Tuesday, April 26, 2016

Butler Co, KS null case for CI


A tall, discontinuous core developed over Butler Co, KS with a tall core on radar by  1858Z. 50dBZ was observed at 36 kft AGL. This cloud shows up on satellite with a shadow. However, the CI never registered.


BAJ

Severe Thunderstorm Warning #1 - Oklahoma


WUUS54 KOUN 261923
SVROUN
OKC053-262000-
/O.NEW.KOUN.SV.W.0109.160426T1923Z-160426T2000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NORMAN OK
222 PM CDT TUE APR 26 2016

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN GRANT COUNTY IN NORTHERN OKLAHOMA...

* UNTIL 300 PM CDT

* AT 222 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR WAKITA...OR 16 MILES NORTHWEST OF MEDFORD...AND MOVING NORTH AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  WAKITA AND MANCHESTER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE HAIL AND DAMAGING WINDS. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 3677 9792 3682 9809 3700 9805 3700 9778
TIME...MOT...LOC 1922Z 201DEG 34KT 3691 9800

$$

BMS


Issued Severe Thunderstorm Warning for thunderstorm in North Central OUN Forecast Area based on 65% Severe Prob, but in next scan, jumped to 73% Severe Prob with MESH jumping to 0.80". Severe Thunderstorm Warning issued for 1" hail and 60 MPH winds.

WWUS54 KOUN 261934
SVSOUN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE
234 PM CDT TUE APR 26 2016

OKC053-262000-
/O.CON.KOUN.SV.W.0109.000000T0000Z-160426T2000Z/
GRANT OK-
234 PM CDT TUE APR 26 2016

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM CDT
FOR NORTHWESTERN GRANT COUNTY...

AT 234 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING LARGE DAMAGING HAIL UP TO GOLF BALL SIZE AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR MANCHESTER...OR 10 MILES SOUTHEAST OF ANTHONY...MOVING NORTH AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
WAKITA AND MANCHESTER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THIS STORM...PREPARE IMMEDIATELY FOR LARGE HAIL AND DAMAGING WINDS. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... REFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

&&

LAT...LON 3681 9794 3682 9806 3700 9805 3700 9778
TIME...MOT...LOC 1934Z 201DEG 34KT 3702 9795

$$

BMS


WWUS54 KOUN 261949
SVSOUN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE
249 PM CDT TUE APR 26 2016

OKC053-262000-
/O.CON.KOUN.SV.W.0109.000000T0000Z-160426T2000Z/
GRANT OK-
249 PM CDT TUE APR 26 2016

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM CDT
FOR NORTHWESTERN GRANT COUNTY...

AT 249 PM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING LARGE DAMAGING HAIL UP TO TWO INCHES IN DIAMETER AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED 7 MILES EAST OF ANTHONY...MOVING NORTH AT 40 MPH.

LOCATIONS IMPACTED INCLUDE...
WAKITA AND MANCHESTER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. ALTHOUGH A TORNADO IS NOT IMMEDIATELY LIKELY...IF ONE IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

THIS IS A SUPERCELL THUNDERSTORM. DUE TO THE ROTATING NATURE OF THESE STORMS...THEY ARE CAPABLE OF PRODUCING ALL TYPES OF SEVERE WEATHER INCLUDING EXTREMELY LARGE HAIL...DESTRUCTIVE STRAIGHT LINE WINDS...AND POSSIBLY TORNADOES. MOVE QUICKLY TO A SAFE SHELTER...PREFERABLY INTO A BASEMENT...OR AN INTERIOR ROOM SUCH AS A BATHROOM OR CLOSET.

&&

LAT...LON 3687 9789 3689 9797 3700 9805 3700 9778
TIME...MOT...LOC 1949Z 201DEG 34KT 3716 9788

$$

BMS


Forecaster: Schuerman

Surface Based Lifted Index Values Now -11 over the KS/OK Border


SPC Mesoanalysis at 18z shows surface based LI's reaching -11. A comparison to CIMSSPWRET Layer Parcel Lifted Index revealed a good correlation near the KS/OK border with best correlation where skies were clear.

Nearby pixels of "GFS" and "Cloudy" Layer Cloud Types appeared to be within 10 to 20 percent of the highest values.

