GOES vs AllSkyLAP East CAPE & Total PWAT

Starting the day across northern Indiana and analyzing the moisture and instability advecting into the region behind overnight convection. Pulling up GOES CAPE and Total PWAT yields blacked out areas over much of Indiana and Illinois due to cloud cover. The AllSkyLAP fills in these blacked out regions with modeled GFS data. Overall, I find this product very useful when trying to analyze building instability and identifying gradients.

I time matched to the AllSkyLAPs window but data drop outs at 15Z, 16Z and 17Z were noticed.

Also of note was. The AllSkyLAP Layer Cloud Type notes Clear (Blue), GFS(Gray) and Cloudy(Yellow). What data is being used in areas under Cloudy regions? GOES, GFS, other?

- Jack Swigert

IWX (more analysis) with CI and All Sky LAPS

Looking at all sky LAPS, there is a clear gradient of two separate areas of higher instability. Values vary between the models and the sky LAPS, but wanted to look at how the LAPS data looks compared to GFS (top right),  HRRR (top left), and Layer H20 PWAT from all sky LAPS.

One reason I am looking at the PWATs is to also gauge the southerly fetch/LLJ. I can see two split areas combining into one. It also looks like where the all sky LAPS is definitely highlighting the same maximum areas as the all sky LAPS which is to be expected given it is derived from GFS in cloudy areas.

Turning to the convective initiation product. Did see where the Severe CI is showing higher probabilities over the western portion of the ILX and LOT forecast areas. That is also coinciding with higher Total Power in GLM but not sure if they'll strengthen to severe.  They are entering that area where the instability increases over western portion of ILX and LOT forecast areas. Will keep watching to see if these storms realize the instability shown.

More to come...

Supercell

MKennedy Nucaps Start

NUCAPS notes: Computed LI values either did not appear or were computationally irrational-- unusable for 700-300 MB, would not appear as a single computation and therefore required a pressure level differential where ie. 850-700 mb was a required selection.

Possible anamoly or true most unstable CAPE MAX near Newton in NUCAPS Gridded at 1000-500 Most Unstable CAPE---comparing to East Mesoscal All-SKY LAP CAPE where only minor gradient seen.

Checking the Model Data for this possible CAPE an0moly showing HRRR upper left, RAP 13 Lower Left, with ARW upper right and lower right GFS. The right panel models indicate greater intensification near Newton and Downstream of Most Unstable Cape anomaly/gradient. See the images below at 00Z & 18/19Z for given model 4 panels.

Waiting on storm development to view event possibilities.


In the meantime, the RGB Day Land Cloud Convection is doing well with GLM highlighted in lower right panel as the developing anvil corresponds to growth and intensification.

Continuing to monitor the pre-convection environment over South Central Illinois near Newton, the RGB view of the Day Cloud Convection Procuct combine wtih the Derived GOES Lifted Index. Newton reads -3.2 no GLM data yet for this time frame of 21:20 Z with models suggesting development later toward 00 z in this location.

21:33 Z showing RGB Dust and ENI 5 minute data with one minute update Lightning, gradients around MCS and developing convection shown well

NUCAPS loading -10 to -30C temp lapse rates shows a white/gray upon transparency adjustment background-clear image more helpful to overlay on Water Vapor or other Sat. Imagery. When monitoring Newton again now looking back at 18Z Lapse Rates between -10 and -30C we can see a similar increase over Newton except in this instance,the gradient is not as pronounced on the Most Unstable Lapse Rates. Here we can view a ramping of the gradient in this region suggesting the data may not be compromised in the Most Unstable Gradient.


The GLM Looping over GOES 16 East Mesoscale 2 Clear IR Channel 10.33 um allows us to see storm propagation and matches the intensification along this warned line of storms in Central Illinois which verified with winds of 70 mph

 

Another interesting possible use of the Split Water Vapor with the radar overlay shows in Newton, selected here as the home location a gradient over this county that may help to intensify cells in this location or just downstream. 

 ++++split Water Vapor Loop gif would not load++++ 

NUCAPS Analysis-IWX Small Blog

While doing some mesoanalysis of the environment, did a quick comparison between NAM12 forecast sounding around the same point at 18Z and the 18Z NUCAPS just to see what it looks like. Images below (1st one is NAM12, 2nd one is NUCAPS):

I am seeing that NUCAPS is resolving a slightly drier airmass aloft while the NAM12 is more saturated. Instability parameters are about the same and also seeing a pretty good presentation of the dry air at low levels. I do like the fact that the time resolution is greater for the NUCAPs.  It is helping me diagnose storm mode and also indicating where the mixing is occurring ahead of the line.

More to come...

Supercell

Usefulness of CI when overlaid over visible satellite

1-minute visible satellite (meso-sector) with GLM 5-min FED with 1-minute updates and CI product overlaid.  Could be useful in determining which cloud features (seen on visible) could be the first ones to be convective (since we probably know that storms will initiate off the CU field in western IL.

Week 2; Day 3

Slightly improved outlook for severe weather today as we move to the midwest US.  We begin today with forecasters located in the Chicago (LOT) and northern Indiana (IWX).

We are expecting redevelopment of isolated storms across the region this afternoon first over LOT and then moving eastward into IWX.  17Z run of the HRRR somewhat picks up on this redevelopment between 2100 and 0000 UTC, though storms appear to remain sub-severe.

Meanwhile, forecasters are currently implementing some new procedures for NuCAPS and comparing legacy vs test product streams in the pre-convective environment.  We will see how things evolve over our region as the day progresses.

-Kristin

NUCAPS, RGB, & GLM Iowa Severe May 8 Week2 HWT

In Advance of the developing severe threat this was notices on NUCAPS comparison to Total Precipitable Water

RGB Cloud Convection Product with NUCAPS Improved Latency and Goes Total Precipitable Water shows close match with actual sounding. 1.09" in NUCAPS Sounding, While Total Precipitable Water is showing 1.21" Northern Nebraska NUCAPS point sounding showing .99 with Total Precipitable showing 1.10" ---Modified Nucaps shows only tenth of an inch added difference with this one from .99" to 1.00" and with the other sounding in Southern South Dakota it increased also to only 1.10 from 1.09 for Nucaps Sounding with precipitable water at 1.21"

Initially, I experienced difficulty loading the ALL Sky LAP CAPE product, but once loaded in a separate window the product arrived without issue.
Then, I compared NUCAPS Modified Points on the Skew-T with the ALL Sky CAPE image time matched to 18:58 Z. This indicates a slightly lower CAPE of values between 50-75 on the soundings than the ALL SKY CAPE image, but the data overall appears to correlate well in this time match.

        The Water Vapor Imagery 4 panel displays shows significant available moisture in mid-level and upper-level regions over the Dakotas and Iowa. Viewing the lower level Water Vapor at the GOES East Conus 7.34 low-level water vapor imagery IR band, the dryer surface level conditions are visibile along the Iowa/Missouri border. This is also an area where an outflow boundary exists and where at 22:49-22:52Z there is a rise in wind damage probability using the Severe Probability Index, but notably no indication of increased CI or any cloud identified with the CI probability product. See the two 4 panel images below.

Below is the GLM Total Energy product data overlaying CI with the Severe Prob product. The GLM seems to be a better indicator of the most active and developing potential for areas or storm clouds with potential for severe threat than the CI in this brief window. This is based on the 21:3Z views through 22:52Z during which time the storms did not reach severe status, but did show strong convection and more organized activity at 22:52Z than the CI product suggests expecially in the Western Iowa and Northern Nebraska region.

 The slide below shows the composite radar Image from 23:12Z with the best rain near the GLM Total Energy indicated storm areas from the 22:52Z image shown above.

MK

CWA TomClemmons FSD 05-08-2018

Synopsis: Upper level Shortwave trough to the NW of the FSD CWA. Forecast has this system moving through the forecast area during peak heating. Sfc low is moving into the wester part of the the forecast area near KSFD with the warm front running east along the MN/IA border with the cold front extending south from KMH. The greatest probability of Tstorms and SVR will be along the cold front and warm front later this afternoon and into the early evening hours.


 Have the GLM Total Energy product loaded up and overlaid on the 10.35 um Clean IR, noticed the greatest are of GLM Total Energy was right along the warm front along the southern edge of the anvil shield.
 

NUCAPE Sounding data came in at 18z. Polled two areas south of FSD CWA that will advect into the area later this afternoon and would feed the area along the front with unstable air. This sounding was very similar to the other sounding taken NW of this sounding. This sounding is showing between 1400 to 1600 CAPE values to advect into eastern portions of the FSD CWA this afternoon. Wind profile is suggested of organized mulicellular storms.

Here is a comparison All-Sky LAP Insatiability Indices moving into the western part of the FSD CWA and the more pronounce unstable area over northern Missouri and southern Iowa. Now compared SPC CAPE (RAP model) at 2000 UTC 28 minutes before. Notice very similar maxi-ma in the same areas in both the LAP data and from the SPC CAP

All-Sky LAPS PW images indicated increasing moisture pooling up to the east of the low between the cold front and the warm front. The first image is from 1928 UTC followed by the 2128 UTC image. Notice the increasing trends of mid-level moisture in the eastern part of the FSD CWA. Would expect storms moving into this area to have more moisture and instability to work with. Remember earlier NUCAPS, soundings to the south, that eastern FSD CWA should be seeing increasing low to midlevel lapse rates.

Built a 4-Panel display using GLM Total Energy, GLM Average Flash Area (bottom left-right) with 5-min and 1-min update. Also on the upper panels used 0.5 Refl to display NLDN 5-min with 1-min update. Also overlaid was the CI Probability with that product upper left. Upper right, had ENTLN with 5-min and 1-min update. As another overlay we had CI Severe Probability, along with GOES Clean Window 10.35 um. I felt this was a good situation awareness display for me to monitor new areas of developing convection.

FSD Mesoanalysis/Analysis 050818

Mesoanalysis:

First glance:

A shortwave trough is moving across the Upper Midwest region causing scattered convection to develop over central and western IA. Earlier 12Z RAOBs showed a dry boundary layer between 700-890mb but steep low level lapse rates.

