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Aug
29
2017

Tropical Cyclone Activity Report – Atlantic Ocean / Caribbean Sea / Gulf of Mexico

Tropical Cyclone 09L (Harvey) is located about 65 miles south-southeast of Port Arthur, Texas

Potential Tropical Cyclone 10L is located about 85 miles northeast of Cape Hatteras, North Carolina – Last Advisory

PDC Disaster Alert, displaying PDC Active Hazards, Tropical Cyclone segments, Wind Radii, positions, and TAOS modeling for Tropical Storm Harvey, Potential TC 10L…and a tropical disturbance with a high chance of developing

Tropical Storm Harvey remains nearly stationary…bringing widespread flash flood emergencies to parts of Texas and Louisiana

Harvey made landfall between Port Aransas and Port O’Connor, Texas, on Friday night as a Category 4 storm. Despite weakening over land, Harvey is bringing catastrophic and life-threatening flooding…as it stalls over the region.

Still a named storm over 72 hours after landfall, Harvey is the longest a Texas land falling hurricane has remained a named storm after landfall on record…according to Colorado State University tropical scientist Dr. Phil Klotzbach.

The center of Harvey, now back over the Gulf of Mexico…will track back inland over southeast Texas Wednesday. The National Hurricane Center is not expecting significant strengthening of Harvey while it’s briefly off the Gulf Coast, so the main concern should remain additional heavy rainfall.

Periods of torrential rain will continue over parts of Texas and Louisiana the next several days, worsening flooding in some areas. Parts of southeast Houston have picked up over 40 inches…nearing an all-time U.S. tropical cyclone rainfall record. this may end up being one of the worst flood disasters in U.S. history, with record-smashing river flooding lasting well into next week.

Here’s a looping animation…showing Harvey recent location and movement

Here’s the latest looping radar image of this part of Texas and Louisiana

Here’s a current satellite image…and what the computer models are showing

Here’s a looping satellite image of this system

Here’s a graphic showing the rainfall outlook

Here’s a graphic showing Watches and Warnings…along with rainfall

The NHC advisory #39 shows sustained winds are 50 mph

Rainfall Totals

Here are the latest rainfall totals through 4 a.m. CDT Tuesday:

  • 43.00 inches in South Houston
  • 41.52 inches in Clear Lake City
  • 40.64 inches in Friendswood
  • 40.20 inches in Pasadena
  • 37.40 inches in Baytown
  • 33.88 inches at Houston Hobby Airport
  • 28.33 inches at Houston Bush Intercontinental Airport
  • 21.88 inches in Smithville
  • 19.64 inches in College Station
  • 14.20 inches in Galveston
  • 12.33 inches near Hackberry, Louisiana
  • 10.07 inches at Austin’s Robert Mueller Municipal Airport
  • 9.37 inches near Victoria
  • 7.68 inches at Lake Charles, Louisiana
  • 3.82 inches near Corpus Christi
  • 2.98 inches at New Orleans/Lakefront


According to the National Hurricane Center (NHC),

Latest radar imagery shows that heavy rainfall continues over
far eastern Texas and southwestern Louisiana.  Outer bands are also
producing heavy rain farther east along portions of the northern
Gulf coast. However, rains have begun to diminish over the Greater
Houston area, where some locations have received more than 50 inches
during this historic event.

Harvey took an eastward jog this evening, but recent satellite
images suggest that a northeastward motion has resumed.  The storm
is expected to move north-northeastward to northeastward between a
ridge over the eastern Gulf of Mexico and a trough over the
east-central United States.  This motion should bring the center
onshore over southwestern Louisiana early Wednesday, and into the
Tennessee Valley region later this week.  The global models
show the system becoming an open trough near the Ohio Valley or
Appalachians in 4 to 5 days.  The latest NHC track forecast has
been shifted eastward partially due to the more eastward initial
position.

There has been little overall change to Harvey's convective
structure since the previous advisory, and the initial intensity
remains 45 kt, which was supported by the earlier aircraft data.
Little change in strength is anticipate before Harvey reaches the
Louisiana coast.  After that time, gradual weakening should occur
while Harvey moves farther inland.

The latest forecast required an extension of the tropical storm
warning eastward to Grand Isle, Louisiana.

HAZARDS AFFECTING LAND:

RAINFALL:  Harvey is expected to produce additional rainfall
accumulations of 6 to 12 inches to the north and east of Houston
from far east Texas into southwestern Louisiana.  Isolated storm
totals will reach 50 inches over the upper Texas coast, including
the Houston/Galveston metropolitan area.  These rains are currently
producing catastrophic and life-threatening flooding over large
portions of southeastern Texas and southwestern Louisiana.  DO NOT
ATTEMPT TO TRAVEL IN THE AFFECTED AREA IF YOU ARE IN A SAFE PLACE.
DO NOT DRIVE INTO FLOODED ROADWAYS.  Please see warnings and
products issued by your local National Weather Service office for
additional information on this life-threatening situation.

Elsewhere, Harvey is expected to produce total rainfall amounts of 5
to 10 inches across portions of southern Louisiana into coastal
Mississippi and Alabama. Rainfall associated with Harvey will spread
north by mid to late week, with rainfall amounts of 4 to 8 inches
spreading into portions of Arkansas and the Tennessee Valley.

