Blog 4 Day 4 on 5 June

Monitoring radar and lightning jump -Flash Density over North AL and south TN.

Also using Prob severe. We already issued a warning for NC and NW AL. Having worked as a broadcast Met in this area for 17+ years it is very familiar to me. Unique experience to evaluate these products in an area where I’ve done many hours of severe now-casting.

Lightning jumps are going off on cell in Lincoln (already warned) and prob severe on line appr. NW AL is now at 82%. Also prob severe high on cell now in Jackson Cty. Prob severe rising rapidly

Am finding combo of flash and light jump very helpful in watching these cells which are developing rapidly. Almost seems as if it would be valuable to have one person doing traditional radar analysis and another using these tools over the same storms.

D Satterfield

Blog 3 Day 4 on 5 June Warn for North AL

Have issued a warning for North AL ahead of he MCS in North AL based on past history, flash extent density and MESH indicating large hail NQA Nexrad shows strong inflow winds in mid levels which should reach surface ahead of the line.

ThetaE Difference Loop – Showing Increasing Instability/Convective Potential???

Attached loop shows the Theta E difference values decreasing over the front range over the last 2 hours.  Looks like a minor surge of moisture creeping northward – which if this is correct should increase convective vigor by 21z.  This appears to be happening already – with storm intensity increasing on radar between 2000 and 2015Z.

Fowle

pGLM colormap (comparison)

As the MCS moves towards the Northern Alabama LMA, I thought it was a good time to compare colormaps and get feedback from each of the forecasters.

I added the following image to the large screen of the situational awareness display within the HWT and asked each forecaster which colormap they preferred – the one on the bottom left or the one on the bottom right.

top left: 200 km2 LJA over MRMS lowest refl. Top right: 600 km2 LJA over refl at -10 C. Bottom left: PGLM flash extent density (colormap 1). Bottom Right: PGLM flash extent density (colormap 2)

All forecasters this week preferred the colormap on the bottom left except for one specific case:  when they want to overlay the data on radar.  For that particular occurance, the bottom left is a bit to similar to the radar. However, all agreed that on its own or overlaid on satellite the colormap on the bottom left is much preferred. (note: the colormap on the bottom right is the default colormap for AWIPS2).

-K. Calhoun

Blog 2 Day 4 on 5 June

Have switched to the HUN CWA as of 1930Z.

Discussion of NSSL WRF sim sat with IR and water vapor.

Large MCS to the NW of the CWA moving into it. The NSSL WRF shows the MCS but is far less robust on the eastern end of it than is apparent in the IR imagery. Also strong cirrus shield is present east of the MCS which is not present in the NSSL WRF. This will have obvious impacts on model performance because of insolation issues etc.

Over the Carolinas we have some convection developing ahead of a surface cold front.. the NSSL WRF is to robust on the convection esp in KGSP area. Although it is doing quite well but a bit fast (by 100km) over the outer banks of NC.

Talking with KP about carolinas and the spatial errors may be due to model limitations on depicting the Appalachians.

DSatterfield & KP

CI GOES E vs GOES W

Taking a look at the highlighted areas, the top image is from GOES-E showing CI values of 92% in an area that developed into decent convective towers. The bottom image is from GOES-W with the same area showing CI values of 46%. Why such a difference?

jca

NearCast ThetaE Diff

Examined the ThetaE difference at 19z.  From a qualitative perspective – the ThetaE difference is greater over PUB than BOU.  Thus – you would expect it is more unstable over the PUB CWA – and thus more vigorous updrafts.  We shall see how this verifies this afternoon.

Simulated Satellite – Thursday

Started off the day by examining the Simulated Satellite products.  Overall – they provided a good starting point over CO.  It showed the stratus burning off in eastern CO in about the right time.  Plus – CI initiates around 18-19z which is evident in the actual satellite obs.  Thus – the NSSL WRF should provide an accurate depiction of overall convective evolution.

18z Top – 19z Bottom

EWP Operations Update – Thursday 6/5 – 2:45 pm

Today, we started operations in the Boulder and Pueblo CWAs, anticipating the development of severe storms in upslope flow in the lee of the Rockies.  Our hope is to have the Boulder group (Anderson and Fowle) monitor the Colorado lightning mapping array during the event.

Given the paucity of cumulus clouds in the Pueblo CWA, we believe that convective initiation will hold off until later.  Also, lightning activity is increasing in the Huntsville lightning mapping array as an MCS approaches from the west-northwest.  Thus, we have decided to re-localize the Pueblo group (Pelczynksi and Satterfield) to Hunstville.

-G. Garfield

Week 4 Coordinator

June 4/5 MCS and Overshooting Tops

An MCS originating in eastern Colorado Wednesday evening (06/04) traversed the southern Plains into the southeast by Thursday (06/05) afternoon. This system had many overshooting tops associated with it, highlighting the locations of the strongest updrafts (and associated hazardous weather) within the massive cloud shield. The overshooting top detection algorithm gives forecasters a tool to easily monitor locations of overshooting tops and trends in detection's over time. It is an especially beneficial tool to have at night (as with this case) in the absence of visible imagery. Below is a loop of IR satellite imagery with overshooting tops overlaid from 0345 through 1845 UTC on the 5th.

SPC storm reports for the 4th and 5th show that the occurrences of severe weather matched up with the locations of the overshooting tops.

- Bill Line, SPC/HWT Satellite Liaison