cieldumort
(Moderator)
Sat Oct 03 2020 03:12 PM
Delta Lounge


Above: Gamma (left) and Invest 92L (right) 10-3-20-1845z. Base image credit: Weathernerds.org

A tropical wave traveling behind what is now Tropical Storm Gamma (formerly Invest 91L/TD25), is slowly gathering more definition, and model support has actually been fairly consistent in developing 92L and looping it around Gamma into the Gulf of Mexico. Interests in the northwest Caribbean to the Gulf of Mexico may want to begin paying close attention, and we are starting a lounge on this disturbance.

Invest 92L has been designated a PTC (TWENTY-SIX) and the title has been designated accordingly. The first NHC forecast takes this incipient tropical cyclone through the northwest Caribbean and into the southern United States. -Ciel

At the 11PM EDT update 10-4-20 NHC is updating Potential Tropical Cyclone to Tropical Cyclone. - Ciel


cieldumort
(Moderator)
Sun Oct 04 2020 05:15 PM
Re: 92L Lounge

As largely advertised, Invest 92L has become a borderline tropical cyclone, TWENTYSIX. Model guidance and indeed official NHC forecast calls for a US landfall in the central southern state area. Title being updated accordingly.

MikeCAdministrator
(Admin)
Mon Oct 05 2020 09:30 AM
Re: Delta Lounge

Delta's trend of NW movement is sketchy, although the center hasn't formed, the impact of Gamma on the track and intensity I think will be in Delta's favor. Meaning the moisture provided by Gamma is going to help Delta get organized, especially on Wednesday/Thursday.

The models are having a hard time this morning with it, but the trend has been generally westward. But I suspect it'll be better handled by tomorrow. Unlike Sally, Delta is expected to move somewhat quickly. Thus the tracks will probably be a bit better, and a wild shift east like Sally had is unlikely. So SE LA/MS seems a lot more likely this go around than Sally did when steering collapsed.

It likely will be weakening at landfall, which is good, but depends on how much it strengthens on Wed/Thursday is to the surge impact.


kspkap
(Weather Watcher)
Mon Oct 05 2020 02:10 PM
Re: Delta Lounge

Mike, here we go again! As I’ve mentioned prior I now live on the MS Gulf Coast which Katrina wiped flat! The Weather Channel just now stated a Cat 3 and some of the models are showing a Cat 4! She is getting stronger and has enough time over the warm gulf water to intensify. Needless to say this one concerns me. I should have stayed in Central Florida!

MikeCAdministrator
(Admin)
Mon Oct 05 2020 03:41 PM
Re: Delta Lounge

yeah Ships Rapid Intensification Indexes (RI) are really high for Delta, so there it's pretty likely the intensity forecast is low right now. I bet because of this they'll bump up the forecast to a major. Euro shifted west into a W. LA landfall, GFS, HWRF, etc in central or Eastern LA.

kspkap
(Weather Watcher)
Mon Oct 05 2020 05:20 PM
Re: Delta Lounge

As per the latest on the Weather Channel from the NHC, Delta is up to 70 mph and will be a major hurricane before it clears the Yucatan. Delta is going to rapidly intensify to a Cat 2 on upwards. They are still saying the models show a Cat 3 possibly to a Cat 4! The pressure is dropping sharply. Gamma supposedly will have an effect on Delta to go west, but then back eastward as Gamma moves toward Florida. Right now landfall for Delta looks like a Katrina landfall, east LA & MS.

cieldumort
(Moderator)
Mon Oct 05 2020 06:38 PM
Re: Delta Lounge


Credit: Sam Lillo @splillo

NW Caribbean under even average times is the most favored region for RI during the month of October in the Atlantic basin. 2020, being a hyperactive year, and given the current very low shear/high SSTs/high humidity environment Delta is now traversing, substantial strengthening throughout its trip to the Gulf, save land interaction, is very possible, and it would not be surprising to see Delta become a solid or even high-end Major before exiting the Caribbean.


cieldumort
(Moderator)
Tue Oct 06 2020 01:21 AM
Re: Delta Lounge

10 06 0z model runs coming in that are adapting to the more southern initial position as well as increased strength are continuing a trend of placing the Yucatan under a direct threat for a Cat 3 - 5 impact, and then an even farther run west, to possibly ride just offshore of the Texas coast before making landfall in Louisiana.

This is a reasonable solution, and an extremely dangerous outcome if verified.

The last two serious hurricanes to directly impact in and around Cancun were Wilma (2005) and Gilbert (1988) (h/t Michael Ventrice). History doesn't necessarily repeat itself, but it can rhyme, and several of the better models have them impacted at Cat 3-5 range.

Later in the period, a trof coming across Texas is expected to turn Delta north and then north-northeast, but timing and relative strength of both are critical. Continued shifts to the left or right are likely. Even tonight recon is finding evidence that a center reformation may again be underway (odd for a hurricane).


Rob Moser
(Verified CFHC User)
Tue Oct 06 2020 07:57 PM
Re: Delta Lounge

As a long term member/observer of FL Hurricane, it seems to me that the National Hurricane Center and possibly some of the models have considerably underestimated the intensity of this years hurricanes, especially those that end up in the Gulf of Mexico. Am curious as to what others think. On the other hand, they seem to be considerably more accurate in directions of the storms.

cieldumort
(Moderator)
Tue Oct 06 2020 08:40 PM
Re: Delta Lounge

Quote:

As a long term member/observer of FL Hurricane, it seems to me that the National Hurricane Center and possibly some of the models have considerably underestimated the intensity of this years hurricanes, especially those that end up in the Gulf of Mexico. Am curious as to what others think. On the other hand, they seem to be considerably more accurate in directions of the storms.



Quick answer is that the Global models (think GFS, EURO, UKMET, etc.) notoriously underestimate intensities in normal years. This year, forecasters have also had to deal with far less data input from flights. Flights have largely been grounded. In addition, models in general don't seem to 'bias up' just because we are in a hyperactive year, per se. All this can contribute. HWRF has done well with intensity this year, EURO has done poorly with direction. Obviously the forecasters at NHC take all this into consideration when they issue official forecasts. In general, intensity is the most difficult thing to predict in any year.



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