Today's Experimental Operations - Tuesday, June 4, 2019

Today's operations will be begin with their focus over the Twin Cities/Chanhassen (MPX) county warning area.  Severe storms have already developed and are approaching the Twin Cities area from the northwest.  The Storm Prediction Center current has a mesoscale discussion out for the area highlighting potential watch issuance within the next few hours with the main threat being damaging winds but large hail is also possible.


Other potential regions of operation include the low-country region of South Carolina, where there is currently a severe thunderstorm watch, and extreme west Texas into southern New Mexico.  We'll monitor the weather situations in these locations and adjust our operations area as needed.

Another Busy Day Ahead

Today looks to be another active day in the HWT,  with a moderate risk issued across portions of Oklahoma, Kansas, and Missouri. We will begin operating in the Norman, OK and Tulsa, OK CWAs monitoring for convective initiation with a risk for severe storms with all hazards possible including the risk for some strong tornadoes into the evening hours if storms can form and maintain themselves.

-Michael

EWP Operations Tuesday, May 21

Today we are continuing on with the strong upper level trough moving into the Midwest. Today will be focused on mainly linear convection focusing on a QLCS moving through Arkansas and Missouri this afternoon. We will be operating in the St. Louis and Little Rock CWAs with an opportunity to also monitor for developing convection back near the center of the upper low in central Kansas later this afternoon.

-Michael

High Risk Day in the HWT

Today is one of those rare days in the parameter space of severe weather. A high risk has been issued for portions of the Texas Panhandle into western and central Oklahoma, including us here in Norman and the OKC metro area. Models continue to paint an ominous picture of numerous waves of tornadic supercells within the warm sector and east of the dryline  throughout SW Oklahoma into the OKC metro area. Flooding will also be a major concern and could potentially have as much impact as the tornadoes. We will be operating in the Norman, OK, Amarillo, TX, and Lubbock, TX CWAs throughout the day.

-Michael

Slight Risk West and East

Operating across the CONUS today with one team of forecasters located in Idaho/Montana in MSO and the other in Illinois (ILX).  The forecasters have also been encouraged to investigate the environments nearby their official CWAs including the ongoing MCS currently crossing the Chicago CWA.

SPC Day 1 outlook for 16 May 2019

For those in Illinois, the environment remains supportive of development  off of outflows from the ongoing MCS or other possible convection.   Though it remains likely that the MCS will continue to remain strong and pose  a threat for strong winds at least across the NE section of the CWA.

All Sky LAP CAPE

For Idaho, it currently remains rather calm, but the CAMS have consistently latched onto expected convection later in the day including supercell storms.

Sandwich IR/VIS product for Western United States

-Kristin

Another Marginal Day in the HWT

Continuing the theme of the week, today figures to be another day with few storms across the country producing some severe reports. Today we are operating across the slight risk area in North Dakota in the Bismark and Grand Forks CWAs where convection should initiate across central North Dakota this afternoon and into the evening. A third group will also be operating in the Memphis CWA looking for redevelopment behind a morning MCS along a trailing outflow boundary which could produce some marginally severe hail and wind across northeast Arkansas and into western Tennessee.



-Michael

Marginal Day in the HWT

Forecasters are beginning the day located in both the Melbourne, FL and Kansas City/Pleasant Hill, MO CWAs each with very different environments.

SPC Day 1 Outlook 14 May 2019

Ongoing convection with a focus on lightning is in store for forecasters in the MLB location.  A (semi-stationary) frontal boundary across central Florida combined with the sea-breeze and plenty of low-level moisture is providing a decent environment for storms capable of producing lightning and high winds.

Surface observations and radar over the SE United States[/caption]
Forecasters beginning in the EAX region will likely be diagnosing the environment and pre-convective initiation products for the first half, if not majority of the operational hours today.  Later today, we expected isolated convection to develop with enhanced lapse rates and associated increase in CAPE as well as increased low-level moisture.  The HRRR doesn't initiate convection until ~0200 UTC, but hopefully we will see activity a bit earlier.

