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Dangerous Caribbean disturbance 95L close to tropical storm strength

By: Dr. Jeff Masters, 1:57 PM GMT on September 23, 2010

A tropical wave (Invest 95L), moving westward at 15 mph though the south-central Caribbean, will bring gusty winds and heavy rain squalls to the northern coasts of Colombia and Venezuela this morning, as well as the Netherlands Antilles Islands. This disturbance will bring dangerous flooding rains to the countries bordering the Western Caribbean this weekend, and may also be a threat to the U.S. Gulf of Mexico coast late next week. A hurricane hunter aircraft is in 95L, and found a large region of surface winds of 35 - 45 mph to the east of 95L's center. If they find a closed circulation, 95L will be upgraded to Tropical Storm Matthew today. Satellite loops show that heavy thunderstorm activity has increased markedly in recent hours, with a solid curved band of intense thunderstorms growing to the northeast of 95L's center. Low-level spiral bands are also developing to the southeast of the center, but a closed surface circulation is not yet obvious from satellite imagery.


Figure 1. Morning satellite image of 95L.

Forecast for 95L
An upper-level high pressure system lies to the west of 95L, near the coast of Nicaragua. The clockwise flow of air around this high will bring a moderate 10 - 15 knots of wind shear over 95L today. By Friday, 95L will move more underneath this upper-level high, causing the shear to decline. The SHIPS model forecasts that shear will fall to the low range, 5 - 10 knots, by Friday afternoon. This drop in shear may allow for rapid intensification of 95L as it approaches landfall near the Nicaragua/Honduras border on Friday night and early Saturday morning. NHC is giving the disturbance an 80% chance of developing into a tropical depression by Saturday.


Figure 2. Forecast track of 95L from an ensemble of runs of the GFS model done at 2am EDT this morning.

The future of 95L depends critically upon the storm's interaction with land over the coming days. If 95L misses making landfall in Nicaragua and Honduras, and instead skirts the north coast of Honduras, the storm is likely to intensify into a hurricane by Monday, as predicted by last night's 00Z (8pm EDT) run of the GFDL model. However, if 95L spends significant time over Honduras, as predicted by the latest 06Z (2am EDT) run of the GFDL model, the storm will likely stay below hurricane strength. 95L is being forced just north of due west by a strong ridge of high pressure. This ridge will keep the storm moving at 15 mph through Saturday. On Sunday, a trough of low pressure diving southwards over the Eastern U.S. will weaken the steering currents over the Western Caribbean and cause 95L to slow and turn more to the north. 95L will begin a period of slow and erratic movement on Sunday that may last many days, as the storm wanders in the Western Caribbean and over Belize, Honduras, and Mexico's Yucatan Peninsula. If the center of 95L spends significant time over water, the storm could easily develop into powerful and dangerous Hurricane Matthew. If the center remains mostly over land, 95L will still generate extremely heavy rains over Central America, but remain below hurricane strength. By late next week, the trough of low pressure over the Eastern U.S. may lift out, allowing a ridge of high pressure to build in and force 95L westwards across the Yucatan Peninsula and into the Gulf of Mexico's Bay of Campeche. Alternatively, the trough of low pressure over the Eastern U.S. may amplify, drawing 95L northwards across Western Cuba and into Florida. The uncertainties in the long-range fate of 95L are high, and depend strongly on slight variations in its track that determine how much time the storm spends over land. One measure of the uncertainty in 95L's future track can be gained by viewing the ensemble forecast from the GFS model. An ensemble forecast is generated by taking the initial conditions in the atmosphere and making slight variations in the temperature, pressure, and humidity fields. Twenty or so tweaks of the initial conditions are made, and the GFS model run twenty separate times for each new set of initial conditions. The resulting ensemble of model runs gives one an idea of how sensitive the future track of the storm might be to errors in characterizing the initial state of the atmosphere. As one can see from this morning's GFS ensemble run (Figure 2), there are a wide range of possibilities for where 95L might go. The main thing I am confident of at this point is that 95L will generate very heavy rains over Nicaragua, Honduras, Belize, and Mexico's Yucatan Peninsula Friday through Tuesday that will likely cause dangerous flooding rains and life-threatening mudslides.

Tropical Depression Lisa
Tropical Depression Lisa continues to churn the waters of the far Eastern Atlantic. By Saturday night, upper level winds out of the west are expected to increase, bringing high wind shear of 20 - 45 knots over Lisa. The high shear may be capable of destroying the storm by early next week. It appears unlikely that Lisa will affect any land areas.

Elsewhere in the tropics
The remnants of Hurricane Julia are still spinning over the far Eastern Atlantic, and are generating some sporadic heavy thunderstorm to the north of the center of circulation. Julia's remains are being given a 10% chance of re-developing by NHC. There are no other threat areas to discuss, and none of the models is calling for development (except for 95L) over the next seven days.

Hurricane Karl's moisture causing flooding in Minnesota, Wisconsin
A plume of very moist air associated with what was Hurricane Karl last week has surged northwards over the Central U.S. over the past two days. This moisture is now being lifted over a warm front draped over Minnesota and Wisconsin, and has generated flooding rains in excess of six inches in southern Minnesota this morning. Flood warnings and flood watches are posted for a wide swath of the upper Midwest today, including most of Minnesota, northern Wisconsin, and Michigan's Upper Peninsula. The latest forecast discussion from the NWS office in Minneapolis notes that the forecast amount of moisture in the air this afternoon is similar in magnitude to the all-time record for this time of year (set on September 2, 1953.) These kinds of rain events are called Predecessor Rain Events (PREs), because they typically precede the actual arrival of the rain shield of a tropical storm.


Figure 3. Radar estimated rainfall over Minnesota.

Next post
I'll have an update on 95L later today. The timing will depend upon what the Hurricane Hunters find.

Jeff Masters

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

Quoting IKE:
Captured by an even deeper trough at hour 216...



