Invest 91L Bringing Heavy Rains to Florida, Cuba, and Mexico

By: Dr. Jeff Masters , 3:44 PM GMT on June 03, 2013

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The Atlantic hurricane season began on June 1, and we already have a threat to discuss. A trough of low pressure has developed over the Western Caribbean, Mexico's Yucatan Peninsula, and Southeast Gulf of Mexico, and is dumping heavy rains over the area. Hurricane Barbara, which died on Thursday as it attempted to cross Mexico's Isthmus of Tehuantepec into the southernmost Gulf of Mexico, has contributed moisture to this disturbance, which has been designated 91L by NHC. Satellite loops show a large area of heavy thunderstorms with poor organization, and there is no evidence of an organized surface circulation trying to form. Wind shear is a high 30 knots, and is forecast to remain high, 20 - 30 knots, over the next five days, so any development should be slow to occur. NHC is giving the disturbance a 20% chance of developing into a tropical cyclone by Wednesday. The Hurricane Hunters are on call to fly into 91L on Tuesday afternoon, if necessary. Regardless of whether or not 91L develops into a tropical depression, heavy rains will be the storm's main threat. Mexico's Yucatan Peninsula, Western Cuba, and South Florida can expect 5 - 8" of rain from the disturbance over the next four days. Heavy rains from 91L may spread up the U.S. East Cost late this week. The computer models predict that 91L should stay large and poorly organized, and if it does develop, it will be difficult for it to get any stronger than a 45 mph tropical storm in the Gulf of Mexico.


Figure 1. Latest satellite image of Invest 91L.

Jeff Masters

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And, what happened to that ghost storm that was supposed to perk up from the perennial Columbian Low again this year? ;)

It's too early still to get excited. Models are still transitioning seasonal data, conditions still not where they need to be for cycolgenesis proper. But, don't fret, I'm thinking the season's going to have several surprises in store for us. :(
Member Since: July 9, 2006 Posts: 184 Comments: 29610
Quoting Jedkins01:


It sounds like Debby too regarding the tornado potential. We had a local tornado outbreak with Debby involving numerous rotating tropical super cells and some confirmed tornadoes resulting in unfortunately killing 1.


Looks like debby...

smell it:)
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395. VR46L
91L Navy Page IR

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Quoting DDR:
Good afternoon
3.5 inches of rain since 8pm last night here in Trinidad,drier weather coming in behind this wave.

Hey DDR!
Yeah, you can see the drier air on the SAL map behind the eastern Carib tropical wave.

I'm currently in central Jamaica (Manchester) and we've been having intermittent showers since Saturday! The weather in Manchester is completely different from the rest of Jamaica. It was given the name due to the similar weather pattern to that of Manchester, England...cool in the winter and wet and cloudy in the spring and summer months.
Member Since: November 6, 2010 Posts: 14 Comments: 8979
Quoting FLWeatherFreak91:

000
FXUS62 KTBW 031933
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
333 PM EDT MON JUN 3 2013

.SHORT TERM (TODAY-WEDNESDAY)...
CURRENTLY AT THE SURFACE...A BROAD AREA OF LOW PRESSURE REMAINS
NEARLY STATIONARY OVER THE SOUTHERN GULF OF MEXICO...WITH A
WEAKENING FRONTAL BOUNDARY STRETCHING FROM THE COASTAL CAROLINAS
SOUTHWESTWARD INTO THE NORTH-CENTRAL GULF. VISIBLE SATELLITE IMAGERY
SHOWS MOSTLY CLOUDY SKIES IN PLACE ACROSS THE FORECAST AREA...WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS SEEN IN RADAR
IMAGERY. MAIN SHORT TERM CONCERN FOR TONIGHT REVOLVES AROUND POPS
ONCE AGAIN.

TONIGHT...
THE FRONTAL BOUNDARY NORTH OF THE FORECAST AREA WILL
DISSIPATE...WHILE THE BROAD AREA OF LOW PRESSURE OVER THE SOUTHERN
GULF REMAINS NEARLY STATIONARY. WITH THE BREAKDOWN OF THE FRONTAL
BOUNDARY NORTH OF THE AREA...THE LOW LEVEL BOUNDARY LAYER FLOW IS
EXPECTED TO SHIFT FROM THE SOUTH-SOUTHWEST AROUND TO THE
SOUTH-SOUTHEAST. WILL KEEP CHANCE POPS ACROSS THE SOUTHERN TWO
THIRDS OF THE FORECAST AREA THIS EVENING...WITH LIGHT CHANCE POPS
ACROSS THE NORTH. AFTER MIDNIGHT...EXPECT THE ACTIVITY TO WIND DOWN
ACROSS THE INTERIOR...BUT WITH PRECIPITABLE WATER VALUES REMAINING
ABOVE 2.0 INCHES AND WEAK SHORTWAVE ENERGY MOVING ACROSS THE
AREA...WILL KEEP SLIGHT CHANCE POPS GOING HERE WITH CHANCE POPS
ALONG THE COAST. OVERNIGHT LOWS ARE EXPECTED TO BOTTOM OUT IN THE
LOW TO MID 70S.

