BULLETIN
Tropical Depression Harvey Intermediate Advisory Number 13A
NWS National Hurricane Center Miami FL AL092017
700 PM CDT Wed Aug 23 2017…HURRICANE HUNTER AIRCRAFT FINDS THAT HARVEY HAS NOT
STRENGTHENED…
SUMMARY OF 700 PM CDT…0000 UTC…INFORMATION
———————————————-
LOCATION…21.7N 92.5W
ABOUT 525 MI…845 KM SSE OF PORT OCONNOR TEXAS
ABOUT 460 MI…740 KM SE OF PORT MANSFIELD TEXAS
MAXIMUM SUSTAINED WINDS…35 MPH…55 KM/H
PRESENT MOVEMENT…NW OR 320 DEGREES AT 2 MPH…4 KM/H
MINIMUM CENTRAL PRESSURE…1003 MB…29.62 INCHES
WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY:None.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Storm Surge Watch is in effect for…
* Port Mansfield to High IslandA Hurricane Watch is in effect for…
* North of Port Mansfield to San Luis PassA Tropical Storm Watch is in effect for…
* Boca De Catan Mexico to Port Mansfield Texas
* North of San Luis Pass to High IslandA Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.A Hurricane Watch means that hurricane conditions are possible
within the watch area. A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
dangerous.A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.Interests in southwestern Louisiana should continue to monitor the
progress of this system.For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area outside
the United States, please monitor products issued by your national
meteorological service.
DISCUSSION AND 48-HOUR OUTLOOK
——————————
At 700 PM CDT (0000 UTC), the center of Tropical Depression Harvey
was located near latitude 21.7 North, longitude 92.5 West. The
depression is moving erratically toward the northwest near 2 mph (4
km/h). A track toward the northwest or north-northwest at a faster
forward speed is expected for the next 48 hours. On the forecast
track, Harvey should be approaching the Texas coast late Friday.Reports from an Air Force Reserve Hurricane Hunter aircraft
indicate that maximum sustained winds remain near 35 mph (55 km/h)
with higher gusts. Some strengthening is forecast during the next
48 hours, and Harvey could become a tropical storm later tonight
and a hurricane on Friday.The minimum central pressure estimated from the Hurricane Hunter
aircraft data and Mexican surface observations is 1003 mb
(29.62 inches).
HAZARDS AFFECTING LAND
———————-
RAINFALL: Harvey is expected to produce total rain accumulations of
10 to 15 inches with isolated maximum amounts of 20 inches over the
middle and upper Texas coast and southwest Louisiana through next
Tuesday, with heavy rainfall beginning as early as Friday morning.
Harvey is also expected to produce total rain accumulations of 3 to
9 inches in portions of south, central, and northeast Texas and the
rest of the lower Mississippi Valley. Rainfall from Harvey could
cause life-threatening flooding.
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…
Port Mansfield to High Island…4 to 6 ft
The deepest water will occur along the immediate coast near and to
the northeast of the landfall location, where the surge will be
accompanied by large and destructive waves. 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: Hurricane conditions are possible within the hurricane watch
area by late Friday, with tropical storm conditions possible by
early Friday.
SURF: Swells generated by Harvey are likely to affect the Texas,
Louisiana, and northeast Mexico coasts by Friday. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.
NEXT ADVISORY
————-
Next complete advisory at 1000 PM CDT.
TROPICAL DEPRESSION HARVEY FORECAST/ADVISORY NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092017
2100 UTC WED AUG 23 2017
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY…
NONE.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT…
A STORM SURGE WATCH IS IN EFFECT FOR…
* PORT MANSFIELD TO HIGH ISLAND
A HURRICANE WATCH IS IN EFFECT FOR…
* NORTH OF PORT MANSFIELD TO SAN LUIS PASS
A TROPICAL STORM WATCH IS IN EFFECT FOR…
* BOCA DE CATAN MEXICO TO PORT MANSFIELD TEXAS
* NORTH OF SAN LUIS PASS TO HIGH ISLAND
A STORM SURGE WATCH MEANS THERE IS A POSSIBILITY OF LIFE-
THREATENING INUNDATION… FROM RISING WATER MOVING INLAND FROM THE
COASTLINE…IN THE INDICATED LOCATIONS DURING THE NEXT 48 HOURS.