Forecaster: Manbearpig

OUN Prestorm Mesoanalysis

Taking a quick look at things as storms are beginning to fire, it appears that the GFS may actually be underdoing the instability a little bit. While the GFS is being used for the LAP data across most of the area, in the few areas where the cloudy sky retrieval is used, there is a slight enhancement in the CAPE. This is shown in the image below across north central Oklahoma.


Some storms are already going up as I type, so I will keep this brief. Very high CAPE (shown above) and extreme low and mid-level lapse rates show allow for any storms that are able to overcome the eroding cap should rapidly intensify. Given that storms are already beginning to fire despite the fact that the best upper level forcing has yet to arrive, I expect widespread convection across the CWA shortly.

-Toki Wartooth

Severe CI shows something!


Severe CI prob actually showed something with the 1845Z analysis over ICT. The Cyan color is a 46%, yellow is 62%, and the green is 56%.  One particular note on the cyan color is the two cells that are shown as 45%.  However, these are discontiguous.  It would be nice to have a value for both cells to differentiate between the two. 

For comparison, here's the regular CI.  There are higher values including 80s in the orange and 94 in the red.



BAJ

Tuesday, April 26 EWP shift: 1 pm - 9pm

Tuesday, April 26 EWP shift: 1 pm - 9pm


SPC 13z Day 1 Convective Outlook:



OUN 12Z RAOB:



Morning SRSOR 1-min visible imagery over OK and N TX shows low clouds in place and gravity waves traversing the region.



Monday, April 25, 2016

Daily Summary: Week 2, Day 1 (25 April 2016)

The start of week 2 GOES-R/JPSS evaluations in the HWT brought us to the Chicago and Milwaukee CWA's.

LAP
- I really like having these plan view displays of where moisture and stability is. The models are often bad with these fields, so having satellite positively influence these fields is helpful.
- I noticed that the CAPE field was underdone compared to SPC mesoanalysis (which uses RAP). Though I sometimes wonder if the mesoanalysis CAPE is sometimes inflated.
- I really like the layer PW
- Perhaps we could ahave a percent of normal for the PW layers


CI
- I personally loved the CI product. I was leaning on regular CI, and it did very well yesterday. Severe CI was low, but we did have severe storms.
- Everything was just borderline severe, so this is maybe why severe CI was low.
- With better temporal and spatial resolution of ABI, maybe we will get more focused probabilities.
- I would like to have an indicator of why the probabilities dropped off.

ProbSevere
- I loved the product, I could see it being useful for braodcasters.
- ProbSevere is what pushed us over to warn yesterday for several storms.
- For many cases yesteday, we were warning just ahead of increases in probsevere
- A couple of storms were borderline (for warnings) when looking at all-tilts radar data. When probsevere spiked to around 70%, that led us to warn.
- I really liked the display.
- With overlay on base radar data, it covers up some of the data, but it really isn't a big deal.

SRSOR 1-min imagery
- We could see a little more twisting of low-level clouds, where the back end of convection formed
- Storm cores relaly stood out in the IR as they strengthened.

NUCAPS
- Temperature and Dew Point at surface were significantly off compared to sfc obs.
- It was not a very dynamic atmosphere yesteday, so there was not much change since the morning, and NUCAPS confirmed this, matching well with the morning RAOBS.
- It would be nice to have capping information in NUCAPS.
- It would be nice if it could automatically take a nearby surface observation and adjust the profile for you.
- If low-level correction is automated, it will be helpful to still see the original profile (dashed lines?).

GOES-R products summary - Wisconsin - Monday


Note the SVR box at the end of the GIF. This shows the SVR activity at the north end of the CAPE as seen in the LAP data. There were more SVRs than this, so the northern portion of the instability had some severe hails.


Note above the summary of the severe weather case with ProbSevere, 0.5 Z/V from KMKX and our polygons.

BAJ

Warning issued for Kane County UPDATED

This storm had been holding steady with a reflectivity core of around 55 dBZ at -20C (according to NUCAPS profiles). There was also a faint TBSS for a few volume scans as well. ProbSevere was in the 50% neighborhood and there were a few lightning jumps around 1 or 2 sigma. We had been hesitant to issue warnings on this storm because previous storms that looked similar failed to produce severe weather.

