Atlantic Tropical Action 2011 - Part IV

[Ed Lizard]

I beat you to posting that in the Texas thread in the Central Forum. I doubt we get a real TC, but I'm glass sixteenth full there, and I'm a full glass quarter full on at least a lemon, and some needed rains spoiling Labor Day.

[Ed Lizard]

I beat you to posting that in the Texas thread in the Central Forum. I doubt we get a real TC, but I'm glass sixteenth full there, and I'm a full glass quarter full on at least a lemon, and some needed rains spoiling Labor Day.

Fudge, Steve posted this on the local KHOU-TV 11 forum 10 minutes before I posted it on the Central subforum.

Still, its a good thing.

[David Reimer]

The Fort Worth NWS Office mentioned the NAM was forming a tropical feature in the GOM. No other models are showing this at this time.

[wxsmwhrms]

The Fort Worth NWS Office mentioned the NAM was forming a tropical feature in the GOM. No other models are showing this at this time.

The GFS does develop it, it is just much slower with it and has it floating around the Gulf for more than a week without hitting anything. It does show a surface low down to 1000 mb over the western Gulf though by early next week. Interestingly, though, it does show a persistent area of heavy convection in the same area the NAM is developing that surface low. Upper level conditions do not look particularly conducive on the GFS early on, but begin to become more favorable in the SW and W Gulf when there begin to be some hints of an upper level anticyclone trying to build over the area.

[Srain]

[blazess556]

Euro is also hinting at a tropical entity forming in the Gulf.

[ag3]

Euro is also hinting at a tropical entity forming in the Gulf.

NAM and GGEM also develop that gulf entity.

[Srain]

Euro is also hinting at a tropical entity forming in the Gulf.

[am19psu]

I still don't understand why it is just sitting there for 2-3 days. I guess if does that at 0z I'll have to buy into it.

[am19psu]

Houston and Corpus love the 12z Euro. What drought?

[Big O]

Houston and Corpus love the 12z Euro. What drought?

Add BRO as Euro suggest SW motion toward lower Texas coast.

[Typhoon Tip]

The CMC solution is quite intriguing.. By D6 it shows a steadily deepening Katia that ends up a "goal post" system passing NE of the Islands; meanwhile, there is ridging N and a trough axis right on the EC - hmmm

[Typhoon Tip]

Add BRO as Euro suggest SW motion toward lower Texas coast.

The DGEX is a riot with that... It develops it and then moves to the upper TX Coast, then...east along the Gulf Coast across FL and up along the SE Coast. My goodness - it gets the whole hurricanology of the U.S. in one swoop!

[Big O]

12z Euro has landfall near BRO.

[Ed Lizard]

Houston and Corpus love the 12z Euro. What drought?

It messes with Labor Day, but you should see the dead trees now in wooded areas, and I think a gentle tropical disturbance that causes no damage at the beaches would generaly be welcome. Memorial Park, old growth public forest, filling up with trees whose leaves have gone brown. Don't know if a good rain can save them. Euro's 3.77" @ IAH through 7 am Monday would be welcome. I hope that model verifies.

[Srain]

HPC Model Diagnostics Discussion through the 12Z Euro output:

...ENERGY OVER THE CNTRL/NWRN GULF OF MEXICO ON THURS...

PREFERENCE: 12Z GFS/12Z UKMET/00Z ECMWF CONSENSUS

THE 12Z NAM IS A STG OUTLIER WITH THE AMPLIFICATION OF A LOW

CENTER OVER THE CNTRL AND NWRN GULF OF MEXICO BY THURS COMPARED TO

THE 12Z GFS...12Z UKMET...AND 12Z ECMWF. THE 12Z GEM GLOBAL DOES

SHOW SOME RELATIVELY STRONGER DEVELOPMENT OVER THE WRN GULF OF

MEXICO...BUT EVEN THIS ATTM IS LIKELY OVERDONE. THE 12Z GEFS MEAN

AND 00Z ECENS MEAN SUPPORT THE RELATIVELY WEAKER/FLATTER

GFS/UKMET/ECMWF CAMP WHICH SHOW A BROAD INVERTED TROF THROUGH THIS

PD...ALTHOUGH THE 12Z ECMWF DOES NOW SHOW A LITTLE MORE WAVE

DEVELOPMENT OVER THE W CNTRL GULF OF MEXICO.

[wxsmwhrms]

HPC Model Diagnostics Discussion through the 12Z Euro output:

...ENERGY OVER THE CNTRL/NWRN GULF OF MEXICO ON THURS...

