I think this particular CA wave will be displaced to the north well before the islands (if it becomes a TC), given the current wind pattern to the east of the Caribbean sea. In any case, if the wave (just as a wave) survives all the way to the east Caribbean it could be an important rain maker to PR and nearing islands. Considering it is July and a El Nino year we should keep particular attention to the possibility of several CV systems this year. For instance, in 1928, just 6 storms were formed, however, the history mark one of the strongest ferocious CV hurricanes that year (San Felipe II, for PR mainland) or lake Okeechobee hurricane in terms of the USA main land of Fla.
12z Euro





opens back up..


Dolores may gift us some Rain, or at least a 40-50% chance.
The Florida blob is embedded within the frontal trof draped from the Eastern Gulf to across Florida into the Atlantic. No independent vort signature at this point but fun to watch.........................Have no idea where it it headed but a best case scenario would be for a drift further SE to give the tip of South Florida some drought relief. 

Quoting 36. ncstorm:

12z Euro





opens back up..


gfs is showing the same thing. Hmm.
For whatever these observations are worth, pressure is falling due West of Tampa, rising due South of Pensacola, and falling slightly due south of Tyndall, AFB:


Tampa:
Station 42036
NDBC
Location:
 28.500N 84.517W
Date: Fri, 17 Jul 2015 18:50:00 UTC
Winds: WSW (240°) at 11.7 kt gusting to 15.5 kt
Significant Wave Height: 3.9 ft
Dominant Wave Period: 6 sec
Mean Wave Direction: W (281°)
Atmospheric Pressure: 29.99 in and falling
Air Temperature: 79.0 F
Dew Point: 76.8 F
Water Temperature: 84.6 F


Tyndall:

Station SGOF1
NDBC
Location:
 29.408N 84.858W
Date: Fri, 17 Jul 2015 19:00:00 UTC
Winds: SW (230°) at 9.9 kt gusting to 9.9 kt
Atmospheric Pressure: 29.98 in and falling
Air Temperature: 84.2 F
Dew Point: 77.5 F


Pensacola:

Station 42039
NDBC
Location:
 28.739N 86.006W
Date: Fri, 17 Jul 2015 18:50:00 UTC
Winds: SSE (160°) at 9.7 kt gusting to 13.6 kt
Significant Wave Height: 3.3 ft
Dominant Wave Period: 5 sec
Mean Wave Direction: W (275°)
Atmospheric Pressure: 30.03 in and rising
Air Temperature: 77.5 F
Dew Point: 73.9 F
Water Temperature: 84.7 F
Slight rotation on Tampa Radar

That is, if you stare at it long enough
Per CIMMS update, the shear over the Gulf area is moderate to strong at the moment regardless of the convection and slight pressure decrease: I am not holding my breath on the Gulf Blob or 93L at this point............................................. .. :)

Quoting 32. JrWeathermanFL:



But I'd even give this thing a shot. It's on the tail end of a front and been firing convection regularly today. Moist environment and under moderate to low wind shear.

And after the rain it dumped on me yesterday, I sensed a bit of tropicalness in the air :P
Something I haven't sensed since Andrea.


That slug of moisture is hammering us in Gainesville right now.
Hey guys sorry I haven't been on since very early morning

I had to head out to the Airport then out to the navy ship and when I got home the power was off seems to be an all islands thing anyway power is back internet is up

Good to see 93L is kicking
Looking at current and earlier charts 93L is slowly but sure organising
Convection has weakened but I would expect this as we head into Dmin and tonight going into morning I would expect convection to burst up again
Still has a good upper level anticyclonic flow and shear is lowering to the W of this system this should help it

Models has jumped W and S for the 18Z run after the 12Z did make a jump N both 00Z(last night) and 06Z(early this morning) runs had shifted W

I think this one will make a run into the Caribbean rather that NE of it or over the NE islands as some models suggest it will be interesting to see what the other model runs show as well as the runs with input from RECON data when they go to fly
Quoting 42. JrWeathermanFL:

