Post Tropical Cyclone Helene: Dissipated Over Mexico

[tireman4]

Rut Roh.......

[srainhoutx]

This disturbance certainly has taken on that 'look' today. We'll focus our discussion for potential tropical development in this thread.

[srainhoutx]

00Z Tracks & Intensity:

[Portastorm]

Well, the convection from earlier today has waned but there definitely appears to be "disturbed" weather down there in the southern BOC. If and how quickly something might organize are likely questions forecasters are going to struggle with over the next 24 hours.

[skidog40]

NHC doesn't know where L is. it is SE of their estimation.

[srainhoutx]

1. SHOWER AND THUNDERSTORM ACTIVITY HAS INCREASED OVER THE PAST FEW
HOURS IN ASSOCIATION WITH THE REMNANTS OF TROPICAL DEPRESSION SEVEN
IN THE EXTREME SOUTHWESTERN GULF OF MEXICO. SURFACE OBSERVATIONS
AND RADAR DATA INDICATE THAT THE CIRCULATION HAS ALSO BECOME A
LITTLE BETTER DEFINED. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE
FOR DEVELOPMENT...AND A TROPICAL DEPRESSION COULD FORM BEFORE THIS
SYSTEM REACHES LAND IN THE NEXT DAY OR SO. THIS SYSTEM HAS A HIGH
CHANCE...70 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD TO NORTHWESTWARD AT
AROUND 10 MPH. INTERESTS ALONG THE GULF COAST OF MEXICO SHOULD
MONITOR THIS SYSTEM...AS A TROPICAL STORM WATCH OR WARNING COULD BE
NEEDED FOR PART OF THE COAST TODAY. AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS SYSTEM THIS
AFTERNOON.

[David Paul]

looking much healthier hour by hour. anticycloinc flow up top too. we'll be giving constant up dates here and of couse twitter and facebook. https://twitter.com/DavidPaulKHOU. you guys are great on this forum by the way.

[Katdaddy]

Getting close to the first visible satellite image of the day. Looking much better than last night.

[srainhoutx]

06Z Tracks & Intensity:

[tireman4]

looking much healthier hour by hour. anticycloinc flow up top too. we'll be giving constant up dates here and of couse twitter and facebook. https://twitter.com/DavidPaulKHOU. you guys are great on this forum by the way.

You are too David. Thank you so much for joining us.

[tireman4]

I wonder, and this is out loud to myself...lol, would or could a front pull or move a system a certain way?

[srainhoutx]

Looking at Alvarado radar, there may already be a hint of a NW trend with the center of circulation. If that trend is correct, that would tend to favor more time over water and a better chance of good RECON data later this afternoon. We will see.

[unome]

I hope Terra gets a better shot today

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[srainhoutx]

12Z Tracks & Intensity:

[Portastorm]

Those 12z tracks do seem to suggest a system which moves inland and basically stalls, much like what we've been seeing from the GFS. I wonder if it will retain enough vorticity once inland to pump Gulf moisture into the southern half of the state.

[srainhoutx]

It looks like RECON will make a quick trip down to investigate...

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1000 AM EDT FRI 17 AUGUST 2012
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 18/1100Z TO 19/1100Z AUGUST 2012
TCPOD NUMBER.....12-091

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. REMARKS: MISSION INTO THE REMNANTS OF TD #7 FOR
17/2000Z WILL FLY AS TASKED ON TCPOD 12-090.

[srainhoutx]

E-mail update from Jeff:

Visible satellite images and radar data from Mexico indicate the area of disturbed weather in the Bay of Campeche is becoming better organized and a tropical depression is likely forming.

The system is moving toward the WNW at around 10mph and on this track will move inland later today or early tonight. However the ridge to its north and northeast is forecast to weaken and break down on the western edge allowing the system to slow and possibly stall as it nears the coast…this has been what the global forecast models have been showing for days now. The main question is does the center stall offshore or inland. Over the weekend the system should start to drift northward as it becomes influenced by the deep trough along the US east coast and it is possible that the center could move inland tonight and then back offshore over the weekend.

Recon aircraft will be flying this system early this afternoon.

[rnmm]

SPECIAL OUTLOOK ISSUED TO UPDATE DISCUSSION OF REMNANTS OF TROPICAL
DEPRESSION SEVEN IN THE EXTREME SOUTHWESTERN GULF OF MEXICO.

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM GORDON...LOCATED OVER THE CENTRAL ATLANTIC OCEAN ABOUT 1100
MILES WEST OF THE AZORES.

1. UPDATED...THE REMNANTS OF TROPICAL DEPRESSION SEVEN OVER THE
SOUTHWESTERN GULF OF MEXICO HAVE NOT YET BECOME SUFFICIENTLY
ORGANIZED TO CONSIDER THE SYSTEM A TROPICAL CYCLONE. HOWEVER...
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE SYSTEM ARE ALREADY
AFFECTING PORTIONS OF THE EAST COAST OF MEXICO...AND LOCALLY HEAVY
RAINS AND GUSTY WINDS WILL CONTINUE IN THIS AREA DURING THE NEXT
DAY OR SO AS THE SYSTEM MOVES NORTHWESTWARD AT AROUND 10 MPH.
ENVIRONMENTAL CONDITIONS STILL APPEAR CONDUCIVE FOR FORMATION...AND
THIS SYSTEM HAS A HIGH CHANCE...80 PERCENT...OF BECOMING A TROPICAL
CYCLONE AT ANY TIME IN THE NEXT DAY OR SO BEFORE IT REACHES LAND.
AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO
INVESTIGATE THIS SYSTEM THIS AFTERNOON...AND A TROPICAL STORM WATCH
OR WARNING WOULD LIKELY BE REQUIRED FOR A PORTION OF THE COAST OF
MEXICO IF ADVISORIES ARE INITIATED.

[srainhoutx]

The 12Z GFS suggests a poorly organized non vertically stacked system dancing along the Mexican Gulf Coast before being picked up by the incoming trough and turning NE toward the SW Louisiana Coast as a very sheared disturbance. Altamira radar suggests a NW motion continues and should skirt inland just S of that location...

[Portastorm]

Looking at the various satellite loops on the NHC site, it seems to me like the circulation center has slowed to a near crawl and is moving northwest ... maybe even a little north-northwest. Anyone else seeing this?