PREFERENCE: 12Z GFS/12Z UKMET/00Z ECMWF CONSENSUS

THE 12Z NAM IS A STG OUTLIER WITH THE AMPLIFICATION OF A LOW

CENTER OVER THE CNTRL AND NWRN GULF OF MEXICO BY THURS COMPARED TO

THE 12Z GFS...12Z UKMET...AND 12Z ECMWF. THE 12Z GEM GLOBAL DOES

SHOW SOME RELATIVELY STRONGER DEVELOPMENT OVER THE WRN GULF OF

MEXICO...BUT EVEN THIS ATTM IS LIKELY OVERDONE. THE 12Z GEFS MEAN

AND 00Z ECENS MEAN SUPPORT THE RELATIVELY WEAKER/FLATTER

GFS/UKMET/ECMWF CAMP WHICH SHOW A BROAD INVERTED TROF THROUGH THIS

PD...ALTHOUGH THE 12Z ECMWF DOES NOW SHOW A LITTLE MORE WAVE

DEVELOPMENT OVER THE W CNTRL GULF OF MEXICO.

LOL, I would say the 12Z EC does show a "little more wave" development. The 12Z EC is really intriguing to me. It looks like it is forming the system in a kind of mid/upper level col area between the trough digging toward the eastern US and the two ridges to the west and east. While that would probably be a light shear area, it would also be a weak steering flow area. It seems like the EC allows the system to just barely get left behind by that trough, which enables it to move SW toward BRO. However, if that trough was just a little stronger, or the system a little deeper, or formed a little more NE (you get the idea), it could get nudged NE toward the central or eastern Gulf Coast by the trough. This would be a nightmare forecast scenario if it comes to pass given the weak steering flow, development close to land, and potentially relatively favorable environment.

[Srain]

LOL, I would say the 12Z EC does show a "little more wave" development. The 12Z EC is really intriguing to me. It looks like it is forming the system in a kind of mid/upper level col area between the trough digging toward the eastern US and the two ridges to the west and east. While that would probably be a light shear area, it would also be a weak steering flow area. It seems like the EC allows the system to just barely get left behind by that trough, which enables it to move SW toward BRO. However, if that trough was just a little stronger, or the system a little deeper, or formed a little more NE (you get the idea), it could get nudged NE toward the central or eastern Gulf Coast by the trough. This would be a nightmare forecast scenario if it comes to pass given the weak steering flow, development close to land, and potentially relatively favorable environment.

http://www.nhc.noaa.gov/1998frances.html

[janetjanet998]

Wake from Irene...

...likely too late in the season to recover that much north of the gulf stream off the coast

Before

[Srain]

Nice and long discussion from Brownsville WFO this afternoon...

.LONG TERM /WEDNESDAY THROUGH MONDAY/...AND NOW IT GETS

INTERESTING. THE BIG PICTURE STRONGLY SUPPORTS A CHANGE FROM THE

HOT AND DRY CONDITIONS EXPERIENCED FOR MOST OF THE SUMMER TO A

MORE HUMID...WETTER...CLOUDIER...AND THUS LOWER TEMPERATURES AS

THE CALENDAR TURNS TO OUR RAINIEST MONTH OF THE YEAR ON AVERAGE.

AS IRENE AND ASSOCIATED TROUGH EXIT...THE "CANICULA" RIDGE WHICH

HAS BEEN PARKED ACROSS THE SOUTHWEST U.S. AND NORTHWEST MEXICO

WILL SPREAD TEMPORARILY INTO THE SOUTHEAST U.S. THIS WILL OPEN THE

DOOR FOR DEEP TROPICAL MOISTURE TO FLOW AROUND THE PERIPHERY OF

THE RIDGE AND INTO THE WESTERN GULF...INCLUDING THE TEXAS AND

LOUISIANA COAST...BEGINNING WEDNESDAY AND CONTINUING THROUGH THE

FIRST HALF OF THE WEEKEND. THEN THINGS GET DICEY. A WEAKNESS

DEVELOPS BETWEEN THE RIDGES AS THE SOUTHWEST U.S. PORTION

REESTABLISHES WHILE THE SOUTHEAST RIDGE FLATTENS A BIT BUT HOLDS.

WITHIN THE WEAKNESS COMES THE POTENTIAL FOR THE FESTERING WEAKNESS

TO WRAP UP INTO A CLOSED LOW. SUCH CLOSED LOWS AT THIS TIME OF

YEAR WITH SUFFICIENT DEEP LAYER MOISTURE OVER 88 DEGREE WATER ARE

NOTHING BUT TROUBLE...AND SUCH HAS BEEN THE CASE FOR A NUMBER OF

RAPIDLY DEVELOPING TROPICAL CYCLONES IN THE PAST. A LOT STILL HAS

TO HAPPEN BETWEEN NOW AND THE WEEKEND...BUT THE 12Z GFS...12Z

ECMWF...12Z CANADIAN GEM ARE ALL IN AGREEMENT WITH SOME KIND OF

DEVELOPMENT AS THE WEEKEND PROGRESSES. QUESTIONS AS TO

WHERE...WHEN...HOW MUCH...AND FINAL TRACK CANNOT BE RESOLVED NOW.

