cmichweather Posted July 28, 2011 Share Posted July 28, 2011 For those following on IR, the center is located somewhere near this black circle. I'm actually encouraged by this, because it seems like the llc has remained vertically stacked with the mid-level reflection despite the weakening of the convection tonight. All in all, once the convection recovers, this should still be in a favorable environment for strengthening. As long as it maintains itself until tomorrow evening then it'll be fine. Tomorrow night might be the time for it to ramp up, the overall satellite presentation right now is disjointed and not impressive but the low level circulation was never exactly directly associated with the deep convection and seemed to be a bit north of the deep convection on satellite. I think as long as we don't have an exposed circulation tomorrow we had a decent shot of a steady intensification now that it moves away from the land effects. Link to comment Share on other sites More sharing options...
Srain Posted July 28, 2011 Share Posted July 28, 2011 BULLETIN TROPICAL STORM DON INTERMEDIATE ADVISORY NUMBER 2A NWS NATIONAL HURRICANE CENTER MIAMI FL AL042011 100 AM CDT THU JUL 28 2011 ...DON MOVING A LITTLE SLOWER TOWARD THE WEST-NORTHWEST... SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...22.6N 88.2W ABOUT 680 MI...1100 KM ESE OF CORPUS CHRISTI TEXAS MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...WNW OR 300 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... NONE SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WATCH IS IN EFFECT FOR... * TEXAS COAST FROM PORT MANSFIELD NORTHWARD TO WEST OF SAN LUIS PASS A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS. FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 100 AM CDT...0600 UTC...THE CENTER OF TROPICAL STORM DON WAS RELOCATED TO NEAR LATITUDE 22.6 NORTH...LONGITUDE 88.2 WEST. DON IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH...15 KM/H. THIS GENERAL MOTION WITH AN INCREASE IN FORWARD SPEED IS EXPECTED THROUGH FRIDAY. ON THIS TRACK...THE CENTER OF DON SHOULD MOVE THROUGH THE SOUTHERN AND CENTRAL GULF OF MEXICO ON TODAY...AND APPROACH THE TEXAS COAST ON FRIDAY. MAXIMUM SUSTAINED WINDS REMAIN NEAR 40 MPH...65 KM/H...WITH HIGHER GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM FROM THE CENTER. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB...29.53 INCHES. HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA BY LATE FRIDAY. NEXT ADVISORY ------------- NEXT COMPLETE ADVISORY...400 AM CDT. $$ FORECASTER BLAKE/BROWN Link to comment Share on other sites More sharing options...
wxmx Posted July 28, 2011 Share Posted July 28, 2011 Repositioned a bit south. That being said, it looks like the 0z Euro will be a bit north of the 12z run. Edit: Yep, CRP area. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 28, 2011 Share Posted July 28, 2011 Repositioned a bit south. That being said, it looks like the 0z Euro will be a bit north of the 12z run. Edit: Yep, CRP area. Me likey. Corpus would be hawt. Link to comment Share on other sites More sharing options...
Srain Posted July 28, 2011 Share Posted July 28, 2011 Repositioned a bit south. That being said, it looks like the 0z Euro will be a bit north of the 12z run. Edit: Yep, CRP area. Cool. Seadrift, TX is looking a bit better with the euro trending up the Coast. San Antonio Bay makes sense and could provide some ease of access... Link to comment Share on other sites More sharing options...
David Reimer Posted July 28, 2011 Share Posted July 28, 2011 Me likey. Corpus would be hawt. I concur! Link to comment Share on other sites More sharing options...
Floydbuster Posted July 28, 2011 Share Posted July 28, 2011 Me likey. Corpus would be hawt. I don't know about you guys, but I have a sneaking suspicion that just as landfall is occurring, Don will begin looking very well organized and probably landfall just below hurricane strength. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 28, 2011 Share Posted July 28, 2011 I don't know about you guys, but I have a sneaking suspicion that just as landfall is occurring, Don will begin looking very well organized and probably landfall just below hurricane strength. I don't allow myself to think negatively like that. If I did, I would never leave for a chase in the first place. Every chase requires some leap of faith. Back to Don... I'm encouraged by that red flareup right over the center. Cool. Link to comment Share on other sites More sharing options...