Slight rotation on Tampa Radar

That is, if you stare at it long enough


I was seeing some of that on radar, too. But kept telling myself the radar station is in the center and everything has a sort of arc because of that and not to project some wishful thinking on it. :D
My home is just southeast of the heavy rains on Thursday. Surprising soaker just when I thought this area was in a dry trend, a sort of rain shadow where storms form east of here and blow east to the east coast of the state.
Quoting 46. wunderkidcayman:

Hey guys sorry I haven't been on since very early morning

I had to head out to the Airport then out to the navy ship and when I got home the power was off seems to be an all islands thing anyway power is back internet is up

Good to see 93L is kicking
Looking at current and earlier charts 93L is slowly but sure organising
Convection has weakened but I would expect this as we head into Dmin and tonight going into morning I would expect convection to burst up again
Still has a good upper level anticyclonic flow and shear is lowering to the W of this system this should help it

Models has jumped W and S for the 18Z run after the 12Z did make a jump N both 00Z(last night) and 06Z(early this morning) runs had shifted W

I think this one will make a run into the Caribbean rather that NE of it or over the NE islands as some models suggest it will be interesting to see what the other model runs show as well as the runs with input from RECON data when they go to fly
93L can't be more disorganized, i don't know what you see but i'm not seeing it.
That radar can play tricks on you if you look long enough as noted below by another blogger: like the apparent rotation just off the coast of Bradenton, Florida:
Southeast sector loop


I have notice in some of the model forecast this seem to show the upper low that NNE of PR will move NNW and its trof that extends into S Bahamas and NW Caribbean will follow a bit thus easing off on the Shear in the Caribbean if this was to prove true and continue and 93L upper anticyclone prevails it could undercut the cyclonic flow from the upper low that's moving NW-NNW and help protect the system from the shear

One good thing is that the shear in the Caribeean is not as strong as it was for the past few weeks
Few weeks it's been about 70-80kts now down to 50kts now will the upper low moving out a bit shear may drop to about 20-40kts with the added introduction of the upper anticyclone could drop it down to 15-30kts I mean conditions won't be perfect but it just might be enough to let it develop and slowly get stronger

Anyway we will have to watch the upper levels closely see what happen

Also if 93L moves and continues on its W movement it will give it better chance to develop in warmer SSTs if it moves more WNW-NW it loses its chances in cooler SSTs
Well, my total today so far is over 4 inches! What a day, it's a little scary to me that all it takes is some weak 850 mb vorticity to pool deep tropical moisture of 2.3-2.4 inches and generate a coastal rain event of 4-8 inches in many places on the west coast of Central Florida. I'm a little scared to see what a robust low might do the moves slowly over the east gulf, whether tropical or not!

With 850 mb troughing having had deepened a little, and the PW going up to 2.3-2.4 inches from 2.1-2.2 yesterday, and increasing convergence over the gulf waters will support another major coastal rain event with 3-6 inches possible in some areas again.


Even with this pattern expecting to depart, model guidance keeps a sw flow in place with deep tropical moisture, likely above normal through the period!