NEEDLESS TO SAY ANYONE WITH LABOR DAY WEEKEND PLANS ON THE TEXAS

COAST NEED TO BE VIGILANT AND KEEP A SHARP EYE ON THE WEATHER.

AS FOR THE SENSIBLE WEATHER...INHERITED FORECAST FOR WEDNESDAY

RAISED RAIN CHANCES BASED ON QUICKER MOVEMENT OF INITIAL BURST OF

MOISTURE...AND THIS IS SPOT ON WITH RAIN CHANCES REACHING 50/50

NEAR THE COAST AND LOWER FARTHER INLAND. WITH THE CHANGE OF AIR

MASS AND DEVELOPING CONVECTION AFTERNOON HIGHS WILL BE HELD DOWN

IN THE 90S EXCEPT LOWER 100S ACROSS THE RIO GRANDE PLAINS AND

HIGHLANDS. MCALLEN AND FALFURRIAS MIGHT SQUEEZE ONE MORE 100

DEGREE DAY TO CLOSE AUGUST...WHICH WOULD TIE THE 29 DAYS OF AUGUST

2009.

HAVE RAISED RAIN CHANCES THURSDAY INTO THE NUMEROUS CATEGORY BASED

ON DEEP LAYER MOISTURE...MODEST VERTICAL MOTION...AND EITHER

MORNING DEVELOPMENT IN THE GULF QUICKLY SENDING BOUNDARIES AND

WORKING ON UNSTABLE AIR ACROSS THE MID VALLEY TO PROVIDE GOOD

COVERAGE OUT TO AT LEAST THE HIDALGO/STARR COUNTY LINE. WITH THE

RAIN EXPECTED TO FEED OFF LOWER CONVECTIVE TEMPERATURES THEN LEAVE

CIRRUS (AT LEAST) IN ITS WAKE HAVE LOWERED HIGHS TO OR A SHADE

BELOW GUIDANCE...UPPER 90S FAR WEST AND LOWER 90S JUST ABOUT

EVERYWHERE ELSE. WILL NOT MENTION HEAVY RAINFALL...THOUGH BRIEF

DOWNPOURS AND 2 INCHES IN A HURRY ARE NEVER OUT OF THE QUESTION

WITH THIS SETUP.

FRIDAY AND SATURDAY`S FORECAST IS A BIT MORE DIFFICULT. AS

MENTIONED THIS TIME SUNDAY...THE INITIAL FORCING WILL BE CHANNELED

FROM THE WEST CENTRAL GULF TO THE UPPER TEXAS COAST AND

LOUISIANA...LEAVING THE VALLEY IN A BIT OF A DEAD ZONE. THAT

SAID...MEAN RH REMAINS AT OR ABOVE 70 PERCENT AND WHILE MUCH IS

HELD ABOVE 700 MB THERE IS ENOUGH EAST/SOUTHEAST FLOW DOWN LOW TO

SUPPORT SCATTERED SHOWERS/STORMS ON FRIDAY AIDED BY DAYTIME

HEATING. CONVECTIVE TEMPERATURES LOWER INTO THE MID AND UPPER 80S

SO DESPITE THE CLOUDS EXPECT AT LEAST 40 PERCENT COVERAGE ON

FRIDAY. SATURDAY IS INTERESTING IF YOU BELIEVE THE MOST RECENT

MODEL RUNS...WHICH SHOW DEEP LAYER /NORTHERLY/ FLOW WITH PLENTY OF

MOISTURE IN THE COLUMN. HUNCH IS MORE OF AN OVERCAST DAY WITH

ENOUGH SURFACE WARMING TO TRIGGER SOME RAIN...BUT MUCH MAY BE

LIGHT AFTER ANY INITIAL CONVECTION DRIPPING FROM MID LEVEL CLOUDS.

THE THICKER CLOUDS EACH DAY WILL KEEP TEMPERATURES DOWN...AND

WOULD NOT BE SURPRISED TO SEE AFTERNOON MAXIMA PEAK IN THE MID TO

UPPER 80S IN THE LOWER VALLEY AND AROUND 90 OR SO

ELSEWHERE...EXCEPT LOWER 90S WEST. FOR NOW...HAVE GONE A FEW

DEGREES HIGHER OWING TO CLIMATOLOGY AND UNCERTAINTY ON FINAL

SITUATION...JUST A COUPLE DEGREES BELOW AVERAGE.

