EPAC: HERNAN - Post-Tropical

[jaguarjace]

08E Floater

[cycloneye]

TROPICAL DEPRESSION EIGHT-E DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082014
200 AM PDT SAT JUL 26 2014

Conventional and microwave satellite imagery indicate that
convection associated with a low pressure system located about 350
n mi southwest of Manzanillo, Mexico, has increased and banding
features have also improved during the past 6 hours. Therefore,
advisories have been initiated on Tropical Depression Eight-E. The
initial intensity is set at 30 kt based on 28-30 kt surface wind
vectors noted in the eastern quadrant of the low in 0350 UTC
ASCAT-B and 0436 UTC ASCAT-A scatterometer data. This intensity is
also supported by a T2.0 Dvorak satellite classification from TAFB.

The initial motion estimate is an uncertain 310/12 kt, which is
based primarily on microwave fixes over the past 12 hours. The
depression is moving northwestward along the southwestern
periphery of a strong mid-level ridge located over the
southwestern and south-central United States, and this general
motion is expected to continue for the next 48 hours or so. After
that time, the cyclone is forecast to gradually weaken over
much cooler waters. As a result, the system is expected to become
more vertically shallow and be steered westward by the strong
easterly low-level trade wind flow. The official forecast track is
similar to but a little north of the consensus model TVCE.

Tropical Depression Eight-E is currently in a low vertical wind
shear environment and over SSTs greater than 29C. Those favorable
conditions are expected to continue for at least the next 24-30
hours, which should allow the cyclone to steadily strengthen at the
typical rate of 20 kt per day. However, due to vertical shear values
of less than 3 kt expected for the next 12-18 hours, it would not
surprise me if the system undergoes a period of rapid
intensification during that time. The official intensity forecast is
slightly higher than all of the available intensity guidance due to
the favorable shear and thermodynamic conditions expected during the
next 24 hours, and the current compact structure of the tropical
cyclone.

FORECAST POSITIONS AND MAX WINDS

INIT 26/0900Z 13.4N 106.3W 30 KT 35 MPH
12H 26/1800Z 14.7N 108.1W 35 KT 40 MPH
24H 27/0600Z 16.4N 110.7W 45 KT 50 MPH
36H 27/1800Z 17.9N 113.2W 55 KT 65 MPH
48H 28/0600Z 19.2N 115.6W 60 KT 70 MPH
72H 29/0600Z 21.2N 119.8W 40 KT 45 MPH
96H 30/0600Z 22.0N 123.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 31/0600Z 22.0N 125.0W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Stewart

[euro6208]

Really impressive activity lately of----------weak storms. The 5th tropical storm that failed to reach hurricane status in the EPAC? Not unless rapid intensification occurs and break the spell.

[somethingfunny]

Really impressive activity lately of----------weak storms. The 5th tropical storm that failed to reach hurricane status in the EPAC? Not unless rapid intensification occurs and break the spell.

The NHC stated in their discussion that rapid intensification with this storm would not be surprising. It wouldn't surprise me either, especially given how quickly it's organized thus far.

[Yellow Evan]

Really impressive activity lately of----------weak storms. The 5th tropical storm that failed to reach hurricane status in the EPAC? Not unless rapid intensification occurs and break the spell.

The forecast peak is 60 knts. Right below cane status.

[Yellow Evan]

P, 08, 2014072612, , BEST, 0, 139N, 1070W, 30, 1007, TD, 34, NEQ, 0, 0, 0, 0, 1011, 150, 50, 0, 0, E, 0, , 0, 0, EIGHT, M,

[hurricanes1234]

Weaker peak of 50 knots is forecast. Unlikely in my opinion that this will become a hurricane at this rate.

000
WTPZ43 KNHC 261432
TCDEP3

TROPICAL DEPRESSION EIGHT-E DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082014
800 AM PDT SAT JUL 26 2014

The tropical depression has not changed much during the past
several hours. Although the system is producing a considerable
amount of deep convection, it is mainly confined to the north side
of the cyclone and is not wrapping around the center. The initial
intensity remains 30 kt based on a blend of the Dvorak intensity
estimates. The environment is currently favorable for the
depression to strengthen, but it is not expected to remain that way
for very long. In about 2 days, the cyclone will be moving over
cooler waters and into an atmosphere of stronger shear and dry air.
The models show less strengthening this cycle, and the official
intensity forecast is a little lower than the previous one based on
this guidance.

The system is moving northwestward at about 13 kt. A slightly
faster west-northwest to northwest motion is expected during
the next couple of days while the cyclone remains embedded in the
fast flow on the southwest side of a strong mid-level ridge over the
southern United States. A gradual turn toward the west with a
decrease in forward speed is expected beyond a few days when the
weakening cyclone becomes steered by the lighter low-level flow.
The models are tightly clustered, and the official track forecast
is essentially an update of the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT 26/1500Z 14.4N 107.3W 30 KT 35 MPH
12H 27/0000Z 15.7N 109.3W 35 KT 40 MPH
24H 27/1200Z 17.3N 111.9W 45 KT 50 MPH
36H 28/0000Z 18.7N 114.4W 50 KT 60 MPH
48H 28/1200Z 20.0N 116.8W 50 KT 60 MPH
72H 29/1200Z 21.6N 120.9W 35 KT 40 MPH
96H 30/1200Z 22.0N 124.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 31/1200Z 22.0N 126.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

[Yellow Evan]

Weaker peak of 50 knots is forecast. Unlikely in my opinion that this will become a hurricane at this rate.