000
FXUS62 KTBW 171910
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
310 PM EDT FRI JUL 17 2015

.SHORT TERM (TONIGHT-SATURDAY)...
A MID LEVEL RIDGE OVER TEXAS EXTENDS JUST TO THE NORTH OF FLORIDA
WHILE A CORRESPONDING TROUGH EXISTS JUST OFFSHORE ALONG THE
EASTERN SEABOARD. ON THE SURFACE A NEARLY STATIONARY BROAD FRONTAL
TROUGH HAS DRIFTED SOUTH NEAR CENTRAL FLORIDA WITH CONDSIDERABLE
CONVECTION ACROSS THE SOUTHERN AND COASTAL AREAS OR THE FORECAST
AREA. PARTS OF THE COASTAL AREA FROM PINELLAS COUNTY NORTH
RECEIVED 6 TO 8 INCHES OF RAIN IN THE PAST 24 HOURS. THIS PROMPTED
A FLOOD WATCH FOR COASTAL ZONES FROM PINELLAS COUNTY NORTH. THE
RAIN HAS BEEN MUCH LESS SIGNIFICANT OVER THE NORTHERN FORECAST
INLAND AREAS. THE SUBTROPICAL RIDGE IS SUPRESSED ACROSS SOUTH
FLORIDA WITH WESTERLY FLOW CONTINUING OVER THE FORECAST AREA. THE
MODELS ARE IN AGREEMENT IN KEEPING A BAND OF DEEP LAYER MOISTURE
PRODUCING MORE WIDESPREAD CONVECTION SATURDAY ACROSS CENTRAL
FLORIDA THROUGH SATURDAY IN ASSOCIATION WITH THE FRONTAL TROUGH.
DAYTIME TEMPERATURES WILL REMAIN COOLER IN RAIN AREAS.

.LONG TERM /SATURDAY NIGHT-FRIDAY/...
NOT MUCH NEED FOR IRRIGATION OVER THE MAJORITY OF WEST CENTRAL AND
SOUTHWEST FLORIDA THROUGH THE LONG TERM PERIOD AS SOUTHWEST FLOW
PROVIDED BY STEADY HIGH PRESSURE CONTINUES ACROSS WEST CENTRAL AND
SOUTHWEST FLORIDA. ABUNDANT GULF MOISTURE AVAILABLE THROUGH THE
PERIOD WILL ENABLE SHOWERS AND THUNDERSTORMS EACH DAY...WITH
COVERAGE THROUGH MUCH OF THE DAY INCLUDING THE OVERNIGHT AND MORNING
HOURS BEING HIGHER THAN MOST WOULD EXPECT DURING OUR NORMAL SUMMER
DIURNAL SEA BREEZE THUNDERSTORMS.

THE ADDITIONAL CLOUD COVER FROM CONVECTION WILL HELP KEEP
TEMPERATURES FEELING A TAD COOLER THAN AVERAGE FOR SUMMER. IT WILL
ALSO HELP SUPPRESS THE HEAT INDEX ACROSS MUCH OF THE AREA. MODEL
GUIDANCE WAS NOT TOO SPREAD IN ITS SOLUTION...PREFERRED A BLEND IN
THE FORECAST.
Quoting 49. Gearsts:

93L can't be more disorganized, i don't know what you see but i'm not seeing it.



Umm yes it can be a whole ton more disorganised so I have no idea what you on about
I am driving to Orlando tomorrow for a family birthday party and spending the night...........Will drive down there carefully and bring along an umbrella......................
Atlantic Tropical Weather Discussion


000
AXNT20 KNHC 171752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI JUL 17 2015

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N19W TO 17N18W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH A BROAD 700 MB TROUGH MOVING OFF THE
COAST OF WEST AFRICA THIS MORNING. 850 MB RELATIVE VORTICITY
FIELDS ALSO SHOW MAXIMUM VALUES ALONG THE WAVE AXIS NEAR
14N...AND IN ASSOCIATION WITH A NORTHERN VORTEX ANALYZED AS A
1011 MB LOW CENTERED NEAR THE NORTHERN TIP OF THE DEPICTED WAVE
AXIS. ISOLATED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 18W-
22W.

TROPICAL WAVE EXTENDS FROM 07N46W TO 17N43W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH A GLOBAL MODEL INDICATED 700 MB
TROUGHING THAT MATCHES UP WELL WITH TOTAL PRECIPITABLE WATER
IMAGERY AND LOW-LEVEL SATELLITE DERIVED WINDS. IT IS LIKELY
ENERGY FROM THE WAVE IMPACTED THE DEVELOPMENT OF A 1009 MB NOW
CENTERED TO THE EAST OF THE WAVE NEAR 11N38W. ISOLATED MODERATE
CONVECTION IS FROM 10N-12N BETWEEN 41W-44W.

