ATL: DON - Remnant - Discussion

[HurricaneBrain]

The only way Don goes to Houston is if he beats the ridge.

[TwisterFanatic]

Looks like its setting up a big feeder band, but I can't really tell.

[KWT]

I think dry air that has always been in the background has somewhat chocked then system of its backgrou8nd convection, but clearly its still popping deep convection near or directly over it centers.

[KWT]

Models just do not do much with this system. They are unanimous on that and it is hard to overlook that. The Euro takes it more south which seems reasonable given the strong easterly flow setting up over the northern GOM especially at 500mb and higher.

That is good news for those in Southern Texas and Northern Mexico.

To be fair its already a number of times stronger then what any model forecasted it to be...

[GCANE]

Looks like an opportunity in the next 24 hrs.

PV anomaly is just starting to get to the surface where it can start sucking up energy out of the water.

Currently in relatively low OHC water but will get a lot better in 24 hrs.

MIMIC-TPW showing a really strong boundary layer in-feed from the south across Don's east side and into the core from the north.

Major change is that shear ahead is dropping fast and the UL jet in the north GOM is dissipating fast.

[somethingfunny]

Don's circulation looks very elongated on the MIMIC-TPW loop... I think Don will rebound, but it's certainly not as healthy as we thought it was yesterday. A hurricane appears very unlikely.

I found this tidbit from FWD's AFD:

TROPICAL DEPRESSION DON ( ) IS LOCATED JUST NORTH OF THE YUCATAN THIS
MORNING AND IS EXPECTED MOVE ONSHORE NEAR CORPUS CHRISTI FRIDAY
EVENING...THEN ON TO THE NORTHWEST AS IT WEAKENS. THERE WILL BE
AN INCREASE IN LOW AND MID LEVEL MOISTURE ACROSS NORTH TEXAS
ASSOCIATED WITH DON. PWATS INCREASE TO AROUND 2 INCHES OVER THE
EASTERN HALF BY MIDDAY FRIDAY...AND 2 1/4 INCHES BY MIDDAY
SATURDAY. AN UNSTABLE AND UNCAPPED ATMOSPHERE FRIDAY AND SATURDAY
SHOULD RESULT IN SCATTERED STRONG CONVECTION AND BENEFICIAL
RAINFALL ACROSS PORTIONS OF NORTH TEXAS...ESPECIALLY OVER THE
SOUTHERN COUNTIES. EXPECTED RAINFALL FROM DON WILL AVERAGE 1/4 TO
1/2 INCH DAILY WITH SOME LOCATIONS POSSIBLY RECEIVING 1 INCH.

HIGH TEMPERATURES WILL BE A LITTLE COOLER FRIDAY AND SATURDAY...
THUS OUR RECORD STRING OF CONSECUTIVE 100 DEGREES DAYS WILL BE IN
JEOPARDY BY SATURDAY.

[dwsqos2]

The most positive thing about Don is that it's a more organized tropical cyclone than TD2 and TD5 of 2010. Methinks the globals will probably be mostly vindicated; missing a small 1000 mb low is not that big of a deal when all but the Euro really don't have the resolution for it. This is very unofficial and all that.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[KWT]

I still wouldn't rule out a hurricane, you only need to see how far Don went from 72hrs ago to where it was yesterday eveing, a similar improvement would probably yield a hurricane.

Right now a combo of dry air to the wesrtt which has somewhat fed into the outer circulation, some shear (probably not being well picked up) and the low heat content mentioned by GCANE probably isn't helping. Once this system starts moving a little quicker away from the Yucatan things will probably get going with a couple of those factors reduced.

[GCANE]

When I look at HYSPLIT per GFS, it looks like Don is struggling a bit with infeed especially on the west side.

It has good ascent on the east side, but not wrapping into the core.

BTW, strong MIMIC-TPW is on the east side.

[dwsqos2]

It's pretty obviously having issues with northeasterly shear as well. Low heat content and dry air don't cause vertical tilt.

[KWT]

It's pretty obviously having issues with northeasterly shear as well. Low heat content and dry air don't cause vertical tilt.

Yeah I'd have to agree, odd that it isn't being picked up mind you...I'm guessing it must be quite a limited area of shear with regards to the height its at and maybe thats why its getting missed...but pretty hard to deny there must be some shear.

