2019 Atlantic Hurricane Season

[Windspeed]

A broad surface trough has developed east of Nicaragua near 80W in the western Caribbean. General easterly showers and thunderstorms are moving into Nicaragua along its western boundary, though the trough itself is moving very slowly if hardly a westward drift. This area may get tagged an invest tonight or tomorrow. The trough was modeled with considerable confidence in most of the main globals over the past four to five days, however, only the GFS has remained persistent to develop a tropical cyclone out of this feature. The NHC has not yet mentioned the area in their outlooks, but I would not be surprised if they begin mentioning it by tomorrow if a diurnal MCS goes up tonight out over the Caribbean or somewhere central to the trough axis. Confidence in TC genesis will probably remain low unless this gets better modeling support, or at least something begins resolving on the ECMWF as well. If a TC does develop, score this a win for the GFS though -- much like it did with Dorian back in late August out over the MDR.

[cptcatz]

^The NHC mentioned it in their 8pm update:

 

2. A broad area of low pressure is expected to form over the western
Caribbean Sea late this weekend.  This system is forecast to move
westward toward Central America early next week, and some
development is possible if the low remains over water while moving
near the coasts of Honduras, Guatemala, and Belize.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

[MJO812]

6 hours ago, cptcatz said:

^The NHC mentioned it in their 8pm update:

 

2. A broad area of low pressure is expected to form over the western
Caribbean Sea late this weekend.  This system is forecast to move
westward toward Central America early next week, and some
development is possible if the low remains over water while moving
near the coasts of Honduras, Guatemala, and Belize.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.

CMC and GFS develop a low in the gulf by the end of next week.

[cptcatz]

Subtropical Storm Melissa has formed:

000
WTNT44 KNHC 111452
TCDAT4

Subtropical Storm Melissa Discussion Number   1
NWS National Hurricane Center Miami FL       AL142019
1100 AM AST Fri Oct 11 2019

Convection increased near the center of the nor'easter centered
southeast of New England overnight. First-light visible satellite
imagery briefly showed an eye-like feature before the convection
around the immediate center began to weaken. However, a large
convective band still persists over the northern semicircle, and
this structure indicated the system has transitioned to a
subtropical cyclone. The latest Hebert-Poteat classification from
TAFB indicates an initial intensity of 55 kt, and this is also
supported by an earlier scatterometer overpass showing a large area
of winds near 50 kt in the northwest quadrant.

Melissa is currently located underneath an upper-level trough,
resulting in a light shear environment. This trough will begin to
lift northeastward later today, and strong upper-level westerlies
should begin to affect the storm by tonight. This pattern is
expected to cause a weakening trend, and Melissa is forecast to
become post-tropical by Saturday night. The post-tropical cyclone is
then expected to be absorbed by an approaching front in 3 to 4 days.

Melissa is currently embedded in weak steering flow under the upper-
level trough, and little net motion is expected today. Later
tonight, an approaching mid-latitude trough currently crossing
the upper Midwest will begin to force an east-northeastward
motion at a faster forward speed. This motion will continue until
the cyclone is absorbed by the cold front. The NHC track forecast is
closest to the ECMWF ensemble mean.

Ongoing hazards from wind and coastal flooding will continue be
covered by non-tropical products from local National Weather Service
forecast offices.

Gale-force winds that extend well northeastward of Melissa into the
central Atlantic that are not included in the wind radii, since they
are associated with a frontal boundary.

Key Messages:

1. While the nor'easter centered southeast of New England has become
Subtropical Storm Melissa, the expected magnitude of wind and
coastal flooding impacts along portions of the U.S. east coast from
the mid-Atlantic states to southeastern New England has not changed.
For information on these hazards, see products issued by local
National Weather Service forecast offices at weather.gov.

2. Melissa is expected to gradually weaken and begin moving away
from the U.S. east coast by tonight, resulting in a gradual decrease
in wind and coastal flooding impacts.