Actually that is one of the things I hate about storms this time of year in my area... usually drags the colder air down behind them. I am not ready for the "cold" air yet (cold by FL standards, anyways).
The furure of TD 15 is obviously way up in the air as far as strength and track. One thing is for sure, if, (and most likely) TD 15 becomes either TS or Hurricane Matthew before hitting Belize, there will be copious amounts of rainful in that entire region. That is the immediate and most certain threat at this time. I hope they are ready, since there is the belief, that he may meander there for some time before heading towards the North, then NE.
Quoting DestinJeff:
Scott is here....

Expect Reed in moment now. Hopefully he brings The Goods.

Please be patient, as he is currently acquiring model consensus from local "Squad" authorities...
1005. angiest
Quoting victoriahurricane:


If it stalls right over the water waiting for the trough 25 inches is definitely possible, though I think that's a bit extreme. I do have a feeling that all of this season has been leading up to this moment right here.


Well the remnants of Allison dumped up to 30 inches here (in one night!), so 25 for a living tropical cyclone sitting half over the water is not too much of a stretch...
1006. angiest
Quoting CaneWarning:
What does Mr. Hebert and his box think about all of this?

TD15 did not pass through the Hebert box as a cyclone.
1007. IKE
Day 10...wow...troughs in the east....good luck getting a tropical system into that....
Quoting anyotherliestotell:
not only is this weak little system supposed to die out over CA, there is nothing even projected to form in the next week. at most a moist wave over the gulf in a week. but don't let that keep you from forecasting none-sense day and night. sad. season is a bust as far as US hits. NONE!
Quoting anyotherliestotell:
not only is this weak little system supposed to die out over CA, there is nothing even projected to form in the next week. at most a moist wave over the gulf in a week. but don't let that keep you from forecasting none-sense day and night. sad. season is a bust as far as US hits. NONE!


Yes, the season has been a bust so far, but that may be about to change for the U.S.
Quoting hydrus:
T.D.15 is annular..;0


LOL
Quoting angiest:


Well the remnants of Allison dumped up to 30 inches here (in one night!), so 25 for a living tropical cyclone sitting half over the water is not too much of a stretch...


Well with the NHC forecasting only 6-10 inches, 25 seems like a stretch. I know NHC has been wrong before, but it can't be THAT far off IMO.
1011. angiest
Quoting tropicfreak:
Models are confusing me what storm are they showing a week out hitting FL??


It depends on the model. 12Z GFS (discussed in my blog) does not show TD15 hitting Florida. Instead, it is a second or third Caribbean storm that forms about a week from now. Euro apparently is taking TD15 there.
Quoting angiest:

TD15 did not pass through the Hebert box as a cyclone.


I think he means the upcoming Hebert Box
TD#15 appears to moving more WNW to me.
1014. angiest
Quoting victoriahurricane:


Well with the NHC forecasting only 6-10 inches, 25 seems like a stretch. I know NHC has been wrong before, but it can't be THAT far off IMO.


I don't think we were forecast to get that much. :)
Quoting IKE:
Day 10...wow...troughs in the east....


According to that, the shield's mostly in good position (mostly).

And Ike, I think the hyperbole in TCHP is rising again.
Quoting victoriahurricane:


they were out there saying this season was way overhyped and we may not even hit 15 named storms. Right now we have 12 (13 if you count Matthew) and it's not even the end of September

And the hypers were comparing it to 2005 with 27 named storms/Hyper season
We *may* make the 18 storms that everybody dropped their predictions too. I still would not call this season hyper but only above average.
But who cares? if you cry fire often enough eventually you'll be right.
I think over 20 by the time it all runs down
Ike,

thanks for this interesting image. do any other models show another deeper trough coming in?

Also, please correct me if I am wrong, but if this scenario pans out, does that mean that 2 troughs would affect Matthew (one coming up and another in the EGOM)?
1015. DaytonaBeachWatcher 7:01 PM GMT on September 23, 2010

Considering the NHC track, I would think Florida should very well be in the discussion
1023. WxLogic
Quoting IKE:
Day 10...wow...troughs in the east....good luck getting a tropical system into that....


And to bring nice cool air down here... hopefully putting an end to my high electric bill. Almost reminds me of Wilma... got pretty chilly after she passed.
1024. angiest
Quoting kshipre1:
Ike,

thanks for this interesting image. do any other models show another deeper trough coming in?

Also, please correct me if I am wrong, but if this scenario pans out, does that mean that 2 troughs would affect Matthew (one coming up and another in the EGOM)?


GFS didn't have that large a trough, but it did show strong troughs up in Canada.
Quoting Hurricanes101:
1015. DaytonaBeachWatcher 7:01 PM GMT on September 23, 2010

Considering the NHC track, I would think Florida should very well be in the discussion


I feel like Tampa is safe. It's a gut feeling, but I think Matthew will go to our South.
Quoting ecflweatherfan:


Actually that is one of the things I hate about storms this time of year in my area... usually drags the colder air down behind them. I am not ready for the "cold" air yet (cold by FL standards, anyways).
So you'd rather have 95 degrees in the shade?

IMO, having slightly "cooler" air come to your area is just about the only good thing to having a 'cane pass by this time of the year.



Quoting scottsvb:
BTW Peeps.. 995 on the models are usually way to high in Mb pressure. From what it looks.. more like 965mb would be the correct pressure.



That would be a high end CAT 2, maybe CAT 3

Intensity chart for those interested
Cotillion,

sorry for this dumb question. but what do you mean by the comment about the shield? Wouldn't another trough pull Matthew even more NNE? thanks
1030. angiest
Quoting DaytonaBeachWatcher:

NO but you can bet your butt it will include florida.


That's not unreasonable...
1032. IKE
Quoting kshipre1:
Ike,

thanks for this interesting image. do any other models show another deeper trough coming in?

Also, please correct me if I am wrong, but if this scenario pans out, does that mean that 2 troughs would affect Matthew (one coming up and another in the EGOM)?


Extended forecast from yesterday showed below normal temps in the SE USA in the 6-10 day and 8-14 day forecasts.

It does look like a secondary trough kicks it on up and out of here.

