Tropical Storm Erica Update 28 Aug 2015

Erika proving difficult to predict. Models getting better organized but still have a wide spread.

The Prime Minister of the Island of Dominica reported that 12 are dead and at least 20 missing as a result or Erica.  Florida Gov. declares a state of emergency in anticipation of a strike by Erica.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...

* Puerto Rico
* Vieques
* Culebra
* Dominican Republic
* Haiti
* Southeastern Bahamas
* Turks and Caicos Islands
* Central Bahamas

A Tropical Storm Watch is in effect for...

* Northwestern Bahamas
* The Cuban Provinces of Ciego de Avila, Camaguey, Las Tunas,
Holguin, and Guantanamo

Updated: 28 Aug 2015  11 AM CDT

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Tropical Storm Erika

Erika became the latest storm or the 2015 season on the 24th of August at 10 PM CDT

Erika is currently moving West at 17 MPH and currently headed toward the Leeward Islands.

Tropical Storm Warnings and Watches are now active for portions of the Leeward Islands, Pureto Rico and the U.S. Virgin Islands.

For more details on this storm please join us at Tropical Cyclone for complete coverage.  We have combined information and graphics from multiple sites to give you as much information as possible all in one place.

TROPICAL STORM ERIKA DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052015
1100 AM AST WED AUG 26 2015

Deep convection associated with Erika has increased during the past
24 hours, but the overall organization of the tropical cyclone has
not changed very much.  Reconnaissance aircraft data indicate that
the center is located near the northwestern edge of the thunderstorm
activity due to moderate northwesterly shear.  The aircraft has
measured believable SFMR winds of around 40 kt this morning, and
the initial intensity is set at that value.

Erika is forecast to pass through an environment of moderate to
strong westerly vertical wind shear during the next two to three
days.  The shear will be caused by an upper-level low that is
expected to remain near eastern Cuba through Friday.  The upper low
is forecast to weaken on Saturday, which should produce a more
conducive upper-level wind pattern over the Bahamas. The NHC
intensity forecast calls for little change in strength through 72
hours, which is in line with the latest statistical guidance.  After
that time, strengthening is indicated due to the expected more
favorable upper-level environment.  The official forecast lies
between the more robust HWRF/GFDL and lower statistical guidance.
An alternative forecast scenario, supported by the GFS model, is
that Erika weakens to a tropical wave due to the shear and
interaction with the Greater Antilles.  The amount of strengthening
on days 4-5 will be dependent in part on how Erika responds to the
the preceding unfavorable shear.

The initial motion estimate is 280/15 kt.  Erika is expected to
move westward to west-northwestward during the next several days
to the south of a subtropical ridge over the western Atlantic.
The track guidance is in good agreement through much of the forecast
period, with the exception of the GFDL model that takes a stronger
storm northwestward much sooner.  The new NHC track is essentially
an update of the previous advisory and is close to a consensus of
the ECMWF, GFS, HWRF, and UKMET.  This is also in good agreement
with the Florida State Superensemble.  One should remember to not
focus on the exact forecast track, especially at the long range
where the average NHC track errors during the past 5 years are about
180 miles at day 4 and 240 miles at day 5.

FORECAST POSITIONS AND MAX WINDS

INIT  26/1500Z 16.1N  57.6W   40 KT  45 MPH
 12H  27/0000Z 16.7N  59.9W   45 KT  50 MPH
 24H  27/1200Z 17.6N  63.0W   45 KT  50 MPH
 36H  28/0000Z 18.7N  65.9W   45 KT  50 MPH
 48H  28/1200Z 19.8N  68.7W   45 KT  50 MPH
 72H  29/1200Z 22.0N  73.7W   45 KT  50 MPH
 96H  30/1200Z 24.4N  77.7W   55 KT  65 MPH
120H  31/1200Z 26.5N  80.5W   65 KT  75 MPH...INLAND

Forecaster Brown

Tropical Outlook 24 Aug 2015

Danny has degraded to a tropical wave but the 2015 season remains active with 2 Invest areas with a 90% and 10% chance of developing in the next 48 hours.