OHweather Posted July 28, 2011 Share Posted July 28, 2011 Tropical storm Don forecast/discussion 2: A current look at tropical storm Don reveals a well definedlow level center and a system with good outflow, especially to the south and east. However, over the past several hours convection has become less consistent near the center of Don, possibly related to proximity to land and mid level dry air. Either way, Don has a well defined circulation and structure, meaning intensification is likely if convection can maintain itself. As has been expected over the past few days, the TUTT overthe BOC has weakened and retrograded, allowing shear over the Gulf in front of Don to drop to generally under 20 knots. The TUTT to the NE of Don is alsoproviding favorable outflow in the eastern/southern quadrants. This general upper level pattern is expected to continue through landfall. As has been discussed over the past few days, dry air fromthe east has overspread much of the Gulf, and is likely having a negative impact on Don. This dry air is not expected to go away before landfall, ass hown well on the 12z ECM for Friday morning: This will likely cause the difficulty in maintaining deep convection consistently to continue through landfall for Don, going back to my point yesterday noting that Don’s convection has waxed and waned consistently through the systems life cycle (not abnormal for a developing system, but problematic if it persists which it may). Given the above factors, believe an intensity forecast similar to my forecast last night seems reasonable. Believe very warm SSTs, fairly low shear and good outflow, especially to the east and south of the system, will attempt to counteract the drier air and allow for gradual but steady intensification through landfall. The storm’s small size is a wild card, making iteasier to mix out dry air and intensify, while also making Don more susceptible to significant limitations due to the drier air. With this in mind will not bring Don up stronger than a minimal Cat 1 through landfall. Anything from strong TS to moderate Cat 2 still seems conceivable at this point in time, depending on how the storm handles the dry air. See no reason to go bullish at this time given current appearance and future environment ahead of the storm. Don is currently moving towards the WNW at about 9MPH, which is significantly slower than the average motion over the past few days, in response to a brief weakening in steering currents caused by a trough along theUS east coast. This trough however is departing to the east and ridging will begin to strengthen north of Don, causing a gradual left turn through landfalland likely increase in forward motion. The 12z ECM shows this well, with solid mid level steering north of Don with a faster steering layer flow. With this in mind will go with a similar track forecast to yesterday, with a general WNW motion through landfall. Will also accelerate Donhours 24-48 as the strengthened ridging leads to a strengthened gradient, which will as mentioned above speed Don up. Don did not responded with a right turn to the weakness in the ridge as was expected yesterday and may not do so, so a slight shift south in forecast is in order. This may be much more of a boarder system than originally thought, due to the current weakness in ridging not turning Don right before the ridging begins to re-strengthen. Forecast track/intensity: Forecast/disco 1 from yesterday for comparison purposes Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 28, 2011 Share Posted July 28, 2011 It's definitely improving overnight-- as I suggested it might! Link to comment Share on other sites More sharing options...
28storms Posted July 28, 2011 Share Posted July 28, 2011 It's definitely improving overnight-- as I suggested it might! I suspect cooler SSTs along the coast, disruptive diurnal max activity over land, and some dry air contributed to the lessening of convection yesterday evening. Nonetheless, the ASCAT pass a few hours ago had the center directly under the convection. It's well organized and shouldn't have much of a problem as it pulls away from the Yucatan. Link to comment Share on other sites More sharing options...
Superstorm93 Posted July 28, 2011 Share Posted July 28, 2011 Not sure I'd call this improving. Link to comment Share on other sites More sharing options...
Superstorm93 Posted July 28, 2011 Share Posted July 28, 2011 Peak at 60mph. THE INTENSITY FORECAST IS TRICKY. WHILE THE LARGE-SCALE ENVIRONMENTDOES NOT APPEAR TO HAVE MUCH SHEAR...THE LOW- AND MID-LEVEL CENTERSARE NOT WELL-ALIGNED INITIALLY...WHICH WAS APPARENT ON A 2316ZSSMIS MICROWAVE IMAGE. THE GFS/ECMWF MODELS HAVE A REASONABLEREPRESENTATION OF THIS INITIAL STRUCTURE AND KEEP THE CENTERS FROMVERTICALLY STACKING...POSSIBLY WHY THESE MODELS DO NOT SHOWMUCH INTENSIFICATION. WHILE THE STATISTICALLY MODELS STILLFORECAST STEADY STRENGTHENING...THE HWRF/GFDL MODELS FORECAST ASLOW DECLINE. ANOTHER FACTOR TO CONSIDER IS THAT THE SIZE OF DONMAKES IT SUSCEPTIBLE TO RAPID CHANGES IN STRENGTH...BOTH UP ANDDOWN...THAT ARE NEARLY IMPOSSIBLE TO FORECAST. GIVEN THE REDUCEDORGANIZATION...THE NHC INTENSITY FORECAST IS LOWERED SOMEWHAT FROMTHE PREVIOUS FORECAST...BUT IS STILL ON THE UPPER END OF THEGUIDANCE ENVELOPE NEAR A COMPOSITE OF THE SHIPS/LGEM MODELS. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 28, 2011 Share Posted July 28, 2011 I suspect cooler SSTs along the coast, disruptive diurnal max activity over land, and some dry air contributed to the lessening of convection yesterday evening. Nonetheless, the ASCAT pass a few hours ago had the center directly under the convection. It's well organized and shouldn't have much of a problem as it pulls away from the Yucatan. Agreed. Not sure I'd call this improving. Then I guess you didn't see it 9 hr ago, when the center had no deep convection over it. Link to comment Share on other sites More sharing options...