Leaves will really start falling here. Got a pile of branches to burn them with.....shhh...global warming.
Quoting anyotherliestotell:
not only is this weak little system supposed to die out over CA, there is nothing even projected to form in the next week. at most a moist wave over the gulf in a week. but don't let that keep you from forecasting none-sense day and night. sad. season is a bust as far as US hits. NONE!


This season is far from over and I have a feeling the real trouble starts NOW.
1035. Levi32
I like the general idea of this forecast. We should see TD 15 clip Nicaragua/Honduras and then try to turn north near the eastern Yucatan. Whether it is onshore or over the water at that point will be one of the biggest determining factors of how this evolves.

Quoting WxLogic:


And to bring nice cool air down here... hopefully putting an end to my high electric bill. Almost reminds me of Wilma... got pretty chilly after she passed.


That is true (ok for slightly cooler, but not too cold)... Wilma dropped the temperature from 83 degrees at 3am to 53 degrees by noon here in my area, and with 70+ mph winds, it made for a nasty windchill.
Don't look at intensity on the models. Just look at the setup and patterns in place. TD 15 could be a strong TS or a major cane headed for FL.
Quoting angiest:


I don't think we were forecast to get that much. :)


Fair enough and this brings up a point that's bothered me for a while now. All the talk of tropical storms/hurricanes regarding damage is mostly about storm surge or winds when in reality rains can be just as or even more deadly. Like Tropical Storm Allison as you mentioned did over 5 Billion in damage and killed 41 people. I think the system should change ranking storms on how dangerous they are wind, rain and surge wise.
1042. hcubed
Quoting MScasinojunkie:
If this thing goes inland in stalls, there should be nothing left of it - right?


Unsure.

We've already seen a couple of storms this year that held together fairly well, even after going over land.

If it can continue to suck up moisture, and if the area it stalls in isn't that hilly, it MIGHT maintain some strength.

Best to keep one eye on it...
1043. NASA101
My guess: Matthew will be much ado about nothing! The way is traveling right now it's hard to see it not hitting Honduras or slightly north of there in Yucatan!
Doubting if NHC current track will verify!
12Z GFDL & HWRF is more likely scenario emerging it bay of camp - may moce north from there if the timing of trough is right!
Quoting jeffs713:
So you'd rather have 95 degrees in the shade?

IMO, having slightly "cooler" air come to your area is just about the only good thing to having a 'cane pass by this time of the year.


Slightly cooler would be nice... Low 80s daytime and mid 60s at night would be awesome.
1048. IKE
Day 7 HPC forecast map...

Quoting Levi32:
I like the general idea of this forecast. We should see TD 15 clip Nicaragua/Honduras and then try to turn north near the eastern Yucatan. Whether it is onshore or over the water at that point will be one of the biggest determining factors of how this evolves.


I sure hope that TD15 doesn't pull a Danielle, Earl, Igor, Julia or a Karl, i.e. rapid intensification (RI) or the W Caribbean, Honduras, Nicaragua, the Yucatan and possibly FL are under the gun.

This is a scary "Wilma" replay?!?!?!?!
i dont know who said it but???? so far this yr has been a bust??? what are talking about?? have you been sleeping?? this yr has been quite active!! maybe no catastrophic US landfalls, but is that how u clasify a season as a bust?? come on person!! after earl i posted that we would be on m b4 the end of the month and boom we are here and its the 23rd.. another storm or 2 could form b4 the 30th.. this season is by far not over.. u got all of october and november.. need i not remind you of the lowest pressure hurricane ever recorded WILMA didnt come till awhile after the "peak" of the season
Quoting victoriahurricane:


Fair enough and this brings up a point that's bothered me for a while now. All the talk of tropical storms/hurricanes regarding damage is mostly about storm surge or winds when in reality rains can be just as or even more deadly. Like Tropical Storm Allison as you mentioned did over 5 Billion in damage and killed 41 people. I think the system should change ranking storms on how dangerous they are wind, rain and surge wise.

Rain is the hardest to estimate the damage of, since it can be so localized, and depends highly on several factors, not limited to precipatable water, topography, speed, areal coverage of the rain, training nature of individual cells, water saturation prior to the storm, etc. You could have 5" and no flooding (if its a drought), or have 1.5" and massive flooding (if the ground was already very saturated).
Quoting WxLogic:


And to bring nice cool air down here... hopefully putting an end to my high electric bill. Almost reminds me of Wilma... got pretty chilly after she passed.

Wilma was a month later. We won't see 50's in south Fl. like we did after that.

They also had the track nailed down as far out as 5 days on Wilma because of the trough being so consistent due to it being late Oct. This time they are still not sure whether we will have a trough deep enough or whether it's going to be a cut off low.

There are way more variables this time.
1054. IKE
Looks like a secondary cold front on the 7 day HPC map above...heading toward the SE USA. Maybe that's the one that gives Matthew a good kick.
1056. Squid28
Quoting jeffs713:
So you'd rather have 95 degrees in the shade?

IMO, having slightly "cooler" air come to your area is just about the only good thing to having a 'cane pass by this time of the year.


Sure makes it a lot easier to sit outside and drink a cold beer while enjoying your MRE before tucking yourself into bed without power for 14 days (Or in my case it sure makes it more pleasant when gutting your house). I have done both directions, oppressively hot, 100% humidity, slappin skeeters the size of pot belly pigs... Think I will defer to door #1 anyday
I asked this yesterday but was not successful in getting any feedback. I'm heading to Cozumel/Cancun for a week vacation starting Sunday. Could someone give me an idea of what to expect? Should I not go? Anybody have a similar experience? Sorry for asking again. Thanks.
Quoting DestinJeff:


don't tell



lol good one
Quoting IKE:
Day 7 HPC forecast map...

Not a pretty picture Ike ;) Let's hope it doesn't split the gap!
Quoting mnborn:
I predict Panama City for landfall! Doom! lol


Um...let's not and say we did...;-)

v/r

Jon
1062. Levi32
12z GFDL is hilarious lol. Matthew runs full boar into central America and then gets cold feet...
Quoting IKE:
Looks like a secondary cold front on the 7 day HPC map above...heading toward the SE USA. Maybe that's the one that gives Matthew a good kick.

Dear Mother Nature:

Please send the second trough down, make it kick Matthew to the Atlantic (away from land, please), reduce my electric bills, give the entire SEUS some cooler weather, and help make my wedding a nice event outside.

Kthx,
The WeatherUnderground.
thanks
Quoting mx3gsr92:
I asked this yesterday but was not successful in getting any feedback. I'm heading to Cozumel/Cancun for a week vacation starting Sunday. Could someone give me an idea of what to expect? Should I not go? Anybody have a similar experience? Sorry for asking again. Thanks.

The NHC in Miami, FL believes that Hurricane Matthew will be visiting the resort at the same time you are.

I would call your airline or travel agent and ask them about their rescheduling policy.
1068. Max1023
This season is NOT a bust. Newfoundland got it's worst storm in memory just a couple days ago.

http://www.cbc.ca/canada/newfoundland-labrador/story/2010/09/23/igor-stranded-cleanup-923.html
1069. xcool
yayy
Quoting jeffs713:

Rain is the hardest to estimate the damage of, since it can be so localized, and depends highly on several factors, not limited to precipatable water, topography, speed, areal coverage of the rain, training nature of individual cells, water saturation prior to the storm, etc. You could have 5" and no flooding (if its a drought), or have 1.5" and massive flooding (if the ground was already very saturated).


That's a very good point, but don't we have the tools to be able to measure how much risk an area about to be hit by a tropical storm has? I'm sure we know whether the ground is saturated or not prior to a tropical storm. Just look at the rainfall reports. It's a hard thing to measure, but many people don't take the rain seriously and some have lost their lives due to that. Heck even Hurricane Igor a minimal Cat 1 did massive damage to Newfoundland washing out roads and bridges. To me unless the hurricane is a major the most deadly aspects are from it's moisture meaning rain and surge.
congrats on the wedding Jeff
1076. IKE
Complete ECMWF...Link
Quoting Levi32:
12z GFDL is hilarious lol. Matthew runs full boar into central America and then gets cold feet...


Levi! Great to see you post...how is school? Thanks for the update today...take care.

v/r

Jon
Quoting Levi32:
12z GFDL is hilarious lol. Matthew runs full boar into central America and then gets cold feet...


'This vehicle is now reversing'.

One thing that'll help TD15 will be that he doesn't look like he'll be small.

That'll give him a wider surface area to allow a better chance to get some water in his circulation rather than being entirely over land. Smaller systems tend to die off quicker over land, you find (unless they were born with much tenacity to counter it).
Really, not that organized...

1080. FLdewey
Quoting 69Viking:


Your man Favre needs to learn how to throw a football to his own team.

At this point a DeLorean and 88mph may be his only hope.
1081. atl134
On that plot Dr. Masters posted of the GFS ensemble... is the white line the GFS ensemble forecast or is it the... base one from which all the other initializations are altered from? I'm wondering since I sorta would expect it to be near the middle of the ensemble cluster, at least for the first couple days.
Quoting DestinJeff:


With The Upgrade, the Continent of Uncertainty has been reduced to perhaps Brownsville to Hatteras.

RIDGES does good work.
Quoting duajones78413:



??????


Reedzone Institute for Dynamic Guidance in Equatorial Systems, or RIDGES. Been around longer than GFS and EURO.
Quoting mx3gsr92:
I asked this yesterday but was not successful in getting any feedback. I'm heading to Cozumel/Cancun for a week vacation starting Sunday. Could someone give me an idea of what to expect? Should I not go? Anybody have a similar experience? Sorry for asking again. Thanks.

I would check with your airline and hotel. With Matthew scheduled to be right by there around that time... may not be a "beach day".
1084. xcool
okay take all forcast models kickk out door now.we have A TROPICAL DEPRESSION
1085. Squid28
Quoting Levi32:
12z GFDL is hilarious lol. Matthew runs full boar into central America and then gets cold feet...


I think the HWRF does ssomething similar but over the yucatan as it is emerging into the BOC/GOM
Quoting atmoaggie:
Really, not that organized...



For a TD I'd say it's organized pretty well. =)

For a tropical storm, getting there.
Quoting tropicfreak:


No there's not. They just found a 1006.3mb and 46kt winds.


Correct. "this" = "just" - always. Not that hard, really, once you get used to it.
1089. xcool
WHXX01 KWBC 231827
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1827 UTC THU SEP 23 2010

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 FIFTEEN (AL152010) 20100923 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
100923 1800 100924 0600 100924 1800 100925 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 13.9N 76.2W 14.5N 78.4W 15.3N 80.7W 16.0N 83.0W
BAMD 13.9N 76.2W 14.3N 78.7W 14.8N 81.3W 15.4N 83.7W
BAMM 13.9N 76.2W 14.4N 78.7W 15.0N 81.3W 15.6N 83.9W
LBAR 13.9N 76.2W 14.3N 79.1W 15.0N 82.2W 15.6N 85.4W
SHIP 30KTS 36KTS 46KTS 58KTS
DSHP 30KTS 36KTS 46KTS 58KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
100925 1800 100926 1800 100927 1800 100928 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 16.8N 85.5W 18.7N 89.8W 19.4N 92.9W 18.3N 95.3W
BAMD 16.2N 85.8W 18.1N 88.9W 19.9N 90.8W 19.9N 92.8W
BAMM 16.5N 86.3W 18.3N 90.1W 19.1N 92.5W 17.4N 94.4W
LBAR 16.5N 88.3W 19.2N 92.6W 21.6N 94.0W 20.7N 94.5W
SHIP 69KTS 88KTS 100KTS 102KTS
DSHP 59KTS 78KTS 41KTS 33KTS

...INITIAL CONDITIONS...
LATCUR = 13.9N LONCUR = 76.2W DIRCUR = 280DEG SPDCUR = 14KT
LATM12 = 13.4N LONM12 = 73.4W DIRM12 = 281DEG SPDM12 = 14KT
LATM24 = 12.8N LONM24 = 70.6W
WNDCUR = 30KT RMAXWD = 30NM WNDM12 = 30KT
CENPRS = 1007MB OUTPRS = 1010MB OUTRAD = 130NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

Quoting atl134:
On that plot Dr. Masters posted of the GFS ensemble... is the white line the GFS ensemble forecast or is it the... base one from which all the other initializations are altered from? I'm wondering since I sorta would expect it to be near the middle of the ensemble cluster, at least for the first couple days.