[GCANE]

Convection is relatively small, but it is firing right over the LLC.

http://rammb.cira.colostate.edu/product ... 280402.jpg

[cycloneye]

TROPICAL STORM DON DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL042011
400 AM CDT THU JUL 28 2011

DON HAS NOT CHANGED APPRECIABLY DURING THE PAST SEVERAL HOURS...
MAINTAINING A SMALL AREA OF CONVECTION NEAR THE CENTER. THERE IS
NOT MUCH ORGANIZATION IN THE INFRARED CLOUD PATTERN...WHICH IS
CONFIRMED BY A TRMM MICROWAVE PASS AT 0608Z. ASCAT DATA FROM 0332Z
SUPPORTED AN INITIAL INTENSITY OF AROUND 35 KT...WITH SATELLITE
CLASSIFICATIONS AT OR BELOW THAT VALUE. THE ASCAT DATA CONFIRMED
THE EARLIER AIRCRAFT MEASUREMENTS THAT DON IS A RATHER SMALL
TROPICAL CYCLONE. THE NEXT AIRCRAFT MISSION IS SCHEDULED FOR 1200Z
THIS MORNING.

THE INTENSITY FORECAST IS TRICKY. WHILE THE LARGE-SCALE ENVIRONMENT
DOES NOT APPEAR TO HAVE MUCH SHEAR...THE LOW- AND MID-LEVEL CENTERS
ARE NOT WELL-ALIGNED INITIALLY...WHICH WAS APPARENT ON A 2316Z
SSMIS MICROWAVE IMAGE. THE GFS/ECMWF MODELS HAVE A REASONABLE
REPRESENTATION OF THIS INITIAL STRUCTURE AND KEEP THE CENTERS FROM
VERTICALLY STACKING...POSSIBLY WHY THESE MODELS DO NOT SHOW
MUCH INTENSIFICATION. WHILE THE STATISTICALLY MODELS STILL
FORECAST STEADY STRENGTHENING...THE HWRF/GFDL MODELS FORECAST A
SLOW DECLINE. ANOTHER FACTOR TO CONSIDER IS THAT THE SIZE OF DON
MAKES IT SUSCEPTIBLE TO RAPID CHANGES IN STRENGTH...BOTH UP AND
DOWN...THAT ARE NEARLY IMPOSSIBLE TO FORECAST. GIVEN THE REDUCED
ORGANIZATION...THE NHC INTENSITY FORECAST IS LOWERED SOMEWHAT FROM
THE PREVIOUS FORECAST...BUT IS STILL ON THE UPPER END OF THE
GUIDANCE ENVELOPE NEAR A COMPOSITE OF THE SHIPS/LGEM MODELS.

BEST ESTIMATE OF INITIAL MOTION IS 300/9... WITH OVERNIGHT MICROWAVE
IMAGES SUGGESTING THE SMALL CENTER HAS BEEN MOVING ERRATICALLY. DON
IS MOVING AROUND THE SOUTHERN PERIPHERY OF A RIDGE OVER THE
SOUTHERN UNITED STATES. THIS RIDGE IS FORECAST TO BUILD SLIGHTLY
DURING THE NEXT DAY OR TWO AS A SERIES OF WEAK IMPULSES MOVE AWAY
FROM THE NORTHERN GULF COAST. THIS SYNOPTIC PATTERN SHOULD STEER
THE CYCLONE GENERALLY TO THE WEST-NORTHWEST AND ACCELERATE IT. THE
TRACK GUIDANCE HAS SHIFTED A BIT TO THE WEST OVERNIGHT WITH LESS
SPREAD THAN EARLIER. THIS SHIFT TO THE LEFT SEEMS REASONABLE WITH
THE BUILDING RIDGE AND THE NHC FORECAST WILL BE MOVED IN THAT
DIRECTION...BUT STILL LIES TO THE RIGHT OF THE MODEL CONSENSUS.


FORECAST POSITIONS AND MAX WINDS

INIT 28/0900Z 23.0N 88.7W 35 KT 40 MPH
12H 28/1800Z 23.9N 90.3W 40 KT 45 MPH
24H 29/0600Z 25.1N 92.5W 45 KT 50 MPH
36H 29/1800Z 26.3N 94.7W 50 KT 60 MPH
48H 30/0600Z 27.3N 97.1W 50 KT 60 MPH
72H 31/0600Z 29.0N 101.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 01/0600Z...DISSIPATED

$$
FORECASTER BLAKE/BROWN

[JtSmarts]

It's rare you have a storm where TS winds only extend 45 miles from the center. Granted he's not "Marco" size but definitely super tiny.

