Latest on Tropical Storm Erika… 10pm Update – ThursRichday #alwx @wvua23

12

Here’s the latest track on Tropical Storm Erika, as it continues to track west at 17mph. Winds are sustained at 45mph with higher gusts. The westward track is throwing a bit of an uncertainty in the future track, as any continuation of a westward motion will cause the entire track to shift west even more. While it is not likely Erika goes into the Gulf of Mexico, that’s not totally out of the question. The risk of this impacting Alabama’s weather is low at this time… We will keep a very close eye on any changes in the path through Friday and over the weekend.

At this time, there is a good chance Erika moves into a mountainous region of Haiti and the Dominican Republic on Friday. This will keep the system from getting better organized and may actually cause weakening. Also, some wind shear and dry air near the center is preventing organization at the moment. Once the storm moves away from the mountainous islands, the environment will favor strengthening and Erika could become a hurricane before impacting the US mainland Sunday night or on Monday.

Here’s the discussion from the NHC:

TROPICAL STORM ERIKA DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015
1100 PM AST THU AUG 27 2015

The center of Erika is not easy to locate tonight, and it
appears that a few smaller swirls are rotating within a larger
gyre. In fact, one of these small swirls moved near St. Croix
producing tropical storm force wind gusts during the past few
hours on the island. Due to the lack of an inner core, the initial
position is based on a mean center of circulation. Despite the poor
organization, the reconnaissance plane currently in Erika was able
to measure 700 mb flight-level winds of 59 kt well to the southeast
of the alleged center. Based on the SFMR, these winds are not at the
surface, and the initial intensity is kept at 40 kt. The central
pressure is not falling, which is another indication that Erika is
not strengthening. The NHC forecast calls for no change in intensity
during the next 36 hours, given the fact that cyclone will be
moving through a very hostile shear environment, and will also feel
the effects of land. Once in the Bahamas, however, the upper-level
flow is expected to become more favorable, and if Erika survives, it
has the opportunity to strengthen some. The NHC forecast is very
close to the intensity consensus and is similar to the previous one.

The best estimate of the initial motion is toward the west or 270
degrees at 15 kt, and this estimate is highly uncertain. Erika
should begin to turn toward the west-northwest during the next
several hours around the periphery of the western Atlantic
subtropical ridge, and should reach the Central Bahamas between 36
and 48 hours. By then, the cyclone will be located on the
southwestern edge of the ridge, and should begin to turn to the
northwest with decreasing forward speed. Most of the track
guidance, including the ECMWF and the GFS global models, show a
tropical cyclone approaching southeast Florida in about 3 days and
moving northward near or over the east coast of Florida during the
latter portion of the forecast period. There is unusually high
uncertainty in this forecast, especially at days 3 to 5, given that
the cyclone has to recover from shear and from the effects of
land for this to occur.

The greatest short-term threat posed by Erika continues to be
very heavy rainfall over portions of the northern Leeward Islands
tonight, and over the Virgin Islands and Puerto Rico on Friday.
These rains could produce flash floods and mud slides.
FORECAST POSITIONS AND MAX WINDS

INIT 28/0300Z 16.6N 65.3W 40 KT 45 MPH
12H 28/1200Z 18.2N 67.4W 40 KT 45 MPH
24H 29/0000Z 19.7N 70.2W 40 KT 45 MPH
36H 29/1200Z 21.1N 73.2W 40 KT 45 MPH
48H 30/0000Z 22.5N 75.5W 45 KT 50 MPH
72H 31/0000Z 25.2N 79.0W 55 KT 65 MPH
96H 01/0000Z 27.3N 80.2W 65 KT 75 MPH
120H 02/0000Z 29.5N 80.7W 75 KT 85 MPH

Richard Scott

WVUA Chief Meteorologist

Hot Friday… Few Weekend Storms Possible… Tropical Update – 4:45pm Thursday #alwx @wvua23

sevenday_640

Good Thursday afternoon! Moisture levels have remained low most of the week, giving a refreshing feel to the air. The cooler temperatures are about to be replaced by warmer temperatures, to remind us Summer is still here… As the deep upper air trough responsible for the drop in moisture and temperatures lifts out, the return to summer will begin; in-fact, we note that moisture levels are already starting to rise a bit in the area. Lows tonight will not get as cool, with upper 60s likely. By Friday, highs will reach the lower 90s, with a mostly sunny sky. I can’t rule out a stray shower on Friday, but the chance of rain is really low.

