BAJ
Thursday, April 28, 2016
LAP struggling with instability in VA
A CAD wedge is breaking across the central Appalachians with instability increasing north of the NC border. However LAP analysis has a very sharp line in CAPE right along the NC/VA border. This looks artificial - perhaps the GFS is too slow in eroding the CAD wedge in VA. Note the clear sky major in wrn NC where wrn VA has the gray of GFS usage.
16Z Mesoanalysis has 1000-1500 j/kg of CAPE in that part of VA and I believe that more - a win for the RAP. Note below that a fair amount of clearing had occurred in VA by 16Z.
Note: LAP products failed to update for a 2 hour period today, a cause for some of the discreteness in areal coverage when compared to the updated RAP.
16Z Mesoanalysis has 1000-1500 j/kg of CAPE in that part of VA and I believe that more - a win for the RAP. Note below that a fair amount of clearing had occurred in VA by 16Z.
Note: LAP products failed to update for a 2 hour period today, a cause for some of the discreteness in areal coverage when compared to the updated RAP.
BAJ
Thursday EWP - Start in Rayleigh and Blacksburg CWA
For Thursday, the two EWP groups have begun operations in the Rayleigh and Blacksburg CWA's.
The LAP products depict instability increasing across the region, capturing the sharp cutoff along a frontal boundary draped along eastern North Carolina/Virginia border.The GFS seems to be a little week with instability (compared to adjusted RAOBs and SPC mesoanalysis). These are the gray areas in the LAP retreival type (upper right). Where the LAP algorithm computes retreivals (clear sky or cloudy sky; using GFS as a first guess), it brings the instability up in line with what the other sources have.
The LAP products depict instability increasing across the region, capturing the sharp cutoff along a frontal boundary draped along eastern North Carolina/Virginia border.The GFS seems to be a little week with instability (compared to adjusted RAOBs and SPC mesoanalysis). These are the gray areas in the LAP retreival type (upper right). Where the LAP algorithm computes retreivals (clear sky or cloudy sky; using GFS as a first guess), it brings the instability up in line with what the other sources have.
The LAP Layer PW fields show dry air moving in aloft, with low-level moistening south of of the boundary.
Convective initiation had begun in the region around 1800 UTC as depicted in the 1-min VIS.
Wednesday, April 27, 2016
Daily Summary: Week 2, Day 3 (27 April 2016)
Today our groups operated in the Kansas City and St. Louis CWA's. The Kansas City group experienced active weather almost from the start, while the St Louis group had more time to evaluate the tools in the pre-convective environment before convection developed in the early evening.
GOES-R LAP
- We noticed an odd shift in the fields every 6 hours. Could this have been due to a different model run being used for the background?
- The Layer PW fields captured elevated dry air intrusion today with moistening at the low levels prior to convective development
- I like being able to see hour-to-hour changes in these fields.
GOES-R CI
- Both CI and severe CI mostly missed on the main line of storms. They both did hit on a storm ahead of the main line
- CI would be great for a warning coordinator; someone who is taking a step back and looking at the bigger picture. I think there is utility there. This would have helped yesterday for that type of use when many storms were present.
- For St Louis, it was showing signals that things were about to break. It would pick up on a cell just before convective initiation.
- It might be useful to tie this in with Hydro WFR; indicating where stuff might go.
- The 30 min full disk gap hurt yesterday; won't be an issue with GOES-R
- Shades of gray might be better for lower probs. Dark blue stands out too much, especially against clouds.
ProbSevere
- It always seemed to increase to significant levels a scan or two after I issued the warning.
- Storms were producing quickly
- Loading ProbSevere with dBz at -20C provided utility
- Tracking dBz at -20C level might help better isolate cells within lines
- With a tornado-producing cell, MESH was low, so probs were also very low.
- For ProbSevere and hail, it might be more of a product for confidence once you have a warning out. A warning coordinator should also be looking at this.
- I don't remember seeing any false alarms yet (high probs with no reports). Maybe only when there was a line when ProbSevere grabbed multiple cores.
- It helped give confidence to issue a new warning on a storm that had already produced and been warned on.
- There was a situation when I thought about letting a warning drop, but ProbSevere stayed high so I re-warned, and it did continue to look severe thereafter.
- This is helpful for monitoring cyclical severe cells
SRSOR
- With one warning I issued, ProbSevere had been slow during the day, and storms were producing severe quickly. In a data sparse region, I saw a cu pop faster than anything else I had seen during the day, and it continued to grow rapidly, so I warned. I probably would not have warned without the SRSOR. This will have great utility in data sparse areas, nudging you to warn in certain situations.
