Tuesday, October 9, 2018

Hurricane Michael

10-9

Michael started out with a look at the MJO and EPS probability of tropical development back on Sept 29.
The GEM picked up on it first, but then again it picks up a lot of stuff that's garbage too.  The general theme was development in the western Caribbean and moving either east or west of FL.
Euro had it in the SW Atlantic on the 2nd
Had nothing on its 12z run the 3rd, but the 4th came around to the idea of a panhandle special




From there it became timing and exact placement.

Even the navgem had it on the 4th.

GFS on the 2nd had sniffed it out - but honestly, every run of the GFS this year has a storm in the Caribbean.  It took it around the gulf, then out over Florida
All clear on the 3rd and 4th

By 12z on the 5th it had locked in.
Once we got to the 5th, it really became an intensity and exact location battle.  The area between NOLA and Big Bend were in question.  That got narrowed down to Mobile to Big Bend as the NAM came on board with a Big Bend hit, then it became Pensacola to just east of Panama City. This is where it remains today, with most guidance taking it ashore around Panama City.

As of tonite, the winds look to be in the 120-125 mph range at landfall per NHC. 

10/10  - will fill in at home

Doing this retrospectively.  There was no indication that Michael would go to 155mph until a couple hours before landfall.  It just kept strengthening.   These are the hurricane hunter obs.  Some of the flights were at the same time, so its not in perfect order, but you can see the history well here. 





Radar from landfall and satellite



NHC Forecast
Track was nailed down pretty early, at least early enough for watches and warnings.  The intensity forecast was the problem.  NHC started its forecast with 65mph winds but mentioned HWRF is more intense. 

By Sunday night the intensity was raised to 100mph.  HWRF was still noted as being more intense but discounted due to the shear that would be around. By Monday 4am, the first discussion of major status came around.  Still noting that there was a lot of shear. The next update was the first to go to major status, with 120mph winds.  The inner core was developing strongly and was able to fend off shear.  
Now that Michael has developed an
inner core, steady to rapid strengthening is predicted during the
next 24 to 36 hours.  The SHIPS Rapid Intensification Index and
DTOPS give a 55-60 percent chance of rapid intensification during
the next 24 hours.  The updated NHC forecast is near the upper-end
of the guidance and calls for rapid strengthening over the next 24
hours, and brings Michael to major hurricane status. 
The 10pm Monday discussion says it all
Michael's steady intensification over the past 48 hours in the face
of 20-kt westerly shear defies traditional logic. Either the shear
calculations are unrepresentative or Michael has become more
inertially stable due to its large eye and large outer wind field,
making it more shear resistant. Having said that, all of the model
guidance calls for the shear to decrease to around 10 kt or less by
36 hours, which argues for at least steady intensification during
that time given that Michael will be moving over warm SSTs of
28.5C-29C, which are about 1-2 deg C above average for this time of
the year.
The prediction remained in the 120mph and 125mph range until the 10pm Tuesday advisory which increased winds to 130mph.  At this point the pressure is 947mb.
Satellite intensity estimates from TAFB and SAB, along
with objective estimates from UW-CIMSS ADT and NHC, support an
intensity of 115-127 kt. However, those also estimates also would
support a central pressure of about 935 mb, which the aircraft has
not measured thus far
The 4am advisory, 8-10 hours before landfall, brought the forecast wind speed to 145mph.

Models.
HWRF was said to have done the best.


I could only go back so far.  Track was pretty tight with the models, making a call for a landfall in the Panama City area easy 3 days before, though the NAM had a sharper west turn and hit Big Bend area.  With the approaching front/trough it was something to watch.

Globals showed intensification as it approached land, but were way off with their pressures and winds.

10/11  Aftermath




At 200 AM EDT (0600 UTC), the center of Tropical Storm Michael was
located near latitude 37.3 North, longitude 75.1 West.  Michael is
moving toward the northeast near 25 mph (41 km/h).  An east-
northeastward motion with a significant increase in forward speed is
expected during the next couple of days.  On the forecast track, the
center of Michael will move away from the coast of the United
States during the next few hours and then begin to race
east-northeastward across the northwestern Atlantic Ocean.

Surface observations indicate that maximum sustained winds have
increased near 60 mph (95 km/h) with higher gusts.  Michael is
expected to continue to strengthen while becoming a post-tropical
low during the next few hours.

Tropical-storm-force winds extend outward up to 275 miles (445 km),
primarily over water to the southeast of the center.  The National
Ocean Service station on the York River recently reported sustained
winds of 62 mph (99 km/h) and a wind gust of 83 mph (133 km/h) at an
elevation of 48 ft (15 m), while the Norfolk Naval Air Station
reported sustained winds of 54 mph (87 km/h) and a wind gust of
75 mph (120 km/h).  Also, a Weatherflow station on the Chesapeake
Light Tower recently reported sustained winds of 81 mph (130 km/h)
and a wind gust of 96 mph (154 km/h) at an elevation of 135 ft
(41 m).

The estimated minimum central pressure is 985 mb (29.09 inches).


Post-Tropical Cyclone Michael Discussion Number  23
NWS National Hurricane Center Miami FL       AL142018
500 AM EDT Fri Oct 12 2018

Satellite imagery and surface observations indicate that Michael has
become a storm-force extratropical low as it moves off of the coast
of the United States.  The initial intensity has been increased to
55 kt based on the surface observations, and some additional
increase in strength is expected during the next 12-24 h.  After
that time, the cyclone should gradually weaken, and it is forecast
to dissipate over the eastern Atlantic by 96 h.  The revised
intensity and size forecast are based mainly on the guidance from
the Ocean Prediction Center.

Michael flooded LI with 4-5 inches of rain as it skirted to the south.  We had no rain overnight here in Newtown


Storm 3 - could be the one! (spoiler, it was)

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