FOR A DEPICTION OF AREAS AT RISK…PLEASE SEE THE NATIONAL WEATHER
SERVICE STORM SURGE WATCH/WARNING GRAPHIC…AVAILABLE AT
HURRICANES.GOV.
A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE
WITHIN THE WATCH AREA. A WATCH IS TYPICALLY ISSUED 48 HOURS
BEFORE THE ANTICIPATED FIRST OCCURRENCE OF TROPICAL-STORM-FORCE
WINDS…CONDITIONS THAT MAKE OUTSIDE PREPARATIONS DIFFICULT OR
DANGEROUS.
A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA…GENERALLY WITHIN 48 HOURS.
INTERESTS IN SOUTHWESTERN LOUISIANA SHOULD CONTINUE TO MONITOR THE
PROGRESS OF THIS SYSTEM.
TROPICAL DEPRESSION CENTER LOCATED NEAR 21.6N 92.6W AT 23/2100Z
POSITION ACCURATE WITHIN 30 NM
PRESENT MOVEMENT TOWARD THE NORTHWEST OR 320 DEGREES AT 2 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
REPEAT…CENTER LOCATED NEAR 21.6N 92.6W AT 23/2100Z
AT 23/1800Z CENTER WAS LOCATED NEAR 21.5N 92.5W
FORECAST VALID 24/0600Z 22.4N 93.0W
MAX WIND 35 KT…GUSTS 45 KT.
34 KT… 60NE 0SE 0SW 0NW.
FORECAST VALID 24/1800Z 23.8N 93.9W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 70NE 50SE 30SW 50NW.
FORECAST VALID 25/0600Z 25.1N 95.2W
MAX WIND 50 KT…GUSTS 60 KT.
50 KT… 40NE 0SE 0SW 0NW.
34 KT… 90NE 70SE 40SW 60NW.
FORECAST VALID 25/1800Z 26.4N 96.3W
MAX WIND 60 KT…GUSTS 75 KT.
50 KT… 50NE 40SE 20SW 30NW.
34 KT…120NE 90SE 50SW 80NW.
FORECAST VALID 26/1800Z 28.6N 97.3W…INLAND
MAX WIND 50 KT…GUSTS 60 KT.
50 KT… 0NE 30SE 0SW 0NW.
34 KT… 60NE 90SE 30SW 30NW.
EXTENDED OUTLOOK. NOTE…ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5…AND FOR INTENSITY NEAR 15 KT EACH DAY
OUTLOOK VALID 27/1800Z 29.0N 97.3W…INLAND
MAX WIND 35 KT…GUSTS 45 KT.
OUTLOOK VALID 28/1800Z 29.0N 96.5W…INLAND
MAX WIND 35 KT…GUSTS 45 KT.
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.6N 92.6W
TCDAT4
Tropical Depression Harvey Discussion Number 13
NWS National Hurricane Center Miami FL AL092017
400 PM CDT Wed Aug 23 2017
High-resolution visible satellite images show that the cloud pattern
of Harvey is a little better organized than it was this morning, but
the system lacks distinct banding features. Surface synoptic
observations, ASCAT data, and Dvorak classifications from TAFB and
SAB indicated that the cyclone has not strengthened, so the current
intensity is held at 30 kt. The global models predict that an
upper-level low over the northwest Gulf of Mexico will essentially
dissipate in a day or so. Therefore, Harvey is expected to remain
in a relatively low-shear environment up to the Texas coast.
Moreover, ocean analyses show that a warm eddy that broke off from
the Loop Current has drifted westward across the Gulf to a location
near the projected path of Harvey. This would also be conducive to
strengthening, so it is likely that the system will become a
hurricane prior to landfall, although this is not explicitly shown
in the NHC forecast for which landfall is indicated between 48 and
72 hours.
Based on the scatterometer data and geostationary satellite fixes
the center hasn’t moved much this afternoon, although recent imagery
suggests a northwestward drift at about 320/2 kt. A weak mid-level
ridge to the northeast of Harvey should cause the cyclone to move
on a northwestward or north-northwestward track through 48 hours.
Later, steering currents weaken as a ridge builds over the
southwestern United States and a trough drops down from the Plains.