Invest 98L is the most interesting with a 90% chance of developing over the next couple of days.

Watch Tropical Cyclone Home for more details on this as well as archives of past storms and other information, 

Hurricane Danny Update: 23 Aug 2015

Danny at Tropical Storm Strength

Tropical Storm Warnings issued for Antigua - Barbuda - Monserrat St Kitts - Nevis - Anguilla

Tropical Storm Watches Issued for Saba - St Eustatius - St Marten Puerto Rico - Vieques - Culebra & U.S. Virgin Islands

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TROPICAL STORM DANNY DISCUSSION NUMBER  21
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042015
1100 AM AST SUN AUG 23 2015

Danny appears to be maintaining its intensity for now.  The
low-level center is estimated to be near the southwestern edge of
the main mass of deep convection, and considerable lightning
activity has recently been occurring near the center.  The current
intensity estimate is held at 45 kt in agreement with the latest
Dvorak estimates and earlier Hurricane Hunter aircraft data.  The
center of the storm should pass very near, or over, the French data
buoy 41300 shortly, and this should provide additional information
about the intensity.  Southwesterly vertical shear of nearly 20 kt
along with dry mid-level air should continue to affect Danny over
the next couple of days.  Both the GFS and ECMWF global models
continue to depict the system opening up into a wave within 48
hours.  Given these unfavorable signs, the official forecast shows
weakening as in the previous advisories.  However, because of the
uncertainties in tropical cyclone intensity prediction, it is
prudent to issue a tropical storm watch for Puerto Rico and the
U.S. Virgin Islands at this time.

Danny continues westward, or 275/13 kt.  A westward to west-
northwestward track is expected over the next few days as the
cyclone moves on the southern side of a low- to mid-level ridge.
The track model guidance has shifted a little south on this cycle,
and so has the official forecast.  This is close to the latest
dynamical model consensus.  If Danny weakens faster than expected,
it could move even farther south of this track.

The system could bring much-needed rainfall to Puerto Rico over the
next few days.

FORECAST POSITIONS AND MAX WINDS

INIT  23/1500Z 15.8N  57.3W   45 KT  50 MPH
 12H  24/0000Z 16.0N  59.3W   40 KT  45 MPH
 24H  24/1200Z 16.5N  61.9W   35 KT  40 MPH
 36H  25/0000Z 17.0N  64.5W   30 KT  35 MPH
 48H  25/1200Z 17.5N  67.1W   30 KT  35 MPH
 72H  26/1200Z 19.2N  72.0W   25 KT  30 MPH...INLAND
 96H  27/1200Z 21.0N  76.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  28/1200Z...DISSIPATED

Forecaster Pasch

Hurricane Danny Update 22 Aug 2015

Danny is weakening but still Category 1 Storm.  Tropical Storm Watches set for portions of the Leeward Islands...

See TropicalCycloneWebsite for more details and graphics.  Also join us on Facebook.

HURRICANE DANNY DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042015
1100 AM AST SAT AUG 22 2015

Danny's cloud pattern is similar to that of six hours ago, with a
central dense overcast and some outer banding in the northeastern
semicircle.  However, the size of the overcast has diminished with
the center getting closer to the edge.  The initial intensity is
decreased to 80 kt based on decreasing satellite intensity
estimates and continuity from the previous advisory.  However, this
could be generous.  NOAA and Air Force Reserve Unit reconnaissance
aircraft are scheduled to investigate Danny this afternoon and
should provide a better estimate of its intensity.