TROPICAL WAVE EXTENDS FROM 09N78W TO 18N79W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH BROAD GLOBAL MODEL INDICATED 700 MB
TROUGHING ACROSS THE WESTERN CARIBBEAN SEA AND MOST RELATIVE
VORTICITY AT 850 MB REMAINING S OF 13N BETWEEN 76W-80W.
SCATTERED MODERATE CONVECTION IS CONFINED S OF 10N BETWEEN 76W-
84W...AND LIKELY MORE ASSOCIATED WITH THE CLOSE PROXIMITY TO THE
MONSOON TROUGH AXIS.



...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
10N20W TO 10N24W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 10N24W TO 12N34W TO 11N38W...THEN RESUMES NEAR
07N47W TO 06N57W. ASIDE FROM CONVECTION ASSOCIATED WITH THE
TROPICAL WAVE ALONG 45W...WIDELY SCATTERED MODERATE CONVECTION
IS FROM 04N-13N BETWEEN 23W-41W.

...DISCUSSION...

GULF OF MEXICO...

UPPER LEVEL NORTHEAST TO EASTERLY FLOW IS OCCURRING OVER MUCH OF
THE GULF ON THE SOUTHEASTERN PERIPHERY OF A MIDDLE TO UPPER
LEVEL RIDGE ANCHORED OVER THE NW GULF WATERS AND WEST TEXAS.
DEBRIS MOISTURE AND CLOUDINESS CONTINUES TO SPREAD SOUTHWESTWARD
FROM ACTIVE CONVECTION OCCURRING ACROSS THE NE GULF. THE AREA OF
CONVECTION STEMS FROM A BROAD AREA LOWER PRESSURE FOCUSED ON A
WEAK 1013 MB LOW CENTERED IN THE FLORIDA BIG BEND REGION NEAR
30N83W. LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH FAVORABLE
MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS
AND TSTMS FROM 26N-30N BETWEEN 82W-89W. OTHERWISE...THE
REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF SURFACE RIDGING
ANCHORED BY A 1018 MB HIGH CENTERED NEAR 25N86W. A RIDGE AXIS
EXTENDS NW FROM THE HIGH TO THE LOUISIANA COAST AND EAST ALONG
25N INTO THE SW NORTH ATLC. GENERALLY MODERATE TO OCCASIONAL
FRESH ANTICYCLONIC WINDS PREVAIL ON THE PERIPHERY OF THE RIDGE
WITH LIGHTER WINDS OCCURRING WITHIN 120 NM OF THE HIGH CENTER.
THE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY AND ANCHORED
ACROSS THE EAST-CENTRAL GULF WATERS THROUGH LATE SATURDAY.

CARIBBEAN SEA...

GENERALLY NORTHERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY W
OF 76W ON THE WESTERN PERIPHERY OF UPPER LEVEL TROUGHING
STEMMING FROM AN UPPER LEVEL LOW CENTERED NE OF PUERTO RICO NEAR
22N61W. MOSTLY FAIR SKIES ARE NOTED ACROSS THE WESTERN CARIBBEAN
EVEN AS A TROPICAL WAVE ALONG 79W CONTINUES WESTWARD. SCATTERED
SHOWERS AND TSTMS REMAIN CONFINED S OF 10N BETWEEN 76W-
84W...INCLUDING PORTIONS OF PANAMA AND COSTA RICA. A FEW
ISOLATED SHOWERS AND TSTMS ARE ALSO OCCURRING IN THE ADJACENT
COASTAL WATERS BETWEEN EASTERN CUBA AND JAMAICA. FARTHER
EAST...ON THE SOUTHERN PERIPHERY OF THE TROUGHING AND UPPER
LEVEL LOW...WEST-SOUTHWESTERLY FLOW ALOFT PREVAILS UNDER MOSTLY
FAIR SKIES...HOWEVER A FEW ISOLATED SHOWERS ARE BEGINNING TO
INITIATE ACROSS HISPANIOLA AND THE ADJACENT COASTAL WATERS N OF
16N. FINALLY...FRESH TO STRONG TRADES CONTINUE ACROSS CENTRAL
PORTIONS DUE TO A STRENGTHENED PRESSURE GRADIENT. THESE WINDS
ARE EXPECTED TO PERSIST THROUGH THE UPCOMING WEEKEND GENERALLY
BETWEEN 70W-80W.

