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HURRICANE HANNA - Nolaken - 07-22-2020 08:39 PM

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Wed Jul 22 2020

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

The National Hurricane Center is issuing advisories on Tropical
Storm Gonzalo, located over the central tropical Atlantic.

1. Data from the Air Force Hurricane Hunters and surface observations
indicate that an area of low pressure over the central Gulf of
Mexico is gradually becoming better defined. However, the
accompanying shower and thunderstorm activity is still poorly
organized. Environmental conditions appear conducive for slow
development of this system, and a tropical depression is likely to
form during the next day or so as it moves west-northwestward at
about 10 mph. Interests in the western Gulf of Mexico should
monitor the progress of this system, as watches or warnings could be
required for portions of the coasts of Texas and Louisiana tonight
or on Thursday.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

Forecaster Cangialosi


RE: Invest 91L - ROLLTIDE - 07-22-2020 10:01 PM

TNT43 KNHC 230242
TCDAT3

Tropical Depression Eight Discussion Number 1
NWS National Hurricane Center Miami FL AL082020
1000 PM CDT Wed Jul 22 2020

Surface observations and data from the Air Force Hurricane Hunters
indicate that the area of low pressure over the central Gulf of
Mexico has developed a closed circulation and a well-defined
center. In addition, recent satellite images show an area of deep
convection expanding over the center. Based on those observations,
advisories are being initiated on Tropical Depression Eight. The
initial intensity is set at 25 kt based on the earlier
reconnaissance data.

The initial motion is an uncertain west-northwestward at 5 kt. A
subtropical ridge to the northeast of the depression should cause
it to continue moving in that general direction through Friday as
it tracks across the northwestern Gulf of Mexico. A slight turn to
the left is expected Friday night and Saturday as a ridge builds to
the north of the system, taking the center of cyclone across the
Texas coast and then inland over southern Texas. The models are in
fairly good agreement on this scenario, and the NHC track forecast
lies near the various consensus models.

The depression is expected to be in generally light to moderate
wind shear conditions, in a fairly moist environment, and over the
warm waters of the Gulf of Mexico for the next couple of days, so
some strengthening seems likely. However, since the depression is
still in its formative stage, the rate of strengthening should be
gradual. After the storm crosses the coast, steady weakening should
commence. The NHC intensity forecast generally follows the IVCN and
HCCA guidance.

Key Messages

1. The depression is expected to strengthen and it could bring
tropical-storm-force winds to portions of the Texas coast, where a
tropical storm watch has been issued.

2. The depression is expected to produce heavy rains across
portions of Louisiana and southern Texas. These rains could result
in flash flooding.


FORECAST POSITIONS AND MAX WINDS

INIT 23/0300Z 25.9N 88.2W 25 KT 30 MPH
12H 23/1200Z 26.3N 89.3W 30 KT 35 MPH
24H 24/0000Z 27.0N 90.8W 30 KT 35 MPH
36H 24/1200Z 27.9N 92.4W 35 KT 40 MPH
48H 25/0000Z 28.2N 94.0W 35 KT 40 MPH
60H 25/1200Z 28.5N 95.3W 40 KT 45 MPH
72H 26/0000Z 28.7N 96.8W 35 KT 40 MPH...INLAND
96H 27/0000Z 28.8N 98.1W 25 KT 30 MPH...INLAND
120H 28/0000Z 28.7N 100.5W 20 KT 25 MPH...INLAND

$$
Forecaster Cangialosi


RE: TD#8 TEXAS BOUND - ROLLTIDE - 07-22-2020 10:05 PM

[Image: storm_08.gif]


RE: TD#8 TEXAS BOUND - Nolaken - 07-23-2020 06:27 AM

BULLETIN
Tropical Depression Eight Advisory Number 2
NWS National Hurricane Center Miami FL AL082020
400 AM CDT Thu Jul 23 2020

...HEAVY RAINS LIKELY OVER PORTIONS OF TEXAS BY THIS WEEKEND...


SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...26.0N 90.0W
ABOUT 425 MI...685 KM ESE OF PORT OCONNOR TEXAS
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES

TCDAT3

Tropical Depression Eight Discussion Number 2
NWS National Hurricane Center Miami FL AL082020
400 AM CDT Thu Jul 23 2020

Satellite images and surface synoptic observations suggest that
the depression has not strengthened thus far, although recent
images show some increase in deep convection near the estimated
center. The initial intensity estimate remains at 25 kt in
agreement with surface data over the Gulf. The cyclone should
remain in a relatively moist, low-shear environment during the next
day or so. However, since the system is not well organized, only
slow strengthening is forecast until the center reaches the coast.
The NHC intensity forecast is near the upper range of the model
guidance at this time.

The center is not well-defined and the initial motion estimate is
an uncertain 290/8 kt. This is more or less consistent with
observations from NOAA data buoy 42001 over the central Gulf. A
continued west-northwestward track is expected over the next day or
so followed by a slight bend toward the west in response to some
building of a mid-level ridge to the north of the cyclone. The
official track forecast is a little faster than the previous one but
not quite as fast as the latest dynamical model consensus.


Key Messages

1. The depression is expected to strengthen and it could bring
tropical-storm-force winds to portions of the Texas coast, where a
tropical storm watch has been issued.

2. The depression is expected to produce heavy rains across
portions of Louisiana and southern Texas. These rains could result
in flash flooding.


FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 26.0N 90.0W 25 KT 30 MPH
12H 23/1800Z 26.4N 91.0W 30 KT 35 MPH
24H 24/0600Z 27.1N 92.3W 30 KT 35 MPH
36H 24/1800Z 27.7N 94.0W 35 KT 40 MPH
48H 25/0600Z 28.0N 95.5W 35 KT 40 MPH
60H 25/1800Z 28.2N 97.0W 40 KT 45 MPH...ON COAST
72H 26/0600Z 28.2N 98.6W 35 KT 40 MPH...INLAND
96H 27/0600Z 28.0N 100.5W 20 KT 25 MPH...INLAND
120H 28/0600Z 28.0N 102.5W 15 KT 15 MPH...INLAND


RE: TS Hanna - Nolaken - 07-24-2020 06:21 AM

BULLETIN
Tropical Storm Hanna Advisory Number 6
NWS National Hurricane Center Miami FL AL082020
400 AM CDT Fri Jul 24 2020

...HANNA EXPECTED TO STRENGTHEN TODAY AND TONIGHT...


SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...26.7N 92.4W
ABOUT 315 MI...510 KM ESE OF CORPUS CHRISTI TEXAS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES

Tropical Storm Hanna Discussion Number 6
NWS National Hurricane Center Miami FL AL082020
400 AM CDT Fri Jul 24 2020

Satellite imagery shows well-defined convective banding features
over the eastern and southern portions of the circulation with some
cooling of the cloud tops. This suggests that the associated
thunderstorm activity is becoming more vigorous. However, surface
observations over the Gulf and a scatterometer pass from a few
hours ago indicate that the system has not strengthened further at
this time. The current intensity estimate is held at 35 kt in
agreement with a Dvorak classification from TAFB. A NOAA Hurricane
Hunter aircraft is scheduled to investigate the storm later this
morning and they should provide a good estimate of Hanna's
intensity. The storm has an impressive upper-level anticyclonic
outflow structure and should remain in a low shear environment
until it reaches the coast. Therefore strengthening is likely
prior to landfall and the NHC intensity forecast is near the model
high end of the intensity model suite.

The storm has moved a little faster toward the west-northwest over
the past several hours, and the initial motion estimate is 290/8
kt. There is very little change to the official track forecast or
reasoning from the previous cycle. A gradual turn toward the west
is likely in 12 hours or so as a mid-level ridge to the north of
Hanna builds a bit. The forecast track takes the center inland
over Texas within the tropical storm warning area on Saturday.
This is in good agreement with the dynamical model consensus and
the latest ECMWF model solution.


Key Messages

1. Hanna is forecast to strengthen and it is expected to
bring tropical-storm-force winds to portions of the Texas coast,
where a tropical storm warning is in effect.