A weak upper level disturbance moves into the area over the weekend, and it is possible a few scattered storms develop across the state. While I don’t expect a weekend washout, the risk of a passing storm has increased a bit, up to 30%. Highs will drop down in the upper 80s on Saturday and Sunday.

Upper level ridging builds back into the area on Monday and Tuesday of next week, so the risk of rain will decrease to 20%. It will look and feel more like a typical summer day, with highs in the lower 90s and lows near 70.

Here’s the latest on Tropical Storm Erika from the National Hurricane Center:

Warnings_1053

TROPICAL STORM ERIKA DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015
500 PM AST THU AUG 27 2015

The center has been wobbling during the day, but the mean
motion is estimated to be 285/13. In the mean, a west-northwestward
track to the south of a subtropical ridge is likely to continue
for the next couple of days. Later in the forecast period, the
cyclone should turn to the right along the southwestern and western
periphery of the ridge. There remains considerable spread in the
track model guidance at days 3 to 5, partly due to differences in
model-predicted intensities at those time frames. The official
track forecast is in good agreement with the latest dynamical model
consensus. The NOAA Gulfstream-IV is currently conducting a
synoptic surveillance mission around Erika to provide the numerical
models with a better depiction of the storm’s environment. These
data will be reflected primarily in the 00Z run of the GFS.

Vertical shear is expected to be fairly strong for the next couple
of days and that, along with the interaction with land, should
preclude significant strengthening for the next 48 hours or so.
Beyond that time, the shear is forecast to relax somewhat, and
this could allow for intensification assuming that the cyclone is
not too disrupted by the mountainous land mass of Hispaniola.
Because of the marginal upper-level wind environment and potential
interaction with land over the next few days, there is unusually
high uncertainty in the forecast intensity, especially at days 3 to
5.

The biggest short-term threat posed by Erika is very heavy rainfall
over portions of the Leeward Islands, which should spread over the
Virgin Islands and Puerto Rico tonight and early Friday. These
rains could produce flash floods and mud slides. More than 12
inches of rain has fallen in Dominica, with reports of fatalities
in that island.

FORECAST POSITIONS AND MAX WINDS

INIT 27/2100Z 16.6N 64.0W 40 KT 45 MPH
12H 28/0600Z 17.9N 66.4W 45 KT 50 MPH
24H 28/1800Z 19.2N 69.2W 45 KT 50 MPH
36H 29/0600Z 20.7N 72.0W 45 KT 50 MPH
48H 29/1800Z 22.1N 74.7W 45 KT 50 MPH
72H 30/1800Z 24.9N 78.8W 55 KT 65 MPH
96H 31/1800Z 27.0N 80.0W 65 KT 75 MPH
120H 01/1800Z 29.5N 80.5W 75 KT 85 MPH

Join us live on WVUA23 weekdays at 5, 6 and 10:00 P.M. and weekends at 10PM for the very latest on your news, weather and sports.