...HISPANIOLA...

CURRENTLY...ISOLATED SHOWERS AND TSTMS ARE BEGINNING TO INITIATE
ACROSS THE ISLAND DUE TO NEAR-PEAK DAYTIME HEATING AND
INSTABILITY. IT IS LIKELY CONVECTIVE AREAL COVERAGE WILL
GRADUALLY INCREASE THROUGH THE EARLY EVENING AND THE BEGIN TO
DIMINISH THROUGH THE EARLY OVERNIGHT HOURS. WITH A MARGINALLY
DIFFLUENT ENVIRONMENT ALOFT ACROSS THE ISLAND...THIS OVERALL
SYNOPTIC REGIME IS EXPECTED TO PERSIST AND GENERATE CONVECTION
DURING THE EARLY AFTERNOON AND LATE EVENING THE NEXT FEW DAYS.


ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY WITH AXIS
EXTENDING FROM 37N67W TO A BASE NEAR 30N71W. THIS SHORTWAVE
TROUGH SUPPORTS A COLD FRONT ANALYZED NORTH OF THE DISCUSSION
AREA FROM 35N66W TO 32N76W AND BECOMES STATIONARY TO 31N80W. LOW-
LEVEL MOISTURE CONVERGENCE SOUTH OF THE FRONT COUPLED WITH
MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED
SHOWERS AND ISOLATED TSTMS ACROSS MUCH OF THE SW NORTH ATLC FROM
26N-33N BETWEEN 66W-79W.

TO THE SOUTHEAST OF THE FRONT...AN
UPPER LEVEL LOW IS CENTERED NEAR 22N61W AND IS GENERATING AN
AREA OF ISOLATED SHOWERS AND TSTMS FROM 21N-27N BETWEEN 54W-63W
ON THE SOUTHERN PERIPHERY OF A SURFACE RIDGE ANCHORED BY A 1022
MB HIGH CENTERED NEAR 29N63W. FARTHER EAST...THE REMAINDER OF
THE EASTERN ATLC IS UNDER THE INFLUENCE OF ANOTHER SURFACE RIDGE
ANCHORED BY A 1023 MB HIGH CENTERED NEAR 32N28W. A WEAKNESS
BETWEEN THE TWO AFOREMENTIONED HIGHS IS ANALYZED AS A SURFACE
TROUGH FROM 31N44W TO 25N54W. POSSIBLE ISOLATED SHOWERS ARE
OCCURRING WITHIN 45 NM EITHER SIDE OF THE BOUNDARY.

FOR ADDITIONAL INFORMATION PLEASE VISIT
WWW.HURRICANES.GOV/MARINE
Where is Grothar...........................

Quoting 53. wunderkidcayman:



Umm yes it can be a whole ton more disorganised so I have no idea what you on about
93L is a mess, that's what i am on about.
Interesting!
Tampa 248 nm Radar composite loop



Whos's Sal??
Quoting 62. Gearsts:




So is that the precursor to one of the storms shown in The Day After Tomorrow??
FLOOD ADVISORY
NATIONAL WEATHER SERVICE MELBOURNE FL
356 PM EDT FRI JUL 17 2015

FLC009-117-127-172130-
/O.NEW.KMLB.FA.Y.0035.150717T1956Z-150717T2130Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000 Z.OO/
BREVARD FL-VOLUSIA FL-SEMINOLE FL-
356 PM EDT FRI JUL 17 2015

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* FLOOD ADVISORY FOR...
NORTHWESTERN BREVARD COUNTY IN FLORIDA...
SOUTHEASTERN VOLUSIA COUNTY IN EAST CENTRAL FLORIDA...
SEMINOLE COUNTY IN EAST CENTRAL FLORIDA...