That's the operational version of the GFS--the run made using the actual state of the atmosphere, as best we know it. Usually, the operational run lies in the middle of the set of ensemble runs, but not always.

Jeff Masters
Quoting Max1023:
This season is NOT a bust. Newfoundland got it's worst storm in memory just a couple days ago.

http://www.cbc.ca/canada/newfoundland-labrador/story/2010/09/23/igor-stranded-cleanup-923.html


Worse than Juan, though?

That was only 7 years ago.
Regarding the models... now that we have a closed off CoC... we will see much better information entered into the next model cycle... therefore more continuity between the models (hopefully).
1094. Levi32
Quoting Eagle101:


Levi! Great to see you post...how is school? Thanks for the update today...take care.

v/r

Jon


Hey Jon, school's good so far.
Quoting IKE:
Complete ECMWF...Link

The ECMWF takes a TC through SW Florida and sends it sailing up the east side of the Appalachian mountains next week.

NOT a good thing, especially if you scoot at CAT 2 or 3 TC through FL up the Eastern Seaboard.
.....BUT STILL A NICE PI WOULDNT YA SAY?
Quoting Levi32:
12z GFDL is hilarious lol. Matthew runs full boar into central America and then gets cold feet...
lmao. The rubber wall northern Guatemala most be coded into GFDL!
Okay Anyone Wanna Post the Newest Models for me? I Just got on the Computer
Quoting DestinJeff:


If it is a deep trough, he may want to.

Things could get hairy, for sure.
Yep...it's really still up for grabs right now.
1101. xcool




interesting
Quoting Cotillion:


Worse than Juan, though?

That was only 7 years ago.


Juan hit Nova Scotia.
1103. Max1023
Quoting atmoaggie:
Really, not that organized...



Looking at that image I see a 30-40knot developing system. Curved banding has become better defined around the center of the system and the cyclonic envelope is expanding. Right now there is little central convection due to subsistence from the banding overcoming the relatively weak surface convergence near the center, as the depression is not deep enough to produce a lot of convergence near the LLC, however once T.D 15 gets down to maybe 1005mb we should see a CDO start to form. DMAX will help it out tonight.
Quoting kshipre1:
congrats on the wedding Jeff

Thank you! Its not until the 17th, but my bride-to-be is getting a little worried it will be hot on the wedding day.
Dang, the last frame of the ECMWF looks like it want to bring an early shot of winter to the Great Lakes! With 500 mb heights of around 540 dm and 850 mb temps running as low as 15*C below average, I wonder if there would even be the potential for some snow there if that were to verify...
1053. Abacosurf 7:11 PM GMT on September 23, 2010

"Wilma was a month later. We won't see 50's in south Fl. like we did after that.
They also had the track nailed down as far out as 5 days on Wilma because of the trough being so consistent due to it being late Oct. This time they are still not sure whether we will have a trough deep enough or whether it's going to be a cut off low.
There are way more variables this time"


I totally agree with that. The "Bowling ball" type Trough that Levi was talking about in his synopsis is the main issue as far as where and when (possible) Matthew) gets pulled Northward. The trough may not dig deep enough, whereas with Wilma in late October, it was very predictable
Quoting ecflweatherfan:
Regarding the models... now that we have a closed off CoC... we will see much better information entered into the next model cycle... therefore more continuity between the models (hopefully).


When will the first runs be out with that data / info used?
1110. Levi32
TD 15 is moving into a favorable environment aloft in the western Caribbean where upper ridging is building in, providing good ventilation of the area.

1111. atl134
Ah okay, thanks Dr. Masters.
Quoting 1900hurricane:
Dang, the last frame of the ECMWF looks like it want to bring an early shot of winter to the Great Lakes! With 500 mb heights of around 540 dm and 850 mb temps running as low as 15*C below average, I wonder if there would even be the potential for some snow there if that were to verify...

Great!!!! A CAT 2/3 storm racing up the E Coast then temps in the 30's and snow. That would be a first!!!!
Quoting victoriahurricane:


Juan hit Nova Scotia.


So it did.
Quoting StormChaser81:


For a TD I'd say it's organized pretty well. =)

For a tropical storm, getting there.
I expected more deep convection before I opened that particular plot up. Most of our invests have shown larger areal coverage of deeper convection than any shown there. (this season, anyway)
1116. xcool
td15 hurricane by 24hrs jmo
Quoting xcool:




interesting


Those are some of the strangest models I've seen and I've seen Presslord in a dress YIKES!
1118. Max1023
Quoting Levi32:
TD 15 is moving into a favorable environment aloft in the western Caribbean where upper ridging is building in, providing good ventilation of the area.



Based on that map I would not be surprised to see some steady strengthening tonight, as soon as 15 develops a CDO it would bomb out if that map verifies. <5 knots of shear and 30+ degree waters, plus good ventilation and a moist atmosphere = pretty fast strengthening.
1119. FLdewey
I've replaced your forecast models with fruit by the foot.
Would the steering uncertainties explain some models last week developing 2 systems in tandem off of Honduras? I have noticed that on a new run IKE posted earlier...not sure which model though.
Quoting Max1023:


Based on that map I would not be surprised to see some steady strengthening tonight, as soon as 15 develops a CDO it would bomb out if that map verifies. <5 knots of shear and 30+ degree waters, plus good ventilation and a moist atmosphere = pretty fast strengthening.


Agreed if that were to verify I wouldn't be surprised with a major bearing down on Honduras/Nicaragua.
Quoting TriMOPER:


When will the first runs be out with that data / info used?


Likely for the 00Z (8pm) Model runs
Quoting Bordonaro:

The NHC in Miami, FL believes that Hurricane Matthew will be visiting the resort at the same time you are.

