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That latest map looks like Texas is going to stay high and dry for the most part.

Cromagnum wrote:That latest map looks like Texas is going to stay high and dry for the most part.

Not so fast...

Cromagnum wrote:That latest map looks like Texas is going to stay high and dry for the most part.

what map and the llc hasnt developed and its not in GOM yet

Split decision still. The gap between the Western ridge and Bermuda high is the key.




Gyre she blows!

GFS and GFS Parallel show a Florida hit still while the CMC shifts westward to Louisiana. The ECMWF shows a central Texas hit and finally the UKMET has a south/central Texas hit.

Forecaster Jack Beven increases chances to a 9 out of 10 or 90% for Tropical Cyclone or Subtropical Cyclone Development.
As of 8:00 am EDT Sun Jun 18 2017 ...
A broad area of low pressure located over the northwestern Caribbean
Sea continues to produce a large area of disorganized showers and
thunderstorms. Gradual development of this system is expected while
it moves slowly northwestward across the Yucatan Peninsula later
today and over the southern or central Gulf of Mexico on Monday and
Tuesday, where a tropical or subtropical cyclone is likely to form.
Regardless of development, heavy rains are expected over portions of
Central America, the Yucatan Peninsula, Jamaica, the Cayman Islands,
and western Cuba during the next several days. An Air Force Reserve
Hurricane Hunter aircraft is scheduled to investigate this system
later today, if necessary.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...90 percent.

I could see the eastern solution playing out, because the system is lopsided east and could follow the convective blowups tugging it east instead of west to Mexico or south TX. We have northerly flow here which would shear it too. Maybe LA to FL panhandle in play??? IMO though.

NWS/NHC Surface Chart for 72 Hours suggests NE Mexico/S Texas solution is likely. This was issued at 07Z after the ECMWF/UKMet guidance came out for 00Z.

Michael Ventrice‏Verified account @MJVentrice · 56m56 minutes ago
Latest Calibrated ECMWF EPS 80-90% with western MDR system. Gulf of Mexico system bearish compared to NHC - 60% though tracks into Texas

From Phillipe Papin of Albany who has done extensive research on Monsoonal Gyres regarding the ECMWF solution from 00Z. Phillipe is the "go to" Specialist with his research in this sort of situation.

I won't hazard a guess at what 93L is going to do. However, I do have a lot of confidence in both the Euro and UKMet models and how they're handling the overall setup. Both models consistently beat the GFS in 5- and 6-day skill scores in the Northern Hemisphere.

The Weather Prediction Center just Updated their Day 3 to 7 Surface Charts. As we can see as of this Update, the current thinking is there may be a potential issue for the Middle/Upper Texas and SW Louisiana Coastal Areas and on to the East. While it is too soon to know the exact impacts to our sensible weather, due to the broad area of low pressure the main threat could be heavy rainfall and elevated tides versus a wind and surge threat. That said this remains a very complex and complicated forecasting challenge, so expect changes over the next couple of days.

When will watches go up if the upper TX coast is in the target area?

Lengthy Sunday morning briefing from Jeff:

Tropical disturbance (93L) in the western Caribbean Sea continues to slowly organize.

Tropical storm likely in the Gulf of Mexico this week.

Discussion:

Satellite images show a large explosion of deep convection along the eastern flank of a broad low level circulation off the eastern coast of Belize. Surface pressure have fallen some in the last 24 hours, but the background surface pressure is already low and this is not yielding much of a pressure gradient yet to increase surface winds. Thunderstorm activity aside from the deep convective blow up remains disorganized.

A USAF mission remains planned for this afternoon into the region.

Track:

Guidance remains stoutly split between a track toward the NE Gulf of Mexico and the NW/W Gulf of Mexico. One group of models being led by the GFS shows a track of the system almost due north and then NNE into the FL panhandle with some support from the HWRF hurricane model. The ECMWF and UKMET show a track toward the NW Gulf of Mexico and there is support from the 84-hr NAM also for this solution. The CMC which was aligning with the GFS yesterday is now down the middle road and brings a system toward Louisiana.

The variations in the track forecast appear to develop out of two aspects. The first is how quickly the trough along the US Gulf coast breaks with the SW portion of this trough moving WSW toward S TX and high pressure building from both the west and east closing the weakness along the central Gulf coast. The GFS is deeper with the trough and lifts the Gulf system faster northward allowing it to become picked up by the tail end of the trough and brought toward FL. The GFS does show a significant slowdown of the system as it approaches the NE Gulf coast suggesting it is barely being captured by the trough and that ridding is building in around the system. The ECMWF and UKMET show a less amplified trough and faster building of the ridge across the US Gulf coast which blocks any trough connection and turns the system WNW/NW toward the NW Gulf. It should be noted that the ECMWF has trended northward in its last run compared to being far south toward the NE MX coast. The second aspect is where does a more defined surface center actually form. The GFS forms a surface center much farther east than the ECMWF over the SE Gulf of Mexico instead of the SC Gulf of Mexico which places the system closer to the weakness in the ridge axis over AL/FL.


Both are viable track solutions and both are supported by climatology. Will lean toward the western track solution for now out of respect to the ECMWF model which tends to grasp the handling of the upper level features better than the GFS and also NHC/WPC have coordinated positions along these lines. Another aspect that will need to be monitored closely is the potential for the system to slow down as it nears the Gulf coast and possibly become trapped under a building ridge. This could result in erratic and slow motions and also linger the system over the Gulf waters for a longer period of time.


With that said the uncertainty remains large and some sort of landfall is possible anywhere from TX to the FL panhandle.

Intensity:

Will lean toward the formation of a tropical storm at some point in the Mon/Tues time period over the SC Gulf of Mexico. Upper level winds currently over the Gulf are unfavorable with nearly 60kts of SW shear across the central Gulf on the SE flank of the upper trough along the Gulf coast. This wind shear should gradually subside but will be dependent on how quickly the trough lifts out. Additionally, the trough axis will linger a mass of dry air across the southern US which may become entrained into the large circulation size of this system. This is shown in some of the SHIPS guidance with mid level RH in the latter periods of only around 50%. With that all said, guidance has generally indicated a gradual increase in intensity as the system approaches the US Gulf coast compared to their previous runs. Several are showing surface pressure down around 1000mb or even lower, but this may be more a factor of the already lowered background pressures of such a sprawling system.


Impacts:

Local forecast from Tuesday onward into next weekend will hinge on the formation and track of this tropical feature. If the eastern track plays out SE TX will be generally hot and dry. If the western track verifies it will be a messy end to the week across SE TX with major changes to the current forecast required. For now will just bump up waves to 5-6 starting on Wednesday across our coastal waters as the large circulation even if it stays east would bring higher swells into the NW Gulf.

12z gfs and cmc shifted W. Models are converging on a western solution.

What general area of the coast?

sambucol wrote:What general area of the coast?

Oy. For now I'd say anywhere from Tampico as an extreme southern solution and Grand Isle as a northern solution. Should narrow it down.

Going to take time.

sambucol wrote:When will watches go up if the upper TX coast is in the target area?

If RECON finds a true center tomorrow that is upgrade worthy, then Watches may go up somewhere along the Mexico/Gulf Coast. Still too soon to know exactly where the NHC will issues Watches...if at all. That said there is a new experimental Watch/Warning Product this season being tested where they can issue Watches/Warning without a declared Tropical Cyclone if there is a threat for landfall within 48 Hours.

Updated Reconnaissance Missions that are tasked for 93L. Mission to 93L for today has been cancelled.

wonder why they cancelled -nothing happening or LLC not forming?