[KWT]

Recon appears to be on its way:

000
URNT15 KNHC 281018
AF303 0204A DON HDOB 02 20110728
100800 3012N 08904W 6913 03251 0077 +093 +081 193016 017 /// /// 03
100830 3010N 08905W 6700 03513 0082 +078 +070 197012 014 /// /// 03
100900 3009N 08906W 6510 03760 0089 +065 +058 192010 011 /// /// 03
100930 3007N 08907W 6315 04006 0081 +054 +048 183011 011 /// /// 03
101000 3006N 08907W 6138 04238 0081 +038 +037 187009 010 /// /// 03
101030 3004N 08908W 5958 04473 0071 +025 //// 199009 010 /// /// 05
101100 3003N 08909W 5753 04754 0061 +011 //// 205011 011 /// /// 05
101130 3001N 08910W 5606 04961 0056 +000 //// 209011 012 /// /// 05
101200 3000N 08911W 5474 05152 0254 -011 //// 209010 010 /// /// 05
101230 2958N 08911W 5349 05338 0266 -024 //// 206008 009 /// /// 05
101300 2956N 08912W 5229 05519 0279 -030 //// 207008 009 /// /// 05
101330 2955N 08913W 5112 05703 0293 -034 //// 213009 009 /// /// 05
101400 2953N 08914W 5006 05867 0304 -042 //// 217009 009 /// /// 05
101430 2952N 08915W 4910 06022 0314 -050 //// 226008 009 /// /// 05
101500 2950N 08915W 4813 06176 0322 -060 //// 221009 009 /// /// 05
101530 2948N 08916W 4710 06343 0335 -070 //// 217011 011 /// /// 05
101600 2947N 08917W 4625 06491 0347 -078 //// 225010 011 /// /// 05
101630 2945N 08918W 4557 06606 0356 -085 //// 234008 008 /// /// 05
101700 2943N 08919W 4478 06741 0365 -090 //// 246009 009 /// /// 05
101730 2942N 08920W 4410 06859 0372 -098 //// 250008 008 /// /// 0

If someone could do the graphics, that'd be great!

[KWT]

Convection is relatively small, but it is firing right over the LLC.

http://rammb.cira.colostate.edu/product ... 280402.jpg

Yep and thats what is helping to sustain this system I think, otherwise it'd probably be a TD again...

Always wary of these systems, because if it does slip into an area of better conditions in 12-36hrs time, if its able to burst with worse conditions then nothing to prevent it strengthening once heat content increases.

[KWT]

I've got the next 30 mins of the recon flight, hopefully that will be enough time to get someone else to do it.

Very busy day today looking at the flight plan!!!

[KWT]

000
URNT15 KNHC 281028
AF303 0204A DON HDOB 03 20110728
101800 2940N 08921W 4340 06983 0380 -107 //// 255008 008 /// /// 05
101830 2938N 08921W 4269 07108 0388 -115 //// 251009 009 /// /// 05
101900 2937N 08922W 4209 07217 0396 -123 //// 258008 009 /// /// 05
101930 2935N 08923W 4148 07328 0402 -128 //// 262010 010 /// /// 05
102000 2933N 08924W 4097 07424 0410 -134 //// 268010 010 /// /// 05
102030 2931N 08925W 4039 07537 0421 -139 //// 268010 011 /// /// 05
102100 2929N 08926W 3992 07627 0430 -146 //// 275011 011 /// /// 05
102130 2928N 08927W 3940 07728 0435 -153 //// 270011 011 /// /// 05
102200 2926N 08928W 3923 07759 0439 -155 //// 274011 011 /// /// 05
102230 2924N 08929W 3923 07761 0441 -158 //// 277009 009 /// /// 05
102300 2922N 08930W 3925 07759 0440 -160 //// 271009 009 /// /// 05
102330 2920N 08931W 3925 07756 0438 -159 //// 274008 008 /// /// 05
102400 2918N 08932W 3926 07754 0439 -160 //// 276007 008 /// /// 05
102430 2915N 08933W 3925 07756 0439 -161 //// 283008 009 /// /// 05
102500 2913N 08934W 3929 07750 0438 -158 //// 281008 008 /// /// 05
102530 2911N 08935W 3926 07754 0440 -156 //// 259007 007 /// /// 05
102600 2908N 08937W 3926 07759 0442 -160 //// 255006 007 /// /// 05
102630 2906N 08938W 3926 07756 0441 -156 //// 256007 007 /// /// 05
102700 2904N 08939W 3926 07759 0442 -155 //// 257006 007 /// /// 05
102730 2902N 08940W 3926 07757 0441 -155 //// 258006 006 /// /// 05