I would call your airline or travel agent and ask them about their rescheduling policy.


I would expect a TON of rain and some wind....
1125. swlavp
1072. betapaul

There are some very knowledgable people on here..But to hang on every word anybody says in a weather blog is rather irresponsible I would think..
When do the Next Computer Models Come out?
Quoting Max1023:
Quoting atmoaggie:
Really, not that organized...



Looking at that image I see a 30-40knot developing system. Curved banding has become better defined around the center of the system and the cyclonic envelope is expanding. Right now there is little central convection due to subsistence from the banding overcoming the relatively weak surface convergence near the center, as the depression is not deep enough to produce a lot of convergence near the LLC, however once T.D 15 gets down to maybe 1005mb we should see a CDO start to form. DMAX will help it out tonight.
IMO, not going to do any intensifying until that happens...
Quoting atmoaggie:
IMO, not going to do any intensifying until that happens...


It doesn't need to intensify, it's got plenty of time to do that, just need more organization, which is growing as the hours pass by. He already has tropical storm force winds.
Quoting victoriahurricane:


I think he means the upcoming Hebert Box


What is a Hebert Box, please?
Quoting atmoaggie:
Really, not that organized...



It is just a depression right now.
Thanks
Quoting xcool:
td15 hurricane by 24hrs jmo

About 36 hrs for Hurricane status, then I foresee RI (rapid intensification) and a strong CAT 2/minimal CAT 3 off of Honduras and then I forsee a CAT 2/3 storm sailing trough SW FL and up the E Seaboard by day 10..
NOT a pretty picture, not at all..
ha ha very funny about the brances Ike. question for you. I am having a hard time seeing how a second trough can swoop potential Matthew out to sea especially if the first trough turns Matthew North the NE into Florida.

Please correct me if I am wrong because I am still learning but the only a second trough can take this out to sea is if it takes a southern route through the keys, up SFL then up the east coast. Is this correct? thanks

AL, 14, 2010092318, , BEST, 0, 175N, 286W, 35, 1004, TS
Quoting sammywammybamy:
When do the Next Computer Models Come out?


There are some that were out at 18Z (2pm)... next up will be 00Z (8pm)
Quoting Fla55Native:


What is a Hebert Box, please?


9/10 storms that have hit Florida in the past have gone through the Hebert Box prior. It doesn't mean that if a storm goes through it will hit Florida 9/10 times though. It just mean if Florida is to be hit by a hurricane it 90% of the time will have passed through either Hebert Boxes.
Quoting atmoaggie:
I expected more deep convection before I opened that particular plot up. Most of our invests have shown larger areal coverage of deeper convection than any shown there. (this season, anyway)


I think the blowup is coming once it situates itself under the ridge.

Wont take much of the convection consolidating for a decent system to start to form.
1141. usa777
Quoting DestinJeff:


It was a dark and stormy night...


"the sea was angry my friend"
Quoting Tazmanian:
AL, 14, 2010092318, , BEST, 0, 175N, 286W, 35, 1004, TS

I am wrong, this is Lisa, NOT Matthew :O)!!


Looks Bad for the Yucatan and Westren Cuba as well as South Florida...
1145. hydrus
Quoting Bordonaro:

About 36 hrs for Hurricane status, then I foresee RI (rapid intensification) and a strong CAT 2/minimal CAT 3 off of Honduras and then I forsee a CAT 2/3 storm sailing trough SW FL and up the E Seaboard by day 10..
NOT a pretty picture, not at all..
Thanks a million there Bordanaro......
Quoting Levi32:
12z GFDL is hilarious lol. Matthew runs full boar into central America and then gets cold feet...
Matthew appears to be pumping Belize in that run.
Quoting Tazmanian:
AL, 14, 2010092318, , BEST, 0, 175N, 286W, 35, 1004, TS


Ah, Lisa's back.
Quoting Max1023:
Quoting atmoaggie:
Really, not that organized...



Looking at that image I see a 30-40knot developing system. Curved banding has become better defined around the center of the system and the cyclonic envelope is expanding. Right now there is little central convection due to subsistence from the banding overcoming the relatively weak surface convergence near the center, as the depression is not deep enough to produce a lot of convergence near the LLC, however once T.D 15 gets down to maybe 1005mb we should see a CDO start to form. DMAX will help it out tonight.


I thought D-Max is in the morning.

It's going into D-Min and that wont help it.
We now have Tropical Storm Lisa
Holy Smokes! It looks like this TD wants to form an eye feature.


Quoting hydrus:
Thanks a million there Bordanaro......

I have an awful feeling about our new TS Matthew, just upgraded..
1152. srada
Hey Everyone

I see we have TD15 and it looks like the East Coast is still considered as a second landfall with the model runs..from the local NWS Wilmington, NC..

THE END OF THE PERIOD AND
BEYOND OFFER SOME HIGHLY VARIED AND EXTREMELY INTERESTING
POSSIBILITIES. FOR ONE A STRONG NORTHERN BRANCH TROUGH MAY PHASE
WITH THE SOUTHERN BRANCH CUTOFF AND BRING ANOTHER ROUND OF HEAVY
RAINFALL TO THE DROUGHT-STRICKEN SOUTHEAST. THE PROSPECTS OF A
TROPICAL SYSTEM COMING NORTH-NORTHEAST OUT OF THE CARIBBEAN ALSO
SEEMINGLY BECOMING MORE LIKELY.
1153. RJT185
Quoting CaneWarning:
And we are all very happy because of that...now lets just move on.


Cute.
1154. Grothar
1155. Seastep
Quoting Bordonaro:

Welcome TS Matthew. Please behave and do no harm..


That's Lisa. ;)

28.6W
Quoting Bordonaro:

Welcome TS Matthew. Please behave and do no harm..
Quoting victoriahurricane:
We now have Tropical Storm Matthew


INCORRECT AL 14 = LISA
Quoting Bordonaro:

About 36 hrs for Hurricane status, then I foresee RI (rapid intensification) and a strong CAT 2/minimal CAT 3 off of Honduras and then I forsee a CAT 2/3 storm sailing trough SW FL and up the E Seaboard by day 10..
NOT a pretty picture, not at all..