* UNTIL 530 PM EDT

* AT 353 PM EDT...DOPPLER RADAR INDICATED HEAVY RAIN DUE TO
THUNDERSTORMS. THIS WILL CAUSE MINOR FLOODING IN THE ADVISORY
AREA. UP TO ONE AND A HALF TO TWO INCHES OF RAIN HAVE ALREADY
FALLEN SINCE 2 PM THIS AFTERNOON.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE... AREAS
AROUND LAKE HARNEY...DELTONA...PORT ORANGE...SANFORD...ALTAMONTE
SPRINGS AND OVIEDO.

ADDITIONAL RAINFALL OF ONE TO TWO INCHES IS EXPECTED OVER THE AREA.
THIS ADDITIONAL RAIN WILL CAUSE MINOR FLOODING OF ROADWAYS AND POOR
DRAINAGE AREAS.

A few sea breeze induced showers and thunderstorms North of us but no relief here in Port Fourchon today. 5 day upper charts show High pressure dome staying parked over ArkLaTex so guess I better grin and bear it.
Dear friends I want to show you a video of the hurricane Dolores near to the Socorro Island, México. http://bit.ly/1CJQIPb Hope wunderground can added to the information of the hurricane Dolores in the site.
Been waiting for this...

... Significant weather advisory for frequent to excessive lightning
and 45 to 55 mph winds for northeastern Palm Beach County until 515
PM EDT...

* at 433 PM EDT... Doppler radar was tracking a strong thunderstorm
near lion country safari park... or near Wellington. This storm was
moving northeast around 10 mph.

* The primary impacts will be frequent to excessive lightning and
gusty winds of 45 to 55 mph. Lightning is the number one weather
related killer in Florida. Trees and open shelters offer no
protection. These winds can down small tree limbs and branches...
and blow around unsecured small objects. Seek shelter in a safe
building until the storm passes.

* Locations impacted include...
West Palm Beach... Wellington... Jupiter... Palm Beach Gardens... Royal
Palm Beach... lion country safari park... the acreage... North County
Airport... Loxahatchee Groves... Loxahatchee NWR and caloosa.
93L paving the way for those waves to follow.
Quoting 67. GeorgefromLosCabos:

Dear friends I want to show you a video of the hurricane Dolores near to the Socorro Island, México. http://bit.ly/1CJQIPb Hope wunderground can added to the information of the hurricane Dolores in the site.

Thanks for sharing this. Gotta LOVE the guy running down the stairs in bare feet!
i do not see anything happern to invest 93L ANYTIME SOON
Quoting 58. Gearsts:

93L is a mess, that's what i am on about.


We have seen much worse


Quoting 62. Gearsts:


Quoting 64. JrWeathermanFL:



So is that the precursor to one of the storms shown in The Day After Tomorrow??


Hmm
It would have to be much bigger than that and be one system for it to be "The Day after Tomorrow" category

Interesting though two storms under one distinct cloud field

Gives the appreance of Hurricane Sandy superstorm size
Quoting 62. Gearsts:




Somehow I feel like this is unrealistic, lol.
Convection starting to rebuild and pop up with 93L
Quoting 57. weathermanwannabe:

Where is Grothar...........................


BAHHHHHLOOOOOOOOOOBBBBBB!
JeffMasters has created a new entry.
I just 93L holds together long enough to bring much needed rain to STX... We are one match away from being a bonfire for STT to roast marshmallows on. :|