NATL: MELISSA - Tropical Storm - Discussion

[GCANE]

Not only dealing with shear but running into mid-level dry air
https://weather.cod.edu/satrad/?parms=m ... orbar=data

[GCANE]

 https://x.com/NbergWX/status/1980517047026008573

[cycloneye]

AL, 98, 2025102112, , BEST, 0, 143N, 713W, 45, 1003, LO

[NDG]

Not sure what they're waiting for to upgrade it to TS. Maybe at 11 AM they will start advisories.

[boca]

 https://x.com/NbergWX/status/1980517047026008573

How would a cut off low affect the track of future Melissa?

[MGC]

Yup, looks like a closed circulation on the western edge of the convective blob. Going to fight shear in the short term. Thinking Jamaica to Cuba threat for landfall. Intensity will depend on the shear......MGC

[LarryWx]

AL, 98, 2025102112, , BEST, 0, 143N, 713W, 45, 1003, LO

https://i.imgur.com/U68KnV8.png

This 12Z position of 14.3N, 71.3W, is near NDG’s estimate and thus we now know with more confidence that the 6Z GFS’ 6 hour position near 14.3N, 70.4W, is ~60 miles too far east.

[Subtrop]

AL, 13, 2025102112, , BEST, 0, 143N, 713W, 45, 1003, TS, 34, NEQ, 100, 70, 0, 40, 1009, 150, 35, 55, 0, L, 0, , 0, 0, MELISSA, M, 0, , 0, 0, 0, 0, genesis-num, 035, TRANSITIONED, alB82025 to al132025,

[Sciencerocks]

[Kazmit]

We have Melissa— curious to see what the NHC cone will look like. Will it split the difference between the GFS and Euro or favor one over the other?

[kevin]

I think the first cone/track will be similar to the latest TVCN (so more heavily favoring the Euro) with a track close to Jamaica and heading towards Cuba with a slight NW component. But with the note that track uncertainty is much larger than usual and that large swings in the forecast track can still take place.

[Subtrop]

NHC will initiate advisories on Tropical Storm Melissa (formerly AL98), located over the Caribbean Sea, at 1100 AM EDT (1500 UTC).

[cycloneye]

 https://x.com/CraigSetzer/status/1980640359379267623

[Buck]

Melissa could be the big one this year, folks. In terms of impact at least. Would be remarkable if she challenged Erin or Humberto strength wise but she won’t need to even come close to wreak havoc.

[TomballEd]

Seeing evidence of dry air (arc clouds), a storm this large with shear and dry air hindering development should slow strengthening. Models, especially the latest GFS suggest Melissa will start building a small but protective anticyclone aloft with screaming westerlies to the north of the storm helping to evacuate the storm. The rate Melissa can intensify with hostile shear pushing dry air into the system probably determines how far W the system gets before it gets pulled N/NE.

[kevin]

And here is the cone. Pretty much as expected, leaning more heavily towards the runs that keep Melissa in the Caribbean instead of making landfall on Haiti. But also quite a bit slower than many of the Euro members that have a faster and cleaner motion due west near the end of the forecast. Basically a 'let's just wait 24 hours because nobody really knows' cone, which is probably indeed the wisest & safest way to go for now.

[TTARider]

looks like the 'we have no idea where it's going' forecast.


https://imgur.com/a/rXA6Ldw

[TomballEd]

And here is the cone. Pretty much as expected, leaning more heavily towards the runs that keep Melissa in the Caribbean instead of making landfall on Haiti. But also quite a bit slower than many of the Euro members that have a faster and cleaner motion due west near the end of the forecast. Basically a 'let's just wait 24 hours because nobody really knows' cone, which is probably indeed the wisest & safest way to go for now.

https://i.imgur.com/5WVsMrP.png

The cone is a function of expected error (I believe 2/3rds likelihood inside the cone based on recent NHC performance, the cones grow smaller as NHC/models they use gets better) that grows larger each forecast day. The cone looks like a big circle because the current forecast shows very slow motion towards the end of the forecast period. Uncertainty is highlighted in the discussion, of course.

[GCANE]

 https://x.com/NbergWX/status/1980517047026008573

How would a cut off low affect the track of future Melissa?

Fujiwhara effect

[Fancy1002]

 https://x.com/NbergWX/status/1980517047026008573

How would a cut off low affect the track of future Melissa?

Fujiwhara effect

I’m wondering if the low is deep enough and Melissa takes a more western track, could the low force Melissa just barely into South Florida making a direct impact on Miami.