I forsee a whole lot of nothing from this depression..
AEMI is looking pretty.
Quoting cirrocumulus:
Holy Smokes! It looks like this TD wants to form an eye feature.




Is that a pinhole eye I see? (sorry I couldn't resist)
1161. xcool
wait & see scenario on td15
1162. will40
Quoting Bordonaro:

Welcome TS Matthew. Please behave and do no harm..


that is not TD 15
Shame that 42058 isn't available...

NDBC: Station 42058 stopped transmitting 11/22/2009. This buoy will be restored to service when it can be worked into the schedule. When the service date is known, it will be posted in the maintenance report.

No date for repair shown in maintenance report...
My whole country is in the cone :(( I hope we get properly prepared for all this water. Doesn't seem we can run from this one (donning my boxing gloves).
Quoting victoriahurricane:
We now have Tropical Storm Lisa



it was downgrade now it will be geting re upgradeed
1167. Max1023
According to the current steering maps the stronger T.D 15 gets the slower it will move = the more time over water before it interacts with Central America. Either way though this storm will be bad, even a depression hitting Central America causes floods and mudslides. In many ways a slow moving depression can cause more damage than a quickly moving hurricane, as rain is the major killer.
1168. Grothar
Quoting victoriahurricane:


9/10 storms that have hit Florida in the past have gone through the Hebert Box prior. It doesn't mean that if a storm goes through it will hit Florida 9/10 times though. It just mean if Florida is to be hit by a hurricane it 90% of the time will have passed through either Hebert Boxes.



TD 15 will Pass through the Extreme South Portion of Hebert Box #2
1170. Thaale
Quoting JeffMasters:


That's the operational version of the GFS--the run made using the actual state of the atmosphere, as best we know it. Usually, the operational run lies in the middle of the set of ensemble runs, but not always.

Jeff Masters

Thanks, Dr. Masters. Good explanation.

It might be helpful also if you considered adding the ensemble mean - the AEMN, I believe - to the ensemble chart, say in green or something. That would make apparent those instances where the ensemble mean differed significantly white operational GFS, thus indicating low confidence. Just an idea.
Quoting victoriahurricane:


Damn you're fat, I edited like 1 second after I posted.


Now that is harsh!..LOL
1172. Seastep
But, it sure looks like TS Matthew to me already.

Don't usually do this, but I'll guess that they upgrade at 5pm.
AL, 15, 2010092318, , BEST, 0, 139N, 762W, 30, 1007, TD, 34, NEQ, 0, 0, 0, 0, 1010, 130, 30, 0, 0, L, 0, , 0, 0, FIFTEEN

No Matthew yet.

Be calm people, be calm...
Thanks for the answer Victoriahurricane, but the question remains, what is a Hebert Box, please?
Quoting StormChaser81:


I thought D-Max is in the morning.

It's going into D-Min and that wont help it.
I *think* he means late, late tonight to early morning...?
1177. Grothar
Quoting Grothar:


what pressure is on that model???? 950mb???
Quoting Fla55Native:
Thanks for the answer Victoriahurricane, but the question remains, what is a Hebert Box, please?


An Hebert Box (pronounced AY-bear, also known as Hebert's Box) is one of two regions of the tropical Atlantic Ocean that are useful as predictors of hurricanes that will strike South Florida, USA. They are named for former National Weather Service and National Hurricane Center forecaster Paul Hebert, who observed in the late 1970s that most strong hurricanes (characterized as those with winds exceeding 110 miles per hour (177 km/h)) which had struck South Florida since 1900 had also passed through one of these two small 335-mile-by-335-mile (517-km-by-517-km) square geographic regions.[1]

Examples include unnamed hurricanes in 1926, 1928, 1933, and 1935, as well as the major hurricanes Donna and Betsy, all of which came through a Hebert Box. Collectively these storms killed more than 2,000 people in Florida. Conversely, storms such as the major hurricanes Floyd and Gert in 1999, which both were headed for Florida at one point, missed the Hebert Boxes and turned away from Florida at the last minute.[1]

The first Hebert Box is located east of Puerto Rico over the US Virgin Islands, between 15° and 20° north latitude and 60° to 65° west longitude. This was the first area that Hebert discovered, and provides an indication for the behavior of Cape Verde type storms, which form off of the western coast of Africa near the islands of the same name. This first box is useful for storms that typically form in the early part of the Atlantic hurricane season (June through early September).

The second Hebert Box is located over the Cayman Islands between 15° and 20° north latitude and 80° to 85° west longitude. This was the second discovered, and provides an indication for the behavior of storms that will move north to hit Florida. These are usually late-season storms that form in this region in late September and October, and this box is mostly concerned with them.[2]

Quoting Cotillion:
AL, 15, 2010092318, , BEST, 0, 139N, 762W, 30, 1007, TD, 34, NEQ, 0, 0, 0, 0, 1010, 130, 30, 0, 0, L, 0, , 0, 0, FIFTEEN

No Matthew yet.

Be calm people, be calm...



i think they will upgrade it too Matthew at 8 or 11pm
1182. Max1023
Quoting atmoaggie:
I *think* he means late, late tonight to early morning...?


I mean the wee hours of the morning, right before sunrise. D-Min is right around sunset, so about 4-5am Est.
Quoting Fla55Native:
Thanks for the answer Victoriahurricane, but the question remains, what is a Hebert Box, please?


It's just an imaginary box where most hurricanes need to pass through to hit florida, there is no real scientific explanation, it's just a term that's used.
1184. Greyelf
Quoting Fla55Native:
Thanks for the answer Victoriahurricane, but the question remains, what is a Hebert Box, please?

Google or Wiki works great for questions such as this.
NEW BLOG!!!!!
Quoting GoodOleBudSir:


Now that is harsh!..LOL


Damn freaking typo lol, sorry sammy that's an oops on my part.
Quoting Fla55Native:
Thanks for the answer Victoriahurricane, but the question remains, what is a Hebert Box, please?