2. Hanna is expected to produce heavy rains across portions of
southern Texas. These rains could result in flash flooding and
isolated minor to moderate river flooding.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0900Z 26.7N 92.4W 35 KT 40 MPH
12H 24/1800Z 27.1N 93.7W 40 KT 45 MPH
24H 25/0600Z 27.3N 95.5W 50 KT 60 MPH
36H 25/1800Z 27.3N 97.1W 55 KT 65 MPH
48H 26/0600Z 27.2N 98.6W 40 KT 45 MPH...INLAND
60H 26/1800Z 26.5N 100.0W 30 KT 35 MPH...INLAND
72H 27/0600Z 26.0N 101.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 28/0600Z...DISSIPATED

$$
Forecaster Pasch


RE: Tropical Storm Hanna - ROLLTIDE - 07-25-2020 11:00 AM

000
WTNT43 KNHC 251458
TCDAT3

Hurricane Hanna Discussion Number 11
NWS National Hurricane Center Miami FL AL082020
1000 AM CDT Sat Jul 25 2020

NOAA Doppler radar data from Corpus Christi and Brownsville, Texas,
along with reconnaissance data from the NOAA Hurricane Hunters
indicate that Hanna has continued to strengthen this morning. A
well-defined but fairly large 30-35-nmi-wide eye has formed and
recent dropsonde data from the eye indicate that the central
pressure has dropped to 978 mb. The aircraft measured a peak 700-mb
flight-level wind speed of 77 kt, which equates to about 69 kt at
the surface. During the past hour, Doppler velocities have sharply
increased with numerous patches of 85-90 kt between 7000-8000 ft
common in the northern eyewall. Although these values would
typically correspond to surface winds of about 75 kt, the Doppler
velocity are occurring in low reflectivity regions of 25-30 dBZ, so
the full effect of those winds are likely not reaching the surface.
This could be why the highest SFMR surface wind observed by the
aircraft was only 63 kt. The initial intensity has been increased to
70 kt, which is a blend of the aircraft flight-level, radar, and
SFMR surface wind speed estimates.

The center position is a tad north of the recon fixes due to some
southward tilt of the eye caused by northerly shear. This has
resulted in a slower westward motion of 270/06 kt. The ridge to the
north of the hurricane has been slowly building westward and
southwestward based on upper-air data over the past 24 hours. This
slow ridging pattern is expected to continue for the next 48 hours,
resulting in Hanna gradually turning toward the west-southwest by
late this afternoon or evening, with landfall occurring in about 12
h along south Texas coast. After landfall, Hanna should continue
its west-southwestward motion until dissipation over the mountainous
terrain of northeastern Mexico in 48-60 h. The new NHC track
forecast is similar to the previous advisory track, and lies close
to the tightly packed consensus model guidance.

Although the deep-layer vertical wind shear is expected to remain
out of the north-northwest to north at about 20 kt, the relatively
large and stable eye, along with the expected convective vigor of
the hurricane, could result in a little more strengthening just
before landfall occurs. After landfall, rapid weakening of the wind
field is expected. However, the weakening peak winds will have no
negative effect on the likelihood for heavy rainfall or the
possibility of isolated tornadoes developing.


Key Messages

1. Life-threatening storm surge is occurring along portions of the
Texas coast from Port Mansfield to Sargent, where a Storm Surge
Warning is in effect. Residents in these locations should follow
advice given by local emergency officials.

2. Hurricane conditions are expected along the Texas coast from Port
Mansfield to Mesquite Bay, where a Hurricane Warning is in effect.
Tropical storm conditions are expected to first reach the coast
within the warning area this morning.

3. Hanna is expected to produce heavy rains across portions of
southern Texas and northeastern Mexico. These rains could result in
life-threatening flash flooding and isolated minor to moderate river
flooding.


FORECAST POSITIONS AND MAX WINDS

INIT 25/1500Z 27.1N 96.3W 70 KT 80 MPH
12H 26/0000Z 26.9N 97.6W 70 KT 80 MPH...INLAND
24H 26/1200Z 26.4N 99.1W 45 KT 50 MPH...INLAND
36H 27/0000Z 25.9N 100.6W 25 KT 30 MPH...INLAND
48H 27/1200Z 25.3N 102.1W 15 KT 15 MPH...POST-TROP/REMNT LOW
60H 28/0000Z...DISSIPATED