Windspeed

56°F and feels freaking amazing outside right now. Driving home from work I even turned on the heat. Granted, I had the windows down. Negligible humidity, inhaling that crisp fresh Canadian + radiational cooled air. Premature Fall ejaculation perhaps, but it feels glorious!

Though convection reinitiated over night, it's elongated along the northern half of the broader wave axis quite a distance away from the estimated vortex track plot. I'm having a tough time finding an ill-defined center on radar but it may be the isolated cluster of cells to the northwest of Grand Bahama. Curved banding of the stronger complex to the north may be limited to mid level turning even if that feature has taken over. At any rate, the system has a stretched appearance and isn't aligned. I am beating a dead horse.

No need to chastise the OP. This is hopefully a learning curve for future reference. Though the system is classified, that is not the point. The issue wasn't "the call" in so much as the excessive nature of the thread and initial post that started it, regardless of TC development.

We all have opinions and ideas to share on any initial area of interest. However, there is a single post by the author in the main seasonal thread that pertains to the disturbance that became TD3. Without any further discussion, much less input from anyone else, decided to begin a storm thread on a non-classified system with language that suggested a potentially dangerous situation unfolding. Now perhaps that could have been the case, and in the future, it most certainly will be the case. We have had times that mere disturbances / invests warranted a serious tone due to practical confidence, modeling and meteorological support. But TD3 was not one of those times. And yes, I realize some systems are missed by the models, but that still isn't the point here.

We have a seasonal thread to iron out differences of opinion on each individual invest. We can share all the data from the models and from leading forecasters, many of whom are on social media. If everyone takes responsibility on their posts and participates accordingly, we don't end up having a thread digress into mockery on the subforum.

TL;DR version: As a general rule, don't start a storm thread on a system until it is officially classified a tropical cyclone. If discussion in the seasonal thread warrants a storm thread on an invest/disturbance, a single person won't need to make that call. Rest assured many will already be hyping on the disturbance. This isn't a race to see who posts first, neither is it journalism. Nobody gets recognition or an award for being the first. Likewise, don't get your feelings hurt if you are proven wrong. Many of us here have been flat wrong many times about tropical systems, but that does not mean we were irresponsible with our words.

466 
WTNT43 KNHC 230232
TCDAT3

Tropical Depression Three Discussion Number   2
NWS National Hurricane Center Miami FL       AL032019
1100 PM EDT Mon Jul 22 2019

The depression has become less organized this evening.  Much of the
deep convection seen earlier in the day has dissipated, and the
cyclone currently consists of a swirl of low-level clouds with some
shower activity.  The initial intensity is held at 25 kt based on
the earlier ASCAT data.

The system is moving northwestward at 9 kt, steered by the
southwestern periphery of the Atlantic subtropical ridge.  A turn to
the north and north-northeast with a notable increase in forward
speed is expected on Tuesday as the depression moves in the
flow between the subtropical ridge and an approaching deep-layer
trough moving across the eastern United States.  The NHC track
forecast is similar to the previous one and keeps the center of the
cyclone offshore of the east coast of Florida.  This prediction is
near the multi-model consensus TVCN.

Significant strengthening of the depression is not expected given
its poor initial state and because it is forecast to move into a
region of strong southwesterly flow aloft by late Tuesday.  In
fact, the global and regional models all show the depression opening
into a trough within the next 24 hours, with the remnants of the
system becoming absorbed within a frontal zone off the southeast
U.S. on Wednesday.  The NHC intensity forecast is a little lower
than the previous one and now shows dissipation occurring sooner, by
36 hours.

Direct impacts from the depression are expected to be limited to 1
to 3 inches of rainfall in the Bahamas and along the east coast of
Florida.


FORECAST POSITIONS AND MAX WINDS

INIT  23/0300Z 26.1N  79.3W   25 KT  30 MPH
 12H  23/1200Z 28.4N  79.8W   25 KT  30 MPH
 24H  24/0000Z 31.7N  78.5W   30 KT  35 MPH
 36H  24/1200Z...DISSIPATED

$$
Forecaster Cangialosi

At least there was a short-lived attempt earlier by the system to organize. That process has hit a brick wall. Papin mentioned mid level dry air may have been pulled down by cool downdrafts, flooding the boundary layer with low Theta-E, as evidenced by soundings. This has retarded additonal convection until the low level column can remoisten, as some convergence may be resumed once low level easterly flow into convection over the penninsula subsides.

