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KF5JRV > WX 07.09.18 12:45l 58 Lines 2496 Bytes #999 (0) @ NA
BID : 20845_KF5JRV
Read: GUEST
Subj: NWS CPHC Central Pacific WX - Sept 07
Path: IW8PGT<CX2SA<SV1CMG<PI8BDG<AB0AF<KF5JRV
Sent: 180907/1115Z 20845@KF5JRV.#NWAR.AR.USA.NA BPQ6.0.16
WTPA44 PHFO 070849
TCDCP4
Hurricane Norman Discussion Number 41
NWS Central Pacific Hurricane Center Honolulu HI EP162018
1100 PM HST Thu Sep 06 2018
Norman's satellite presentation certainly has not improved since
this afternoon, with deep convection continuing to shear northward
away from the low level circulation center (LLCC). No eye is noted
in infrared imagery and animation is not very helpful in locating
the center. With 30 to 40 kt of vertical shear continuing across
Norman and tilting its core this evening, we relied on timely 0341
UTC and 0431 UTC SSMIS imagery to track the LLCC. Subjective Dvorak
current intensity estimates were 4.5/77 kt from all three analysis
centers, and ADT from UW-CIMSS was 66 kt. Given the continued
apparent deterioration of this system, an initial intensity of 75
kt seems reasonable for this advisory.
We rebested the 0000 UTC Norman position slightly to the left and
slower to more align it with later SSMIS imagery. With this
adjustment, the initial motion estimate for this advisory is a more
northerly 325/7 kt. Norman is moving northwestward along the
western flank of a ridge and into an upper trough to its north.
Track guidance is tight through 48 hours, then pretty much all over
the map afterwards as each model handles a shear-decapitated Norman
differently. We maintained a forecast track in the middle of the
envelope, along ECMWF through 24 hours, then along TVCE consensus
from 36 through 72 hours. The forecast track was tapped slightly to
the right through 72 hours to account for the more northerly
initial motion, with the current track almost on top of the previous
one at 96 and 120 hours.
Norman will continue to experience very strong shear through 72
hours. This will weaken the tropical cyclone rather rapidly,
particularly in light of the cooler sea surface temperatures ahead.
Norman is expected to become a remnant low in 3 days.
FORECAST POSITIONS AND MAX WINDS
INIT 07/0900Z 22.5N 151.7W 75 KT 85 MPH
12H 07/1800Z 23.3N 152.5W 60 KT 70 MPH
24H 08/0600Z 24.4N 153.6W 50 KT 60 MPH
36H 08/1800Z 25.5N 154.6W 40 KT 45 MPH
48H 09/0600Z 26.5N 155.4W 35 KT 40 MPH
72H 10/0600Z 28.5N 157.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 11/0600Z 30.5N 158.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 12/0600Z 32.5N 160.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Powell
73 de Scott KF5JRV
Pmail: KF5JRV@KF5JRV.#NWAR.AR.USA.NA
email: KF5JRV@ICLOUD.COM
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