The initial motion is now 285/10.  There is no change in the
forecast philosophy from the previous advisory, with Danny expected
to turn westward and accelerate later today as the subtropical ridge
to the north of the cyclone builds westward and strengthens.  This
general motion is expected to persist for the next several days
taking Danny across the Leeward Islands in about two days, and near
Puerto Rico and Hispaniola in 3 to 4 days.  The track model
guidance remains in good agreement with this, and the forecast
track lies near the center of the track guidance envelope.

Danny is expected to move through a dry and stable air mass and
encounter moderate to strong southwesterly vertical wind shear for
at least the next three days.  This should cause continued
weakening, and the cyclone is forecast to be a tropical storm as it
moves over or near the northeastern Caribbean Islands.  The
intensity forecast becomes lower confidence at days 4 and 5 due to
the uncertainty in how much land Danny will encounter, disagreements
between the dynamical models over the forecast shear, and continued
divergence between the models forecasting Danny to dissipate and the
models forecasting it to survive.  The latter part of the forecast
compromises between these extremes by showing a continued weakening
trend.

A tropical storm watch is being issued for portions of the Leeward
Islands at this time.  Additional watches or warning may be
necessary for this area, as well as the Virgin Islands and Puerto
Rico, later today or tonight.


FORECAST POSITIONS AND MAX WINDS

INIT  22/1500Z 15.4N  52.0W   80 KT  90 MPH
 12H  23/0000Z 15.7N  53.7W   70 KT  80 MPH
 24H  23/1200Z 16.1N  56.1W   60 KT  70 MPH
 36H  24/0000Z 16.6N  58.7W   55 KT  65 MPH
 48H  24/1200Z 17.2N  61.3W   50 KT  60 MPH
 72H  25/1200Z 18.5N  66.0W   45 KT  50 MPH
 96H  26/1200Z 20.5N  71.0W   40 KT  45 MPH
120H  27/1200Z 22.0N  75.5W   30 KT  35 MPH

Forecaster Beven

2015 Season Heats Up

The 2015 season is starting to heat up.  As we approach the peak of the season and are all watching Hurricane Danny (which is now a Category 2 Storm) there are 3 more Invest areas in the Atlantic with between a 10 and 50% chance of becoming organized over the next 5 days...

Invest 97L Models

Hurricane Danny Update 21 Aug 2015

Update: 21 Aug 2015 10 AM CDT

Hurricane Danny Now Category 2 Storm

Tropical Storm Danny has become a small but powerful Category 2 Hurricane.

Still moving WNW at 10 MPH the pressure has dropped to 28.82"  A Hurricane Hunter Aircraft is scheduled to fly into Danny later this afternoon.

The small eye has become better defined, and it is now embedded in a circular central dense overcast. In addition, the ragged outer banding has increased in coverage and now surrounds the central convection.

Imagery suggests that low-level moisture has wrapped around the cyclone and pushed the drier air farther away. This could be helping both the intensification and the increase in outer banding.

The subtropical ridge north of Danny remains weaker than normal due to a deep-layer trough over the western Atlantic. This trough is expected to lift northward in a couple of days, allowing the ridge to build westward and strengthen. This evolution should cause Danny to turn more westward with some increase in forward speed.

Danny is currently in an environment of light vertical wind shear. However, it is about to encounter increasing upper-level southwesterly flow associated with a trough over the northeastern Caribbean, with the shear forecast to increase to over 20 kt by 96 hours. This, combined with the abundant dry air remaining along the forecast track, should cause Danny to weaken below hurricane strength as it approaches the Caribbean islands

The models are in good agreement this morning.  Areas along the Leeward Islands should keep a close eye on Danny. (Information from the National Hurricane Center)

TS Danny Becomes First Hurricane of 2015

Tropical Storm Danny now 1st Hurricane of the 2015 Season.

Tropical Storm Danny has become the first Hurricane of the 2015 Season with wind speeds now at 75 MPH, the pressure has dropped to 29.30". Danny's cloud pattern has continued to improve since the previous advisory, and a 10 nautical mile diameter eye has become embedded in the center of a small central dense overcast.