It's possible. Conditions look good for two days. The thing is models aren't very aggressive. But why are you so pessimistic?

[Yellow Evan]

Not much deepening is expected by the GFS.

[Yellow Evan]

Meanwhile, the 6z HWRF is more aggressive calling for the equivalent of a minimal hurricane.



6z GFDL keeps it a mid-level TS.



0z GFDL keeps both 93E an 08E weak TS

[cycloneye]

08E HERNAN 140726 1800 14.9N 107.7W EPAC 35 1005

[Yellow Evan]

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 35 38 41 44 47 49 48 45 38 31 21 DIS DIS
V (KT) LAND 35 38 41 44 47 49 48 45 38 31 21 DIS DIS
V (KT) LGE mod 35 38 40 43 45 46 44 39 34 30 26 22 18
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 1 5 7 8 9 12 17 12 12 16 31 33 24
SHEAR ADJ (KT) -3 -4 0 3 5 3 -1 2 1 -1 -4 -4 4
SHEAR DIR 229 297 292 312 306 289 260 226 263 321 353 354 2
SST (C) 29.7 29.9 29.7 29.4 28.7 27.1 25.4 24.6 24.3 24.0 23.7 23.6 23.2

[cycloneye]

TROPICAL STORM HERNAN DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP082014
200 PM PDT SAT JUL 26 2014

Satellite data indicate that the depression has strengthened. The
cloud pattern has become better organized during the past several
hours with banding features now more distinct and symmetric around
the center. A recent ASCAT pass showed maximum winds near 35 kt,
and Dvorak classifications from TAFB and UW-CIMSS also support a
similar wind speed. Based on these data, the initial intensity is
increased to 35 kt, making the cyclone Tropical Storm Hernan.

Some additional strengthening appears likely during the next day or
so while the environmental conditions remain favorable. Beyond that
time, however, Hernan will be moving over cooler water and into an
atmosphere of stronger shear and dry air. These expected hostile
conditions should cause the storm to lose strength. The intensity
guidance has not changed significantly, and this forecast is an
update of the previous one.

Hernan is moving northwestward at about 13 kt on the southwest side
of a strong mid-level ridge centered over the southern United
States. This steering pattern is expected to persist, and that
should keep the system moving west-northwestward to northwestward at
about the same speed for the next couple of days. After that time,
a gradual turn toward the west with a decrease in forward speed is
expected when the weakening cyclone is steered by the lighter
low-level flow. The models have shifted northward this cycle, and
the official track forecast is adjusted in that direction.

FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 15.4N 108.3W 35 KT 40 MPH
12H 27/0600Z 16.7N 110.0W 45 KT 50 MPH
24H 27/1800Z 18.3N 112.5W 50 KT 60 MPH
36H 28/0600Z 19.7N 114.7W 50 KT 60 MPH
48H 28/1800Z 20.9N 117.0W 45 KT 50 MPH
72H 29/1800Z 22.6N 121.2W 30 KT 35 MPH
96H 30/1800Z 23.0N 124.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 31/1800Z 23.0N 127.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Cangialosi

[TropicalAnalystwx13]

Tropical Storm Hernan is quickly becoming better organized, with expanding outflow in all quadrants and deepening central convection. Is a period of rapid intensification on the way?

2014JUL26 211500 2.9 1003.1 43.0 2.9 3.0 4.1 0.7T/6hr OFF OFF -47.66 -61.28 EMBC N/A -3.9 15.44 108.35 FCST GOES13 42.1

[somethingfunny]

This ASCAT pass showing only 30-knot winds is the reason why NHC went with a minimal tropical storm for the advisory and lowered their forecast. Hernan is looking quite healthy however.

[TropicalAnalystwx13]

This ASCAT pass showing only 30-knot winds is the reason why NHC went with a minimal tropical storm for the advisory and lowered their forecast. Hernan is looking quite healthy however.

Yeah, and that ASCAT pass is a good deal old (6 hours now). We'll see if we get a new pass later this evening.

[Yellow Evan]

This ASCAT pass showing only 30-knot winds is the reason why NHC went with a minimal tropical storm for the advisory and lowered their forecast. Hernan is looking quite healthy however.

Yeah, and that ASCAT pass is a good deal old (6 hours now). We'll see if we get a new pass later this evening.

ASCAT has a low bias.

[Yellow Evan]

Hernan has a chance to become a hurricane. But it also has a chance to fizzle out like the last number of systems. Most likely it'll be a 50-55 knt TS. Celling is around 70 knts IMO.

I think it's possible it could RI, but not for long. Something like Calvin 11 seems plausible.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[cycloneye]

EP, 08, 2014072700, , BEST, 0, 158N, 1083W, 40, 1002, TS

[Yellow Evan]

EP, 08, 2014072700, , BEST, 0, 158N, 1083W, 40, 1002, TS

Seems reasonable, though they may bumb it up to 45 knts when adv comes around IMO.