Richard Scott
WVUA Chief Meteorologist
rscott@wvua23.com
Twitter: RichardWVUA23
Facebook: WVUA23RichardScott

Latest on Tropical Storm Erika… Thursday Update – 4pm #alwx @wvua23

Warnings_1053

TROPICAL STORM ERIKA DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015
500 PM AST THU AUG 27 2015

The center has been wobbling during the day, but the mean
motion is estimated to be 285/13. In the mean, a west-northwestward
track to the south of a subtropical ridge is likely to continue
for the next couple of days. Later in the forecast period, the
cyclone should turn to the right along the southwestern and western
periphery of the ridge. There remains considerable spread in the
track model guidance at days 3 to 5, partly due to differences in
model-predicted intensities at those time frames. The official
track forecast is in good agreement with the latest dynamical model
consensus. The NOAA Gulfstream-IV is currently conducting a
synoptic surveillance mission around Erika to provide the numerical
models with a better depiction of the storm’s environment. These
data will be reflected primarily in the 00Z run of the GFS.

Vertical shear is expected to be fairly strong for the next couple
of days and that, along with the interaction with land, should
preclude significant strengthening for the next 48 hours or so.
Beyond that time, the shear is forecast to relax somewhat, and
this could allow for intensification assuming that the cyclone is
not too disrupted by the mountainous land mass of Hispaniola.
Because of the marginal upper-level wind environment and potential
interaction with land over the next few days, there is unusually
high uncertainty in the forecast intensity, especially at days 3 to
5.

The biggest short-term threat posed by Erika is very heavy rainfall
over portions of the Leeward Islands, which should spread over the
Virgin Islands and Puerto Rico tonight and early Friday. These
rains could produce flash floods and mud slides. More than 12
inches of rain has fallen in Dominica, with reports of fatalities
in that island.

FORECAST POSITIONS AND MAX WINDS

INIT 27/2100Z 16.6N 64.0W 40 KT 45 MPH
12H 28/0600Z 17.9N 66.4W 45 KT 50 MPH
24H 28/1800Z 19.2N 69.2W 45 KT 50 MPH
36H 29/0600Z 20.7N 72.0W 45 KT 50 MPH
48H 29/1800Z 22.1N 74.7W 45 KT 50 MPH
72H 30/1800Z 24.9N 78.8W 55 KT 65 MPH
96H 31/1800Z 27.0N 80.0W 65 KT 75 MPH
120H 01/1800Z 29.5N 80.5W 75 KT 85 MPH

Latest Track on Tropical Storm Erika… Wednesday Update – 10pm #alwx @wvua23

Warnings_1053

The new track of Tropical Storm Erika from the National Hurricane Center has shifted east some, as the latest forecast models shift east. The latest path takes Erika just to the east of the Florida coastline. Keep in mind, there’s still a chance the center of the storm could impact Florida to end the weekend and start the work-week, possibly as a hurricane. There are lots of uncertainties in the exact path of Tropical Storm Erika, but confidence in a path will increase as we move into the weekend.

Here’s the latest on Tropical Storm Erika from the National Hurricane Center:

TROPICAL STORM ERIKA DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015
1100 PM AST WED AUG 26 2015

Erika is a very disorganized tropical storm. Although convection
has increased and is a little closer to the center tonight, data
from both NOAA and Air Force reconnaissance plane indicate that
the surface pressure is not falling, and the maximum winds remain
about 40 kt. These winds are confined to squalls to the north and
east of the center.

Erika will be moving through a hostile wind shear environment as
predicted by global models and the SHIPS guidance. On this
basis, the NHC forecast weakens Erika to a 35-kt tropical storm
and keeps that intensity for the next 48 hours. Erika, however,
could even degenerate into a trough during the next day or so. If
Erika survives the next 3 days and reaches the Bahamas, the
environment is expected to become quite favorable. In fact, global
models and the HWRF/GFDL pair forecast Erika to become a hurricane
by the end of the forecast period. The NHC forecast is a little
below the intensity consensus to reflect the possibility that the
cyclone could dissipate before it reaches the Bahamas, and then it
will be too late to take advantage of the more conducive environment
there.

