Aug 27 Sunday 2017

Tropical Report

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sun Aug 27 2017

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

The National Hurricane Center is issuing advisories on Tropical
Storm Harvey, located inland over southeastern Texas.

1. An elongated area of low pressure located over northeast Florida is
producing a widespread area of disorganized showers and
thunderstorms. This system is expected to move over the western
Atlantic later today, and has a brief opportunity to become a
tropical or subtropical depression during the next day or so,
before it merges with a cold front. Regardless of development, the
low is expected to cause increasing winds and rough surf along the
coasts of Georgia, the Carolinas, and Virginia through mid-week.
Heavy rain is also expected to continue over portions of the Florida
peninsula during the next 24 hours. Please refer to products from
your local National Weather Service forecast office for more
information on this system.
* Formation chance through 48 hours…medium…40 percent.
* Formation chance through 5 days…medium…50 percent.

2. A tropical wave over western Africa is forecast to emerge over the
far eastern Atlantic Ocean tonight or early Monday. Environmental
conditions appear to be conducive for slow development by the middle
of next week while the wave moves westward about 15 to 20 mph.
* Formation chance through 48 hours…low…near 0 percent.
* Formation chance through 5 days…low…20 percent.

Forecaster Roberts

 

HARVEY CAUSING CATASTROPHIC FLOODING IN SOUTHEASTERN TEXAS

Tropical Storm Harvey Discussion Number 28
NWS National Hurricane Center Miami FL AL092017
400 AM CDT Sun Aug 27 2017

Although the radar presentation of the inner core of Harvey has
degraded considerably, the system continues to produce intense
convection in bands to the east and southeast of the center. The
current intensity estimate is set to 40 kt based on surface
synoptic data over southeastern Texas. Since the center is
expected to remain mainly over land during the forecast period,
continued weakening is likely. Given that a significant portion of
the circulation is over water, however, this weakening should be
very slow to occur. The official intensity forecast is
similar to the model consensus.

Harvey has been meandering overnight and now appears to be drifting
south-southwestward. The cyclone is trapped between mid-level
highs to its west-northwest and east-southeast. Over the next
couple of days, the flow on the southern periphery of a trough
dropping over the east-central United States should cause Harvey to
move slowly southeastward to eastward. Later in the forecast
period, increased ridging to east of the cyclone should cause
Harvey to turn northward. The official track forecast is close
to the latest model consensus and brings the center to the coast
and, briefly, just offshore of southeastern Texas. At this time,
it is not expected that Harvey will move far enough out over the
water to result in regeneration.

The biggest concern with Harvey is now the rain, a lot of rain.
Rainfall totals of nearly 20 inches have been reported in the
Houston area. This is resulting in catastrophic flooding which,
unfortunately, will continue for some time.

Key Messages:

1. While Harvey’s winds are decreasing, life-threatening hazards
will continue from heavy rainfall over much of southeastern
Texas and from storm surge along portions of the Texas coast.

2. Catastrophic and life-threatening flooding is expected across the
middle and upper Texas coast from additional rainfall of 15 to
25 inches, with isolated storm totals as high as 40 inches, through
Thursday. Please heed the advice of local officials and do not
drive into flooded roadways. Refer to products from your local
National Weather Service office and the NOAA Weather Prediction
Center for more information on the flooding hazard. A summary of
rainfall totals compiled by the Weather Prediction Center can be
found at: www.wpc.ncep.noaa.gov/discussions/nfdscc1.html

3. A Storm Surge Warning remains in effect for portions of the
Texas coast. Life-threatening storm surge flooding will be slow to
recede due to the slow motion of Harvey and a prolonged period of
onshore flow. For a depiction of areas at risk, see the Storm Surge
Watch/Warning Graphic at hurricanes.gov.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 29.2N 97.7W 40 KT 45 MPH
12H 27/1800Z 29.0N 97.4W 35 KT 40 MPH…INLAND
24H 28/0600Z 28.7N 97.0W 30 KT 35 MPH…INLAND
36H 28/1800Z 28.5N 96.6W 30 KT 35 MPH…NEAR THE COAST
48H 29/0600Z 28.5N 96.1W 30 KT 35 MPH…INLAND
72H 30/0600Z 29.4N 95.6W 30 KT 35 MPH…INLAND
96H 31/0600Z 30.8N 95.5W 25 KT 30 MPH…INLAND
120H 01/0600Z 32.0N 95.0W 25 KT 30 MPH…INLAND

$$
Forecaster Pasch