At 2230z, ProbSevere spiked to 82%, there was a 3-sigma lightning jump, and the reflectivity core intensified. Those triggers were enough to prompt a Severe Thunderstorm Warning.


---UPDATE---

Shortly after the warning was issued, 1" hail was reported within the warning. As mentioned in a previous blog post, we had warned on a storm with similar characteristics as this one that did not verify, or so we thought. The first storm we warned on, which looked very similar to this storm, did actually verify, but we did not get the report until well beyond an hour after the first warning expired. Had we known that our first warning verified, we would have had a warning out for this storm earlier.

---UPDATE---

This storm continued into the Chicago metro with borderline severe characteristics. Shortly before the storm exited the original warning, ProbSevere spiked to 85% and there was a 4-sigma lightning jump. Despite a lack-luster reflectivity signature, the ProbSevere and lightning jump were enough to prompt a new warning for this storm.



-Toki Wartooth

Severe Thunderstorm Warning #3 - Southern Wisconsin


WUUS53 KMKX 252226
SVRMKX
WIC089-131-252300-
/O.NEW.KMKX.SV.W.0003.160425T2226Z-160425T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MILWAUKEE-SULLIVAN WI
525 PM CDT MON APR 25 2016

THE NATIONAL WEATHER SERVICE IN SULLIVAN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN WASHINGTON COUNTY IN SOUTHEASTERN WISCONSIN...
  CENTRAL OZAUKEE COUNTY IN SOUTHEASTERN WISCONSIN...

* UNTIL 600 PM CDT

* AT 525 PM CDT...TRAINED WEATHER SPOTTERS REPORTED TWO SEVERE  THUNDERSTORMS PRODUCING HALF DOLLAR SIZE HAIL AND DAMAGING WINDS  IN EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE  EXTENDING FROM NEAR SAUKVILLE TO NEAR CEDARBURG...AND MOVING EAST  AT 35 MPH.

* LOCATIONS IMPACTED INCLUDE...
  MEQUON...GRAFTON...CEDARBURG...PORT WASHINGTON...SAUKVILLE...THIENSVILLE AND GERMANTOWN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE IN THE PATH OF THESE STORMS...PREPARE IMMEDIATELY FOR LARGE HAIL AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG BUILDING AND AWAY FROM WINDOWS.

THESE STORMS HAVE A HISTORY OF PRODUCING LARGE HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS!

&&

LAT...LON 4346 8780 4337 8788 4330 8789 4326 8791
      4323 8791 4325 8815 4340 8810 4349 8779
TIME...MOT...LOC 2225Z 258DEG 30KT 4339 8800 4328 8805

$$

BMS/BAJ


Issued New Severe Thunderstorm Warning as first warning for this area was getting close to expiration time, still receiving confirmed hail with these thunderstorms as they head to the bay. Severe Probs at 93% with 1.06" MESH. That confirms the hail reports we are seeing with these thunderstorms.


WWUS53 KMKX 252248
SVSMKX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE-SULLIVAN WI
548 PM CDT MON APR 25 2016

WIC089-131-252258-
/O.CAN.KMKX.SV.W.0003.000000T0000Z-160425T2300Z/
WASHINGTON WI-OZAUKEE WI-
548 PM CDT MON APR 25 2016

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN WASHINGTON AND CENTRAL OZAUKEE COUNTIES IS CANCELLED...
   
THE STORMS WHICH PROMPTED THE WARNING HAVE 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 SULLIVAN.

LAT...LON 4346 8780 4337 8788 4330 8789 4326 8791
      4323 8791 4325 8815 4340 8810 4349 8779
TIME...MOT...LOC 2246Z 258DEG 30KT 4343 8775 4332 8781

$$

BMS

VERIFICATION INFORMATION:
17:32 - Pea to Penny Sized Hail (0.50-0.75") reported in Grafton, Ozaukee County, WI -  6 Minute Warning Lead Time
17:35 - Golf Ball Sized Hail (1.75") reported in Port Washington, Ozaukee County, WI - 9 Minute Warning Lead Time
17:35 - Ping Pong Ball Sized Hail (1.50") reported in Cedarburg, Ozaukee County, WI - 9 Minute Warning Lead Time

Forecaster: Schuerman/Jackson