Fixes from the reconnaissance planes indicate that Erika is moving
toward the west or 280 degrees at 14 kt. The cyclone is embedded
within well-established steering currents south of the Atlantic
subtropical ridge. This persistent pattern will likely keep the
cyclone or its remnants, in case it weakens, on a west to
west-northwest motion for the next 3 days. After that time, the
system will be in between the southwestern edge of the subtropical
ridge and a mid-level trough, which is forecast to be nearly
stationary along the east-central portion of the United States.
This will force the cyclone to turn more to the northwest or even
northward. Guidance shifted farther east tonight, and consequently,
the NHC track forecast was adjusted slightly eastward, and it is
very close to the consensus of the ECMWF and the GFS models.

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.

Sunny for Now… Isolated Weekend Storms… Wednesday Forecast Update/Tropical Update – 4pm #alwx @wvua23

sevenday_640

Good Wednesday afternoon! Today has turned out to be another beautiful Fall like day across the state with very low humidity and bluebird skies. Temperatures have only reached the lower 80s this afternoon, which is below average for this time of the year. Expect temperatures to drop quickly tonight, with areas near and north of I-20 reaching the upper 50s once again. A the deep upper air trough across the east lifts out of the area over the weekend, temperatures and moisture levels will rise a bit. Expect highs to return into the lower 90s Friday through the weekend.

As a weak moisture axis moves into the area from the east over the weekend, a passing shower or storm is possible. At this time, it appears that most areas will remain dry this weekend, and the best chance of an isolated storm will happen during the afternoon hours. Expect lows to return into the lower 70s, as moisture levels rise.

Tropical Storm Erika continues to move west across the Atlantic, now approaching the Lesser Antilles as a weak tropical storm. Below is the track and discussion from the National Hurricane Center:

Warnings_1053

TROPICAL STORM ERIKA DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015
500 PM AST WED AUG 26 2015

The satellite presentation of the tropical storm has become less
organized since the previous advisory, with the low-level center
becoming exposed to the northwest of the thunderstorm activity.
A NOAA Hurricane Hunter aircraft investigating Erika this afternoon
has not found flight-level or SFMR winds as strong as reported this
morning, but the aircraft did not sample much of the eastern portion
of the circulation. The initial intensity is held at 40 kt, but
this could be generous.

The intensity forecast philosophy has not changed since this
morning. Erika is forecast to move through an area of moderate to
strong westerly shear during the next two to three days. Although
the NHC intensity forecast during that time shows no change in
intensity, weakening is possible during the next couple of days. In
fact, Erika could degenerate into a trough of low pressure due to
the shear and interaction with the Greater Antilles. After 72
hours, the upper-level environment is forecast to become more
conducive for development and all of the guidance, including the
global models, shows intensification. Therefore, the days 4 and 5
intensity forecast again calls for strengthening, but is below the
intensity consensus and near the SHIPS model. The official forecast
leans toward the lower side of the guidance to reflect the
possibility that the cyclone’s structure would be too disrupted to
fully take advantage of the more conducive environment late in the
period.

The initial motion remains 280/15 kt. Erika is forecast to move
west-northwestward during the next three to four days to the south
of a subtropical ridge over the western Atlantic. After that time,
the global models show a weakness in the ridge developing over the
far western Atlantic, which should cause Erika to turn
northwestward. All of the models have shifted eastward at days
four and five, but the normally reliable GFS and ECMWF define
the western edge of the guidance. Out of respect of
these models and the previous NHC forecast, the updated track
has only been moved slightly eastward late in the period. As a
result, the new forecast lies west of the multi-model consensus at
96 and 120 h. 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 26/2100Z 16.6N 58.9W 40 KT 45 MPH
12H 27/0600Z 17.1N 61.2W 40 KT 45 MPH
24H 27/1800Z 18.1N 64.0W 40 KT 45 MPH
36H 28/0600Z 19.2N 66.8W 40 KT 45 MPH
48H 28/1800Z 20.5N 69.6W 40 KT 45 MPH
72H 29/1800Z 22.7N 74.3W 40 KT 45 MPH
96H 30/1800Z 25.0N 77.7W 55 KT 65 MPH
120H 31/1800Z 27.5N 80.0W 65 KT 75 MPH

Join us live on WVUA23 weekdays at 5, 6 and 10:00 P.M. and weekends at 10PM for the very latest on your news, weather and sports.

