ProbSevere and mature convection

This cell in Laramie Co, WY had a storm report of 1.75″ hail, measured, at 3:51 MDT.

2150Z ProbSevere: 54%, MESH 1.05″

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2156Z was 18%, .70″

Cluster of high CI values turns into storms

A pronounced cluster of higher CI values evolves into a cluster of convection.

Time stamp 2007Z.

Time stamp 2045Z.

Scott Rudge.

Lightning Jump Detection + ProbWarn

For the first time, we have storms in an LMA domain strong enough to produce images on lightning jump grid.

The four-panel image below contains a 3-sigma lightning jump (top left: orange fill region) the pGLM lightning grid (top right: max flash extent density as high as 18 flashes per min), MRMS reflectivity at -10 C (bottom left), and ProbSevere (94%) overlaid on MRMS MESH (bottom right).

AWIPS2 Screenshot from 2136 UTC on 7 May 2014.

This particular combination has provided a couple ideas for lightning jump algorithm development.  (1) inclusion of metadata similar to the mouse-over ability of the ProbWarn product.  The mouse over for the lightning jump should contain the current flash rate as well as the degree of jump in sigma. (2) Combination with a product similar to ProbWarn (if not, the ProbWarn product itself.  This could provide the forecaster information from satellite,  lightning and radar all-in-one product.  The advantage this provides is that approaches a forecaster-over-the-loop type product without becoming a “black box” as all the information that is part of the product is also provided as metadata.  I look forward to working with CIMSS-WI and other researchers on this type of development.

-K. Calhoun, Week 1 Coordinator and Lightning Jump PI

Texas/Oklahoma Dryline Convection and Satellite Product 4-panel Display

This 4-panel satellite product display provides forecasters with an opportunity to view multiple satellite-based products in conjunction with each other and other observational products. In this particular display, we have transparent nearcast instability field with IR underlayed in the upper left, GOES-R CI and VIS in the upper right, OTD and VIS in the lower left, and NLDN lightning and PGLM total lightning in the lower right.

At 1845 UTC, the NearCast theta-e difference field (instability) had a nose of instability surging from central Texas into central Oklahoma. As a cu field developed within the unstable air, GOES-R CI began to target several cloud objects with probabilities of convective initiation greater than 50%.

By 1935 UTC, several cloud objects with higher probabilities did develop into mature storms within the axis of greatest instability as shown in the NearCast product. Lightning was also being mesaured with this developing convection. Meanwhile, high probabilities of CI, including some >90%, were being detected along the NearCast instability boundary into Oklahoma.

By 2010 UTC, a line of mature convection had developed along the NearCast instability boundary from north Texas into Oklahoma, where CI was detecting relatively high probabilities.

By 2130 UTC, many of these storms were becoming severe, one of which had an overshooting top detected, indicating a particularly strong updraft.

Participants this week have found this 4-panel display to be quite useful, as it helps to reduce the amount of displays they must toggle through. Additionally, many of these products are enhanced when used in conjunction with one another and other observation-based tools.

- Bill Line

possibililty for more severe WY, NE, CO next few hours

Nearcast forecast instability still at its highest across parts of CO, WY, and NE over the next few hours.  Some data gaps here, but the surrounding trend in the data around the gaps lead me to believe there’s still a good road for these storms to travel and hold strength, if not intensify in some areas where daytime heating continues…

Lightning Density/Weak Rotation

The storm that developed earlier this afternoon cycled a few times through its development. At times is showed decent rotation, which was warned on by the Denver WFO. The storm continued to show signs of some possible hail and weak rotation as it crossed the border into Wyoming. The lightning density tool did a good job in picking up on the storm, as show above. Lightning density seems to be a neat tool for awareness, not only for lightning being produced, but also what storms may be the strongest.

More Severe Storms and some ProbSevere False Alarms

More storms continue to fire along and ahead of the dryline over north central Texas and western Oklahoma Wednesday afternoon.  Another storm became severe warned over Baylor and Archer counties in Texas at 2123 UTC (Figure 1).  The NOAA/CIMSS ProbSevere model had high probabilities (> 70%) on this storm for nearly an hour prior to the warning being issued.  The first severe report with this storm was 1.75" (golf ball) hail at 2130 UTC 7 May 2014 in Westover, TX.

Figure 1.  NOAA/CIMSS ProbSevere and MRMS composite reflectivity at 2118 UTC 7 May 2014--notice the latest warnings features a storm with very high ProbSevere values and had high values for nearly an hour preceding the warning.

Further north, many storms over Oklahoma have had high ProbSevere values but have yet to receive severe thunderstorm warnings nor severe reports, contributing the false alarm counts (Figure 2).  These storms have favorable environmental conditions and have exhibited strong satellite growth rates--along with MRMS MESH values around 1.00"--which explains high probabilities.  Discussions with EWP forecasters are ongoing on why these storms do not seem to be producing severe weather.

Figure 2.  NOAA/CIMSS ProbSevere and MRMS composite reflectivity at 2100 UTC 7 May 2014.  Notice many storms over Oklahoma with high ProbSevere values (white and pink contours)--as of this writing these remain as false alarms as no severe reports have been received with these storms.

-Sieglaff

Marginally Severe Storm just south of the CWA

 Just before 20Z, storms have developed and the Throckmorton storm looks to be close to severe threasholds. Confidence is high that a warning will be needed for the storm. Prob severe has reached 99% with estimated hail size around an inch. Growth rate and glaciation are strong.

The storm weakened a bit as it entered the CWA, but then strengthened quickly. Growth rate and glaciation was strong. A warning was issued.

Scott Rudge.

Formerly Tornadic Storm in CO moving into CYS area

Storm moving into our area out of Weld Co., CO.  Seems to have lost its rotational signature, but is already cycled a couple of times…and at the least has exhibited some signs of strong downdraft wind wrapping around.   Jared issuing SVR for wind at 2115ZCYS

of interest…total lightning has been relatively steady on this storm over the past 15 minutes.  

Only some ebbs and flows…nothing notable…

ltg

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Severe Weather over Colorado

With the fast and furious pace of severe weather over the Central US today some posts need to be condensed.  Below is an image of three severe storms over Colorado--with storms of interest labeled with 'A', 'B', and 'C'.

Figure 1.  NOAA/CIMSS ProbSevere and MRMR composite reflectivity at 2044 UTC 7 May 2014.  Storms of interest are marked with yellow A,B, and C.

The NOAA/CIMSS ProbSevere model had probabilities in excess of 50% with varying lead-time for these storms.  The first ProbSevere > 50% for these storms occurred at 2020, 2024, and 2034 UTC and the first NWS warnings on these storms occurred at 2101, 2026, and 2055 UTC, respectively (A, B, C), which translates into 41, 2, and 21 minutes of lead-time.

-Sieglaff