Srain Posted July 28, 2011 Share Posted July 28, 2011 Watches extended down to Brownsville...there remains a lot of uncertainty regarding track and intensity as well... 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 Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 28, 2011 Share Posted July 28, 2011 The 4 am CDT package is totally blah all around-- however, it make sense. Landfall point shifted a bit S, to near Baffin Bay (a little S of CRP). Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 28, 2011 Share Posted July 28, 2011 Bottom line is that, as usual with these small systems, it can do everything from becoming a 'cane to totally going poof! over the next 24 hr. It's just so hard to know. Intensity forecasting remains a mystery. Link to comment Share on other sites More sharing options...
LakeEffectKing Posted July 28, 2011 Share Posted July 28, 2011 Bottom line is that, as usual with these small systems, it can do everything from becoming a 'cane to totally going poof! over the next 24 hr. It's just so hard to know. Intensity forecasting remains a mystery. Certainly intensity forecast is more of a challange, however, I think the models are of lesser value with such a system (size). This has already "overperformed" from 48 hours ago when it was essentially just reactivated to invest status. Track forecasting, at times, can be fairly straightforward Link to comment Share on other sites More sharing options...
David Reimer Posted July 28, 2011 Share Posted July 28, 2011 Morning update on Tropical Storm Don. Be advised this is mainly for those non-weather savvy folks living in my home state. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 28, 2011 Share Posted July 28, 2011 Recent warm (cold?) towers have gone up. I don't think it makes it to 60 knots, but my natural glass half full optimism has me rooting for Don to get some Knot(t)s. If it could become a hurricane, we'd be several days early (August 2nd, IIRC) on the climatological first hurricane of the season. Link to comment Share on other sites More sharing options...
RaleighWx Posted July 28, 2011 Share Posted July 28, 2011 My morning discussion, not too different from the NHC track. http://www.examiner.com/weather-in-raleigh/tropical-storm-don-not-strengthening-heading-towards-the-south-texas-coast Link to comment Share on other sites More sharing options...
David Reimer Posted July 28, 2011 Share Posted July 28, 2011 Some convection going this morning. Recon should be in the system shortly. Link to comment Share on other sites More sharing options...
Mr Torchey Posted July 28, 2011 Share Posted July 28, 2011 Don Hulio is about to go boom. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 28, 2011 Share Posted July 28, 2011 Aircraft now approaching Don from the North, and still an impressive lack of moisture. 114730 2350N 08954W 8432 01548 0079 +174 +041 038011 012 017 001 00 Link to comment Share on other sites More sharing options...
wxmeddler Posted July 28, 2011 Share Posted July 28, 2011 Wow, as soon as it hit the rain... BAM! FL winds go nuts. Link to comment Share on other sites More sharing options...
RaleighWx Posted July 28, 2011 Share Posted July 28, 2011 Looks like the center may be on the northwest edge of the convection. Link to comment Share on other sites More sharing options...
David Reimer Posted July 28, 2011 Share Posted July 28, 2011 Looks like you're correct. Link to comment Share on other sites More sharing options...
wxmeddler Posted July 28, 2011 Share Posted July 28, 2011 53 kts at 991 mb level with the dropsonde near the COC. Obviously they missed the center with it. Link to comment Share on other sites More sharing options...
wxmeddler Posted July 28, 2011 Share Posted July 28, 2011 VORTEX Message is out.. and something interesting. Remarks Section - Additional Remarks... MAX OUTBOUND SFC WINDS VISUALLY 45 KTS SOME RAIN CONTAMINATION ON SFMR FIX MADE INSIDE CONVECTIVE BAND SLIGHTLY NORTH OF ACTUAL CTR Link to comment Share on other sites More sharing options...
David Reimer Posted July 28, 2011 Share Posted July 28, 2011 VORTEX Message is out.. and something interesting. Remarks Section - Additional Remarks... MAX OUTBOUND SFC WINDS VISUALLY 45 KTS SOME RAIN CONTAMINATION ON SFMR FIX MADE INSIDE CONVECTIVE BAND SLIGHTLY NORTH OF ACTUAL CTR Also of interest is the extremely low dewpoint, only 8C. Link to comment Share on other sites More sharing options...
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