-Kristin Calhoun

ProbWind with report Leesburg VA

We had given some thought about operating in Kentucky or Virginia with one group today, so we have been paying a bit of attention in the eastern US.  One storm west of Washington DC had ProbSevere, specifically ProbWind rapidly rise this afternoon, while most storms had ProbWind remain 5% or less.  The figure below shows the rapid increase of ProbWind (blue, upper left) and the black line at 1905 UTC represents a wind report of trees down blocking a road.

ProbSevere time series from the ProbSevere website.  The upper left panel show the time trends of the various ProbSevere models.  Note how ProbWind rapidly increases between 1845 and 1900 UTC.  A report of trees down blocking a road was received at 1905 UTC.

-J. Sieglaff

Today's Experimental Operations - May 2, 2019

Today's operations will be focused over the SJT (San Angelo), FWD (Dallas/Fort Worth), and EWX (Austin/San Antonio) county warning areas.  Focus is once again ahead of an outflow boundary left over from overnight storms.  To keep with the theme this week, storms are again on-going at the start of the operations period with a severe thunderstorm watch in place over a portion of the operations area.  Supercells will be possible today but the scenario will be messy with storm interactions and mergers likely.   The main threats today are hail and high winds but a few tornadoes are possible.

ProbTor Training Point

A quick conversation with the forecasters from both CWAs (OUN and SJT) today, we reiterated a training point--the best way to use ProbTor is in a relative manner--are there any storms that stand out relative to their neighbors?  Yesterday, environmental predictors resulted in relative high ProbTor values, but today the storms are in environments that are much more marginal.  As such, ProbTor values are considerably lower than yesterday--so forecasters are looking for relative differences and not absolute values.

-J. Sieglaff

Today's Experimental Operations - May 1, 2019

Today's operations will be focused over the OUN (Norman), SJT (San Angelo), and FWD (Dallas/Fort Worth) county warning areas.  We are highlighting operations south of a remnant outflow boundary that has been left from storms that occurred overnight/early this morning roughly in the area of the Red River Valley.  Storms are currently on-going at the start of operations, with a severe thunderstorm watch over the operations areas that stretches from central OK all the way down to SW Texas.  Supercells will be the primary storm mode to start but might transition to a linear system later in the operations period.  The main threats today are large hail and high winds but tornadoes are still possible (lower probabilities than yesterday though).

A Quick Start to the Convective Day

After our day 2 debrief, forecasters began operations as severe thunderstorms were already developing over the OUN and SJT.  A common theme from the day 2 debrief, was forecasters really liked the trends captured by ProbSevere.  While work continues on getting ProbSevere time series plotting capabilities in AWIPS-II, forecasters are utilizing time series capabilities from the ProbSevere website.  Forecasters mentioned they appreciated being able to quickly see how the first storms evolved by using the ProbSevere time series.  Also noted by forecasters were strong satellite growth rates and very high CAPE in the hail growth region lending to very rapidly increasing ProbHail values, even before MESH reached 1.00".

ProbSevere time series capability from the ProbSevere website for the first severe thunderstorm of the day in the Norman WFO, near the Red River.

AWIPS-II 0.5 degree reflectivity and NOAA/CIMSS ProbSevere for the evolution of a rapidly developing thunderstorm near the Red River on May 1 2019.

-J. Sieglaff

Week 2 Day 2

Today figures to be an active day across the southern plains. We will be operating across Oklahoma and Missouri today monitoring for storms capable of all hazard types.