TUESDAY THROUGH WEDNESDAY...
THE 12Z GFS AND 12Z ECMWF ARE IN GOOD AGREEMENT SHOWING THE BROAD
AREA OF LOW PRESSURE OVER THE SOUTHERN GULF OF MEXICO...SLOWLY
CONSOLIDATING AND STRENGTHENING SLIGHTLY THROUGH THE PERIOD TO A
1004/1005 MB LOW BY WEDNESDAY EVENING. THE 12Z CANADIAN ON THE
OTHERHAND IS MUCH MORE AGGRESSIVE WITH THE DEVELOPMENT OF THE
LOW...SHOWING A 998 MB LOW BY WEDNESDAY EVENING OVER THE CENTRAL
GULF. THE CANADIAN IS KNOWN TO BE OVERLY AGGRESSIVE WITH THE
DEVELOPMENT OF TROPICAL SYSTEMS...SO HAVE LEANED THE FORECAST IN
FAVOR OF THE GFS AND ECMWF
. THIS RESULTS IN A SOUTH TO SOUTHEAST
BOUNDARY LAYER FLOW CONTINUING TO ADVECT DEEP TROPICAL MOISTURE
ACROSS THE AREA THROUGH THE PERIOD...WITH PRECIPITABLE WATER VALUES
REMAINING IN THE 2.00 TO 2.25 RANGE. WITH ABUNDANT MOISTURE IN PLACE
ALONG WITH SOME WEAK UPPER LEVEL IMPULSES ROTATING THROUGH THE
REGION...EXPECT UNSETTLED WEATHER AND LOCALLY HEAVY RAINFALL TO
CONTINUE THROUGH THE PERIOD. HIGH TEMPERATURES ARE EXPECTED TO TOP
OUT IN THE MID 80S...WITH LOWS IN THE LOW TO MID 70S.

&&

.LONG TERM...
NO CHANGES MADE TO THE EXTENDED FORECAST FROM THE PREVIOUS SHIFT.
PLEASE REFERENCE THE LATEST PRODUCTS FROM THE NATIONAL HURRICANE
CENTER AND THE WEATHER PREDICTION CENTER.

THE FUTURE OF A WEAK LOW PRESSURE AREA LOCATED NEAR THE YUCATAN
PENINSULA WILL BE THE BIGGEST FACTOR IN THE LONG TERM FORECAST
PERIOD. MODEL GUIDANCE HAS BEEN ON A CONSISTENT TREND OF BRINGING
THE WEAK LOW PRESSURE AREA TOWARDS FLORIDA BY THIS WEEKEND. DEEP
TROPICAL MOISTURE WILL CREATE HEAVY RAINFALL AMOUNTS EXPECTED TO BE
IN THE 3 TO 6 INCH RANGE...WITH HEAVIER LOCALIZED AMOUNTS...FOR THIS
EVENT. THE CURRENT AIR MASS IS EXPECTED TO BECOME MORE FAVORABLE AND
EFFICIENT FOR HEAVY RAIN PRODUCTION.


MODEL GUIDANCE IS TRENDING TOWARDS A MORE CONSISTENT SOLUTION
FEATURING A LOW...NOT ENTIRELY TROPICAL IN CHARACTERISTICS...TRAVERSING
FLORIDA BY THE WEEKEND. THE 12Z GFS HAS THE LOW REACHING THE OPEN
GULF OF MEXICO WEDNESDAY INTO THURSDAY...PROVIDING OUR AREA WITH
BANDS OF RAIN AND FAVORABLE DYNAMICS FOR TORNADIC ACTIVITY. A 30 KNOT
700 MB JET BEGINS TO EASE IN OVER PORTIONS OF SW FLORIDA AROUND
06-12Z ON THURSDAY ACCORDING TO THE 12Z GFS. THE 12Z CMC OFFERS A
SLIGHTLY STRONGER LOW PRESSURE AREA AT THIS TIME...WHICH HAS THE 700
MB JET REACHING THE AREA BETWEEN 12Z AND 18Z ON WEDNESDAY.

LOWER LCLS CAN BE EXPECTED THANKS TO THE TROPICAL NATURE OF THE
AIRMASS...WITH THE 12Z GFS FEATURING AROUND A 700 FT LCL FOR TPA...A
500 FT LCL AT SRQ...A 600 FT LCL AT LAL...AND A 700-800 FT LCL AT
FMY AROUND 18Z THURSDAY...WHICH IS CONDUCIVE FOR TORNADOES. WITH THE
LOW FORECAST TO PASS WEST OF THE AREA...THE LOW LEVEL JET ON THE
RIGHT SIDE OF THE SYSTEM WILL BE ACCESSIBLE TO POTENTIAL TORNADIC
CONVECTION. THE 12Z GFS AND 00Z ECMWF ARE CONSISTENT WITH AN
INCREASING 0-1 KM HELICITY TREND STARTING AT 00Z THURSDAY...WITH
VALUES PEAKING BETWEEN 100-200 M2/S2 ACROSS MUCH OF THE CWA ON
THURSDAY AFTERNOON. 0-1 KM BULK SHEAR VALUES EASILY PEAKING ABOVE
20-25 KNOTS ALSO RAISES A LARGE RED FLAG FOR TORNADIC ACTIVITY. 0-6
KM BULK SHEAR VALUES OF 25-35 KNOTS ARE RESPECTABLE.