[KWT]

000
URNT15 KNHC 281042
AF303 0204A DON HDOB 04 20110728
102800 2859N 08941W 3926 07755 0441 -155 //// 274006 006 /// /// 05
102830 2857N 08942W 3926 07757 0442 -155 -158 272005 006 /// /// 03
102900 2855N 08943W 3926 07758 0442 -155 //// 268005 006 /// /// 05
102930 2852N 08945W 3926 07757 0441 -155 //// 268006 006 /// /// 05
103000 2850N 08946W 3926 07757 0441 -155 //// 285005 005 /// /// 05
103030 2848N 08947W 3926 07758 0442 -155 //// 296004 005 /// /// 05
103100 2846N 08948W 3926 07755 0441 -155 //// 282005 005 /// /// 05
103130 2843N 08949W 3926 07758 0442 -155 //// 283005 005 /// /// 05
103200 2841N 08950W 3926 07755 0441 -155 //// 291004 005 /// /// 05
103230 2839N 08952W 3926 07756 0441 -155 //// 289004 004 /// /// 05
103300 2836N 08953W 3927 07753 0441 -160 //// 289003 003 /// /// 05
103330 2834N 08954W 3925 07758 0441 -160 //// 261003 004 /// /// 05
103400 2832N 08955W 3926 07755 0440 -160 //// 244003 003 /// /// 05
103430 2829N 08956W 3926 07754 0439 -153 //// 228004 005 /// /// 05
103500 2827N 08957W 3926 07754 0439 -154 //// 229006 006 /// /// 05
103530 2825N 08958W 3926 07754 0440 -153 //// 219005 006 /// /// 05
103600 2823N 08959W 3926 07754 0439 -155 //// 216005 005 /// /// 05
103630 2820N 09001W 3926 07753 0438 -155 //// 216005 005 /// /// 05
103700 2818N 09002W 3927 07753 0439 -155 //// 213005 007 /// /// 05
103730 2816N 09003W 3925 07754 0438 -156 //// 197005 006 /// /// 05

[KWT]

000
URNT15 KNHC 281047
AF303 0204A DON HDOB 05 20110728
103800 2813N 09003W 3927 07751 0438 -157 //// 187006 007 /// /// 05
103830 2811N 09003W 3925 07757 0438 -155 //// 174005 006 /// /// 05
103900 2808N 09004W 3927 07754 0440 -155 //// 171004 004 /// /// 05
103930 2806N 09004W 3925 07757 0439 -155 -155 178006 006 /// /// 03
104000 2804N 09004W 3927 07751 0439 -155 -156 179005 005 /// /// 03
104030 2801N 09004W 3926 07755 0439 -157 //// 164005 005 /// /// 05
104100 2759N 09004W 3926 07752 0438 -155 -156 190005 005 /// /// 03
104130 2756N 09004W 3926 07754 0439 -155 -157 200005 005 /// /// 03
104200 2754N 09005W 3925 07757 0440 -154 -158 207005 006 /// /// 03
104230 2751N 09005W 3920 07764 0439 -155 -158 210006 007 /// /// 03
104300 2749N 09005W 3926 07752 0438 -154 -159 205008 008 /// /// 03
104330 2746N 09005W 3927 07750 0437 -155 -159 197008 008 /// /// 03
104400 2744N 09005W 3926 07750 0436 -155 -160 200007 007 /// /// 03
104430 2741N 09005W 3925 07752 0436 -158 -162 189006 006 /// /// 03
104500 2739N 09006W 3926 07749 0435 -155 -163 196005 006 /// /// 03
104530 2736N 09006W 3926 07749 0435 -156 -165 201007 007 /// /// 03
104600 2734N 09006W 3926 07749 0434 -155 -166 200008 008 /// /// 03
104630 2732N 09006W 3926 07749 0433 -155 -167 199007 007 /// /// 03
104700 2729N 09006W 3927 07747 0434 -155 -169 196008 008 /// /// 03
104730 2727N 09006W 3926 07750 0434 -155 -170 197007 008 /// /// 03
$$
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