Re: live show today
Posted by Chris in Tampa on 8/13/2017, 1:20 pm
I see the ECMWF has a little something now. Very different from the GFS which is very bullish on it and everywhere from US, Canada to offshore. Even Bermuda in one run. One run did zig zags before going into Canada. ECMWF doesn't go out that far, though it in the most recent run that picks up on it, it takes a more southerly solution just north of Cuba. Meanwhile GFS shifted from Carolinas to skirting off the east coast and into Canada. Too early to get a sense of whether it will be the Gulf, E. Coast, Canada, Bermuda or somewhere inbetween. Or no development at all.

GFS is often so random in the long range.

I never noticed, but most of the time when you click the GFS images at Tropical Tidbits you get a model sounding at any point you click.

GFS:
https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=atl&pkg=mslp_pcpn_frzn

I don't understand a lot of it, but I do find the hodograph interesting.

I was reading some about them:
http://weather.cod.edu/sirvatka/hodo.html
http://www.spc.noaa.gov/exper/soundings/help/hodoarea.html

The second site, some of which doesn't apply, says this about the LM and RM:

"Potential left- (LM) and right-moving (RM) supercell motions (based on the Bunkers technique) are marked by the black circles with cross hairs."

Even that, the cross hairs part doesn't apply. Still not sure what the first part means, a lot of technical stuff in the imagery. I thought I would mention the LM and RM in case anyone wanted to investigate.

But you can at least get wind at various levels from it. In some of the previous runs of the GFS for 91L I was clicking some of the highest wind areas in it.

You can also see some shear and dry air in the rest of the imagery. SHR listed to the right averaged over two different depths.


Some other stuff from those images, which I just Googled some stuff about...


PWAT: "Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column over a given location, usually extending from the surface to 300 mb."

From: http://w1.weather.gov/glossary/index.php?word=PWAT



DCAPE:
https://www.weather.gov/media/lmk/soo/DCAPE_Web.pdf
http://glossary.ametsoc.org/wiki/Downdraft_convective_available_potential_energy

- DACAPE is the maximum energy available to a descending parcel of air
- Used to estimate the potential strength of rain-cooled downdrafts within thunderstorms
- The higher the value of DCAPE, the stronger the downdraft potential
- DCAPE values over 1000 J/kg are often significant and imply steep low-level lapse rates which are conducive to downward transport of higher momentum air to the surface resulting in gusty winds and possibly wind damage




RH - Relative humidity

"Is a ratio, expressed in percent, of the amount of atmospheric moisture present relative to the amount that would be present if the air were saturated.  Since the latter amount is dependent on temperature, relative humidity is a function of both moisture content and temperature.  Relative Humidity is derived from the associated Temperature and Dew Point for the indicated hour."

From: https://graphical.weather.gov/definitions/defineRH.html
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/dvlp/rh.rxml



SRH - Storm Relative Helicity

"SRH (Storm Relative Helicity) is a measure of the potential for cyclonic updraft rotation in right-moving supercells, and is calculated for the lowest 1-km and 3-km layers above ground level. There is no clear threshold value for SRH when forecasting supercells, since the formation of supercells appears to be related more strongly to the deeper layer vertical shear. Larger values of 0-3-km SRH (greater than 250 m**2/s**2) and 0-1-km SRH (greater than 100 m**2/s**2), however, do suggest an increased threat of tornadoes with supercells. For SRH, larger values are generally better, but there are no clear "boundaries" between non-tornadic and significant tornadic supercells."

From: http://www.spc.noaa.gov/exper/mesoanalysis/help/help_srh1.html



CIN - Convective inhibition

"(CIN or B-) - A numerical measure of the strength of "capping," typically used to assess thunderstorm potential. Specifically, it represents the cumulative effect of atmospheric layers the are warmer than the parcel moving vertically along the adiabat. Low level parcel ascent is often inhibited by such stable layers near the surface. If natural processes fail to destabilize the lower levels, an input of energy from forced lift (a front, an upper level shortwave, etc.) will be required to move the negatively buoyant air parcels to the point where they will rise freely. Since CIN is proportional to the amount of kinetic energy that a parcel loses to buoyancy while it is colder than the surrounding environment, it contributes to the downward momentum."

From: https://forecast.weather.gov/glossary.php?word=convective%20inhibition
http://www.spc.noaa.gov/exper/mesoanalysis/help/begin.html
That link also has info about surface parcel CAPE (sbCAPE) and most unstable parcel CAPE (muCAPE).



Omega vertical velocity (Pa/s) perhaps might be what that is. I start Googling that and my brain hurts from looking at the massively long equations without numbers.



DGZ is Dendritic Growth Zone. Relates to snow.

http://training.weather.gov/wdtd/courses/winterawoc/documents/color_PDFs/IC652.pdf
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live show today - jimw, 8/12/2017, 7:40 am
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