Tuesday, May 19, 2015
Missing CI in multiple cloud layer decks
The GOES-R CI algorithm has trouble detecting Convective Initiation when there are clusters of clouds of multiple levels in the same area. Two areas of initiation occurred today, one near the Red River, and one near the south of the Dallas/Fort Worth area where multiple decks of clouds prevented the CI product from tracking the cells. The CI algorithm requires at least 10% overlap of objects between two successive time periods, and without being at the office to look at the overlap, it is not known if these were missed due to mistracking or if the algorithm just did not detect convective clouds due to the multiple cloud layers. Something we will need to look into for the future. In the scalloped areas from 1900 UTC and 2000 UTC, one can see the difficulty of pulling out distinct features in the visible imagery, yet by 2000 UTC, full blown thunderstorms had developed.
Prob severe rate
Issued severe thunderstorm warning for hail. Prob severe ranged from 90 to a maximum of 94%, which lined up well with with my warning thoughts.
ProbSevere 5.69″ MESH
The ProbSevere jumped up to 96% with MESH over 5″ when ABQ radar went into clear air mode for 2 scans.
-snowstrm
-snowstrm
2000z FWD
GOES CI is picking up on CI across west central portions of the cwa…but interestingly enough not picking up on the circled likely severe cell and cell to its ne below. Prob severe of 80% and DTA detected at 1930z. (Fig2)Overshooting top detection has not picked up on this cell either. The GOES-R superscan (Fig 1) is very nicely showing the overshooting top on this and cell to the ne.
Storm Pulsing Back Up Over OUN CWA
Using ProbSevere and the ENI lightning flash rate time series, I issued a new SVR warning. I like having both data side by side to add confidence when examining the raw radar data. This storm has pulsed up and down over the last hour or two, so the ProbSevere helps keep the SA up when it maxed out at 80% when I issued the warning.
1930z FWD
Latest GOES R- LAP algorithm trends indicating increasing instability and moisture across the CWA to the south of a fairly stationary warm front across Oklahoma.
Highest instability/moisture exists across se portions of the CWA…tapering to moderate across nw portions of the region. (Fig 1&2)This matches fairly well with model progs. But this enviromnment is being advecting nw based on s/se flow low-level flow. Model analysis indicates strongest deep layer shear values will be across nw portions of the cwa (around 40kt)…with marginal values across se portions (25 kt). Combined shear/instability fields indicate highest potential for organized severe weather will be across NW half of the cwa this afternoon…with more isolated threat farther se. In general large hail and wind threat are supported by the high instability and adequate to strong shear. Tornado threat exists as well based on modest low-level helicity and shear values.
Highest instability/moisture exists across se portions of the CWA…tapering to moderate across nw portions of the region. (Fig 1&2)This matches fairly well with model progs. But this enviromnment is being advecting nw based on s/se flow low-level flow. Model analysis indicates strongest deep layer shear values will be across nw portions of the cwa (around 40kt)…with marginal values across se portions (25 kt). Combined shear/instability fields indicate highest potential for organized severe weather will be across NW half of the cwa this afternoon…with more isolated threat farther se. In general large hail and wind threat are supported by the high instability and adequate to strong shear. Tornado threat exists as well based on modest low-level helicity and shear values.
LAP Data for Mesoanalysis
The LAP data provided useful information for analyzing the current environment in the Lubbock CWA (and surrounding region) as well as trends in the data. Precipitable Water and CAPE are two great examples.
The PW image shows the approaching dryline from New Mexico with increasing PW out ahead of it. A loop of the data shows increasing values from MAF CWA north into very southern portion of LUB. A similar trend is seen in the CAPE values with max values of 2500 to 3000 well to the south. The 12Z KMAF Sounding (below) shows the low level moist airmass. When modified it indicates CAPE Values approaching 3800.
Expect the best chance of severe storms will be the Eastern portion of the LUB CWA as conditions continue to destabilize this afternoon and dry line progresses eastward.