THE 12Z CMC CONTINUES TO BE CONSISTENT WITH A STRONGER LOW COMING
ASHORE BETWEEN PANAMA CITY AND TALLAHASSEE AROUND 00Z FRIDAY. THE
12Z GFS BRINGS THE WEAK LOW/TROUGH INTO THE BIG BEND OF
FLORIDA...LIKELY INTO THE SUWANNEE RIVER VALLEY ON FRIDAY AS WELL.
EITHER WAY...MOST OF THE COUNTY WARNING AREA AND MARINE OF
RESPONSIBILITY WILL SEE SOME EFFECTS FROM THIS SYSTEM AS
FORECAST AT THIS TIME.

&&

.AVIATION...
SHOWERS...WITH AN OCCASIONAL THUNDERSTORM...SPREADING ACROSS THE
WESTERN PENINSULA THIS AFTERNOON. WINDS UP TO 10 KNOTS OUT OF THE
SOUTH TO SOUTHWEST...WITH VARIABLE GUSTINESS AROUND SHOWERS AND
THUNDERSTORMS. THUNDERSTORM ACTIVITY SHOULD DIMINISH AFTER
SUNSET...WITH SOME SHOWER ACTIVITY CONTINUING THROUGH THE PERIOD.
COULD SEE THUNDERSTORMS START UP SOMETIME NEAR THE END OF THE TAF
PERIOD.

&&

.MARINE...
WINDS AND SEAS WILL INCREASE DURING THE WEEK WITH EXERCISE CAUTION
OR SMALL CRAFT ADVISORY HEADLINES EXPECTED TUESDAY NIGHT THROUGH
THURSDAY NIGHT OVER PORTIONS OF THE COASTAL WATERS AS AN AREA OF LOW
PRESSURE APPROACHES FROM THE SOUTHWEST AND EVENTUALLY TRACKS THROUGH
NORTH FLORIDA LATE IN THE WEEK.

&&

.FIRE WEATHER...
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS AS ABUNDANT
MOISTURE WILL REMAIN ACROSS THE REGION KEEPING RELATIVE HUMIDITY
VALUES WELL ABOVE CRITICAL LEVELS.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA 74 85 74 87 / 30 70 40 70
FMY 74 85 73 85 / 40 70 70 70
GIF 72 86 72 86 / 50 70 40 70
SRQ 75 84 74 86 / 40 60 50 70
BKV 72 85 72 87 / 20 70 40 60
SPG 76 85 75 85 / 40 60 50 70

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

$$

SHORT TERM/MARINE/FIRE WEATHER...JELSEMA
LONG TERM/AVIATION...GARCIA




It sounds like Debby too regarding the tornado potential. We had a local tornado outbreak with Debby involving numerous rotating tropical super cells and some confirmed tornadoes resulting in unfortunately killing 1.
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Quoting StormTrackerScott:


I agree, I am talking as a whole. People seem to be getting more and more reckless when chasing. The fact of the matter is that these tornadoes can be very unpredictable and people should use caution when chasing.


theres no way to really regulate chasing either
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Quoting mikatnight:


Or, they could get the Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses...
especially designed to help people develop a relaxed attitude towards danger. They work by turning completely dark at the first sign of something bad about to happen, thus preventing the wearer from seeing anything that might be alarming.


And towel day was just a few days ago!
Link
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Quoting Bluestorm5:
Very impressive! So we might have to have couple of those to get the whole area or they're trying to get quicker scan time for regular radar that scans the area?

They can aim the phased array radar like a gun and follow any suspect areas and not have to wait for a scan by normal rotating radar. The phased array radar would only be used to look at particular areas during severe weather. The normal rotating radar is what we'll usually see.
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Quoting CybrTeddy:


But that wasn't Samaras, he wasn't the type of guy who'd go in to "get the shot." He was truly trying to save lives.


I agree, I am talking as a whole. People seem to be getting more and more reckless when chasing. The fact of the matter is that these tornadoes can be very unpredictable and people should use caution when chasing.
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Measurable Rain in NWFL - Finally! Thank goodness!
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Quoting sar2401:

No, put them back in, you'll need them to see. :-) What would posses you to want to go to Florida in August? Geez, hurricanes, heat, humidity, getting struck by lightning, alligators...well, I guess it's kind of like south Alabama, but I live here. :-)


Or, they could get the Joo Janta 200 Super-Chromatic Peril Sensitive Sunglasses...
especially designed to help people develop a relaxed attitude towards danger. They work by turning completely dark at the first sign of something bad about to happen, thus preventing the wearer from seeing anything that might be alarming.
Member Since: Posts: Comments:
Off weather topic.. what a game between the Miami Heat and Indiana Pacers today,I'm rooting for Indiana but i think the Heat will win...I'm a Lakers fan :)
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Quoting nigel20:
Good afternoon friends!