FORECAST POSITIONS AND MAX WINDS

INIT  11/1500Z 38.5N  69.6W   55 KT  65 MPH
 12H  12/0000Z 38.2N  69.3W   45 KT  50 MPH
 24H  12/1200Z 38.4N  67.7W   35 KT  40 MPH
 36H  13/0000Z 39.0N  65.1W   30 KT  35 MPH...POST-TROPICAL
 48H  13/1200Z 39.9N  61.0W   30 KT  35 MPH...POST-TROPICAL
 72H  14/1200Z 41.3N  52.6W   30 KT  35 MPH...POST-TROPICAL
 96H  15/1200Z...ABSORBED

$$
Forecaster Latto

[yoda]

Melissa was able to transition from a STS to a TS before becoming post-tropical soon

 

Tropical Storm Melissa Discussion Number   6
NWS National Hurricane Center Miami FL       AL142019
500 PM AST Sat Oct 12 2019

Convection has continued to persist near the center of Melissa
throughout the day, and only in the past few hours have the affects
of increasing westerly shear begun to erode the convection from the
western side of the cyclone.  A pair of scatterometer passes late
this morning showed that the wind field associated with the storm
had contracted, with the strongest winds occurring within 50 n mi of
the center. They also revealed that the radius of maximum winds had
decreased to 20 n mi.  Based on these data along with a tropical
structure apparent in satellite and microwave data, it is likely
that Melissa completed a transition to a tropical cyclone at some
point this morning.  A recent Dvorak classification from TAFB, an
objective estimate from UW-CIMSS ADT, and an earlier scatterometer
pass all support an initial intensity of 45 kt for this advisory.

The westerly shear beginning to affect Melissa is expected to
gradually increase over the next few days. Through tonight, the
cyclone will move over waters of 23-24 C. In addition, the upper
trough over the storm that has aided in maintaining its convection
will weaken and lift northeast of the cyclone over the next day or
so. The combination of these factors should cause Melissa to weaken,
and the cyclone is forecast to become a post-tropical remnant low by
Sunday.  The global model intensity forecasts appear to be
capturing the strongest winds in a frontal zone well-removed to the
northeast of Melissa and not directly associated with the cyclone
itself. Thus, the NHC forecast is very similar to the previous one,
and continues to be lower than the global model guidance.

Melissa is moving east-northeastward, or 070/10 kt. The increasing
westerly flow will cause the cyclone to gradually accelerate through
Monday. This motion will continue, with a slight turn to the east in
a few days, just before the cyclone is absorbed by a frontal zone.
The new NHC track forecast is close to the previous one and in the
middle of the various consensus aids.

Ongoing hazards from coastal flooding will continue to be covered by
non-tropical products from local National Weather Service forecast
offices.

Key Messages:

1. Although Melissa is forecast to weaken and move away from the
east coast, minor to moderate coastal flooding is still expected
along portions of the U.S. Mid-Atlantic and southeastern coasts
around times of high tide for the remainder of the weekend. For more
information, see products issued by local National Weather Service
forecast offices at weather.gov.


FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 38.4N  65.6W   45 KT  50 MPH
 12H  13/0600Z 39.0N  63.5W   35 KT  40 MPH
 24H  13/1800Z 39.8N  60.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  14/0600Z 40.7N  55.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  14/1800Z 41.6N  51.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  15/1800Z 42.4N  39.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  16/1800Z...ABSORBED BY A FRONTAL ZONE

$$
Forecaster Latto

[cptcatz]

There's a disturbance in the central Atlantic right now that the GFS and Euro are hinting at and the CMC is going full throttle with. Will be interesting to see if the NHC mentions it at 8pm.

[NavarreDon]

Up to 40% for this little ditty. Not an expert but seems like lots of shear to deal with?


.

[NorthHillsWx]

14 hours ago, NavarreDon said:

Up to 40% for this little ditty. Not an expert but seems like lots of shear to deal with?


.

Certainly a lot of shear but a lot of models are latching onto a weak system developing. This would seem to max out as one of the classic gulf half-cyclones maybe attaining low end TS winds. Good news with this system is it has its moisture aimed at the SE, a region that has dealt with significant drought issues over the summer. Recent rains along with the potential for some tropical rain would do a lot of favors for these areas.

[NavarreDon]

Certainly a lot of shear but a lot of models are latching onto a weak system developing. This would seem to max out as one of the classic gulf half-cyclones maybe attaining low end TS winds. Good news with this system is it has its moisture aimed at the SE, a region that has dealt with significant drought issues over the summer. Recent rains along with the potential for some tropical rain would do a lot of favors for these areas.

Up to 50% on the 8:00am update. Totally agree on the drought buster benefits. It has been unbelievably dry in Navarre!


.

[Seminole]

12Z GFS a little more bullish with the BOC system. Higher end TS off PC coast Saturday. 

[cptcatz]

If this hits Florida as a high end TS or low hurricane, I gotta give it to the GFS.  Three weeks ago the GFS was consistently showing this exact system impacting somewhere in Florida on October 19-20.  Pretty impressive.