- I think there is utility in knowing the environment, EL, temps, and comparing this with measured cooling in IR imagery on the one minute scale.
Lightning Jump
- This was slow with devleopment throughout the day.
- There weren't really any significant jumps until after the storm went severe
- Lightning seemed to only steadily increase in storms yesterday, not reaching high levels until after they went severe.
NUCAPS
- I saw an area where I though things would come together later. I picked a NUCAPS retrieval location and adjusted the profile. I could analyze how the moisture profile evolved during the early day, which was helpful. In the morning Springfield RAOB, there was deep moisture. In the afternoon NUCAPS sounding, moisture had decreased with drying aloft, which compared well with GOES Water Vapor imagery.
- We have areas by my office in Texas where NUCAPS will be helpful, including a big gap in RAOB data in central Texas. This will allow us to capture the mid-day, pre-storm environment between RAOB data (in space and time).
GOES-R LAP
- We noticed an odd shift in the fields every 6 hours. Could this have been due to a different model run being used for the background?
- The Layer PW fields captured elevated dry air intrusion today with moistening at the low levels prior to convective development
- I like being able to see hour-to-hour changes in these fields.
GOES-R CI
- Both CI and severe CI mostly missed on the main line of storms. They both did hit on a storm ahead of the main line
- CI would be great for a warning coordinator; someone who is taking a step back and looking at the bigger picture. I think there is utility there. This would have helped yesterday for that type of use when many storms were present.
- For St Louis, it was showing signals that things were about to break. It would pick up on a cell just before convective initiation.
- It might be useful to tie this in with Hydro WFR; indicating where stuff might go.
- The 30 min full disk gap hurt yesterday; won't be an issue with GOES-R
- Shades of gray might be better for lower probs. Dark blue stands out too much, especially against clouds.
ProbSevere
- It always seemed to increase to significant levels a scan or two after I issued the warning.
- Storms were producing quickly
- Loading ProbSevere with dBz at -20C provided utility
- Tracking dBz at -20C level might help better isolate cells within lines
- With a tornado-producing cell, MESH was low, so probs were also very low.
- For ProbSevere and hail, it might be more of a product for confidence once you have a warning out. A warning coordinator should also be looking at this.
- I don't remember seeing any false alarms yet (high probs with no reports). Maybe only when there was a line when ProbSevere grabbed multiple cores.
- It helped give confidence to issue a new warning on a storm that had already produced and been warned on.
- There was a situation when I thought about letting a warning drop, but ProbSevere stayed high so I re-warned, and it did continue to look severe thereafter.
- This is helpful for monitoring cyclical severe cells
SRSOR
- With one warning I issued, ProbSevere had been slow during the day, and storms were producing severe quickly. In a data sparse region, I saw a cu pop faster than anything else I had seen during the day, and it continued to grow rapidly, so I warned. I probably would not have warned without the SRSOR. This will have great utility in data sparse areas, nudging you to warn in certain situations.
- I think there is utility in knowing the environment, EL, temps, and comparing this with measured cooling in IR imagery on the one minute scale.
Lightning Jump
- This was slow with devleopment throughout the day.
- There weren't really any significant jumps until after the storm went severe
- Lightning seemed to only steadily increase in storms yesterday, not reaching high levels until after they went severe.
NUCAPS
- I saw an area where I though things would come together later. I picked a NUCAPS retrieval location and adjusted the profile. I could analyze how the moisture profile evolved during the early day, which was helpful. In the morning Springfield RAOB, there was deep moisture. In the afternoon NUCAPS sounding, moisture had decreased with drying aloft, which compared well with GOES Water Vapor imagery.
- We have areas by my office in Texas where NUCAPS will be helpful, including a big gap in RAOB data in central Texas. This will allow us to capture the mid-day, pre-storm environment between RAOB data (in space and time).
Interesting Tornado Warning #3 - Saint Louis (LSX) & Extremely Low Severe Probs
KLSX 0.5 SRM Velocity Image - Tornado Warned Storm
KSLX 0.5 Reflectivity - Tornado Warned Storm
This is the same storm where I originally had a Tornado Warning on it, then I thought the storm had moved out of the warning area into the adjacent CWA, but what I did not notice was the rotation was straddling the County Line, therefore I needed to re-issue the Tornado Warning, and for quite awhile this storm has straddled the county line before canceling the warning after it moved into the adjacent CWA, the circulation for that matter... Below are my text warnings (and more explanation below...)
