Tropical Weather Discussion

000 

abio10 pgtw 131000
msgid/genadmin/joint typhoon wrncen Pearl Harbor hi//
subj/significant tropical weather advisory for the Indian Ocean
/reissued/131000z-131800zdec2018//
ref/a/msg/joint typhoon wrncen Pearl Harbor hi/130251zdec2018//
ampn/ref a is a tropical cyclone formation alert./
Rmks/
1. North Indian Ocean area (Malay Peninsula west to coast of Africa):
   a. Tropical cyclone summary: none.
   B. Tropical disturbance summary:
      (1) the area of convection (invest 94b) previously located
near 6.0n 89.5e, is now located near 7.4n 88.4e, approximately 511
nm east of Colombo, Sri Lanka. Animated enhanced infrared satellite
imagery shows a slowly consolidating low level circulation center
(LLCC) with persistent deep convection. Upper-level analysis
indicates moderate (15-25 knots) vertical wind shear, offset by good
poleward outflow. Sea surface temperatures (28-30 celsius) in the
surrounding area remain favorable for development. Global models
generally agree on a northwest trajectory, but vary on the timing
and intensity. Models indicate the disturbance reaching tropical
strength with in the next 30-48 hours. Maximum sustained surface
winds are estimated at 22 to 28 knots. Minimum sea level pressure is
estimated to be near 1001 mb. The potential for the development of a
significant tropical cyclone within the next 24 hours is upgraded to
high. See ref a (wtio32 ptwc 130300) for further details.
      (2) no other suspect areas.
2. South Indian Ocean area (135e west to coast of Africa):
   a. Tropical cyclone summary: none.
   B. Tropical disturbance summary:
      (1) the area of convection (invest 91s) previously located
near 5.9s 91.9e, is now located near 5.7s 93.5e, approximately 434
nm north-northwest of Cocos Islands. Animated multispectral imagery
shows that a broad, slightly elongated low level center (llc) is
mostly obscured by convection. A 130655z amsr2 gw1 89ghz microwave
image shows a small area of deep convection over the llc with some
formative banding to the south. A 130303z metop-a partial ascat pass
shows a swath of 20 to 25 knot winds to the northwest. 91s is
currently sitting in a marginal environment with favorable sea
surface temperatures (26 to 28 celsius) and very good poleward
westward outflow. 91s is between very high vertical wind shear (vws)
(40 to 50 knots) to the north of the llc and low vws (5 to 10 knots)
to the south of the llc. Global models are in good agreement that
91s will track southwestward and intensify over the next several
days. Maximum sustained surface winds are estimated at 20 to 25
knots. Minimum sea level pressure is estimated to be near 1004 mb.
The potential for the development of a significant tropical cyclone
within the next 24 hours is upgraded to medium.
      (2) no other suspect areas.
3. Justification for reissue: upgraded area in 2.B.(1) to medium.//
Nnnn

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