Ed, snow and hurricane fan

No support for the HWRF, but fun to look at.

Does a mess now keep it South of the highest peaks of Hispaniola? Cuba has mountains as well, but most systems survive Cuba. Fred didn't, but it was already almost dead from Hispaniola. And Fred did rise from the dead. Intensity depends on track, and track on intensity. 12Z GFS weak system reorganizing near the Yucatan and hitting Mexico as probably a TS seems as likely as anything else.

That is some Easterly shear over Grace.

Those islands seem small, but Dorian, they destroyed the LLC which was SW of the MLC. On its own, might have taken days for them to align. Those islands helped Dorian organize by destroying the LLC so a new one could form. Not saying Cat 5 in the Bahamas. But the volcanoes on islands like Guadeloupe are big enough to disrupt weak surface circulations.

One monster Florida Panhandle GEFS member but I don't have software. A week from Saturday.

Question about modeling something East of the Lesser Antilles and West of the Cape Verdes. I assume flights from L. Antilles to Europe head NE, from watching a documentary about Air France crash (involved pitot icing in an ITCZ thunderstorm) by the time those flights get North of the Equator they are far closer to Africa than the Caribbean. Or I assume almost all initialization data is remote satellite sensing. Winter storm AFDs, often mentioned potential systems aren't in North American ballon sonde network, clear implication more confidence when models ingest surface obs and balloon soundings. And I assume more ACCARS from Trans-Pacific flights. Or how well can we really expect models to handle something in the MDR between the Lesser Antilles and Cabo Verde?

Sort of OT, Houston, last 2 afternoons sea breeze overperformed, yesterday, a tropical funnel touched down and knocked down 5 power poles NW suburbs (Cy-Fair area). Lots of pictures. On topic: LLC, GFS kills it. it never does get back to water, new low level center forms NE, model probably correct. But if the models were always correct, it'd get boring. PTC7 looks like a rinse and repeat of Fred. https://www.click2houston.com/news/local/2021/08/12/photos-funnel-clouds-spotted-in-houston-area/

The mangled remains of the LLC should head almost due West per CIMMS shallow steering, or it could cross Cuba and come back into the Caribbean South of Havana. If there is anything left, maybe not. CIMSS analsyis vorticity is badly tilted, currently further East over Cuba, but they might also drift mostly West and get back into the Caribbean. My gut, Fred is dead, but I see possibilities for it to develop South of Cuba, and therefore possible shift everything about 5 degrees further West, and there is a city near 30N and 90W, and it comes from the Caribbean it'd have time over water.

Tropics thread, Fred and GFS forecast Grace (95L, I think, hits S Carolina and drifts SW and meanders), 15 day total rain in excess of 20 inches parts of the Florida Panhandle.

Not an expert, I remember, maybe 10 or 15 years ago, another sheared TC hit Hispaniola, a naked swirl popped out, and dissipated. I see convection NW of the naked LLC* developing, maybe this will be different, but my gut is odds at least 50/50 the LLC opens up and the trailing mid-level vort so close to Cuba can't form a new LLC. *LLC looks like a wheel riding up the North Coast of Cuba, I am not actually sure it has West winds, anyone have obs? No guarantees, NHC probably has to keep advisories going for a couple more forecast cycles, but it may not even hit Florida as a TD.

12Z GFS, hard to be sure this is 95L, (GFS kills it near G. Antilles and revives something on 850 mb vort), then it starts strengthening and turning to sea before a sharp left turn to hit SC Edit to add- implied flood disaster as weak TD Fred hits and doesn't move fast, and then presumably Grace moves slowly SW, reaches the Gulf Coast, and meanders just dropping rain. Edit to add H to 'its

School year had started by Eta (we missed a day for no reason for Laura and a day for flooding for Beta), or I do not know. No 0Z models, no watching satellite loops until 1 am, when I'm teaching.

When Andrew was found to be a 50 knot open wave on recon, but 1992 AVN (now even better and renamed GFS) showed it quickly closing a circulation again, Bob Sheets made the decision to keep advisories on it as a TS because ending advisories to restart 12 or 24 hours later was deemed not in the interest of public safety. Safety comes before science. 1992, they couldn't have PTC'd Andrew, I do not know if they could PTC a named storm.

Euro 250 mb winds (there is no low over the Panhandle on Euro) are about 10 knots less at 96 hours where NHC 10 am EDT forecast is in 96 hours than GFS winds. That might make a difference with how much Fred strengthens. A lot of things will affect the final strength. WxBell tripled my price, AccuWx, models are not as good...

95L is now 20/40, although SHIPS hasn't been run on it for 2 model cycles, I suspect soon to be 3 model cycles. I don't think SHIPS takes a lot of computer power, not surprised they wouldn't run the dynamic hurricane models on something ~5 days from land.

Sort of. No evidence yet of a closed circulation with winds from the West to the South of the center.

Everything, as mentioned in the disco, depends on how much land interaction. SHIPS GFS input is 20 knots Westerly shear, although NHC disco mentioned Euro not as hostile.

20% of 18Z GEFS w/ sub 1000 mb low in/near Gulf in 13 days.

This would be a great time for anyone w/ 10 - 15 day Euro ensembles to post them. For the future possible 95 or 96L that may track South of the Greater Antilles.

From disco

PTC 6 in 30 minutes.

1) 94L looks good but arc clouds on visible suggests dry air issues and it doesn't quite look closed.. I still suspect a PTC in 90 minutes for Martinique and St. Lucia TS advisories. 2) GFS catches every hill in Puerto Rico, Hispaniola and Cuba with 94L, and still brings a TD or even a minimal TS to the Florida Panhandle. Small differences in track could mean less land, more water. OTOH, the no land SHIPS only slowly intensifies it, increasing shear from West after 3 days. After, some GFS ensembles support decent wave approaching Yucatan from Caribbean on Euro at 240 hours.

Twitter, hints tomorrow some people lower numbers, but while peak September season may be in a suppressive MJO phase, mid-late August looks favorable and hints of STR weakness near/just West of East Coast, while peak season may be slow, before peak season (mid August) may be busy, and ECUSA could be involved. If MJO is 40 days, who knows the October pattern for Florida or ECUSA.

Looks like bad data, (reports near there- less than 1 foot wave) parts of Alaska still under advisories. Hawaii in the clear.