SUNDAY AND MONDAY WILL HIGHLY DEPEND ON WHAT DEVELOPS ALONG OR

NEAR THE TEXAS OR NORTHEAST MEXICAN COAST. FOR NOW HAVE EXTENDED

THE MOSTLY CLOUDY SKIES AND BELOW AVERAGE DAYTIME

TEMPERATURES...AND PUSHED RAIN INTO THE MODERATE CATEGORY. AS FOR

WINDS...HAD TO DO SOME SURGERY BASED ON THE TRENDS BUT DID NOT

BITE COMPLETELY ON THE 25+ KNOT SPEEDS UNTIL WE GET A BETTER SENSE

OF THE SYSTEM`S DEVELOPMENT AND INTERACTION WITH ANY INCREASE IN

HIGHER PRESSURES ACROSS THE SOUTHERN U.S. AS ALWAYS...STAY TUNED

FOR DETAILS AS THE WEEK PROGRESSES.

[dtk]

I'm sort of intrigued by this potential Gulf development. The other models have already been discussed, but the experimental GFS/EnKF seems to be on board for some slow development as well (more so than the operational GFS):

[HurricaneJosh]

So is this Gulf thing for real? Would be a nice change of pace from long-tracking African cyclones, which just get incredibly tedious after a while.

[ag3]

I'm sort of intrigued by this potential Gulf development. The other models have already been discussed, but the experimental GFS/EnKF seems to be on board for some slow development as well (more so than the operational GFS):

The NAM picked up this threat yesterday somehow and continues it on its 18z run. I know the NAM shouldnt be used for tropical but for some reason, it sniffed this threat 1st this time.

Here's the 18z NAM:

[Srain]

So is s Gulf thing for real? Would be a nice change of pace from long-tracking African cyclones, which just get incredibly tedious after a while.

Let's just say the Coastal Texas WFO's are starting to honk since we have a Holiday Weekend ahead...

[dtk]

The NAM picked up this threat yesterday somehow and continues it on its 18z run. I know the NAM shouldnt be used for tropical but for some reason, it sniffed this threat 1st this time.

Right, though it seems too aggressive in terms of spinning this up so quickly. The globals don't seem to get anything real going until later in their forecasts (i.e. past the end of the NAM integration).

[phil882]

Houston and Corpus love the 12z Euro. What drought?

So is this Gulf thing for real? Would be a nice change of pace from long-tracking African cyclones, which just get incredibly tedious after a while.

The one thing I would caution out at this point are that the models seem to be latching on to a very large disturbance which doesn't seem to have much organization with it (think like Frances 1998) That wouldn't bode too well for any robust intensification as a tropical cyclone, but it could certainly be a drought-buster for folks in Texas. In essence for the general public its the best possible solution to end the drought.

Would sorta wreck the OHC though

[wxsmwhrms]

18Z GFS is more aggressive with development has a 1003 mb with intense 850 mb vortmax just offshore of Houston at 144 hours. Really does not look all that different from the ECMWF, maybe a little NE of the EC as far as development location. Upper level conditions don't look great as the system probably develops as has been discussed out of a large almost monsoon like feature, but are forecast in the model to improve with time if a low level system can form and stay over water.

[Sunny and Warm]

I'm sort of intrigued by this potential Gulf development. The other models have already been discussed, but the experimental GFS/EnKF seems to be on board for some slow development as well (more so than the operational GFS):

If this were to spin up this weekend, wouldn't it tend to pump up the ridge to its east, and create a weakness for TD12 to go through just beyond hour 168? I guess the question is does the strength of this entity effect TD12's path eventually, and what strength would create doubt in your mind as to whether TD12 would recurve more easily?

[Ed Lizard]

The one thing I would caution out at this point are that the models seem to be latching on to a very large disturbance which doesn't seem to have much organization with it (think like Frances 1998) That wouldn't bode too well for any robust intensification as a tropical cyclone, but it could certainly be a drought-buster for folks in Texas. In essence for the general public its the best possible solution to end the drought.

Would sorta wreck the OHC though

Ending the drought and reducing the oceanic heat content in September when sun angle/day length won't permit any rewarming would be a good thing, drought relief and some protection from any freak tropical cyclones like we had 3 years ago.

[wxsmwhrms]

I'm sort of intrigued by this potential Gulf development. The other models have already been discussed, but the experimental GFS/EnKF seems to be on board for some slow development as well (more so than the operational GFS):

FWIW the FIM shows the development as well. 995-996 mb low meandering off the coast of SE TX/SW LA days 5-7.