A preliminary report from a rain gauge has broken the Texas tropical
cyclone rainfall record.  The Cedar Bayou gauge, east of Highlands,
Texas, has reported 51.88 inches of rain as of 3 PM CDT.  This total
is higher than the previous record of 48 inches set during tropical
cyclone Amelia of 1978 at Medina, Texas.

STORM SURGE:  The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline.  The water is
expected to reach the following heights above ground if the peak
surge occurs at the time of high tide...

Holly Beach to Morgan City...2 to 4 ft
San Luis Pass to west of Holly Beach including Galveston Bay...1 to
3 ft Morgan City to Grand Isle...1 to 2 ft

The deepest water will occur along the immediate coast near the
area of onshore winds. Surge-related flooding depends on the
relative timing of the surge and the tidal cycle, and can vary
greatly over short distances. For information specific to your
area, please see products issued by your local National Weather
Service forecast office.

WIND:  Tropical storm conditions are occurring over portions of
the warning area along the coast and are likely to persist through
Wednesday.

SURF:  Swells generated by Harvey are still affecting the coasts of
Texas and Louisiana.  These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.

TORNADOES: A few tornadoes are possible through Wednesday across
parts of Louisiana, Mississippi, southern Alabama, and southeast
Arkansas.


Potential
Tropical Cyclone (10L)
remains active…moving offshore from the North Carolina coast – Last Advisory

Possible development of a tropical depression or storm is fading. The next name on the list of tropical storms for the Atlantic this year is Irma.

The main impacts of this disturbance will be locally dangerous surf and rain that slows travel.

A period of rain is forecast from Myrtle Beach, South Carolina, to Wilmington, North Carolina; Norfolk, Virginia; Ocean City, Maryland; Philadelphia; Atlantic City, New Jersey; New York City and Martha’s Vineyard, Massachusetts.

Here’s a satellite image, and what the computer models are showing

According to the NHC Advisory 8A, sustained winds were 40 mph

Potential Tropical Cyclone 10L Alerts graphic

Rainfall graphic showing the forecast through Tuesday

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

According to the NHC: 
Visible satellite images indicate that a more well-defined
circulation has begun to form east of the Outer Banks, and surface
observations indicate that pressures are falling.  The low is
becoming extratropical, and there is no longer a possibility of it
becoming a tropical cyclone.  In addition, the associated
tropical-storm-force winds that have been occurring to the southeast
of the center are limited to marine areas, so this will be the last
NHC advisory on this system.  Maximum winds are estimated to be 40
kt to the southeast of the center.

Baroclinic influences are expected to cause the low to deepen as an
extratropical cyclone during the next day or two, and it is forecast
to produce sustained hurricane-force winds over the northwestern
Atlantic by late Wednesday.  Gradual weakening is forecast after 36
hours, and the cyclone is likely to be absorbed by another
extratropical system over the north Atlantic by day 5.

The low continues to accelerate toward the northeast with an initial
motion of 050/21 kt, and it should move even faster toward the
northeast or east-northeast across the north Atlantic through day 4,
embedded in the mid-latitude westerlies.  The track, intensity, and
wind radii forecasts incorporate guidance provided by NOAA's Ocean
Prediction Center.

Strong winds on the northern and western side of a frontal boundary
associated with the low are expected to affect portions of the
mid-Atlantic coast.  As a result, high wind warnings are in effect
for coastal sections of northeastern North Carolina, southeastern
Virginia, and the eastern shore of Virginia and Maryland through
this evening.

HAZARDS AFFECTING LAND

WIND:  Strong winds, with gusts up to 55 mph, are expected across
coastal portions of northeastern North Carolina, southeastern
Virginia, and the eastern shore of Virginia and Maryland through
this evening.

RAINFALL:  The system is expected to produce total rain
accumulations of 1 to 3 inches from the southeast Virginia coast
into the Delmarva through Wednesday. The heavier rains may result in
some flooding concerns along coastal areas.

SURF:  Swells generated by this disturbance will affect portions of
the North Carolina and Virginia coasts during the next day or so,
creating dangerous surf and rip current conditions.

 

>>> Finally, a tropical wave and associated low pressure area located near the Cabo Verde Islands…and is producing a large area of showers and thunderstorms.

This tropical disturbance is being referred to as Invest 93L, here’s a satellite image…and what the computer models are showing

A low pressure area is located just west of the Cabo Verde Islands.
This system continues to become better organized, and any
significant increase in the associated thunderstorm activity would
result in the formation of a tropical depression within the next day
or two.  The low is forecast to move generally west-northwestward at
15 to 20 mph over the tropical Atlantic during the next several
days. Heavy rain is possible over portions of the northwestern Cabo
Verde Islands for a few more hours.

* Formation chance through 48 hours…high…90 percent
* Formation chance through 5 days…high…90 percent

 

Atlantic Ocean

Potential Tropical cyclone 10L – Last Advisory

NHC textual forecast advisory
NHC graphical track map
NOAA satellite image

NOAA satellite image of the Atlantic

Caribbean Sea

There are no current tropical cyclones

NOAA satellite image of the Caribbean Sea

Gulf of Mexico

Tropical cyclone 09L (Harvey)

NHC textual forecast advisory
NHC graphical track map
NOAA satellite image

Latest satellite image of the Gulf of Mexico

 

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