| cieldumort |
| (Moderator) |
| Fri Oct 08 2021 11:18 PM |
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Pamela: TX/GOM Potential
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Above: Broad Low Pressure Invest 91E 10-8-21 5:40PM Image credit: Zoom Earth
A broad area of low pressure associated with a stout tropical wave that just crossed over from the southern Caribbean to the East Pac and presently situated a few hundred miles south-southeast of Tehuantepec, MX is largely forecast by models to develop into a strong tropical cyclone, potentially Major Hurricane, and recurve into mainland Mexico with at least some semblance of continuity all the way across into Texas and/or the Gulf of Mexico by mid to late next week.
This feature has already been Invest tagged, 91E, E for it developing in the Eastern Pacific, with NHC development odds of 90% within 5 days as of this entry.
Some may recall that we opted not to open a Lounge on the system that went on to become World Record Setting Hurricane Patricia , but that situation was different. At the time there were already two posts, one in the Forecast Lounge, and one in Other Storm Basins, covering two distinct and separate vorticities within a Central American Gyre, and early on the vort that went on to become Patricia was not explicitly forecast by models to land back in the Gulf. By the way, this was a fascinating event, and that thread is still up if you would like to check it out: ExTrop Patricia Off To Great Lakes
This is a situation at first blush may seem to be an exception to the rule here, in that the Forecast Lounge is explicitly for systems in or forecast for the Atlantic, with the notable exception of Hawaii, but in reality the strongest reason for inclusion is that several quality models and on numerous runs already advertise that 91E, in some fashion, will wind up in the Gulf next week, with some degree of redevelopment, with or without crossing parts of Texas first. Thus, we are opening a rare Lounge on this system at this time.
For interests in Texas and/or eastern, Gulf-facing Mexico, next week will likely see a threat of heavy to very heavy rains and potential flooding, regardless. More to come.
Invest 91E has become a Tropical Cyclone and the title has been updated accordingly
| cieldumort |
| (Moderator) |
| Sun Oct 10 2021 03:20 PM |
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Re: 91E: TX/GOM Potential
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Invest 91E has become a Tropical Cyclone and is now TD SIXTEEN in the EPAC, likely to become Pamela today, and could easily undergo Rapid Intensification at least once.
Now that official NHC forecasts have been issued, it will be best to pay closest attention to them, as well as to continue to monitor model forecasts from quality models like the GFS.
For now, NHC is predicting dissipation over northeastern Mexico. If that were to verify, copious moisture would likely stream into much of the United States from dissipating ex-Pamela.
Early QPF forecast out of WPC for 10/14-10/16
| cieldumort |
| (Moderator) |
| Sun Oct 10 2021 05:04 PM |
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Re: 16E: TX/GOM Potential
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The majority of the 12z model suite today takes a remnant, Post-TC, or still marginally intact TD Pamela near or into/across Texas. Very heavy, potentially flooding rains would be the primary risk in this scenario for Texas, but no redevelopment in the Gulf.
| cieldumort |
| (Moderator) |
| Mon Oct 11 2021 08:03 PM |
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Re: Pamela: TX/GOM Potential
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Pamela is now explicitly forecast by nearly all of the models and indeed NHC itself to cross into Texas either as a marginal Tropical Depression, Trof or, as is shown by NHC, as a Post-Trop Low. Whichever way, heavy to very heavy rain may result, especially if either or both A)Training sets up and/or B) Core rain event unfolds.
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
642 PM CDT Mon Oct 11 2021
Quote:
LONG TERM (Wednesday through Monday)...
The latest round of model guidance continues to suggest an active
weather pattern will be in place across south central Texas for the
mid-week period, especially Wednesday evening into Thursday morning.
The main concern continues to be focused on heavy rainfall.
South-southeast flow in the lower-levels of the atmosphere will be
well-established across south central Texas on Wednesday. We will see
plenty of moisture from the Gulf of Mexico move northward across the
region with 850mb dewpoints ranging from 14-19C through Wednesday
morning. Meanwhile, the remnants of tropical system Pamela will be
moving north-northeastward across central Mexico. Near the surface,
the leading edge of a weak Pacific front will likely be stalled
somewhere across the southern Edwards Plateau and Hill Country
region. With the stalled front, plenty of moisture and daytime
heating, we should see scattered to numerous showers and
thunderstorms develop over the above mentioned regions during the
afternoon hours. By mid evening Wednesday, the models suggest the
remnant surface low associated with Pamela will move out of
northeast Coahuila Mexico into south central Texas. The exact path
and speed of this surface low remains in question, but will no doubt
serve as a focus for heavy rainfall generation Wednesday evening into
Thursday. Precipitable water values will be very close to
climatological maximums for this time of year and with soundings
showing deep moisutre and tall, skinny CAPE profiles, efficient
rainfall producing showers and storms are guaranteed. While we will
continue to see changes in subsequent model data, our main time
period of concern will be Wednesday evening into Thursday for areas
along and west of the Interstate 35 corridor. Widespread 2-5" amounts
are expected and we will certainly see localized amounts much higher
than this, especially near the remnant circulation of Pamela.
Rain chances should begin to decrease from west to east by late
Thursday afternoon. However, as mentioned above much will depend on
just how quickly the remnants of Pamela shift northeast of the
region. For now, we will keep a slight chance for showers and storms
along the Rio Grande, with rain chances in the 30-60% range farther
east into the I-35 corridor. Moisture levels do begin to drop on
Friday, but with a fairly stout cold front moving in from the
northwest and southwesterly flow aloft, we will keep a chance of
showers and storms in the forecast for most areas Friday. If the cold
front moves through quicker (GFS model), rain chances may need to be
reduced in the afternoon hours across the Hill Country and into the
I-35 corridor.