Hi Nigel. How are things in paradise?
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Quoting TropicalAnalystwx13:

Was talking to a mechanical engineering student at Missouri's University of Science and Technology and that's the value he stated, referencing Dr. Don Burgess (retired federal research meteorologist/part time with OU/CIMSS).
Do you have a link to the paper? Or a link to the conversation if it was on a forum?

The whole premise seems a little ridiculous to me. Perhaps in an idealized model simulation, but in the real world, eh, I'm doubtful winds scale very well at all. They may be roughly scalable but I'd still expect large error margins/range of values.
Member Since: August 24, 2010 Posts: 19 Comments: 4358
Good afternoon. This is exactly what I think of when someone says "June invest", lol. A nice sheared mess.



Obviously regardless of development very heavy rain is really the only major threat from this system, especially for Florida.
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Quoting StormTrackerScott:


If Storm Chasers don't learn from this then we will see more Storm Chasers die at the hands of Mother Nature. It seems that over the last 10 years Storm Chaser are getting more and more careless when chasing while only trying to get that "money shot". I am hoping that this serves as a wake up call. Rest in Peace Tim.


But that wasn't Samaras, he wasn't the type of guy who'd go in to "get the shot." He was truly trying to save lives.
Member Since: July 8, 2005 Posts: 259 Comments: 24972
Quoting TomTaylor:
The future of weather radar:




This radar loop shows the evolution of the El Reno tornado and associated storms around the OKC metro area on the 30th as seen by MPAR. MPAR stands for Multifunction Phased Array Radar and is essentially the next generation of weather radar. I don't know too much about MPAR but its main advantages over existing weather radars are faster scan rates and the ability to chose where you want the radar to look. MPAR can complete a scan in under a minute, whereas WSD-88 can take 4-5 minutes depending on scan mode. The higher temporal resolution is extremely beneficial for examining severe weather threats which often evolve on very short time scales. In addition, I'd assume greater spatial resolution and more tilts should be achievable with this technology but I'm not entirely sure.
Very impressive! So we might have to have couple of those to get the whole area or they're trying to get quicker scan time for regular radar that scans the area?
Member Since: August 1, 2011 Posts: 28 Comments: 8123
Quoting moonlightcowboy:
Mid-level shear is conducive at 5-10 kts, but there's still too much upper level shear although some relaxing seems to be forecast. Clearly 91L has some surface rotation although still quite unorganized, and marginal convection is still managing to be swept from over the coc. No readily visible closed low-level center that I can see, but my eyes are not what they used to be either. The real killer, however, for development now is dry air to its north and west;)

I see the NHC has upped its chances to 20%. Personally, that seems a bit optimistic given current conditions and observations. However, "IF" it can maintain some low to mid-level rotation, create some lift with convection, get some winds cycling, and gradually build some structure with relaxing shear, it might, just might spin up. That's a big IF though, I think. :)



Great to see ya post, MLC! Kudos for bringing up the midlevel shear product; I like that one for blob watching(with the lowest mean layer wind product also, to help judge advection potentials).

I, personally, think the moderating influence on our monsoon gyre here will be the dryer air to the N and W. With each low level vort that asserts its dominance; We should see influx of this airmass, causing separation from the gyre, and the subsequent ejection of energy. Rinse, repeat, ad nauseum...
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Quoting nigel20:
Good afternoon friends!


afternoon nigel!
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Quoting moonlightcowboy:
Mid-level shear is conducive at 5-10 kts, but there's still too much upper level shear although some relaxing seems to be forecast. Clearly 91L has some surface rotation although still quite unorganized, and marginal convection is still managing to be swept from over the coc. No readily visible closed low-level center that I can see, but my eyes are not what they used to be either. The real killer, however, for development now is dry air to its north and west;)

I see the NHC has upped its chances to 20%. Personally, that seems a bit optimistic given current conditions and observations. However, "IF" it can maintain some low to mid-level rotation, create some lift with convection, get some winds cycling, and gradually build some structure with relaxing shear, it might, just might spin up. That's a big IF though, I think. :)


Actually, it's been at 20% since early yesterday. So far, the NHC is not getting too excited about 91L.
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Quoting CybrTeddy:


Looking slightly better than before. But its the typical sheared and elongated system that usually form early in the season.
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Quoting docrod:


Thanks - odd that the Navy is labeling the floaters as GOES13. That threw me.


