Things to ponder – Harvey!

Last check Harvey has some issues. 1)  Max Sustained Winds  (40mph),  2) Minimum Central Pressure 1005mb (High),   Forward Speed 18mph (a tad fast).  Poorly developed and being twisted and churned on either side.   The 500mb is in the Northern Gulf of Mexico.  The HIGH is weak at all levels.  NHC is not even certain about the strength, but tend to think.  NO.  Met. Larry Olson (Mike Scott….)

GULFIR172310115

 

000
WTNT44 KNHC 190233
TCDAT4

Tropical Storm Harvey Discussion Number 7
NWS National Hurricane Center Miami FL AL092017
1100 PM AST Fri Aug 18 2017

Microwave and conventional geostationary satellite images indicate
that Harvey’s center is still displaced to the east of a persistent
cluster of deep convection due to about 15 kt of northeasterly
shear. With no notable changes in the cyclone’s structure since
the last advisory, the maximum wind estimate remains 35 kt, which
is in line with the latest Dvorak CI numbers.

Recent microwave fixes suggest that Harvey’s center may have slowed
down or wobbled northward temporarily, and the 12-hour motion
estimate is a slightly slower 275/16 kt. A low- to mid-level ridge
extending across the western Atlantic should keep Harvey on a swift
westward course across the Caribbean Sea for the next 48 hours.
Once Harvey moves into the northwestern Caribbean Sea by 72 hours,
it will reach the western edge of the ridge, and it will likely
slow down and gain some latitude due to a cut-off low over the
northwestern Gulf of Mexico. Although the track guidance envelope
has shifted slightly northward on this cycle, especially around the
72-hour period, there are no significant changes from six hours ago.

Northeasterly or northerly shear is forecast to continue for the
next 36 hours or so, which should prevent significant strengthening
while Harvey moves westward across the eastern and central
Caribbean Sea. By 48 hours, the vertical shear over the cyclone
drops drastically, but the system’s fast motion could still
limit the amount of intensification that will occur. The best
opportunity for strengthening would likely be around day 3 when
Harvey begins to slow down as it approaches Belize and the Yucatan
Peninsula. The updated NHC intensity forecast is the same as the
previous one during the first 48 hours, and it was nudged a little
lower at 72 hours to fall closer to the HFIP Corrected Consensus
(HCCA) model and the ICON intensity consensus. A lot of
uncertainty remains, however, since models like SHIPS and HWRF
bring Harvey near or to hurricane intensity before it reaches land
while the GFS and ECMWF continue to weaken the circulation while it
moves across the Caribbean Sea.

FORECAST POSITIONS AND MAX WINDS

INIT 19/0300Z 13.7N 64.1W 35 KT 40 MPH
12H 19/1200Z 14.0N 66.8W 35 KT 40 MPH
24H 20/0000Z 14.3N 70.4W 40 KT 45 MPH
36H 20/1200Z 14.5N 74.3W 40 KT 45 MPH
48H 21/0000Z 14.8N 78.1W 45 KT 50 MPH
72H 22/0000Z 16.5N 84.7W 55 KT 65 MPH
96H 23/0000Z 18.0N 89.5W 45 KT 50 MPH…INLAND
120H 24/0000Z 19.0N 92.5W 40 KT 45 MPH…OVER WATER

TROPICAL STORM HARVEY FORECAST/ADVISORY NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092017
0300 UTC SAT AUG 19 2017

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE CARIBBEAN SEA AND THE ADJACENT LAND AREAS OF
EASTERN CENTRAL AMERICA AND NORTHERN SOUTH AMERICA SHOULD MONITOR
THE PROGRESS OF HARVEY.

TROPICAL STORM CENTER LOCATED NEAR 13.7N 64.1W AT 19/0300Z
POSITION ACCURATE WITHIN 40 NM

PRESENT MOVEMENT TOWARD THE WEST OR 275 DEGREES AT 16 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT……. 60NE 0SE 0SW 60NW.
12 FT SEAS.. 60NE 0SE 0SW 45NW.
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 13.7N 64.1W AT 19/0300Z
AT 19/0000Z CENTER WAS LOCATED NEAR 13.7N 63.2W

FORECAST VALID 19/1200Z 14.0N 66.8W
MAX WIND 35 KT…GUSTS 45 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 20/0000Z 14.3N 70.4W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 20/1200Z 14.5N 74.3W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 21/0000Z 14.8N 78.1W
MAX WIND 45 KT…GUSTS 55 KT.
34 KT… 60NE 0SE 0SW 60NW.

FORECAST VALID 22/0000Z 16.5N 84.7W
MAX WIND 55 KT…GUSTS 65 KT.
50 KT… 30NE 20SE 0SW 30NW.
34 KT… 90NE 50SE 40SW 80NW.

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 23/0000Z 18.0N 89.5W…INLAND
MAX WIND 45 KT…GUSTS 55 KT.

OUTLOOK VALID 24/0000Z 19.0N 92.5W…OVER WATER
MAX WIND 40 KT…GUSTS 50 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 13.7N 64.

 

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