EPAC: ANDRES - Post-Tropical

[cycloneye]

[CrazyC83]

Based on that RapidSCAT, agreed with 50 kt for the initial intensity. Also the genesis time I could see being pushed back to 0000Z.

[CrazyC83]

Notice this in the discussion...is he touring the NHC or is this a joke?

000
WTPZ41 KNHC 281453
TCDEP1

TROPICAL STORM ANDRES DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012015
900 AM MDT THU MAY 28 2015

Deep convection associated with the tropical cyclone has continued
to expand this morning with a large area of cloud top temperatures
colder than -70 degrees Celsius. The convection has also become
better organized with an increase in banding and a developing
central dense overcast. Dvorak data T-numbers from both SAB and
TAFB were T2.5, which support upgrading the depression to a 35-kt
tropical storm.

The initial motion estimate is 295/12. Andres is located to the
south and southwest of a mid-level ridge that extends from
south-central Mexico west-southwestward over the eastern Pacific.
This ridge is expected to be the main steering influence during the
next several days, and should cause Andres to move
west-northwestward to northwestward. After 48 hours, track guidance
spread increases, with the GFDL, HWRF, and ECMWF models taking
Andres on a more northerly track, while the GFS and GFS ensemble
maintain a northwesterly motion. The NHC track forecast remains
near the multi-model consensus for now.

Warm water and low shear during the next 2-3 days should allow for
steady strengthening. In fact, the SHIPS RI index indicates a 60%
chance of at least a 30-kt increase during the next 24 hours. The
updated NHC forecast calls for a faster rate of intensification over
the next 36 h than the previous one. In 2 to 3 days, the cyclone
will be approaching slightly cooler waters which should induce
weakening by the end of the forecast period.

FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 11.6N 111.3W 35 KT 40 MPH
12H 29/0000Z 12.3N 112.4W 45 KT 50 MPH
24H 29/1200Z 13.0N 113.3W 60 KT 70 MPH
36H 30/0000Z 13.8N 114.0W 70 KT 80 MPH
48H 30/1200Z 14.8N 114.6W 80 KT 90 MPH
72H 31/1200Z 16.7N 115.6W 80 KT 90 MPH
96H 01/1200Z 18.0N 117.0W 65 KT 75 MPH
120H 02/1200Z 19.0N 118.0W 50 KT 60 MPH

$$
Forecaster Brown and Barack Obama (PRESIDENT)

[cycloneye]

He is touring NHC today.

[Yellow Evan]

Why didn't the NHC factor in RapidScat?

[TropicalAnalystwx13]

Why didn't the NHC factor in RapidScat?

It tends to overestimate winds. Although a 3z RapidScat pass showed 45-50kt barbs, a 5z ASCAT pass showed 30kt winds:

[Yellow Evan]

Why didn't the NHC factor in RapidScat?

It tends to overestimate winds. Although a 3z RapidScat pass showed 45-50kt barbs, a 5z ASCAT pass showed 30kt winds:

How do you know ASCAT just doesn't underestimate? I'd give it the benefit of the doubt.

[xtyphooncyclonex]

I would give it 40 knots given the uncertainty

[TropicalAnalystwx13]

Why didn't the NHC factor in RapidScat?

It tends to overestimate winds. Although a 3z RapidScat pass showed 45-50kt barbs, a 5z ASCAT pass showed 30kt winds:

How do you know ASCAT just doesn't underestimate? I'd give it the benefit of the doubt.

ASCAT does underestimate, and it's been around long enough for NHC to adjust to that bias. They usually add 5kt to what is shows.

The 5z pass indicated 25kt winds (not 30kt as I originally stated, my mistake), which supported an initial intensity of 30kt.

[cycloneye]

Up to 45kts at 18z Best Track.

EP, 01, 2015052818, , BEST, 0, 117N, 1118W, 45, 998, TS

[Yellow Evan]

The 5z pass indicated 25kt winds (not 30kt as I originally stated, my mistake), which supported an initial intensity of 30kt.

Not entirely out of the question it could have intensified to 40-50 knots since then, based on RapidScat. We don't know for sure if it overestimates yet.

[TropicalAnalystwx13]

The 5z pass indicated 25kt winds (not 30kt as I originally stated, my mistake), which supported an initial intensity of 30kt.

Not entirely out of the question it could have intensified to 40-50 knots since then, based on RapidScat. We don't know for sure if it overestimates yet.

Did you read what I wrote? The RapidScat pass was at 3z, the ASCAT pass was at 5z.

Andres has certainly intensified to 45-50kt by this point. However, the 9z and 15z intensities seem generally fine to me (maybe 40kt at 15z?).

[TropicalAnalystwx13]

Andres is really consolidating, and I wouldn't be surprised to see it begin rapid intensification sometime within the next 24 hours as it builds an inner core.

[Yellow Evan]

The 5z pass indicated 25kt winds (not 30kt as I originally stated, my mistake), which supported an initial intensity of 30kt.

Not entirely out of the question it could have intensified to 40-50 knots since then, based on RapidScat. We don't know for sure if it overestimates yet.

Did you read what I wrote? The RapidScat pass was at 3z, the ASCAT pass was at 5z.

Andres has certainly intensified to 45-50kt by this point. However, the 9z and 15z intensities seem generally fine to me (maybe 40kt at 15z?).

Hmm, must have missed it, sorry. That makes sense then. I'd personally average the two, and go with around 40 knots (maybe 35 due to low Dvorak) at 9z, and def 40 knots at 15z.

[Yellow Evan]

On my phone so I can't post, but ATCF went with 45.

[Kingarabian]

Still has some ways to go:



But it's pretty scary we're getting storms with massive size this early. If this was in July/August/September then we're looking at a possible Cat4-5.

[Yellow Evan]

Honestly I would not rule out Cat 4 still has a few days.

[TropicalAnalystwx13]

On my phone so I can't post, but ATCF went with 45.

Just upped it further to 50kt.

EP, 01, 2015052818, , BEST, 0, 114N, 1121W, 50, 998, TS, 50, NEQ, 30, 0, 0, 0, 1010, 200, 30, 0, 0, E, 0, , 0, 0, ANDRES, D,

[Yellow Evan]

On my phone so I can't post, but ATCF went with 45.

Just upped it further to 50kt.

EP, 01, 2015052818, , BEST, 0, 114N, 1121W, 50, 998, TS, 50, NEQ, 30, 0, 0, 0, 1010, 200, 30, 0, 0, E, 0, , 0, 0, ANDRES, D,

Yet SAB/SSD are at T2.5 due to constraints.

[TropicalAnalystwx13]

A recent ASCAT pass showing several 40-45kt wind barbs and one 50kt barb is likely why NHC upped it: