EPAC: OLAF - Post-Tropical

#161 Postby **Alyono** » Mon Oct 19, 2015 3:24 pm

here is the scary thing. If this takes a bit longer to slow, we could have a landfall in the 4 to 5 day time frame.

it should slow, but we've been saying this for 3 days

#162 Postby **Yellow Evan** » Mon Oct 19, 2015 3:29 pm

Alyono wrote:here is the scary thing. If this takes a bit longer to slow, we could have a landfall in the 4 to 5 day time frame.

it should slow, but we've been saying this for 3 days

ECMWF/GFS seem to be forecasting a ridge over Hawaii once the ridge to the north re-builds though.

#163 Postby **Alyono** » Mon Oct 19, 2015 3:29 pm

been looking at some of the past forecasts, it has been back to the 1990s in terms of model performance.

#164 Postby **cycloneye** » Mon Oct 19, 2015 3:35 pm

Category 4

HURRICANE OLAF DISCUSSION NUMBER 20
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192015
200 PM PDT MON OCT 19 2015

Olaf has continued to rapidly intensify today. The hurricane has a
classical appearance on satellite imagery with a small, clear eye
surrounded by a CDO with cloud tops of -70C to -80C. Dvorak
estimates from TAFB and SAB and UW-CIMSS were T6.0/115 kt, and these
are the basis for the initial intensity. Olaf has strengthened 45 kt
in the last 24 hours, and some additional strengthening is still
possible in the next day or two. However, there could also be
fluctuations in intensity due to eyewall replacement cycles that are
not accounted for here. The new NHC forecast shows a peak of 125 kt
at 12 h to 36 h and then a slow decay as the cyclone begins to move
over slightly cooler SSTs and into a drier environment later in the
period. The official forecast is above the intensity consensus and
close to the FSU Superensemble.

The initial motion estimate is 275/10, as Olaf continues to move
westward to the south of a mid-level ridge centered near 30N/140W.
This ridge will gradually weaken as a trough advances over the
north-central Pacific, and this will allow Olaf to finally begin
gaining some latitude as it gradually turns northwestward and then
northward during the forecast period. The UKMET model still is on
the left side of the guidance envelope for the first 48 hours, but
has shifted toward a sharper northward turn after that time. This
puts the GFS and ECMWF now on the left side of the guidance
envelope. Overall, the new NHC track forecast is an update of the
previous one and is still left of the consensus. The official
forecast is between the UKMET and the rest of the guidance in the
first 48 hours, and then lies along the left side of the track model
envelope at days 3 through 5.

FORECAST POSITIONS AND MAX WINDS

INIT 19/2100Z 10.0N 138.7W 115 KT 130 MPH
12H 20/0600Z 10.3N 140.1W 125 KT 145 MPH
24H 20/1800Z 10.9N 141.6W 125 KT 145 MPH
36H 21/0600Z 11.7N 143.1W 125 KT 145 MPH
48H 21/1800Z 12.6N 144.4W 120 KT 140 MPH
72H 22/1800Z 14.7N 146.1W 110 KT 125 MPH
96H 23/1800Z 17.7N 147.0W 100 KT 115 MPH
120H 24/1800Z 20.0N 147.0W 85 KT 100 MPH

$$
Forecaster Brennan

#165 Postby **Alyono** » Mon Oct 19, 2015 4:27 pm

CMC deterministic does not agree with its ensemble

#166 Postby **Yellow Evan** » Mon Oct 19, 2015 4:46 pm

CDO seems to be cooling, but so is the eye. I am also seeing signs of dry air to the west, but I still expect a little more intensification before an eyewall replacement cyclone starts.

#167 Postby **Kingarabian** » Mon Oct 19, 2015 5:00 pm

Alyono wrote:been looking at some of the past forecasts, it has been back to the 1990s in terms of model performance.

It's expected to see models windshield wipe. But I just want to know why the Euro continues to initialize Olaf wrong. The 12z run initialized Olaf as a Tropical Storm while it was already a cat. 3.

#168 Postby **Alyono** » Mon Oct 19, 2015 5:28 pm

Kingarabian wrote:
Alyono wrote:been looking at some of the past forecasts, it has been back to the 1990s in terms of model performance.

It's expected to see models windshield wipe. But I just want to know why the Euro continues to initialize Olaf wrong. The 12z run initialized Olaf as a Tropical Storm while it was already a cat. 3.

shouldn't matter in this case

#169 Postby **Alyono** » Mon Oct 19, 2015 5:36 pm

18Z MU shifts slightly south and west again. Still recurving, though I have no confidence in the forecasts

#170 Postby **Yellow Evan** » Mon Oct 19, 2015 5:37 pm

18z GFS is east towards the USA through day 8.

#171 Postby **Alyono** » Mon Oct 19, 2015 5:41 pm

yep, moving to the NE now. The slight west shift occurred through the first 4 days

#172 Postby **Kingarabian** » Mon Oct 19, 2015 5:44 pm

12z Euro ensembles also shifted a bit east. Still west of the operational model.

#173 Postby **Alyono** » Mon Oct 19, 2015 6:26 pm

Kingarabian wrote:12z Euro ensembles also shifted a bit east. Still west of the operational model.

a bit? Substantially east

Chris_in_Tampa · #174 Postby **Chris_in_Tampa** » Mon Oct 19, 2015 7:14 pm

5 day model plots.

#175 Postby **Kingarabian** » Mon Oct 19, 2015 7:29 pm

Alyono wrote:
Kingarabian wrote:12z Euro ensembles also shifted a bit east. Still west of the operational model.

a bit? Substantially east

I see it now. Was looking at the MSLP anomalies on TropicalTidbits.com

#176 Postby **Kingarabian** » Mon Oct 19, 2015 7:38 pm

Chris_in_Tampa wrote:5 day model plots.

[img]http://i.imgur.com/IzDldff.gif[img]

Latest visible imagery shows it on track to miss the next forecast point as well unless it abruptly jumps north.

#177 Postby **Yellow Evan** » Mon Oct 19, 2015 7:45 pm

Eye not visible anymore likely since it was overshot by the CDO.

#178 Postby **Kingarabian** » Mon Oct 19, 2015 8:01 pm

Yellow Evan wrote:Eye not visible anymore likely since it was overshot by the CDO.

Possible ERC starting? Hope we get a bigger and nicer looking eye.

Chris_in_Tampa · #179 Postby **Chris_in_Tampa** » Mon Oct 19, 2015 8:07 pm

#180 Postby **Kingarabian** » Mon Oct 19, 2015 8:11 pm

Chris, you think we'll get any missions? Has there even been a synoptic mission solely with no recon missions done for a storm?

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