I think the Navy is one of the direct readout users:

Direct readout users who wish to examine the data should be aware that the data are for testing purposes only at this time.
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okay for us to get a strong tropical storm the wind shear would need to reduce to <10 knots... In Dr. Masters blog, and I quote, he says," Wind shear is a high 30 knots, and is forecast to remain high, 20 - 30 knots, over the next five days, so any development should be slow to occur."

with shear at 20-30 knots, no convection will be able to consistently fire near the center enough to form a well defined core, something this storm probably won't ever do, as the circulation is rather pathetic.
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Good afternoon friends!
Member Since: November 6, 2010 Posts: 14 Comments: 8979
Quoting nrtiwlnvragn:


In Testing


Thanks - odd that the Navy is labeling the floaters as GOES13. That threw me.
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Quoting SouthernIllinois:

I honestly don't even think it'll become a TS. Just a big old rainmaking system that is going to bring many headaches.


That's the ticket! ;) Too many things encumbering any kind of maturity at this point for sure.
Member Since: July 9, 2006 Posts: 184 Comments: 29610
Quoting docrod:
Question about GOES13: working or not?

Wiki says down as of May 22
Link

NOAA .....
Link
.... says imaging and sounding are down and GOES14 has taken over but the status board below shows green.

On the Navy's sat page, the current 91L floater image is labeled as coming from GOES13
Link



In Testing
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Quoting CybrTeddy:
NWS Norman indicates they're closely looking at the data during the El Reno tornado and we'll have an update tomorrow or so per their twitter feed. Seems an upgrade to at least EF4 is likely.


If Storm Chasers don't learn from this then we will see more Storm Chasers die at the hands of Mother Nature. It seems that over the last 10 years Storm Chaser are getting more and more careless when chasing while only trying to get that "money shot". I am hoping that this serves as a wake up call. Rest in Peace Tim.
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Member Since: July 8, 2005 Posts: 259 Comments: 24972
Question about GOES13: working or not?

Wiki says down as of May 22
Link

NOAA .....
Link
.... says imaging and sounding are down and GOES14 has taken over but the status board below shows green.

On the Navy's sat page, the current 91L floater image is labeled as coming from GOES13
Link

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Quoting allancalderini:
Thanks Dr.Masters.Btw I finally got my wish today from 9 to 12 I receive the rain I want it was falling so hard it was amazing and there were lightnings and thunder what more I could wish for.hope it continues to rain the heat is unbelivable hope more rain fall soon. Btw sorry If I wrote something wrong right now I from my blackberry as they are no lights right now in some parts of the city.

What part of Honduras are you in?
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Don't understand our local Met's? in the late News last night they said to expect heavy rain and stormy weather today and for the rest of the week,here in South Florida (Miami)cloudy but not a drop of rain today?.Interesting looking at the Gulf of Mexico Rainbow loop satellite you can see a lot of clouds over Florida but again not rain,so don't know where are the 10-20" that we are supposed to get this week?.You have to understand the Met's backwards,when they said sunny and dry expect a lot of rain,when they said 70% of rain and storm expect no rain!! LOL!!!!!.
It will be a interesting week,first to see if the low in the GOM develops?, second to seeif South Florida will get the heavy rain they are predicting?,will see what finally happens.
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NWS Norman indicates they're closely looking at the data during the El Reno tornado and we'll have an update tomorrow or so per their twitter feed. Seems an upgrade to at least EF4 is likely.
Member Since: July 8, 2005 Posts: 259 Comments: 24972
Quoting TomTaylor:
Where's the 20% reduction coming from? As far as I'm aware, there are no reduction guidelines for AGL winds to surface winds in a tornado.

...And I doubt there ever will be guidelines because each tornado is so different and the flow around them is so turbulent (hurricanes, which do have wind reduction guidelines to the surface, are much more laminar) it wouldn't make sense to use these generalizations.

Was talking to a mechanical engineering student at Missouri's University of Science and Technology and that's the value he stated, referencing Dr. Don Burgess (retired federal research meteorologist/part time with OU/CIMSS).

Out for now.
Member Since: July 6, 2010 Posts: 113 Comments: 34205
362. DDR
Quoting allancalderini:
Thanks Dr.Masters.Btw I finally got my wish today from 9 to 12 I receive the rain I want it was falling so hard it was amazing and there were lightnings and thunder what more I could wish for.hope it continues to rain the heat is unbelivable hope more rain fall soon. Btw sorry If I wrote something wrong right now I from my blackberry as they are no lights right now in some parts of the city.

