Differential heating boundary example in 1-minute visible imagery

Storm example (J-Money):

In addition to terrain enhancement and the approach of a mid-level short-wave, rapid storm intensification appeared to occur near the edge of a persistent cumulus field (differential heating boundary).  The attached loop of 1-minute imagery shows this nicely.

The Value of High Temporal Satellite Data

Impressive temporal detail in the SRSOR one minute visibile satellite. See the loop below and notice the detail in the character of the overshooting top and how it changes with time. Compare this with the reflectivity and velocity on the 4.0 elevation angle (~40 KFT). Trends in the overshooting top can be seen quicker in the one minute satellite data compared to the radar, especially when the radar is using meso-SAILS which further slows the upper cuts. The temporal increase in satellite data can fill the void of the temporal loss in radar data with meso-SAILS.

-dryadiabat

LJA and Severe CI

Thunderstorms finally beginning to develop across Pecos County in west Texas as midlevel shortwave trough continues to slowly apprach the area.  Recent development has seen a 8 sigma jump in lightning activity across south-central Pecos County. 

Severe CI actually peaked at 64% for this storm...

NUCAPS example in MAF's CWA

NUCAPS example (J-Money):

We looked at a NUCAPS example in West TX late this afternoon (data at 19z), near the area where terrain enhanced convection was firing.  After modifying the sounding for representative surface temperature/dew point (KFST surface observation site), we compared the ML CAPE and mid-level environment to the latest SPC meso-analysis.  The comparison was favorable (SPC CAPE 1000-1500, with the NUCAPS sounding around 1200).  Dry well mixed mid-level environment also seems quite representative compared to observed mid-level lapse rates from the meso-analysis data and actual GOES-13 water vapor imagery.

Due to the presence of broken clouds, steep mid-level lapse rates, and fairly uniform surface conditions, the environment appears to be favorable to maximize the success of NUCAPS retrieval abilities.

This is an optimal example of when NUCAPS soundings could be used operationally with confidence, and thus will provide good material for training purposes.  Please see attached.

                                                 Original NUCAPS sounding.

                                                Modified NUCAPS sounding

                                      1-minute visible imagery near KFST

                                       ML CPAPE from SPC meso-analysis


     

LMA Color Curves

Of the three color curves currently available for LMA, the default LMA curve appears to highlight the flash densities the best.

NUCAPS Soundings for Tuesday

In stark contrast to yesterday, today's NUCAPS soundings appear to be much more representative that the soundings viewed yesterday near CPR.  In today's case, the atmosphere has quite a bit of dry midlevel air which is likely allowing for a more represetative retrieval.  Only minor modifications of the boundary layer temp/dewpoint were needed. 

torman1

Convection Southwest of Stockton

We're monitoring the convection just southwest of Stockton where CI had the highest values of the day (strong - red), followed by the highest prob severe values of the day. Trends on radar using All-Tilts in Midland have been steady the last few minutes and the storm is clearly sub-severe. Interestingly, 40-50 dBZ core depths are very similar along a line from just southeast of Stockton westward to the Brewser County line where the cell that has the higher prob severe signal is located. We'll continue to monitor trends in this cell to see if CI and prob severe where accurately able to differentiate which cell had the greatest potential.

UPDATE: About one hour later this cell has become the most intense on radar with 50 dBZ to around 33 KFT and 60-65 dBZ throughout the hail growth zone. Also noteworthy, the severe CI was higher about an hour ago as this convection began to develop than with any other convection seen today. Values were around 50 approximately an hour ago.

-dryadiabat

CI product usefulness on terrain enhanced thunderstorms

More CI stuff in MAF's CWA: (J-Money)

Regular CI images continue to do a good job depicting initiation along the ridge line of the Davis Mountains, with little potential off the ridge line.  For the first time today (as of about 2015z), Severe CI is showing a little more potential with one of these storms (probabilities into the green ranges).  See the attached loop.

Preliminary Thoughts on CI False Alarm and Detection

Some of the initial moderate (yellow to orange) CI signals in Jeff Davis County around 17z where the strongest signals seen so far in the day. These yielded very shallow ~30 dBZ returns on radar but convection did not sustain. Further east near Fort Stockton was where radar showed the first substantial convection of the day with relatively deep 50 dBZ cores, albeit likely sub-severe. CI values were low prior to initiation of this convection. More recently strong CI values were noted in far northern Brewster County but has since waned. Around the time values peaked in Brewster County, weak shallow convection was noted on Midland radar, but the convection did not sustain. As of this writing convection is still struggling but weak shallow returns have increased in spatial coverage primarily across Pecos County. CI has show weak to moderate values in this area over the last 30 minutes. At least minimal lead time from when a signal appears on radar seems to be achieved with these moderate values, particularly over Culberson and Reeves counties. Will continue monitoring for continuity to gain a better unstersand of false alarm and detection rate of the CI products, but initial assessment is that the false alarms in the CI product may be relatively frequent (at least for the weak and moderate signals). 

-dryadiabat

Regular CI in MAF

Regular CI product in MAF's area:

CI has accurately portrayed initiation over the ridge line of the Davis Mountains so far, with very low values elsewhere.  This product has done well, as forcing has been insufficient to generate much else off the ridge line. -J-Money