-snowstrm
The PW image shows the approaching dryline from New Mexico with increasing PW out ahead of it. A loop of the data shows increasing values from MAF CWA north into very southern portion of LUB. A similar trend is seen in the CAPE values with max values of 2500 to 3000 well to the south. The 12Z KMAF Sounding (below) shows the low level moist airmass. When modified it indicates CAPE Values approaching 3800.
Expect the best chance of severe storms will be the Eastern portion of the LUB CWA as conditions continue to destabilize this afternoon and dry line progresses eastward.
-snowstrm
LUB Early Analysis
Lubbock CWA not experiencing severe convection at beginning of shift, but departing cells observed to the north and northeast. Based on mesoanalysis, will also watch MAF and ABQ CWAs for emerging storms that could be mature in the LUB area.
CI gave a useful signature for developing storms in Pecos Co TX, and Roosevelt Co NM.
For example. Roosevelt Co storm first acquired a probability of severe (albeit small 7%) at 1906Z. CI first passed 50% at 1815Z. By time of writing (1940Z) it had trended down.
At 1950 two areas have CI >60%, Dickens Co and Briscoe Co.
AMA 12Z sounding was not judged to be representative. Based on modified MAF sounding 3800 SBCAPE can be achieved, also represented by RAP mesoanalysis.
-Holaday
CI gave a useful signature for developing storms in Pecos Co TX, and Roosevelt Co NM.
For example. Roosevelt Co storm first acquired a probability of severe (albeit small 7%) at 1906Z. CI first passed 50% at 1815Z. By time of writing (1940Z) it had trended down.
At 1950 two areas have CI >60%, Dickens Co and Briscoe Co.
AMA 12Z sounding was not judged to be representative. Based on modified MAF sounding 3800 SBCAPE can be achieved, also represented by RAP mesoanalysis.
-Holaday
Monday, May 18, 2015
Daily Summary: Week 3, Day 1 (May 18, 2015)
Forecasters operated in Lubbock and Midland CWA's.
NUCAPS
- Nice supplemental sounding to have midday/ early afternoon
- Its nice to be able to adjust it
-
GOES-R CI
- A lot of mixed results yesterday
- It didn’t pick up well on development in some places, but better in others
- In midland area, it did real well for us
- For large storm with tor, 86% percent before it developed.
- 60% probability has best score for initiating convection
- In convective situation, it is important to know when that first initiation will occur, even if it isn’t severe to start.
ProbSevere
- It lets you sort the storms quickly, it shows you trends in storms
SRSOR
- Over Northeast outside of our area
Lightning jump
- Mouse-over and have trend-line/meteogram pup-up with readout
Pickles 5/18/2015 23z
Utlility of Lightning Jump Detection algorithm in providing situational awareness on total lightning increase.
At 2241z…LJDA…detected a 3 sigma jump with the storm of concern. (Fig1) At that time ENTLN data reported 177 cloud flashes…only 9 of which were CG. (Fig2) Then at 2250z ENTLN reported 351 flashes…4 CG. (Fig3) The LJDA provided good situational awareness on this doubling of total lightning count and subsequent intensification. which based on 65-70 dbz reflectivity at 25000 ft was valid. (Fig 4) The other interesting note…is that most of the lightning was IC and not CG. CG data would have told you very little about this storms intensification.
Fig1.
At 2241z…LJDA…detected a 3 sigma jump with the storm of concern. (Fig1) At that time ENTLN data reported 177 cloud flashes…only 9 of which were CG. (Fig2) Then at 2250z ENTLN reported 351 flashes…4 CG. (Fig3) The LJDA provided good situational awareness on this doubling of total lightning count and subsequent intensification. which based on 65-70 dbz reflectivity at 25000 ft was valid. (Fig 4) The other interesting note…is that most of the lightning was IC and not CG. CG data would have told you very little about this storms intensification.
Fig1.
Fig2.
Fig3.
Fig4.
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