WFUS53 KLSX 280002
TORLSX
ILC135-280030-
/O.NEW.KLSX.TO.W.0005.160428T0002Z-160428T0030Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
702 PM CDT WED APR 27 2016
THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A
* TORNADO WARNING FOR...
EAST CENTRAL MONTGOMERY COUNTY IN SOUTH CENTRAL ILLINOIS...
* UNTIL 730 PM CDT
* AT 702 PM CDT...LOCAL LAW ENFORCEMENT REPORTED A TORNADO NEAR NOKOMIS. DOPPLER RADAR SHOWED THIS TORNADO MOVING EAST AT 15 MPH.
* LOCATIONS IMPACTED INCLUDE...
NOKOMIS...COALTON...OHLMAN AND WENONAH.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TO REPEAT...A TORNADO HAS BEEN CONFIRMED BY LOCAL LAW ENFORCEMENT. TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF YOU ARE IN A MOBILE HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.
&&
LAT...LON 3928 8914 3929 8946 3935 8947 3935 8914
TIME...MOT...LOC 0002Z 265DEG 15KT 3933 8937
$$
BMS
WWUS53 KLSX 280015
SVSLSX
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
715 PM CDT WED APR 27 2016
ILC135-280030-
/O.CON.KLSX.TO.W.0005.000000T0000Z-160428T0030Z/
MONTGOMERY IL-
715 PM CDT WED APR 27 2016
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 730 PM CDT FOR EAST CENTRAL MONTGOMERY COUNTY...
AT 715 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD. A TORNADO MAY DEVELOP AT ANY TIME. THIS DANGEROUS STORM WAS LOCATED OVER NOKOMIS...MOVING EAST AT 15 MPH.
LOCATIONS IMPACTED INCLUDE...
NOKOMIS...OHLMAN AND WENONAH.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF YOU ARE IN A MOBILE HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.
IF A TORNADO OR OTHER SEVERE WEATHER IS SPOTTED REPORT IT TO THE NATIONAL WEATHER SERVICE OR YOUR NEAREST LAW ENFORCEMENT AGENCY WHO WILL RELAY YOUR REPORT. THIS ACT MAY SAVE THE LIVES OF OTHERS IN THE PATH OF DANGEROUS WEATHER.
&&
LAT...LON 3932 8914 3930 8938 3935 8942 3935 8914
TIME...MOT...LOC 0015Z 264DEG 15KT 3933 8930
$$
BMS
Then as the warning above was warning expiration, I issued a new Tornado Warning:
WFUS53 KLSX 280027
TORLSX
ILC135-280100-
/O.NEW.KLSX.TO.W.0006.160428T0027Z-160428T0100Z/
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
727 PM CDT WED APR 27 2016
THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A
* TORNADO WARNING FOR...
EAST CENTRAL MONTGOMERY COUNTY IN SOUTH CENTRAL ILLINOIS...
* UNTIL 800 PM CDT
* AT 726 PM CDT...TRAINED WEATHER SPOTTERS REPORTED A FUNNEL CLOUD OVER NOKOMIS A TORNADO MAY DEVELOP AT ANY TIME. DOPPLER RADAR SHOWED THIS DANGEROUS STORM MOVING EAST AT 15 MPH.
* LOCATIONS IMPACTED INCLUDE...
NOKOMIS...OHLMAN AND WENONAH.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF YOU ARE IN A MOBILE HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING DEBRIS.
&&
LAT...LON 3930 8934 3935 8939 3935 8914 3932 8914
TIME...MOT...LOC 0026Z 270DEG 12KT 3934 8930
$$
BMS
WWUS53 KLSX 280029
SVSLSX
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
728 PM CDT WED APR 27 2016
ILC135-280038-
/O.EXP.KLSX.TO.W.0005.000000T0000Z-160428T0030Z/
MONTGOMERY IL-
728 PM CDT WED APR 27 2016
...THE TORNADO WARNING FOR EAST CENTRAL MONTGOMERY COUNTY WILL EXPIRE AT 730 PM CDT...
THE TORNADO WARNING THAT WAS PREVIOUSLY IN EFFECT HAS BEEN REISSUEDFOR EAST CENTRAL MONTGOMERY COUNTY AND IS IN EFFECT UNTIL 800 PM CDT. PLEASE REFER TO THAT BULLETIN FOR THE LATEST SEVERE WEATHER INFORMATION.
TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE ST LOUIS .