Danny is moving WNW at 12 MPH

Danny's compact size makes it subject to significant fluctuations in strength, both up and down, and such fluctuations are notoriously difficult to forecast. Low-shear conditions are expected to continue for the next 36 hours or so, which argues for some further strengthening during that time. However, the cyclone continues to be surrounded by dry mid-level air, which could penetrate into the core and disrupt the intensification process.

By 48 hours and beyond, the vertical wind shear is forecast to become southerly to southwesterly and increase to near 15 kt. As a result, Danny is expected to be weakening as it approaches the Leeward Islands.

The models are in better agreement but the storm is still quite a way out in the Tropical Atlantic and the final track is still not certain.  Areas along the Windward Islands should keep a close eye on Danny.

See TropicalCycloneWebsite for more details and graphics.  Also join us on Facebook.

HURRICANE DANNY DISCUSSION NUMBER   9
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042015
1100 AM AST THU AUG 20 2015

Danny's cloud pattern has continued to improve since the previous
advisory, and a 10 n mi diameter eye has become embedded in the
center of a small central dense overcast. Water vapor imagery
indicates that upper-level outflow has become more symmetrical. The
initial intensity of 65 kt is based on NHC objective Dvorak
classifications of T4.1-T4.2 using an eye feature.  Conventional and
microwave satellite images indicate that Danny is an unusually small
tropical cyclone.

Satellite fixes indicate that Danny is now moving west-northwestward
or 295/10 kt. The latest model guidance remains in very good
agreement on Danny moving west-northwestward for the next 48-72
hours toward a weakness in the subtropical ridge along 60W
longitude. A mid- to upper-level trough north of Bermuda is forecast
by the global models to begin lifting out to the north in 96-120
hours, which should allow the subtropical ridge to the north of
Danny to build back westward, forcing Danny on a more westward track
on days 4 and 5. The NHC official forecast track is essentially an
update of the previous advisory through 72 hours, but was shifted a
little north of the previous track after that in agreement with the
consensus model TVCN.

Danny's compact size makes it subject to significant fluctuations in
strength, both up and down, and such fluctuations are notoriously
difficult to forecast.  Low-shear conditions are expected to
continue for the next 36 hours or so, which argues for some further
strengthening during that time. However, the cyclone continues to be
surrounded by dry mid-level air, which could penetrate into the core
and disrupt the intensification process. By 48 hours and beyond, the
vertical wind shear is forecast to become southerly to southwesterly
and increase to near 15 kt.  As a result, Danny is expected to be
weakening as it approaches the Leeward Island.  The official
intensity forecast calls for a peak intensity somewhat higher and
earlier than the previous advisory, ending up close to the IVCN
consensus model.

FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 12.5N  44.8W   65 KT  75 MPH
 12H  21/0000Z 13.1N  46.0W   70 KT  80 MPH
 24H  21/1200Z 14.0N  47.6W   75 KT  85 MPH
 36H  22/0000Z 14.7N  49.4W   75 KT  85 MPH
 48H  22/1200Z 15.2N  51.5W   70 KT  80 MPH
 72H  23/1200Z 16.0N  56.4W   65 KT  75 MPH
 96H  24/1200Z 16.9N  61.7W   65 KT  75 MPH
120H  25/1200Z 18.0N  66.6W   55 KT  65 MPH

Forecaster Stewart

Tropical Storm Danny Update 19 Aug 4PM CDT

Tropical Storm Danny slows but still moving West

Tropical Storm Danny has slowed to 10 MPH and is still moving west.  The storm is also interacting with some dry-air from the North and West that may be causing this slow down and the downgrade in the forecast intensity being lowered. Danny is still expected to reach Hurricane strength in the next couple of days.

The models are in better agreement this evening but the storm is still quite a way out in the Tropical Atlantic and the final track is still not certain.  Areas along the Windward Islands should keep a close eye on Danny.