NUCAPS soundings: Noticed that NUCAPS doesn't have a current swath (17Z) over the central Plains. The latest availability sector is further east over the east coast and western Atlantic.

ALL Sky LAP products: Looking at Layer PWATs and CAPE products. Seeing a broad swath of instability and layer moisture moving from Ozarks to OAX. Also seeing a secondary area of increased instability gradients from the SW of the region from GID to ABR CWAs. Could be from those high low-level lapse rates within the conditionally unstable environment?

RAP13 is showing initiation around 20-23Z (especially the later part of this time period). Initiation is already occurring near an apparent warm front overlaid from FSD to the IA/MN border. Did see a fairly stout gradient in DCAPE from the southeast portion of the FSD area to the DMX area. DMX area is showing around 1000 J/kg while the southeast areas are showing a gradient between 700-1000 J/kg. With conditional surface based CAPE gradient (shown on NAM12/HRRR and GOES All Sky LAP products, from the western side of FSD CWA to the southeast side could see convective initiation but weak in nature until it approaches the far southern tip of the forecast area where a "surge" of instability is seen on all products though the All sky product maxima/tongue is displaced east compared to the other models.

Possible impacts: Damaging winds (isolated) mainly over southeast portion of FSD CWA. Could also see marginally severe hail threat.

Nowcasting:

NUCAPS soundings came in (18Z): Shows about 800-1000 J/kg of DCAPE and as much as 2500-3000 J/kg of MUCAPE. I am a little suspicious of this particular sounding data given the superadiabatic surface layer from the soundings. There is also a mid level cap that may be broken by the shortwave trough. Side note Suggestion: on the readouts, when we select the readout for a NSHARP sounding it would be nice to have a designation on the readout map either displayed on the NSHARP sounding display (top right in color circled area) or on the sounding availability map as maybe a white dot when selected.

The following NUCAPS sounding was more useful in diagnosing the environment. The sample was taken over NW area sampling the inflow airmass.

Wind profiles from HRRR suggest storm motions from the SW at around 20-25 kts which coincides with the current storm motions.

Tried to load NUCAPS Plan View data as a comparison to All Sky LAPS CAPE and HRRR CAPE but it is not available. Only lapse rates are available in Plan View. Even then the data was completely useless or hard to really resolve anything useful.

Looking at GLM Event Density, Average Flash area, and Total Energy decided to also load the NLDN and ENTLN Lightning Plot. The Event density coincides well with the land based systems. I would like to see more training on the average flash area in how to show how the lightning strike area coincides with the event density and Total Energy. Please do not just do another module, especially for something so new as GLM! It has taken me personally hours of handling the data WITH the presence of the GLM SMEs at the EWP to have even a modest understanding of the flash area, total energy, and flash extent. Perhaps average flash area is more of a IDSS application product than use in warning operations.

I do like the Total Energy product most as it is more intuitive (brighter color means higher energy).  Showing cases from previous blog posts last week where less messy convection stronger severe convection) was taking place made it easier to see how the average flash area where a lightning strike was detected going into the anvil. Also, changing the color table of the event density definitely helped in visualizing the stronger updrafts (lightning events).

GOES East CI probability was useful due to its good time latency today (compared to yesterday). Seeing 10-30% probability across western portion of FSD area within bands of cumulus clouds. Severe CI did show some areas over the western portion of the FSD CWA. Seemed to have anomalously high probs (80%) of Severe CI for 1-2 time steps. 

Prob Wind did increase on a storm moving from the FSD area into the northern portion of DMX area. Noticed it went up to 60%. Radar coverage is more limited as the storm moved outside the Rmax. Did look at SRM and there was about 40 knots at lowest tilt which was about 10kft AGL. There is another cell that is to the southwest of this one that is also showing a gradual (but lower) increase in ProbWind and ProbHail (insert image).

There were some other cells to the northwest over Aberdeen's area that actually started exhibiting higher Prob Severe values which could be due to deformation zone/cold conveyor belt development on the northwest flank of the upper low.

That's all for today folks!

Cheers!

Supercell

Storms beginning to fire.

Morning convection across northern Iowa left a outflow boundary across far northern counties of the CWA that looked to be the focal point for new convection this afternoon. Cap remained in place further south in the warm sector throughout most of the day. Moisture advecting ahead of approaching shortwave and weak frontal boundary was quite noticeable on the AllSkyLAP Sfc-900 PWat

Destabilization continued to weaken the cap with the low level moisture advection and slight cooling aloft.

19Z Forecast RAP sounding for point A near Fort Dodge, IA with plenty of CIN in place

 23Z Forecast RAP sounding for point B near Ft. Dodge, IA showing a much weaker cap with low level moisture advecting in and slight cooling aloft.

By 23Z, the cap had weakened enough across north-central and northwest IA for storms to fire near the previous outflow boundary and approaching frontal boundary. So far everything has looked sub-severe. To be seen if more storms develop back down across western IA as that weak frontal boundary moves in.

- Jack Swigert