Superstorm93 Posted July 22, 2013 Share Posted July 22, 2013 That's pretty interesting how the strong CCKW completely overwhelmed the less than favorable MJO Current presentation is somewhat impressive. It's starting to look like 98L will become a tropical cyclone. Link to comment Share on other sites More sharing options...
wxmeddler Posted July 22, 2013 Share Posted July 22, 2013 This would be a great case study for HS3, but they don't start science missions until August 20th. Link to comment Share on other sites More sharing options...
TropicalAnalystwx13 Posted July 22, 2013 Share Posted July 22, 2013 NHC left it at 30%. I don't agree with that, but hey, they're the experts and I'm the amateur. A TROPICAL WAVE ACCOMPANIED BY A SURFACE LOW CONTINUES TO PRODUCESHOWER AND THUNDERSTORM ACTIVITY SEVERAL HUNDRED MILES SOUTHEAST OFTHE CAPE VERDE ISLANDS. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVEFOR SOME DEVELOPMENT OVER THE NEXT DAY OR SO BEFORE THE WAVE MOVESINTO A LESS FAVORABLE ENVIRONMENT LATER IN THE WEEK. THIS SYSTEMHAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONEDURING THE NEXT 48 HOURS AS IT MOVES WESTWARD TO WEST-NORTHWESTWARDAT 15 TO 20 MPH. INTERESTS IN THE CAPE VERDE ISLANDS SHOULDMONITOR THE PROGRESS OF THIS DISTURBANCE. Link to comment Share on other sites More sharing options...
TropicalAnalystwx13 Posted July 23, 2013 Share Posted July 23, 2013 Here's a sea surface temperature map...looks like the system should track over sub-26C waters for a brief period of time -- Link to comment Share on other sites More sharing options...
Srain Posted July 23, 2013 Share Posted July 23, 2013 The Eurosip looks a bit promising for the big show. The WPAC is crazy! Link to comment Share on other sites More sharing options...
mupawxnut Posted July 23, 2013 Share Posted July 23, 2013 The Eurosip looks a bit promising for the big show. The WPAC is crazy!So what does this mean? Link to comment Share on other sites More sharing options...
wxmeddler Posted July 23, 2013 Share Posted July 23, 2013 So what does this mean? This is the European seasonal ensemble. The blue areas show where the ensemble is predicting lower than average pressures. Lower pressures = surface convergence = Higher likelihood of TC genesis (Caution: This is just one ingredient!). WPAC stands for Western Pacific (aka. Typhoons), where as the map shows, a very strong signal of lower than average pressures. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 23, 2013 Share Posted July 23, 2013 New GFS supports 'Hurricaneman's 1/0/0 for July. Might technically be a TD between 24 and 36 hours, but 'Dorian' is saved for a more deserving system. If the GFS is correct. Link to comment Share on other sites More sharing options...
AutoPenalti Posted July 23, 2013 Share Posted July 23, 2013 SHOWERS AND THUNDERSTORMS HAVE BECOME A LITTLE MORE CONCENTRATED NEAR THE CENTER OF A SURFACE LOW PRESSURE SYSTEM. ADDITIONAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE LATER TODAY BEFORE ENVIRONMENTAL CONDITIONS BECOME LESS CONDUCIVE FOR DEVELOPMENT ON WEDNESDAY. THIS SYSTEM HAS A MEDIUM CHANCE...40 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT 15 TO 25. A NEARLY STATIONARY HIGH PRES LOCATED N OF AREA NEAR 41N142W EXTENDS A SURFACE RIDGE SOUTHWARD ACROSS THE NW PORTION OF THE FORECAST REGION N OF 20N W OF 128W. VERY WEAK PRES GRADIENT DOMINATES THE REMAINDER OF THE NORTH WATERS...PARTICULARLY N OF 20N E OF 128W. A TROUGH OR WEAK LOW PRES IS FORECAST TO DEVELOP ACROSS THE NE WATERS IN ABOUT 12-24 HOURS. THE MOST RECENT SCATTEROMETER PASSES SHOWED VARIABLE WINDS OF 5-10 KT ACROSS THAT AREA. TRADE WINDS OF 15-20 KT ARE NOTED S OF THE RIDGE AND N OF THE MONSOON TROUGH FROM 11N TO 16N W OF 125W. A PAIR OF ASCAT PASSES CONFIRMED THE PRESENCE OF THESE WIND SPEEDS. GAP WINDS OF 20-25 KT CONTINUE OVER THE GULF OF PAPAGAYO Link to comment Share on other sites More sharing options...