Hello allan,good to know,the heat has been crazy here as well a full 2-3 degrees celcius above average the past 2 months.
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Mid-level shear is conducive at 5-10 kts, but there's still too much upper level shear although some relaxing seems to be forecast. Clearly 91L has some surface rotation although still quite unorganized, and marginal convection is still managing to be swept from over the coc. No readily visible closed low-level center that I can see, but my eyes are not what they used to be either. The real killer, however, for development now is dry air to its north and west;)

I see the NHC has upped its chances to 20%. Personally, that seems a bit optimistic given current conditions and observations. However, "IF" it can maintain some low to mid-level rotation, create some lift with convection, get some winds cycling, and gradually build some structure with relaxing shear, it might, just might spin up. That's a big IF though, I think. :)

Member Since: July 9, 2006 Posts: 184 Comments: 29610
360. DDR
Good afternoon
3.5 inches of rain since 8pm last night here in Trinidad,drier weather coming in behind this wave.
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Models trying to spin 90L up to a moderate TS. I find it to be possible but unlikely. Shear is around 20kts and should fall to about 10-20kts. The system is over the warm loop current of the Gulf which will help support some its convection. However, dry air is another factor that will inhibit a system from have a decent western side. So I give a 50% of becoming a weak TS. Regardless, this will bring rain and t-storms to south Florida and spreading up the Central Florida by tomorrow. Once this is all said and done I see 6-9 inches of rain with locally 12'' for Florida.
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Quoting FunnelVortex:
I'm going to Florida for the first half of August, if it is going to be an active hurricane season, I should keep my eyes out.

No, put them back in, you'll need them to see. :-) What would posses you to want to go to Florida in August? Geez, hurricanes, heat, humidity, getting struck by lightning, alligators...well, I guess it's kind of like south Alabama, but I live here. :-)
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Quoting TropicalAnalystwx13:

This tornado was weird though. If we use the 20% reduction for surface winds, that gives 195 mph-210 mph, which is a high-end EF4 to EF5. When OUN went surveying, they found no evidence of tree debarking, ground scouring, or wind rowing...things you would expect from a tornado of this magnitude.

Strange.
Where's the 20% reduction coming from? As far as I'm aware, there are no reduction guidelines for AGL winds to surface winds in a tornado.

...And I doubt there ever will be guidelines because each tornado is so different and the flow around them is so turbulent (hurricanes, which do have wind reduction guidelines to the surface, are considerably more laminar in flow) it wouldn't make sense to use these generalizations.

Quoting sar2401:

Well, I sure hope it works better than our dual polarization radar just recently installed here in Alabama. It's down for maintenance almost as often as it's up. But that MPAR thing, that will be the real deal. My nephew is in the Navy, and he's the MPAR operator on an unnamed ship, and does all kinds of secret squirrel things. He did tell me the the MPAR radar they use can differentiate between an albatross and an incoming sea skimming missile at 20 miles, so it should work pretty good on tornadoes. The only problem is that is took the NWS about 10 years to scrape up the money for dual-pol radar, and an MPAR installation is like a zillion times more expensive.
Neat. Yea, money is always an issue, probably won't see this technology fully incorporated for at least another 15-20 years. However, I'd expect a few more of them to be installed in severe weather prone regions in the next 5-10 years. NSSL an the HWT are going to have do a lot more testing with the OKC radar so they can "prove" it is worth it to congress before that happens though.
Member Since: August 24, 2010 Posts: 19 Comments: 4358
Quoting StormTrackerScott:
This may look sloppy now but expect this to get much better organized over the next 72 hours. I wouldn't rule out a 70mph landfalling TS on Friday near Cedar Key.


I would
Member Since: Posts: Comments:
Thanks Dr.Masters.Btw I finally got my wish today from 9 to 12 I receive the rain I want it was falling so hard it was amazing and there were lightnings and thunder what more I could wish for.hope it continues to rain the heat is unbelivable hope more rain fall soon. Btw sorry If I wrote something wrong right now I from my blackberry as they are no lights right now in some parts of the city.
Member Since: October 15, 2011 Posts: 0 Comments: 4488
354. VR46L
The Spag models seem to have some sort of agreement



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353. VR46L
Quoting SouthernIllinois:

I honestly don't even think it'll become a TS. Just a big old rainmaking system that is going to bring many headaches.


Yeah ! I know what you mean . I hope she sheds some of the rainfall before she gets there .
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Quoting StormTrackerScott:
This may look sloppy now but expect this to get much better organized over the next 72 hours. I wouldn't rule out a 70mph landfalling TS on Friday near Cedar Key.


GFS isn't doing much with it. Takes it as low as 1003mb in a few days.

Euro takes it to above 25m/s as it crosses Florida, which comes to (at least?) 55mph sustained, which is well above the Ships intensity model.
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WOW!!

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Moved.
Member Since: August 24, 2010 Posts: 19 Comments: 4358

000
FXUS62 KTBW 031933
AFDTBW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
333 PM EDT MON JUN 3 2013

.SHORT TERM (TODAY-WEDNESDAY)...
CURRENTLY AT THE SURFACE...A BROAD AREA OF LOW PRESSURE REMAINS
NEARLY STATIONARY OVER THE SOUTHERN GULF OF MEXICO...WITH A
WEAKENING FRONTAL BOUNDARY STRETCHING FROM THE COASTAL CAROLINAS
SOUTHWESTWARD INTO THE NORTH-CENTRAL GULF. VISIBLE SATELLITE IMAGERY
SHOWS MOSTLY CLOUDY SKIES IN PLACE ACROSS THE FORECAST AREA...WITH
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS SEEN IN RADAR
IMAGERY. MAIN SHORT TERM CONCERN FOR TONIGHT REVOLVES AROUND POPS
ONCE AGAIN.