As a result, Harvey should decelerate while making landfall and
move very slowly just inland of the coast. Some of the track
guidance models, such as the HWRF, have shifted southwestward in
comparison to their previous run. The official track forecast is
very close to the previous one through 48 hours and is a little
slower and to the west after that time. This is very close to the
latest dynamical model consensus, TVCN. It should be noted that
synoptic surveillance data are currently being collected by the NOAA
G-IV jet aircraft and these data will be assimilated into, and
hopefully improve the forecasts by, the global models.
Key Messages:
1. Harvey is likely to bring multiple hazards, including heavy
rainfall, storm surge, and possible hurricane conditions to portions
of the Texas coast beginning on Friday.
2. Heavy rainfall is likely to spread across portions of eastern
Texas, Louisiana, and the lower Mississippi Valley from Friday
through early next week and could cause life-threatening flooding.
Please refer to products from your local National Weather Service
office and the NOAA Weather Prediction Center for more information
on the flooding hazard.
3. A Storm Surge Watch is in effect from Port Mansfield to High
Island, Texas, indicating the possibility of life-threatening
inundation from rising water moving inland from the coast during the
next 48 hours. For a depiction of areas at risk, see the Storm
Surge Watch/Warning Graphic at hurricanes.gov.
4. The Potential Storm Surge Flooding Map is available on the NHC
website. This product depicts a reasonable worst-case scenario –
the amount of inundation that has a 10 percent chance of being
exceeded at each individual location. Because the Flooding Map is
based on inputs that extend out only to about 72 hours, it best
represents the flooding potential in those locations within the
watch area.
FORECAST POSITIONS AND MAX WINDS
INIT 23/2100Z 21.6N 92.6W 30 KT 35 MPH
12H 24/0600Z 22.4N 93.0W 35 KT 40 MPH
24H 24/1800Z 23.8N 93.9W 40 KT 45 MPH
36H 25/0600Z 25.1N 95.2W 50 KT 60 MPH
48H 25/1800Z 26.4N 96.3W 60 KT 70 MPH
72H 26/1800Z 28.6N 97.3W 50 KT 60 MPH…INLAND
96H 27/1800Z 29.0N 97.3W 35 KT 40 MPH…INLAND
120H 28/1800Z 29.0N 96.5W 35 KT 40 MPH…INLAND
http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/211729.shtml?gm_track#contents
http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/211729.shtml?wsurge#contents
The top-2 links are very informative and for people along those areas, these links might be very useful to you.
GMZ001-240845- Synopsis for the Gulf of Mexico 434 PM EDT Wed Aug 23 2017 .SYNOPSIS…Tropical Depression Harvey is centered near 21.6N 92.6W at 5 PM EDT, moving NW, or 312 degrees at 2 kt. Maximum sustained winds are 30 kt gusting to 40 kt. Harvey is forecast to intensify to tropical storm strength this evening, moving inland over southern Texas Friday night. $$
GMZ011-240845- NW Gulf including Stetson Bank- 434 PM EDT Wed Aug 23 2017
TROPICAL STORM WARNING TONIGHT E winds 10 to 15 kt. Seas 4 to 5 ft. THU NE to E winds 20 to 25 kt. Seas 5 ft, building to 11 ft in the afternoon. Scattered showers and isolated thunderstorms.
THU NIGHT TROPICAL STORM CONDITIONS EXPECTED. E winds 25 to 30 kt,increasing to 35 to 40 kt late. Seas 17 ft, building to 24 ft late. Scattered showers and isolated thunderstorms. FRI TROPICAL STORM CONDITIONS EXPECTED. SE winds 45 to 55 kt. Seas 22 to 27 ft. Scattered showers and isolated thunderstorms.
FRI NIGHT TROPICAL STORM CONDITIONS POSSIBLE. SE to S winds 45 to 55 kt. Seas 18 ft, subsiding to 13 ft late. Scattered showers and isolated thunderstorms.
SAT TROPICAL STORM CONDITIONS POSSIBLE.
SAT NIGHT TROPICAL STORM CONDITIONS POSSIBLE.
SUN S winds 20 to 25 kt. Seas 7 ft.
SUN NIGHT TROPICAL STORM CONDITIONS POSSIBLE.
MON NIGHT SW to W winds 20 to 25 kt. Seas 6 to 8 ft.
Floyd, Times Are Changin 