Snow_Miser Posted July 23, 2013 Share Posted July 23, 2013 Up to 40% at 8 am. FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...1. A SURFACE LOW PRESSURE SYSTEM LOCATED A COUPLE HUNDRED MILESSOUTH-SOUTHEAST OF THE CAPE VERDE ISLANDS HAS BECOME BETTER DEFINEDTHIS MORNING. ALTHOUGH THUNDERSTORM ACTIVITY HAS DECREASED...SOMEFURTHER DEVELOPMENT OF THIS DISTURBANCE IS STILL POSSIBLE LATERTODAY BEFORE ENVIRONMENTAL CONDITIONS BECOME LESS CONDUCIVE FORDEVELOPMENT ON WEDNESDAY. THIS SYSTEM HAS A MEDIUM CHANCE...40PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURSAS IT MOVES WEST-NORTHWESTWARD AT 15 TO 20 MPH. INTERESTS IN THECAPE VERDE ISLANDS SHOULD MONITOR THE PROGRESS OF THIS DISTURBANCE. Link to comment Share on other sites More sharing options...
dtk Posted July 23, 2013 Share Posted July 23, 2013 Yeah, they're testing out the higher-res GFS that's supposed to roll out eventually. The new 20 member ensembles are run at T574 (current GFS resolution) which is pretty helpful. Both systems show promise. It's run on the Jet machine Boulder, CO (ESRL) and not the WCOSS, so the data is delayed by 24 hours. http://www.hfip.org/products/about.html Sort of. This version of the GFS model is using a Semi-Lagrangian (SL) dynamic core, so the T574 ensemble here is not the same effective resolution as our T574 Eulerian model. They actually use different corresponding grids (hence a difference in their effective resolution in physical space)....the SL uses a coarser, linear grid whereas the Eulerian requires a higher resolution, quadratic grid. The same holds true for the deterministic component...the T1148 SL is not the same as doubling the resolution from the T574 Eulerian....it's more like 1.3x (going from 1760 to 2304 grid points in the latitudinal direction). For the future operational upgrade, we are actually bypassing the T1148 SL GFS in favor of a T1534 SL version. The HFIP demo is using T1148 mostly due to resource constraints, and the fact the the T1534 was a bit of a work in progress when they were putting together their test plan. The T1534 will likely also include extensive physics changes, whereas the T1148 HFIP version is our standard operational package. Link to comment Share on other sites More sharing options...
am19psu Posted July 23, 2013 Share Posted July 23, 2013 Can you explain the difference between a Semi-Lagrangian and Eulerian framework from a modeling perspective? Link to comment Share on other sites More sharing options...
dtk Posted July 23, 2013 Share Posted July 23, 2013 Can you explain the difference between a Semi-Lagrangian and Eulerian framework from a modeling perspective? Not very well, but...... Eulerian is pretty simple and involves finite-differencing from an Eulerian (physical space, grid point) perspective. A SL scheme also has a grid associated with it, but views tendencies from a Lagriangian (flow-following) perspective. To accomplish this, one estimates where a parcel is coming from (departure points). This allows for a much different effective (and flow-dependent, flexible) resolution, which is much more computationally efficient and allows one to use a much larger time step. The scheme is much more stable. It's way more complicated then that, especially since there are also spectral dynamics involved...at least for the NCEP and ECMWF formulations. For technical reading, see Chapter 3 in : www.ecmwf.int/research/ifsdocs/CY38r1/IFSPart3.pdf or here overview description here: http://www.ecmwf.int/newsevents/training/rcourse_notes/NUMERICAL_METHODS/NUMERICAL_METHODS/Numerical_methods6.html I will try to see if I can dig up some tutorial slides from one of my colleagues at EMC. Link to comment Share on other sites More sharing options...
wxmx Posted July 23, 2013 Share Posted July 23, 2013 Models are still very divergent wrt 98L track. There's a binary interaction of 98L with a low embedded in the ITCZ in the GFS, which effectively works as a leash and allows a more westerly track. Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 23, 2013 Share Posted July 23, 2013 FIM tracks 98L across the Atlantic. Sends it into Hispaniola, but perhaps for just a wave, that wouldn't be terminal. Link to comment Share on other sites More sharing options...