Hebert Box link below :O):
Link
Quoting Bordonaro:

Welcome TS Matthew. Please behave and do no harm..


look at the lat/long..... that's Lisa.
REED Forecast Model Run is in process right now...
The Caribbean and GOM season has just begun. Be prepared for a roller coaster ride for the next 4 weeks with the MJO coming on strong in that region. Even if TD 15 doesn't hit the US.. it won't be last storm down there.
Quoting BaltOCane:


look at the lat/long..... that's Lisa.

Sorry, I corrected my original post everyone..
1193. Patrap
TD-14 RGB

1194. kwgirl
Quoting usa777:


"the sea was angry my friend"
And our anchor dragged!
WHO KNOWS?
Quoting Tazmanian:



i think they will upgrade it too Matthew at 8 or 11pm


11pm's probably a good bet.
all will be fine Jeff. your wedding will be great. in reality though, just be careful of the tropical systems as we all know how October can be in Florida.

Good luck!
Quoting Max1023:


I mean the wee hours of the morning, right before sunrise. D-Min is right around sunset, so about 4-5am Est.


Understood and I agree. =)
Levi, I'm a big fan of your blog - usually hide in the background and just watch (I live in FL so I always worry about another hit) and learn - but thanks - I am learning a lot from you!
Thanks for the link Bordonaro. I found the same info while I was waiting. A bit lazy on my part. I had never heard of the Hebert Box before.
NWS MLB 7-day forecast: this is for next Thursday, and note they had alotted for some increase in the pressure gradient (denoting "Breezy" conditions).

Thursday...Partly cloudy with a chance of showers and a slight chance of thunderstorms. Breezy. Highs in the upper 80s. Chance of rain 40 percent.
Quoting mx3gsr92:
I asked this yesterday but was not successful in getting any feedback. I'm heading to Cozumel/Cancun for a week vacation starting Sunday. Could someone give me an idea of what to expect? Should I not go? Anybody have a similar experience? Sorry for asking again. Thanks.


not sure if anyone has answered you yet but sounds iffy to me, but if the storm misses that area there is no need to miss your vacation.
just wait and watch a few more days.. this storm could possibly fizzle out, who knows at this point. Most resorts will allow you to cancel at the last minute if they go under a warning.
YOU'RE IN THE WRONG BLOG!!!!!!
NEW BLOG!
1206. unf97
Good afternoon everyone.

Well, TD 15 on satellite imagery is looking very impressive this afternoon. This cyclone is really spinning up very quickly, which was always my biggest concern as the system is now really drawing and tapping that deep tropical moisture from the SW Caribbean and now the Eastern Pacific. This is going to become a very large cyclone and my heartfelt prayers go out to the people of Honduras, Nicaragua, Belize and the Yucatan Peninsula as the threat of severe flooding looms big in those countries this weekend. Matthew will slow to a crawl this weekend dumping copious amounts of flooding rains especially in the mountainous terrain of the Central America region.

For the first time this season, the Gulf coast and the Florida peninsula especially really have to start thinking about making preparations of a significant tropical cyclone affecting the region. We still have about a week at least before any possible CONUS impact. But suffice to say, this hurricane season is indeed living up to the pre-season expectations of being an active one indeed. I am afraid that we probably will have at least 3-4 other cyclones to develop later into October into the November. But, we will cross that bridge when it occurs.


We just now have to monitor closely what future Matthew will do in the coming days and follow the golden rule: Pray and hope for best, but prepare for the worst.

Quoting Tazmanian:




lol
seems all the smart ones are left,,too bad reno,, tell me when the last hurricane hit reno?
Quoting atl134:
On that plot Dr. Masters posted of the GFS ensemble... is the white line the GFS ensemble forecast or is it the... base one from which all the other initializations are altered from? I'm wondering since I sorta would expect it to be near the middle of the ensemble cluster, at least for the first couple days.


The white line is actually the official operational GFS model run forecasted path.

The other ensemble model paths are alterations to the operational run based on tweaks to particular data information being off from the original. They are there mostly to compare if something deviates from the original forecasted model path.


Anthony
It looks like Honduras/Yucatan may take the brunt of Matthew-to-be. If this were mid-October or later, I'd say that Florida would have to watch this one closely, but the troughs aren't quite as strong in late September as they will be later in the year. Unless this system slows down in forward speed soon and with a trough not settling into the east coast of the U.S. until Sunday, I would tend to think that Florida will be bypassed in favor of points further south.
Oh...and time to refresh, folks. New blog entry now up.


Anthony
just checking in for the reed forecast bring it on
LIKE BATHTUB WATER
1214. xcool
newwwwwwwwwwwww blogggggggggggggggggggggggggggggggggggggggg
Quoting ConchHondros:


You mean to say it caters to the lowest common denominator? Sweet sign me up! Oh wait, I have a degree...never mind.


And you're sooo wise because of it...
Quoting swlavp:
1072. betapaul

There are some very knowledgable people on here..But to hang on every word anybody says in a weather blog is rather irresponsible I would think..


I wouldn't call it irresponsible. Maybe putting a little bit too much faith into one man, but I can see what you mean.

I just like how he didn't say anything without backing it up with solid data and an explanation that us without degrees (which apparently are made fun of) can understand.

There are several VERY knowledgeable people that comment, but very few really explained their comments to a degree that noobs could comprehend.

He wasn't quick to state facts like he knew it all, but instead offered his opinion based on the data acquired at that time. That's rare here...

I don't even know what happened so I'm just spouting off what I DO know (which isn't much).
I have come to understand that a hurricane that moves very slowly or stalls usually weakens due to upwelling of cooler waters from below. Question. If a hurricane were to stall over an area where the depth of warm water is very very deep, would the upwellinf effect cause it ti weaken,maintain,or strengthen itself?? Thank You
Ithink it has
TD#15 LOOKING HEALTHY
1220. hydrus
Some green in ther..
1221. hydrus
1222. hydrus
1223. hydrus
Lisa is struggling.