The weak low level vortex assisted by the temporary banded convection earlier this afternoon is already showing signs of elongation and stretching lattitudinally without support of sustained additional convection to keep it tight / well-defined. Our TD may open back up into the wave axis as this process amplifies / shear increases tomorrow. Simply put, this system is on life support; without sustained convection, TD3 will dissipate faster than anticipated.

 

No, the disturbance doesn't look half bad. The strong easterly mid level flow that had hampered it has become more southerly due to the disturbance now being positioned on the SW periphery of the Bermuda ridge, which is backing East in response to the strong advancing E CONUS trough. The southwest entrance of the wave at the surface has therefore become more convergent. NHC increase the odds of cyclogenesis and 94L may become a TD, perhaps even weak TS. But we need to see the low level wave axis cutoff in a rather short period of time into a vortex, preferably at the point of that increased surface convergence. Though Invest 94L has a small window of moderate favorability for TC genesis before hostile atmospheric flow and frontal boundary merger, that does not mean it will occur.

This disturbance did not need its own thread. It could have been fleshed out under the main seasonal thread like the majority of past invests and areas of interest. If we create a thread for every single invest that pops up, especially when the season becomes active, the board is going to become gluttered fast with systems that never develop.

OTOH, if an invest is determined to be of high risk for tropical cyclogenesis, especially if land impacts are certain, or at the very least it has overwhelming modeling support at becoming a named tropical cyclone then, sure, thread away. Otherwise please wait until we have a named storm. Waiting for a named storm used to be more moderated though there were exceptions. This board is nice because it isn't overly moderated. Let's not ruin that.

At any rate, per the NHC, there is only a 10% chance of development in the next 48 hrs. Odds only go up 20% for the 5 day outlook. The reason the system lacks any modeling support is due to two factors: 1) Limited surface convergence at the moment: Though the disturbance does have showers and storms and a weak surface low, it still lacks enough diffluence that there isn't alot of lift in the atmosphere. The mid levels also do not scream favorability and there is lingering dry air. 2) Additonally, the disturbance doesn't get genesis support beyond 48 hrs due to modeled strong southwesterly shear in the mid levels associated with an advancing trough off the eastern CONUS. The weak area of low pressure becomes absorbed into a frontal merger. Perhaps something more substantial can stall or evolve between the Carolinas and Bermuda in 5-7 days with a lingering surface trough, but at this point it's a crapshoot.

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sun Jul 21 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A weak area of low pressure just to the east of the
Central Bahamas is producing disorganized showers and a few
thunderstorms.  Some slight development is possible over the
next few days while the disturbance moves westward to
west-northwestward at around 15 mph.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...20 percent.

Forecaster Pasch

Gulf should rebound rather quickly too, if it hasn't already. Gotta watch.

Did not see a recent banter thread so thought I would just post here. This new video by Pecos Hank discussing super computer mesocyclone and tornado genesis with Dr. Leigh Orf is an absolute must watch:

This video by Pecos Hank discussing super computer mesocyclone and tornado genesis with Dr. Leigh Orf is an absolute must watch:

Even though we are still beyond 72 hrs from a trackable feature, if one does indeed resolve, there are already two different camps between the GFS vs ECMWF runs over the past few days. Though both models do have a sharp surface trough / low pressure system over the SE US & NE GOM, the ECMWF is more aggressive in southern advancement of that boundary and an attached 850-700 mb vortex. Cyclogenesis on the Euro is much further south out over the GOM, versus the GFS runs which keeps the feature either inland or in closer proximity to land.

Granted we are still early into in these model runs and confidence should remain low for now. If given a scenario of better modeling agreement on the eventual placement of the surface trough, even with a disturbance positioned out over the GOM doesn't guarantee TC development. That being said, last night's 0z ECMWF was the most aggressive in development so far:

A boundary is forecast to stall and linger over the north GOM next week. An MCS currently organizing over Kansas may push SSE with the boundary and move off the Panhandle coastline possibly developing a sharp surface trough / area of low pressure, which some of the globals are trying to close off into a tropical or sub tropical cyclone. At least something to watch for development towards the mid-to-late week timeframe.

Though T#s have decreased and intensity has come down, still a formidable Cat 4 and looking quite good on SAT.

Barbara's eye finally cleared and became more stable after some old vortex convection dissipated. As such, ADT # responded upwards this afternoon, but has since leveled off to around 7.0. We're probably observing a high end 4 / borderline 5 now.

The EPAC has finally taken off with its second named storm, Barbara reaching Major Hurricane status and Category 4 intensity.

Strong storms moved through TYS and MRX but most things have calmed down and seem rather tame at the moment.

Tornado warning north of Knoxville. Rotation/strong winds moving towards Maynardville.