am19psu Posted July 23, 2013 Share Posted July 23, 2013 Not very well, but...... Eulerian is pretty simple and involves finite-differencing from an Eulerian (physical space, grid point) perspective. A SL scheme also has a grid associated with it, but views tendencies from a Lagriangian (flow-following) perspective. To accomplish this, one estimates where a parcel is coming from (departure points). This allows for a much different effective (and flow-dependent, flexible) resolution, which is much more computationally efficient and allows one to use a much larger time step. The scheme is much more stable. That sounds pretty awesome and very complex compared to the finite differencing schemes we're all used to using. Link to comment Share on other sites More sharing options...
Srain Posted July 23, 2013 Share Posted July 23, 2013 Models are still very divergent wrt 98L track. There's a binary interaction of 98L with a low embedded in the ITCZ in the GFS, which effectively works as a leash and allows a more westerly track. The reliable guidance has suggested multiple areas of potential vortisity embedded within the ITCZ may be the source of TC Genesis thus why the lack of consistency. That sounds pretty awesome and very complex compared to the finite differencing schemes we're all used to using. Agreed. Great stuff, dtk. Thanks for your input. Link to comment Share on other sites More sharing options...
IsentropicLift Posted July 23, 2013 Share Posted July 23, 2013 Looking at the satellite loop this morning for 98L you can see a fairly well defined swirl. Anyway it appears to be at least holding its own right now. Link to comment Share on other sites More sharing options...
patrick05 Posted July 23, 2013 Share Posted July 23, 2013 latest ASCAT... Link to comment Share on other sites More sharing options...
IsentropicLift Posted July 23, 2013 Share Posted July 23, 2013 latest ASCAT... Closed circulation? Link to comment Share on other sites More sharing options...
wxmx Posted July 23, 2013 Share Posted July 23, 2013 ASCAT shows there's a healthy closed low. Also, there's a curved band developing to the left and north (number 6). If trends continue, this should become TD #5 later today. Link to comment Share on other sites More sharing options...
phil882 Posted July 23, 2013 Share Posted July 23, 2013 Given the current satellite presentation and recent ASCAT pass... this is already nearly a tropical depression. Unfortunately, time has just about run out for the system, as its beginning to move into a more stable environment, cooler SSTs, and will no longer be aided by the departing CCKW that was overhead yesterday. What we should start to see (and already are to some extent) is that the system will struggle convectively as easterly shear starts to pick up and more stable air approaches the low level circulation. The GFS solution doesn't make much sense, since it has the storm developing in the 24-36 hour range, a time when the storm will be under the lowest SSTs and the most stable environment. The time for development is today, otherwise 98L is unlikely to develop at all. Link to comment Share on other sites More sharing options...
IsentropicLift Posted July 23, 2013 Share Posted July 23, 2013 12z GGEM takes 98L into SE FL in ten days as a minimal TS Link to comment Share on other sites More sharing options...
Superstorm93 Posted July 23, 2013 Share Posted July 23, 2013 A SURFACE LOW PRESSURE SYSTEM LOCATED A COUPLE OF HUNDRED MILESSOUTH OF THE CAPE VERDE ISLANDS IS MOVING WESTWARD AT ABOUT 10 MPH.THIS SYSTEM HAS A WELL-DEFINED CIRCULATION...AND ONLY A SMALLINCREASE IN THE AMOUNT AND ORGANIZATION OF THE THUNDERSTORMACTIVITY WOULD RESULT IN THE FORMATION OF A TROPICAL DEPRESSION.ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE FAVORABLE FORDEVELOPMENT DURING THE NEXT DAY OR SO BEFORE UPPER-LEVEL WINDS ANDOCEAN TEMPERATURES BECOME LESS CONDUCIVE BY THURSDAY. THIS SYSTEMHAS A HIGH CHANCE...60 PERCENT...OF BECOMING A TROPICAL CYCLONEDURING THE NEXT 48 HOURS. Link to comment Share on other sites More sharing options...
Srain Posted July 23, 2013 Share Posted July 23, 2013 So we now have a Cherry. Link to comment Share on other sites More sharing options...