See TropicalCycloneWebsite for more details and graphics.  Also join us on Facebook.

TROPICAL STORM DANNY DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042015
500 PM AST WED AUG 19 2015

Satellite imagery shows that Danny's deep convection collapsed late
this morning, with the experimental Saharan Air Layer (SAL) Meteosat
imagery suggesting that dry-air entrainment could be the cause.
Although visible satellite pictures still show a vigorous
circulation and some renewed convection, the system overall has lost
organization and become more embedded in the Intertropical
Convergence Zone since yesterday. With little change in the Dvorak
classifications, the initial intensity is kept at 45 kt in agreement
with the latest CI number from TAFB.

Given the current appearance of the cyclone, it might be that
dry air associated with the SAL intruding from the north and west
has become a greater impediment to intensification.  Dry air aside,
other atmospheric parameters governing intensification would seem to
favor some strengthening during the next 2 to 3 days, and the
official forecast shows modest strengthening.  After that time,
significantly drier mid-tropospheric air and an increase in westerly
flow aloft associated with an enhanced and persistent mid-oceanic
trough across the Caribbean region is expected to induce weakening
as shown in the ECWMF solution.  There is a large discrepancy
between the statistical and dynamical model guidance, with the
GFS-based statistical guidance continuing to show more
intensification and the regional hurricane models showing only
modest strengthening followed by weakening.  The official intensity
forecast is similar to but a little lower than the previous one at
later times, consistent with the multi-model consensus.

The cyclone has been moving generally west but at a slower forward
speed (280/08) in response to a weakening subtropical ridge to the
north of the cyclone.  A west-northwestward motion is expected
during the next next 2 to 3 days, at which time an interesting
split in the model guidance occurs.  The GFS shows a much stronger
representation of Danny moving west-northwestward near and north of
the Greater Antilles in 3 to 5 days.  The ECWMF solution, on the
other hand, depicts Danny as a shallower feature from the start and
as a weakening cyclone as it nears the Lesser Antilles on a westward
track.  The new forecast track maintains the philosophy of the
previous one by showing a general westward track in the extended
range, giving more weight to the ECMWF solution that shows
weakening.


FORECAST POSITIONS AND MAX WINDS

INIT  19/2100Z 11.5N  42.0W   45 KT  50 MPH
 12H  20/0600Z 12.1N  43.2W   50 KT  60 MPH
 24H  20/1800Z 12.6N  44.8W   55 KT  65 MPH
 36H  21/0600Z 13.1N  46.3W   60 KT  70 MPH
 48H  21/1800Z 13.8N  47.9W   65 KT  75 MPH
 72H  22/1800Z 15.0N  51.8W   75 KT  85 MPH
 96H  23/1800Z 16.0N  56.9W   70 KT  80 MPH
120H  24/1800Z 16.8N  62.0W   60 KT  70 MPH


Forecaster Kimberlain

Tropical Storm Danny gains strength while moving West

Tropical Depression 4 became Tropical Storm Danny with the 4 PM CDT NHC advisory.  As of the 10 PM (Advisory 3) Danny has gained strength with 50 MPH winds and is moving WNW at 12 MPH.  TS Danny should be close to Hurricane strength by this time tomorrow.

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Stay safe and come back often "Doc"

NHC Tropical Atlantic Discussion

TROPICAL STORM DANNY DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL042015
1100 PM AST TUE AUG 18 2015

Danny has become a little better organized since the last advisory,
with a central convective feature and some outer banding in the
southeastern semicircle.  At 2200 UTC, PIRATA buoy 41026 reported
42-kt sustained winds just north of the center, and an ASCAT-B
overpass near 2330 UTC showed many 40-45 kt vectors.  Based on
these data, the initial intensity is increased to 45 kt.  The ASCAT
data also showed that the storm was a little larger than previously
thought.