-Michael

Week 2 of the 2019 EWP Underway

6 National Weather Service forecasters are in Norman, Oklahoma at the Hazardous Weather Testbed for the 2019 Experimental Warning Program--Satellite and Radar Convective Applications Experiment.  Monday is being used as a training and AWIPS-II product familiarity/procedure building day.  This will serve all participants well in the coming week as much more active convective weather is expected starting Tuesday.  Many satellite and radar products will be evaluated, including NOAA/CIMSS ProbSevere v2.  ProbSevere v2 explicitly produces probability of severe hail, severe wind, and tornado.  One element of focus for the 2019 evaluation is the inclusion of a 'double contour'--one ProbSevere contour that is the maximum of ProbHail and ProbWind for a storm and an outer contour that is the ProbTor probability for a storm.  The double contour approach was a widely requested enhancement by participants of the 2018 HWT EWP as a mechanism for forecasters to monitor severe wind/hail as well as tornado threat on a single display (often all tilts radar).

J. Sieglaff

Week 1 Day 4 Operations

Today will be our last day of operations for the week as we continue to follow a low across the southern U.S. Today we will be in southern Alabama and the Florida Panhandle.

-Michael

Week 1 Day 3 Operations

Today we are operating again in south central Texas as an upper level low continues to meander across the southern U.S.

-Michael

Week 1 Day 2 Operations

Today we will be operating across west and central Texas looking for developing storms along a slow moving front.

HWT Spring Experiment Begins

The 2019 combined satellite and radar Spring Experiment started today and will run for 6 of the next 7 weeks evaluating various satellite based products as well as some radar derived products. Today is generally a familiarization day as forecasters get set up to operate in forecast and warning mode over the next few days looking at some active weather hopefully. Look here for updates throughout the week on the satellite based products.

- Michael

DLH - Nifty Convection Monitoring Procedure

2150Z: I decided to try looking at smoothed GLM data overlaid on visible satellite by using the "interpolate image" & "interpolate colors" options along with some transparency in AWIPS. On the same image I also overlaid ProbSevere polygons & GOES CI probabilities. It was much easier for me to interpret GLM trends while having some of the texture from the visible satellite imagery. The identification of new updraft growth in the GLM flash extent density data was much more evident with this procedure vs just using the GLM data alone. ProbSevere polygons were useful in monitoring the intensity trends of the storm at a glance. Finally having the GOES CI probability helped in a zoomed-out view to identify potential area of new convection. I'm impressed at the amount of data I'm able to view in this procedure without the whole thing looking too cluttered.

Loop of above procedure showing storm evolution in SW MN:

Peter Sunday

DLH - Mesoscale Discussion

2100Z: Storms have been ongoing for a while across the region but waited to write this post until the modified NUCAPS soundings were in. Right off the bat the all-sky CAPE does not seem to capture the general spatial pattern well compared to SPC mesonalysis/HRRR & observations. The all-sky suggests CAPE over 1000 J/kg over NW MN & SE MN & along a narrow tongue from southern MN up towards the Twin Cities. However mesoanalysis shows CAPE minima in these areas along with high CIN. Furthermore the all-sky LAP CAPE does not seem to capture the extent of the stable capped region in NE MN where storms have struggled in so far today.
2030Z LAP all-sky CAPE:

2000Z MLCAPE Mesoanlysis:

Furthermore visible satellite shows little cu development in the regions of suggested highest instability in NW & SE MN, with minimal GOES CI probabilities as well. 
2030 Visible Satellite/CI probablities:

Gridded NUCAPS 500-700 mb lapse rates match up quite well with mesoanalysis with rather marginal values of 6-6.5 C/km across most of MN. However, NUCAPS does not appear to pick up on the EML moving up from SD up into SW MN where mesoanalysis as well as the HRRR/GFS/NAM all suggest values greater than 7 C/km.
NUCAPS/HRRR/GFS/NAM 500-700 mb lapse rates:

 Overall, the thermodynamic environment does not have me too concerned about widespread severe weather today. Effective bulk shear values of 30-40 kts suggests some organization is possible & it will be interesting to see if the current cells eventually merge into a line as the HRRR suggests, and create more of a damaging wind threat. Some cells have spiked up at times this afternoon with ProbHail & ProbWind values over 80% but otherwise have not been able to maintain this intensity.

Peter Sunday