LAT...LON 3932 8914 3930 8938 3935 8942 3935 8914
TIME...MOT...LOC 0026Z 265DEG 15KT 3933 8930
$$
BMS
Then... It appeared that the bulk of the circulation had moved out of the county to the Northeast, so not long after issuing the new Tornado Warning, I went ahead and canceled it.
WWUS53 KLSX 280034
SVSLSX
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
733 PM CDT WED APR 27 2016
ILC135-280043-
/O.CAN.KLSX.TO.W.0006.000000T0000Z-160428T0100Z/
MONTGOMERY IL-
733 PM CDT WED APR 27 2016
...THE TORNADO WARNING FOR EAST CENTRAL MONTGOMERY COUNTY IS CANCELLED...
THE STORM WHICH PROMPTED THE WARNING HAS MOVED OUT OF THE AREA. THEREFORE THE WARNING HAS BEEN CANCELLED.
TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE ST LOUIS .
LAT...LON 3930 8934 3935 8939 3935 8914 3932 8914
TIME...MOT...LOC 0032Z 270DEG 12KT 3934 8927
$$
BMS
THEN, what was also noticed from one of the other Tornado Warnings that I had issued, was the Severe Probs we're VERY low, we're talking single digits, and there was no MESH Hail information either, telling me that there was no hail in this storm, just the tornado potential.
Super Rapid Scan Used To Issue Warning In Radar-Sparse Area
A line of storms moved through northern Missouri, which has very bad radar coverage. Because of the poor coverage, radar signatures (and to an extent ProbSevere) will often times miss severe weather in this area. This is perhaps an area where super rapid scan data could be of use. In the loop shown below, you can actually see some explosive growth in the storms in this area. This growth was enough to give me confidence to issue a warning in this area, despite poor radar sigantures and ProbSevere around 60%.
---UPDATE---
This storm ended having 60mph wind reports and 1 1" hail report.
-Toki Wartooth
This storm ended having 60mph wind reports and 1 1" hail report.
-Toki Wartooth
ProbSevere for a line with hail cores
Severe cores are producing warning level hail along a squall. ProbSevere goes for the whole line where it should highlight the greatest cores individually.
BAJ
Severe Thunderstorm Warning #3 - Saint Louis (LSX)
WUUS53 KLSX 272351
SVRLSX
MOC055-280030-
/O.NEW.KLSX.SV.W.0016.160427T2351Z-160428T0030Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
650 PM CDT WED APR 27 2016
THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN CRAWFORD COUNTY IN EAST CENTRAL MISSOURI...
* UNTIL 730 PM CDT
* AT 650 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 7 MILES SOUTHEAST OF ROLLA...AND MOVING NORTHEAST AT 30 MPH.
* LOCATIONS IMPACTED INCLUDE...
CUBA AND STEELVILLE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...DESTRUCTIVE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.
TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.
&&
LAT...LON 3786 9153 3809 9152 3810 9152 3816 9143
3798 9122
TIME...MOT...LOC 2350Z 234DEG 25KT 3789 9166
$$
BMS
I've been watching this Severe Thunderstorm continue to move Northeast for over the past hour with continuous Severe Probs of 70% or better, with MESH over 1.00" most times as well, so went ahead and proactively issued the Severe Thunderstorm Warning based on the Severe Probs history with this thunderstorm.
Forecaster: Schuerman
Operations update: A great day in Missouri!
Today turned out to be fairly active day in the Kansas City and St Louis CWA's. Deep convection began fairly early in the afternoon in the Kansas City area, leading that group into warning operations and heavy use of the 1-min imagery, ProbSevere and Lightning Jump. The St Louis group had a lot more time early in the shift to interrogate tools such as 1-min imagery, CI, NUCAPS, LAP, and the satellite-derived winds, before eventually transitioning to warning ops.
The 1-min visible animation below depicts the ongoing deep convection across S Iowa and N Missouri, with newer development along the Missouri/Illinois border.
The 1-min visible animation below depicts the ongoing deep convection across S Iowa and N Missouri, with newer development along the Missouri/Illinois border.
Shear Increases Over North-Central MO
By 23z vertical wind shear became more noticeable as showers east of the storm complex began to form as feeder cells. The twisting with height suggests good storm relative inflow and continued tornadic potential. Another feature that was noticed was a trend for the anvil blow-off to appear to move southeast as the squall line approached. 
A review of upper level winds did confirm some winds that were almost due westerly in the 200 hPa layer. This combined with the northward motion of cells and the spilling out of cirrus from the overshooting top made the cirrus shield look deceptive to the environmental flow, as all winds noted below 200 hPa were from the south and southwest.
Forecaster: Manbearpig
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