TropicalAnalystwx13 Posted July 23, 2013 Share Posted July 23, 2013 Given the current satellite presentation and recent ASCAT pass... this is already nearly a tropical depression. Unfortunately, time has just about run out for the system, as its beginning to move into a more stable environment, cooler SSTs, and will no longer be aided by the departing CCKW that was overhead yesterday. What we should start to see (and already are to some extent) is that the system will struggle convectively as easterly shear starts to pick up and more stable air approaches the low level circulation. The GFS solution doesn't make much sense, since it has the storm developing in the 24-36 hour range, a time when the storm will be under the lowest SSTs and the most stable environment. The time for development is today, otherwise 98L is unlikely to develop at all. What about Friday and beyond (near the Leeward Islands)? Conditions look favorable there for re-intensification...or just plain development if it doesn't form today. Link to comment Share on other sites More sharing options...
Superstorm93 Posted July 23, 2013 Share Posted July 23, 2013 18z SHIPS text (run on OFPI track) has SST's and instability being the main negative contributors in the short-medium range. Even though there are some large hurdles, it still intensifies it slowly after 36 hours. * ATLANTIC SHIPS INTENSITY FORECAST * * GOES PROXY USED, OHC AVAILABLE * * INVEST AL982013 07/23/13 18 UTC * TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120 V (KT) NO LAND 25 27 29 32 36 43 48 53 55 56 58 60 61 V (KT) LAND 25 27 29 32 36 43 48 53 55 56 58 60 61 V (KT) LGE mod 25 26 27 29 32 39 46 52 56 58 60 64 67 Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP SHEAR (KT) 12 10 11 11 8 2 3 10 10 12 10 15 20 SHEAR ADJ (KT) -2 -4 -6 -4 -3 0 0 0 0 0 0 -1 4 SHEAR DIR 70 59 54 38 39 228 280 241 248 255 252 244 221 SST (C) 26.6 26.7 26.8 26.8 26.4 25.4 25.8 26.4 27.0 27.4 27.8 28.1 28.0 POT. INT. (KT) 121 123 124 125 121 112 116 121 128 131 136 141 140 ADJ. POT. INT. 119 123 126 127 122 112 116 122 128 129 134 141 139 200 MB T (C) -53.7 -53.8 -54.1 -54.0 -54.0 -54.5 -54.3 -54.3 -54.2 -54.5 -54.5 -54.6 -54.5 TH_E DEV (C) 4 4 5 5 5 5 6 7 8 9 10 11 12 700-500 MB RH 72 74 74 73 74 76 69 63 54 52 47 46 47 GFS VTEX (KT) 8 7 7 8 8 9 9 8 8 7 7 7 7 850 MB ENV VOR 19 14 16 22 31 26 27 21 4 0 -8 -4 -15 200 MB DIV 24 13 -3 -2 9 13 20 7 6 0 4 30 22 700-850 TADV 2 0 -3 -4 -2 -1 0 6 7 6 -3 -2 -5 LAND (KM) 725 868 1017 1192 1373 1783 1919 1685 1525 1399 1137 876 485 LAT (DEG N) 12.3 xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x LONG(DEG W) 23.7 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x STM SPEED (KT) 12 15 16 18 19 20 21 21 19 17 17 19 19 HEAT CONTENT 9 2 0 0 0 0 0 0 4 5 9 25 22 FORECAST TRACK FROM OFPI INITIAL HEADING/SPEED (DEG/KT):275/ 10 CX,CY: -9/ 1 T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 595 (MEAN=623) GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 17.1 (MEAN=14.5) % GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 49.0 (MEAN=65.0) Link to comment Share on other sites More sharing options...
Ed Lizard Posted July 23, 2013 Share Posted July 23, 2013 Can't help being my usual glass half full optimistic self, seeing at least the potential for Florida breaking their near 8 year hurricane drought. Glass 3/64ths full, even lowering the net and using 1012 mb as a discriminator, 12Z GEFS are not optimistic. FIM9 Link to comment Share on other sites More sharing options...
Superstorm93 Posted July 23, 2013 Share Posted July 23, 2013 18z tracks have shifted south a bit with the TVCN looking interesting. Link to comment Share on other sites More sharing options...
HurricaneJosh Posted July 23, 2013 Author Share Posted July 23, 2013 Digging the W heading of those tracks. Link to comment Share on other sites More sharing options...
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