Richard Scott
WVUA Chief Meteorologist
rscott@wvua23.com
Twitter: RichardWVUA23
Facebook: WVUA23RichardScott

Midday Update on Tropical Storm Erika… Wednesday Update – 1pm #alwx @wvua23

174619W5_NL_smMi

Here’s the latest discussion from the National Hurricane Center on Erika:

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

10pm Tuesday Eve Update on Tropical Storm Erika… #alwx @wvua23

12

Good Tuesday evening! Latest word from the National Hurricane Center suggests Tropical Storm Erika is poorly organized and is having a tough time in some wind shear and dry air. Erika maintains it’s Tropical Storm status at this time, but it is possible Erika dies out much like Danny. Above is the forecasted track, given the system survives. Once the storm moves over the Bahamas this weekend, there the environment should be more favorable for development. It could become a hurricane somewhere near the southeast coast of Florida. This is a tricky forecast…

New update from the National Hurricane Center on Tropical Storm Erika:

TROPICAL STORM ERIKA DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL052015
1100 PM AST TUE AUG 25 2015

Both NOAA and Air Force hurricane hunter planes investigated Erika
and found a disorganized storm. The central pressure rose to 1006
mb, and the strongest winds were confined to the eastern semicircle.
The low-level center remains exposed to the north of the limited
thunderstorm activity. Based on the current appearance on satellite
imagery, and data from the plane, the initial intensity is
generously kept at 35 kt.

The intensity forecast continues to be highly uncertain. Erika
has a large cyclonic envelope, and this is a favorable factor
for the cyclone to strengthen. However, SHIPS model forecasts
a hostile west-northwesterly shear over the cyclone and, in fact, it
only strengthens Erika a little bit at the end of the forecast
period. This coincides with the solution of the GFS and the ECMWF
global models which either weaken the cyclone or show little
change in strength. The NHC forecast follows the intensity
consensus, and shows a modest strengthening beyond 3 days. By then,
the cyclone is expected to be near the Bahamas where the environment
could be a little more favorable for intensification. However, I
will not be a surprised if Erika dissipates like Danny in the
the northeastern Caribbean Sea where the environment is hostile.

Erika is embedded within the easterly flow south of a moderate
subtropical ridge which is covering the western Atlantic. This
pattern will likely continue to steer Erika between the west and
west-northwest at about 15 kt for the next 2 to 3 days. As the
cyclone reaches the western edge of the ridge in the area of the
Bahamas, the cyclone is then expected to decrease in forward speed.
The NHC forecast is very similar to the previous one and follows
very closely the multi-model consensus.

Tropical storm watches and warnings have been adjusted and added for
some of the islands of the northeastern Caribbean by the respective
Meteorological Services.
FORECAST POSITIONS AND MAX WINDS

INIT 26/0300Z 16.0N 54.4W 35 KT 40 MPH
12H 26/1200Z 16.4N 56.9W 35 KT 40 MPH
24H 27/0000Z 17.0N 60.1W 35 KT 40 MPH
36H 27/1200Z 17.8N 63.2W 40 KT 45 MPH
48H 28/0000Z 18.8N 66.0W 40 KT 45 MPH
72H 29/0000Z 21.0N 70.9W 45 KT 50 MPH
96H 30/0000Z 23.0N 75.0W 55 KT 65 MPH
120H 31/0000Z 26.0N 78.5W 65 KT 75 MPH

Join us live on WVUA23 weekdays at 5, 6 and 10:00 P.M. and weekends at 10PM for the very latest on your news, weather and sports.

Richard Scott
WVUA Chief Meteorologist
rscott@wvua23.com
Twitter: RichardWVUA23
Facebook: WVUA23RichardScott

Follow

Get every new post delivered to your Inbox.

Join 5,148 other followers