TONIGHT...
THE FRONTAL BOUNDARY NORTH OF THE FORECAST AREA WILL
DISSIPATE...WHILE THE BROAD AREA OF LOW PRESSURE OVER THE SOUTHERN
GULF REMAINS NEARLY STATIONARY. WITH THE BREAKDOWN OF THE FRONTAL
BOUNDARY NORTH OF THE AREA...THE LOW LEVEL BOUNDARY LAYER FLOW IS
EXPECTED TO SHIFT FROM THE SOUTH-SOUTHWEST AROUND TO THE
SOUTH-SOUTHEAST. WILL KEEP CHANCE POPS ACROSS THE SOUTHERN TWO
THIRDS OF THE FORECAST AREA THIS EVENING...WITH LIGHT CHANCE POPS
ACROSS THE NORTH. AFTER MIDNIGHT...EXPECT THE ACTIVITY TO WIND DOWN
ACROSS THE INTERIOR...BUT WITH PRECIPITABLE WATER VALUES REMAINING
ABOVE 2.0 INCHES AND WEAK SHORTWAVE ENERGY MOVING ACROSS THE
AREA...WILL KEEP SLIGHT CHANCE POPS GOING HERE WITH CHANCE POPS
ALONG THE COAST. OVERNIGHT LOWS ARE EXPECTED TO BOTTOM OUT IN THE
LOW TO MID 70S.

TUESDAY THROUGH WEDNESDAY...
THE 12Z GFS AND 12Z ECMWF ARE IN GOOD AGREEMENT SHOWING THE BROAD
AREA OF LOW PRESSURE OVER THE SOUTHERN GULF OF MEXICO...SLOWLY
CONSOLIDATING AND STRENGTHENING SLIGHTLY THROUGH THE PERIOD TO A
1004/1005 MB LOW BY WEDNESDAY EVENING. THE 12Z CANADIAN ON THE
OTHERHAND IS MUCH MORE AGGRESSIVE WITH THE DEVELOPMENT OF THE
LOW...SHOWING A 998 MB LOW BY WEDNESDAY EVENING OVER THE CENTRAL
GULF. THE CANADIAN IS KNOWN TO BE OVERLY AGGRESSIVE WITH THE
DEVELOPMENT OF TROPICAL SYSTEMS...SO HAVE LEANED THE FORECAST IN
FAVOR OF THE GFS AND ECMWF
. THIS RESULTS IN A SOUTH TO SOUTHEAST
BOUNDARY LAYER FLOW CONTINUING TO ADVECT DEEP TROPICAL MOISTURE
ACROSS THE AREA THROUGH THE PERIOD...WITH PRECIPITABLE WATER VALUES
REMAINING IN THE 2.00 TO 2.25 RANGE. WITH ABUNDANT MOISTURE IN PLACE
ALONG WITH SOME WEAK UPPER LEVEL IMPULSES ROTATING THROUGH THE
REGION...EXPECT UNSETTLED WEATHER AND LOCALLY HEAVY RAINFALL TO
CONTINUE THROUGH THE PERIOD. HIGH TEMPERATURES ARE EXPECTED TO TOP
OUT IN THE MID 80S...WITH LOWS IN THE LOW TO MID 70S.

&&

.LONG TERM...
NO CHANGES MADE TO THE EXTENDED FORECAST FROM THE PREVIOUS SHIFT.
PLEASE REFERENCE THE LATEST PRODUCTS FROM THE NATIONAL HURRICANE
CENTER AND THE WEATHER PREDICTION CENTER.

THE FUTURE OF A WEAK LOW PRESSURE AREA LOCATED NEAR THE YUCATAN
PENINSULA WILL BE THE BIGGEST FACTOR IN THE LONG TERM FORECAST
PERIOD. MODEL GUIDANCE HAS BEEN ON A CONSISTENT TREND OF BRINGING
THE WEAK LOW PRESSURE AREA TOWARDS FLORIDA BY THIS WEEKEND. DEEP
TROPICAL MOISTURE WILL CREATE HEAVY RAINFALL AMOUNTS EXPECTED TO BE
IN THE 3 TO 6 INCH RANGE...WITH HEAVIER LOCALIZED AMOUNTS...FOR THIS
EVENT. THE CURRENT AIR MASS IS EXPECTED TO BECOME MORE FAVORABLE AND
EFFICIENT FOR HEAVY RAIN PRODUCTION.


