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2019 Atlantic Hurricane Season


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Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Jul 29 2019

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

Shower activity associated with a tropical wave over the eastern
Caribbean Sea has decreased since yesterday.  Atmospheric conditions
as well as land effects should inhibit the development of this
system as it moves west-northwestward for the next several days.
This disturbance, however, could still produce an increase in
cloudiness and thunderstorms over Puerto Rico, the Greater Antilles
and portions of the Bahamas during the next few days.

1. * Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

Forecaster Avila
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Disturbance near the Cape Verdes is up to 40% for the 5-Day Outlook.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Tue Jul 30 2019

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

1. A tropical wave continues to produce disorganized showers and
thunderstorms over Hispaniola, Puerto Rico, and the Virgin Islands.
This disturbance is forecast to move west-northwestward to
northwestward during the next several days, producing locally heavy
rainfall over portions of the northern Caribbean and the Bahamas.
Conditions could become marginally conducive for development late
this week when the disturbance moves near Florida and the
northwestern Bahamas.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

2. A tropical wave located over the eastern tropical Atlantic, a few
hundred miles south-southwest of the Cabo Verde Islands, continues
to produce a broad area of disorganized showers and thunderstorms.
No significant development of this system is expected for the next
few days while it moves westward at about 15 mph. Thereafter,
upper-level winds are forecast to gradually become more conducive,
and a tropical depression could form over the weekend several
hundred miles east of the Lesser Antilles.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Stewart

 

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12z euro doesn't do much with it and makes it stay weak for a while. 18z legacy GFS and regular GFS bring it further west however. Another thing, brings PR more into play as GFS brings a strong TS/cat 1 into PR.
Yeah the 12z ECMWF has some very strong 400-300 mb southwesterly winds moving in a line from Cuba across the Bahamas and Bermuda in the 5-7 day range. The GFS is more aligned with the Hudson to Nova Scotia trough and better supportive stacked southerly flow. Hence the GFS has a borderline major hurricane rounding the western periphery of backing 580 dm heights versus the ECMWF which is NOT southerly stacked in flow, which just decapitates any tropical entity that would dare move near the SE CONUS / Bahamas.
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Yeah, the reason the GFS models bomb this into a beast is because of an amazing amount of outflow channels it gets near the Bahamas. One off to the north, one to the southeast into an upper level low, and another one into an upper low feature in the Gulf of Mexico. 

ice_screenshot_20190731-211955.png

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ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Jul 31 2019

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

1. An area of disturbed weather stretching from central and eastern
Cuba northward to the central and southeastern Bahamas is forecast
to move northwestward tonight and Thursday, and then move
northward on across Florida and the northwestern Bahamas on Friday.
This system is expected to produce locally heavy rainfall over
portions of the Greater Antilles, the Bahamas and Florida during the
next few days. Conditions could become marginally conducive for
development over the weekend while the system turns and accelerates
northeastward off the southeastern U.S. coast.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

2. A broad low pressure system is producing a large area of cloudiness
and shower activity several hundred miles west-southwest of the Cabo
Verde Islands.  Environmental conditions are not expected to be
conducive for significant development of this disturbance during
the next couple of days while it moves westward at about 15 mph
across the central tropical Atlantic Ocean. However, conditions are
forecast to become more conducive for development over the weekend,
and a tropical depression is likely to form by early next week
several hundred miles east of the Lesser Antilles.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Stewart

 

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2 hours ago, bigtenfan said:

Looks like the 12z GFS  never really fully develops it  and takes a weak system harmlessly out to sea 

My moneys on that scenario right now. We need overall shear to relax and the atmosphere to moisten more as we get deeper into the heart of the season. Too many things need to be just perfect for this one. 

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On 8/1/2019 at 12:26 AM, Windspeed said:

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Jul 31 2019

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

1. An area of disturbed weather stretching from central and eastern
Cuba northward to the central and southeastern Bahamas is forecast
to move northwestward tonight and Thursday, and then move
northward on across Florida and the northwestern Bahamas on Friday.
This system is expected to produce locally heavy rainfall over
portions of the Greater Antilles, the Bahamas and Florida during the
next few days. Conditions could become marginally conducive for
development over the weekend while the system turns and accelerates
northeastward off the southeastern U.S. coast.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...10 percent.

2. A broad low pressure system is producing a large area of cloudiness
and shower activity several hundred miles west-southwest of the Cabo
Verde Islands.  Environmental conditions are not expected to be
conducive for significant development of this disturbance during
the next couple of days while it moves westward at about 15 mph
across the central tropical Atlantic Ocean. However, conditions are
forecast to become more conducive for development over the weekend,
and a tropical depression is likely to form by early next week
several hundred miles east of the Lesser Antilles.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...high...70 percent.

Forecaster Stewart

 

Shows you how fickle forecasting tropical systems can be

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Fri Aug 2 2019

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

1. An elongated area of low pressure located over the central tropical
Atlantic Ocean several hundred miles southeast of the Lesser
Antilles continues to generate limited showers and thunderstorms.
Some slow development of this system is possible, and a tropical
depression could form well east of the Leeward Islands by early next
week while the low moves west-northwestward at 10 to 15 mph.
Upper-level winds are forecast to become less conducive for
development as the system approaches the Leeward Islands Tuesday and
Wednesday.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Zelinsky/Ramos
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Agree with the increase in storms. Things are quiet and will likely remain that way through late August. OTOH, September and October are shaping up to be very active. ENSO has transitioned to neutral into at least early Winter. Westerly wind shear should be low across the Atlantic MDR. Easterly windshear should become more favorable by late August as the SPH backs north and surface pressures fall. Could be a really interesting setup for the MDR into the Caribbean and not just from a climatological perspective. SSTs/OHC temps and depth throughout the region is running above climo mean and will be conducive for TC development when atmospheric conditions improve.