[NavarreDon]

System is now invest 96L

 

https://www.tropicaltidbits.com/sat/satlooper.php?region=gom&product=ir

 

[NavarreDon]

18Z GFS never gets below 1000. Looks like 1-4” for most of the Panhandle.


.

[Indystorm]

Just watched WWL TV out of New Orleans.  They are currently expecting the heaviest  wx to be along the coast east of them but are still quite concerned about winds that could topple the two cranes at the collapsed Hard Rock Hotel.   Even if the tropical system misses there will be a front coming through early this next week.

[NavarreDon]

Nice write up from MOB on the possible impacts for my forecast area.

 

 

SHORT TERM /Thursday night Through Saturday night/...

 

Attention through the short-term forecast period will focus on the

potential sub-tropical storm likely to develop across the

southwestern Gulf of Mexico. A disturbance now organizing within

the Bay of Campeche will begin to lift northeastward by Thursday

night in response to southwesterly steering flow to the east of an

upper level low pressure system over central Texas. The

disturbance will likely become entangled with the upper low and

frontal boundary initially stalled to it`s north. There will

likely be a brief period where shear may relax slightly on Friday

before the system interacts with stronger westerlies aligned

along the northern Gulf Coast ahead of the next approaching upper

trough. This may allow for some gradual strengthening of the

surface low before reaching the northern Gulf of Mexico and

becoming increasingly sheared. This system is likely to become

increasingly baroclinic in nature before reaching the northern

Gulf Coast and remain a hybrid type system. The potential for this

system to be truly tropical when reaching the Gulf Coast appears

low at this time.

 

The ultimate track, timing, and intensity of the system is also

in question as there remains model differences. The ECENS is

further west and weaker with the GEFS to the east and stronger.

This system has yet to form a low level center and there will

likely be shifts in model guidance until this occurs. In addition,

since this system will not likely be completely tropical in

nature, there likely will be wind and rain impacts far from the

center. At this point, we will continue to indicate increasing

rain chances, gusty winds, and potential coastal flooding across

our forecast area from Friday through Saturday night. Impacts

will depend upon the eventual track and intensity. Please continue

to monitor the latest forecast through the end of this week into

the weekend. /JLH

 

 

.

 

[NavarreDon]

96L got it's cherry at 2:00 am

[NavarreDon]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Thu Oct 17 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Showers and thunderstorms associated with a broad area of low
pressure located over the Bay of Campeche have increased and
become a little better organized during the past several hours.
Recent satellite wind data also indicate that the system is
producing winds to near tropical storm force.  Environmental
conditions are expected to be conducive for additional development,
and a tropical or subtropical storm is likely to form later today
or tonight while the system moves generally northeastward over
the western Gulf of Mexico.  The low is forecast to approach the
northern or northeastern Gulf Coast on Friday or Saturday and
regardless of development, the system is likely to produce gusty
winds and rough surf over those areas.  Heavy rainfall is also
possible across portions of the southeast U.S. late this week and
this weekend.  Interests along the northern and northeastern Gulf
coast should monitor the progress of this system.  For more
information about marine hazards while the low moves across the Gulf
of Mexico during the next couple of days, see products issued by the
Tropical Analysis and Forecast Branch of the National Hurricane
Center. An Air Force Reserve reconnaissance aircraft is scheduled to
investigate the system this afternoon, if necessary.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

[NavarreDon]

17 hours ago, cptcatz said:

If this hits Florida as a high end TS or low hurricane, I gotta give it to the GFS.  Three weeks ago the GFS was consistently showing this exact system impacting somewhere in Florida on October 19-20.  Pretty impressive.

Not only likely but, the euro had been showing a LA landfall until the latest run. This is from MOB's overnight.

Global spectral models are in general agreement projecting the
upper level trough currently moving eastward over west Texas to
essentially interact with the disturbance and rapidly advance it
northeastward over the Gulf. This system is likely to become
increasingly baroclinic in nature before reaching the northern
Gulf Coast and remain a hybrid type system. The models do vary in
the eventual track and timing of the system. With the ECMWF now
projecting the low moving onshore east of Destin, Florida Saturday
morning and the GFS near Port St. Joe, Florida. Keep in mind
though there still remains a great deal of uncertainty in the
eventual track as the disturbance has still not developed a low
level center...so inherently there will be more error at this
point in the model tracks, and the model forecast will
undoubtedly change as the system develops. Also, since this system
is expected to evolve into more of hybrid/baroclinic system the
rain and wind impacts will possibly extend far from the center.