The SPC did upgrade to a slight risk for much of the eastern TN Valley including an enhanced risk for the northeastern portion.

Quote

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0243 PM CDT Mon Jun 24 2019
Valid 242000Z - 251200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE UPPER OHIO VALLEY AREA SOUTHWARD TO THE NORTHEAST TENNESSEE AREA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENH RISK AREA...ACROSS PORTIONS OF WEST-CENTRAL TEXAS...AND OVER THE SOUTHERN WISCONSIN/NORTHERN ILLINOIS VICINITY...

...SUMMARY... Scattered strong to severe storms capable of damaging winds will continue to evolve over the central/southern Appalachians and Ohio Valley today. Other more isolated severe activity may yet occur over northern Illinois/southern Wisconsin and vicinity, and is expected to develop in the next couple of hours over west-central/southwest Texas.

...Discussion... Convection continues to evolve this afternoon as anticipated; with reasoning communicated in prior outlooks still appearing valid at this time, no outlook changes are needed. ..Goss.. 06/24/2019
.PREV DISCUSSION... /ISSUED 1105 AM CDT Mon Jun 24 2019/
...Central/Southern Appalachians... Morning satellite and radar imagery show a well-defined remnant MCV over southern KY. This trough is embedded with a larger upper trough rotating across the OH/TN valleys. The air mass ahead of the feature is heating rapidly and will become very unstable by mid-afternoon. Strengthening midlevel winds, coupled with strong instability and affects of the MCV will pose a more substantial risk of bowing thunderstorm structures capable of damaging wind gusts. A few supercells cannot be ruled out, along with a risk of isolated tornadoes. Therefore have upgraded much of WV and vicinity to an ENH risk and 30% severe wind probabilities.

...AL/GA... A very warm/humid air mass remains in place today over this region with strong CAPE values expected. Most 12z CAM solutions suggest pockets of afternoon thunderstorm development, although models differ on placement and timing. Those storms that form will pose a risk of strong/damaging wind gusts.

Vanu began a westward drift and should avoid landfall as a strong cyclone. Globals show a westward motion for a few days before eventually getting sheared off. A weaker system may still get pulled via the low level flow into Pakistan/NW India so flooding rainfall may still be a concern in the coming week.

Day 1 Outlook Graphic...

SPC sticking with marginal for Tennessee and Ohio Valleys.

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0752 AM CDT Wed Jun 12 2019

   Valid 121300Z - 131200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE OHIO/TENNESSEE VALLEYS INTO THE SOUTHEAST AND COASTAL
   CAROLINAS...MISSOURI/ARKANSAS VICINITY...AND WEST TEXAS...

   ...SUMMARY...
   Isolated strong to severe thunderstorms will be possible today
   across parts of the Ohio/Tennessee Valleys into the Southeast and
   coastal Carolinas, Missouri/Arkansas vicinity, and west Texas.
   Marginally severe hail and strong/gusty winds should be the main
   threats.

   ...Synopsis...
   For convective purposes, the mid/upper-level pattern will be
   dominated by a high-amplitude, synoptic-scale trough now located
   from northwestern ON across the upper Mississippi Valley, to the
   KS/MO border area and deep south TX.  By 12Z, this trough should
   shift eastward to Lakes Superior and Michigan, IN, middle TN, AL,
   and the north-central Gulf.  Several embedded/minor shortwaves will
   traverse the associated cyclonic-flow field through the period,
   contributing to relatively maximized potential convective coverage
   on the mesoscale.  Farther west, a weak shortwave trough will move
   inland over parts of the Pacific Northwest and northern CA,
   contributing to locally gusty dry thunderstorms, as noted in the SPC
   fire-weather outlook.

   At the surface, 11Z analysis showed a wavy, quasistationary frontal
   zone from southern SC across central/southern GA, to near the LA
   coastline, and across deep south TX.  This boundary should move
   little through the day, while becoming more diffuse west of
   central/eastern GA.  Another cold front was drawn from Hudson Bay
   across northern ON, Lake Superior, to a low near CID, to another
   weak low near TUL, and finally, to yet another weak low near INK. 
   This front will move eastward/southeastward through the period,
   reaching lower MI, southern MO, the Arklatex region, and portions of
   central/southwest TX by 00Z.  By 12Z, the approach of the mid/upper
   trough will induce frontal-low formation over southeastern Lower MI.
   The cold front will extend from the MI low across eastern TN,
   southeastern MS, and south-central TX.