 

 

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TS Chantal is aliiive...  fairly odd to have formation so far north [40N], but she's supposed to bend south into warmer SST, but more unfavorable atmo layers, at least for a while, then...

000
WTNT44 KNHC 210232
TCDAT4

Tropical Storm Chantal Discussion Number   1
NWS National Hurricane Center Miami FL       AL042019
1100 PM AST Tue Aug 20 2019

Recent scatterometer wind data and passive microwave satellite
images indicate that the small low pressure system that the NHC has
been monitoring for the past few days has developed a well-defined
surface wind circulation and contains tropical-storm-force winds
south of the cyclone's center. Therefore, the low has become
Tropical Storm Chantal.

The initial motion estimate is 085/19 kt. NHC model guidance is in
excellent agreement that Chantal will move eastward around the
northern periphery of the Bermuda-Azores high and gradually slow
down during the next 48 hours. Thereafter, the cyclone is forecast
to drop southward around the eastern portion of the ridge, possibly
stalling over warmer waters. The NHC forecast track lies close to
the consensus models HCCA and TVCN.

Chantal is expected to remain in a moderate southwesterly to
westerly vertical wind shear regime for the next 48 hours or so,
followed by a significant decrease in the shear through 120 h. After
48 hours, the southward motion is also expected to move Chantal over
warmer water with SSTs around 27C. However, mid-level moisture is
expected to be quite sparse with humidity values forecast to be less
than 40 percent based on the GFS and ECMWF SHIPS intensity guidance.
Therefore, little or no significant intensification is expected
throughout the forecast period, and the official intensity forecast
closely follows a blend of the HCCA and IVCN consensus models.
Although the official forecast calls for Chantal to remain a
tropical cyclone through the 120 h, the abundance of dry air that
the cyclone will be moving through could result in erosion of the
deep convection sooner than currently expected.

FORECAST POSITIONS AND MAX WINDS

INIT  21/0300Z 40.2N  56.2W   35 KT  40 MPH
 12H  21/1200Z 40.3N  52.6W   35 KT  40 MPH
 24H  22/0000Z 40.2N  48.5W   35 KT  40 MPH
 36H  22/1200Z 39.0N  44.7W   35 KT  40 MPH
 48H  23/0000Z 37.4N  42.3W   35 KT  40 MPH
 72H  24/0000Z 34.9N  42.5W   35 KT  40 MPH
 96H  25/0000Z 34.6N  44.8W   35 KT  40 MPH
120H  26/0000Z 36.0N  44.8W   35 KT  40 MPH
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Westerly windshear has dramatically decreased across the Caribbean and much of the MDR below 20-25° latitude. Additionally there are signs of backing Azores ridging, which should continue to relax easterlies somewhat over the next week. Robust waves and inverted troughs are exiting Africa during this time. Though the globals are reluctant to latch onto anything yet aside from occasional blurps out of the GFS, I expect a shift towards favorable atmospheric conditions and a decrease in subsidence going into early September. Some of these waves should be strong enough to break off the suppressed ITCZ and amp up moisture feed, convergence and lift across the lower central development region. Essentially, aside from obvious climatological cues, I don't expect things to be quiet much longer.

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ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Fri Aug 23 2019

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

The National Hurricane Center is issuing advisories on Tropical
Depression Chantal, located about 765 miles west of the Azores.

1. Surface and radar data indicate that a weak area of low pressure is
located just east of the upper Florida Keys and the southeastern
coast of the Florida peninsula.  This system is producing a large
area of disorganized cloudiness and showers that extends primarily
northeast of the center over the northwestern Bahamas and the
adjacent Atlantic Ocean.  The low is forecast to move near or over
the Florida peninsula through tonight, which should limit
development during that time.  Environmental conditions appear
conducive for development once the system moves northeastward back
over the Atlantic waters on Saturday.  A tropical depression is
likely to form this weekend or early next week while the low moves
from near the coast of east-central Florida to offshore of the
southeastern United States coast.  Regardless of development,
locally heavy rains are possible over the northwestern Bahamas and
southern and central Florida through the weekend.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...70 percent.

2. Showers and thunderstorms have increased since yesterday in
association with a tropical wave located about 1400 miles
east-southeast of the Windward Islands.  Additional slow development
of this system is possible during the next few days as it moves
generally westward at about 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...20 percent.

Forecaster Beven

 

two_atl_5d0 (1).png

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Invest 99L east of the Lesser Antilles is looking very suspicious that it is trying to cutoff the wave axis in the low levels. It clearly has cyclonic turning in mid levels evident on visible. Convection keeps pivoting west and wsw of the axis however. If mid level flow can relax just a bit more and the disturbance can sustain or, even better, an MCS develop at the low level cutoff, we may have a a classified storm in the MDR. Perhaps the NHC did not have a great look at the feature this morning. ASCAT missed. But I figure the odds will increase to moderate on the 2PM AST 5-day outlook besides.8023b3112437ee4ad1e8880565e6769d.gif

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From Eric Webb

S9I9LRe.png&key=a59fa9ecdc5c0c02d85e7826587be9520438aac1e709ce823881a50638773552

Yeah I was referring to ASCAT this morning. Still, even with respect to that most recent successful pass, the overall circulation still looks rather weak. Obviously directional winds on the N-NW side are going to be stronger due to the folding of the axis and easterlies. If convection can ramp up again this evening, we may have an interesting development. Still expect odds to go up at 2 PM.
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