MODEL GUIDANCE IS TRENDING TOWARDS A MORE CONSISTENT SOLUTION
FEATURING A LOW...NOT ENTIRELY TROPICAL IN CHARACTERISTICS...TRAVERSING
FLORIDA BY THE WEEKEND. THE 12Z GFS HAS THE LOW REACHING THE OPEN
GULF OF MEXICO WEDNESDAY INTO THURSDAY...PROVIDING OUR AREA WITH
BANDS OF RAIN AND FAVORABLE DYNAMICS FOR TORNADIC ACTIVITY. A 30 KNOT
700 MB JET BEGINS TO EASE IN OVER PORTIONS OF SW FLORIDA AROUND
06-12Z ON THURSDAY ACCORDING TO THE 12Z GFS. THE 12Z CMC OFFERS A
SLIGHTLY STRONGER LOW PRESSURE AREA AT THIS TIME...WHICH HAS THE 700
MB JET REACHING THE AREA BETWEEN 12Z AND 18Z ON WEDNESDAY.

LOWER LCLS CAN BE EXPECTED THANKS TO THE TROPICAL NATURE OF THE
AIRMASS...WITH THE 12Z GFS FEATURING AROUND A 700 FT LCL FOR TPA...A
500 FT LCL AT SRQ...A 600 FT LCL AT LAL...AND A 700-800 FT LCL AT
FMY AROUND 18Z THURSDAY...WHICH IS CONDUCIVE FOR TORNADOES. WITH THE
LOW FORECAST TO PASS WEST OF THE AREA...THE LOW LEVEL JET ON THE
RIGHT SIDE OF THE SYSTEM WILL BE ACCESSIBLE TO POTENTIAL TORNADIC
CONVECTION. THE 12Z GFS AND 00Z ECMWF ARE CONSISTENT WITH AN
INCREASING 0-1 KM HELICITY TREND STARTING AT 00Z THURSDAY...WITH
VALUES PEAKING BETWEEN 100-200 M2/S2 ACROSS MUCH OF THE CWA ON
THURSDAY AFTERNOON. 0-1 KM BULK SHEAR VALUES EASILY PEAKING ABOVE
20-25 KNOTS ALSO RAISES A LARGE RED FLAG FOR TORNADIC ACTIVITY. 0-6
KM BULK SHEAR VALUES OF 25-35 KNOTS ARE RESPECTABLE.


THE 12Z CMC CONTINUES TO BE CONSISTENT WITH A STRONGER LOW COMING
ASHORE BETWEEN PANAMA CITY AND TALLAHASSEE AROUND 00Z FRIDAY. THE
12Z GFS BRINGS THE WEAK LOW/TROUGH INTO THE BIG BEND OF
FLORIDA...LIKELY INTO THE SUWANNEE RIVER VALLEY ON FRIDAY AS WELL.
EITHER WAY...MOST OF THE COUNTY WARNING AREA AND MARINE OF
RESPONSIBILITY WILL SEE SOME EFFECTS FROM THIS SYSTEM AS
FORECAST AT THIS TIME.

&&

.AVIATION...
SHOWERS...WITH AN OCCASIONAL THUNDERSTORM...SPREADING ACROSS THE
WESTERN PENINSULA THIS AFTERNOON. WINDS UP TO 10 KNOTS OUT OF THE
SOUTH TO SOUTHWEST...WITH VARIABLE GUSTINESS AROUND SHOWERS AND
THUNDERSTORMS. THUNDERSTORM ACTIVITY SHOULD DIMINISH AFTER
SUNSET...WITH SOME SHOWER ACTIVITY CONTINUING THROUGH THE PERIOD.
COULD SEE THUNDERSTORMS START UP SOMETIME NEAR THE END OF THE TAF
PERIOD.

&&

.MARINE...
WINDS AND SEAS WILL INCREASE DURING THE WEEK WITH EXERCISE CAUTION
OR SMALL CRAFT ADVISORY HEADLINES EXPECTED TUESDAY NIGHT THROUGH
THURSDAY NIGHT OVER PORTIONS OF THE COASTAL WATERS AS AN AREA OF LOW
PRESSURE APPROACHES FROM THE SOUTHWEST AND EVENTUALLY TRACKS THROUGH
NORTH FLORIDA LATE IN THE WEEK.

&&

.FIRE WEATHER...
NO FIRE WEATHER CONCERNS OVER THE NEXT FEW DAYS AS ABUNDANT
MOISTURE WILL REMAIN ACROSS THE REGION KEEPING RELATIVE HUMIDITY
VALUES WELL ABOVE CRITICAL LEVELS.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA 74 85 74 87 / 30 70 40 70
FMY 74 85 73 85 / 40 70 70 70
GIF 72 86 72 86 / 50 70 40 70
SRQ 75 84 74 86 / 40 60 50 70
BKV 72 85 72 87 / 20 70 40 60
SPG 76 85 75 85 / 40 60 50 70

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

$$

SHORT TERM/MARINE/FIRE WEATHER...JELSEMA
LONG TERM/AVIATION...GARCIA


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Why are some people's posts hidden by default?
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Quoting sar2401:

Your post is #280 on my screen. Sounds like it's time to clear you cache and restart your computer.


I restarted the browser, seems ok now. Just bizarre. I saved a screenshot just so I could prove I wasn't crazy.*



* According to my wife, still not conclusive.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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