The initial motion is now 285/12.  Danny is on the south side of
the subtropical ridge.  The dynamical models forecast the ridge to
weaken during the next 48-72 hours due to developing mid- to
upper-level troughs near Bermuda and over the northeastern
Atlantic.  This should result in Danny continuing on a
west-northwestward track with a decrease in forward speed.  After
72 hours, the trough near Bermuda should move northward and allow
the subtropical ridge to intensify.  In response, Danny is expected
to turn westward with an increase in forward speed.  The GFS had a
better initialization of Danny on the 1800 UTC run, and it now
forecasts a faster forward motion.  Otherwise, there are no
significant changes in the track guidance since the last advisory.
Thus, the new forecast track is an update of the previous track and
lies near the consensus models and the center of the guidance
envelope.

Danny is forecast to be in an environment of light vertical wind
shear through the forecast period, and earlier Windsat data
suggest the storm has tight convective banding near the center.
In addition, the Rapid Intensification Index of the SHIPS model has
about a 50 percent chance of 25 kt of strengthening during the next
24 hours.  However, there is abundant dry air near Danny,
particularly to the north of the storm, and the dynamical models
forecast Danny to encounter increasingly drier air through the
forecast period.  The intensity forecast, which follows the overall
trend of the intensity guidance, calls for continued strengthening
through 96 hours, followed by a slight weakening due to dry air.
The new forecast has a higher peak intensity than that of the
previous advisory, but is not as intense as the SHIPS and LGEM
models.  There are two alternative possibilities for this forecast.
The first is that rapid intensification occurs in the next 24 hours
before dry air entrains into Danny's core.  The second is that
enough dry air starts entraining during the next 24 hours to cause a
slower rate of development than currently forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  19/0300Z 11.2N  38.8W   45 KT  50 MPH
 12H  19/1200Z 11.6N  40.2W   55 KT  65 MPH
 24H  20/0000Z 11.9N  41.7W   60 KT  70 MPH
 36H  20/1200Z 12.3N  42.9W   70 KT  80 MPH
 48H  21/0000Z 12.8N  44.1W   75 KT  85 MPH
 72H  22/0000Z 13.5N  47.5W   85 KT 100 MPH
 96H  23/0000Z 14.5N  51.5W   90 KT 105 MPH
120H  24/0000Z 15.0N  56.5W   85 KT 100 MPH


Forecaster Beven

Tropical Depression 4 forms in the Eastern Atlantic.

It has been a relatively slow tropical season so far but as we approach the peak of the season we are tracking the fourth tropical system of the year.

Following the anniversary of Hurricane Camille yesterday, and on the eve of Hurricane Katrina's tenth anniversary folks around here are, quite naturally, watching this one closely.

The National Hurricane Center this morning upgraded the tropical wave they were following to a Depression. With winds of 35 MPH and a good looking circulation this becomes the 4th tropical system of the 2015 season.  

Movement is currently West at 13 MPH and is expected to reach Tropical Storm strength later today and Hurricane strength in 48 hours or so.

FORECAST POSITIONS AND MAX WINDS



INIT  18/1500Z 10.6N  36.5W   30 KT  35 MPH

 12H  19/0000Z 11.0N  37.9W   35 KT  40 MPH

 36H  20/0000Z 11.6N  40.9W   50 KT  60 MPH

 24H  19/1200Z 11.3N  39.5W   40 KT  45 MPH
 48H  20/1200Z 12.1N  41.9W   60 KT  70 MPH

120H  23/1200Z 14.0N  52.4W   85 KT 100 MPH

 72H  21/1200Z 13.2N  44.2W   70 KT  80 MPH

 96H  22/1200Z 13.7N  47.8W   80 KT  90 MPH

This system is still a long way from being a threat to the Windward Islands and even further from any possible impact on the U.S. but remember - While it may be a slow season so far it only takes one storm...

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Stay safe and come back often...  "Doc"