[beanskip]

Frankly, a bit surprised NHC hasn't initiated some sort of pre-cyclone advisories on this system. Seems quite likely that at least a tropical storm will make landfall within 48 hours in an area still recovering from Michael. It's getting very little play in the panhandle. 

[beanskip]

NHC will start "Potential Tropical Cyclone 16" advisories at 11.

[Windspeed]

A surface trough in the Bay of Campeche has nearly closed off a low-level vortex. TD is very close to being classified and this likely becomes a tropical storm. Conditions are favorable in the short term for intensification, however, as the system moves NNW, it will probably encounter less favorable conditions due to frontal interaction. For any significant strengthening, it will need to get its act together fast. That is possible though as it is currently under decent atmospheric conditions and upper level divergence.

 

This system is expected to bring significant flooding into the Mississippi Valley this weekend as it interacts with a mid-latitude trough and merges into a frontal boundary.

[NorthHillsWx]

Invest 97L looking healthy this morning. Would not be surprised to see this thing be a quick-developing TS today given the organization this morning. Hostile environment ahead but definitely showing some spin on IR and first visible shots this morning

[NorthHillsWx]

2 minutes ago, Windspeed said:

A surface trough in the Bay of Campeche has nearly closed off a low-level vortex. TD is very close to being classified and this likely becomes a tropical storm. Conditions are favorable in the short term for intensification, however, as the system moves NNW, it will probably encounter less favorable conditions due to frontal interaction. For any significant strengthening, it will need to get its act together fast. That is possible though as it is currently under decent atmospheric conditions and upper level divergence.

Same time haha

[yoda]

2 minutes ago, Windspeed said:

A surface trough in the Bay of Campeche has nearly closed off a low-level vortex. TD is very close to being classified and this likely becomes a tropical storm. Conditions are favorable in the short term for intensification, however, as the system moves NNW, it will probably encounter less favorable conditions due to frontal interaction. For any significant strengthening, it will need to get its act together fast. That is possible though as it is currently under decent atmospheric conditions and upper level divergence.

It has about 24-36 hours before it gets absorbed by the front (NHC also states this in their 8am TWO)... sounds like another system that develops in the GOM and then is gone 48 hours later... I think this would be the 3rd system this year that's done that

[Windspeed]

It has about 24-36 hours before it gets absorbed by the front (NHC also states this in their 8am TWO)... sounds like another system that develops in the GOM and then is gone 48 hours later... I think this would be the 3rd system this year that's done that

This is a good thing as any slower setup would nearly guarantee a north gulf coast hurricane. As it stands, this may still end up making landfall as a "strong" tropical storm. Which again, the flooding potential is the real threat here during frontal merger up the Mississippi Valley.

[Windspeed]

To say it's been rare to see GOM development this late in October would be an understatement. The last purely GOM system to become a TC this late in the calender year was Juan in 1985:

 

 

The reasons meteorologically-speaking are fairly straight forward. Early October is very different than late October. Strong frontal boundaries and the jet stream have typically overtaken and suppressed favorable atmospheric dynamics for cyclogenesis by this point.

[NavarreDon]

Watching this one closely from Navarre!

[Windspeed]

Since we now have a TC showing up within modeling, the moisture stream is shifting east into the Tennessee Valley. There will still be significant moisture stream up into the Mississippi Valley in combo with the frontal boundary, so the flood threat is still possible there. However, with a well-developed surface low such as TC, the flooding threat may shift east into the Tennessee Valley and Southeast. This is a late development that needs to be watched. Of course many areas in the Southeast still need the rain.

[NavarreDon]

Up to 60% on the 2pm NHC outlook.


.

[yoda]

2 minutes ago, NavarreDon said:

Up to 60% on the 2pm NHC outlook.


.

Yeah... but the TWO makes it seem it only has like 24 hours left or so

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Thu Oct 24 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. Showers and thunderstorms continue to show signs of organization in
association with a low pressure system located over the Bay of
Campeche.  However, recent satellite data indicate that the
circulation is elongated and not well defined.  This system
could become a short-lived tropical depression before it merges with
a cold front by late Friday.  Regardless of development, gale-force
winds are expected behind the cold front over the western Gulf of
Mexico on Friday and Saturday.  For more information, see High Seas
Forecasts issued by the National Weather Service.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...medium...60 percent.

High Seas Forecasts issued by the National Weather Service can be
found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and
online at ocean.weather.gov/shtml/NFDHSFAT1.php

Forecaster Cangialosi