   ...Southeastern CONUS to Ohio Valley...
   Scattered thunderstorms should develop through this afternoon in an
   arc of favorable buoyancy and weak CINH, wrapping around the
   southern/western Appalachians, along and outside of the low-theta-e
   damming air mass.  Isolated severe hail and damaging to marginally
   severe gusts are possible.

   The most favorable conditions at various levels for severe will be
   horizontally displaced from each other across this broad, arching
   area, but individual elements may contribute to at least marginal
   severe potential locally.  Moisture quality and theta-e will be
   greatest over the FL/GA/Carolinas swath, while mid/upper flow,
   cooling aloft, and deep shear will increase northward/northwestward
   through the western Appalachians/Ohio Valley lobe.  Warm and moist
   advection north of the frontal zone, across western GA and eastern
   portions of AL/KY, will contribute to destabilization through the
   afternoon, in tandem with diabatic heating, enabling a narrow
   corridor of 500-1500 J/kg MLCAPE to develop there.  Despite modest
   midlevel lapse rates, pockets of 1500-2500 J/kg MLCAPE should
   develop this afternoon in the Southeast.  Weak low-level flow is
   forecast area-wide, except for some hodograph enhancement possible
   above the surface late afternoon and evening near the Atlantic
   coastal areas of GA/Carolinas.  An assortment of boundaries will
   focus convection, including the frontal zone, outflow, differential-
   heating areas, confluence lines in the warm sector, and sea breezes.


   ...Ozarks and vicinity...
   Airmass recovery following the morning clouds/convection should
   become favorable for the next round of thunderstorms -- this time
   including surface-based cells -- by mid/late afternoon.  Seasonably
   cold, -16 to -18 deg C 500-mb temperatures will spread over this
   region this afternoon, near the mid/upper-level trough.  When
   juxtaposed with residual boundary-layer moisture, afternoon surface
   diabatic heating and related strengthening of low/middle-level lapse
   rates, forecast soundings reasonably suggest around 500-1000 J/kg
   MLCAPE with little or no MLCINH and a well-mixed subcloud layer.

   Organization will be tempered by lack of more robust moisture and
   shear, with little directional shear and effective-shear magnitudes
   generally less than 30 kt.  However, strong anvil-level flow will
   aid in ventilation aloft, and the most robust cells may offer
   marginally severe hail/gusts.  With convective potential extending
   northward into much of IA, the northern bound of the marginal risk
   area is, in reality, much fuzzier than the graphical line indicates,
   but already low-end severe potential still appears to diminish with
   northward extent into lesser magnitudes of cloud-layer shear and
   low-level theta-e.

   ...TX Big Bend/Trans Pecos...
   Isolated thunderstorms may develop this afternoon over this region
   south of the cold front, especially near higher terrain where
   diabatic heating will erode MLCINH preferentially.  Severe hail and
   strong to marginally severe gusts are possible from any sustained
   convection that can form, though convective coverage is in question.
   Low-level convergence will be maximized near the generally
   southward-moving surface low, and any associated convergence zone
   extending southward.

   The main uncertainty involves whether associated lift will be
   sufficient to form/maintain thunderstorms long enough to produce
   severe, in an environment characterized by steep low/middle-level
   lapse rates and adequate boundary-layer moisture.  Surface dew
   points in the mid 50s to low 60s F contribute to potential MLCAPE
   1500-2500 J/kg in modified model soundings.  In areas south to
   southeast of the low where an easterly surface wind component will
   enhance directional shear, 35-45 kt effective-shear magnitudes may
   be found.  Any severe threat in this region should be conditional
   and short-lived, decreasing markedly after dark.

   ..Edwards.. 06/12/2019

TC Vayu in the NW Indian Ocean / Arabian Sea is forecast to become a Category 2 cyclone in the coming days and make landfall over the NW Indian and Pakistani coastline / borderlands. HWRF is most agressive in intensification making Vayu a Category 4 cyclone. The late track may be quite problematic for significant flash flooding as the cyclone will slow down and drift somewhere between Sindhu (Indus) of Pakistan and Mahi River Valleys.

Big tropical AEW is over the eastern Atlantic Ocean now, showing rotation in the mid-levels and within the convection, deep convection has developed with the wave.  Anyone if this has a chance to develop?

OTOH, if you will glance at the central Atlantic, you will easily notice a very strong and persistent westerly upper level jet out of the Caribbean very typical of this time of year. Anything that would come out of the eastern MDR is going to get shredded until that subtropical jet lifts out.

Though they kept the graphic marginal, the wording is such that they definitively left the door open for a slight risk to be added tomorrow over the eastern Valley. Perhaps even a small area of enhanced if buoyancy and lapse rates are in line with the sharpening trough. We shall see...