Continued Development throughout IA/MO Captured by UW-CTC

Continued convective development has been occurring throughout IA/MO over the past hour.  UW-CTC has been consistently detecting strong cooling within the cloud tops of the developing storms.  The following sequence of images (valid 1955 UTC through 2015 UTC) shows the consistent nature of the detections for this case by the UW-CTC algorithm:

Could not get AWIPS 2002 UTC image due to technical issues with AWIPS-2

A fellow colleague has stated that these detections were not only ahead of the warnings associated with the storms, but also ahead of the severe watches that were issued.  The two following images show the watch areas issued for the region.  The first watch, which is a Tornado Watch for MN/WI area was first issue at 1925 UTC.  UW-CTC had multiple detections in the MN area prior to the watch being issued in the MN/WI domain.

The second watch area, a Severe T-Storm Watch for S.W. WI, IA, and western IL, was issued at 2035 UTC.  Again, the UW-CTC product had multiple strong detections within this domain prior to the watch being issued.

Perhaps the UW-CTC could aid in situational awareness for watch issuance, too?

Impressive Cld top cooling rate, Iowa

Forecaster comments from EWP blog...

Severe convection currently evolves along the cold front over C Iowa with Cld top cooling product showing impressive cooling rates below -65 K/15 min e.g. over Warren and Polk counties.

SimSat has problems with tropical low

Forecaster comments from EWP blog...

A weak tropical low moved from Cuba to the NE during the daytime hours and was forecast to affect far SE Florida. Comparing SimSat and real IR/WV data, significant differences can be seen especially regarding the cirrus canopy. The main reason for the differences may be the much stronger development of this depression than expected 21 h ago. NHC also increased probs to 40 %, indicating a consolidating system. This evolution may have resulted in a better defined depression’s center with stronger convective development. Therefore those products may have to be used carefully for tropical lows, which reveal stronger intensification rates compared to what models forecast.

Iowa CTC Lead Time

Forecaster comments from EWP blog...

The cloud top cooling product in central Iowa indicated nearly 40 C/15 km of cloud top cooling for a storm in Boone and Story counties.  This product preceded intense radar reflectivity in the area by nearly an hour.

CI north of Kansas City

CI has been occurring along a cold front stretching from the surface low over the upper Midwest. The UAHCI has been producing Strength of Signals values over 60 for many of the southern storms that have begun developing in Iowa and Missouri. This example of the UAHCI at 1915 UTC occurs near in Northeast Kansas, yet with the fast flow, the cell did not initiate until just south of the Iowa border in Missouri. The UAHCI algorithm produced approximately 20 minute lead time on this particular cell considering satellite scan time and algorithm run time. The radar imagery in the second image is from 1951 UTC.

MLB-CI/CTC Example

Forecaster comments from EWP blog...

Here is an example of how UAH Convective Initiation (CI) and CIMSS Cloud Top Cooling (CTC) can be used to anticipate convective development.  Here in the first image at 1940Z, let’s look at the CI product in the top left panel:

CI (top left panel) at 1940Z.

 

Focus on the Lake/Marion/Sumter County line.  There is a maximum in CI there of 80, indicating likely convective development.  If we look at the CTC in the same area on the next image (top right panel), we see a developing max CTC over -20C/15min, which is a strong indicator of a developing severe thunderstorm.

1945Z CTC (top right panel).

 

Although this did not ultimately become a severe thunderstorm, we did observe a few lightning strikes shortly after this time.  This progression from strong CI signal to strong CTC can be a good indicator of a developing thunderstorm.

CI along sea breeze over NE Florida

Forecaster comments from EWP blog...

Westward moving sea breeze front helped to spark sporadic showers/thunderstorms during the afternoon hours. We captured the interaction of an already ongoing weak shower, as front moved in from the east.

 1932 Z; UAH-CI and Cloud top cooling

1940 Z; UAH-CI and Cloud top cooling

The southern parts of Nassau and Charlton county and Baker county were monitored. At 1932Z an increase in cloud top cooling was noticed and 8 min later, CI product also had probabilities of 70 % plus for this area. At the same time, a cooling rate of roughly -15K/15 min was detected. Rapid development occurred thereafter with 50 dBz and more seen in the JAX radar side at 1947 Z, which gave a good lead time for focusing on the potential hot-spot over NE Florida. The storm was a pulsating one with rapid weakening thereafter.

UAH-CI Signal Precedes UW-CTC Signal…Both Precede Convective Initiation

Forecaster comments from EWP blog...

The more I look at these products, the more I’m convinced they work very well in tandem with each other.  Given an environment that supports convective growth, a strong UAH-CI signal (upper image, top left panel) typically precedes a strong UW-CTC signal (middle image, top right panel).  In this case, the strong UAH-CI signal (1615 UTC) preceded the UW-CTC signal (1645 UTC) by about 30 minutes.  By 1715-1730 UTC, 30-45 minutes later, deep-moist convection did indeed form as evidenced by the numerous CG strikes (bottom image, bottom left panel).  We’ve seen this all week…UAH-CI gives us a heads up that general convection is initially building, then a short time later UW-CTC typically picks up on the stronger convection building.  Given a strong cap isn’t present and instability is sufficient, deep-moist convection typically develops 30-60 minutes thereafter.

1615 UTC. Notice the 70% UAH-CI signal in the top left panel.

1645 UTC...30 minutes later. Notice strong cloud-top-cooling signal in the UW-CTC product (top right panel).  

1715-1730 UTC...30-45 minutes later. Deep-moist convection did indeed develop in the vicinity of aforementioned CI/CTC signals, as evidenced by numerous CG lightning strikes (bottom left panel).

UW-CTC Working as Expected in MN/IA

The UW-CTC product has been capturing the initial and ongoing convective development taking place first within the MPX CWA domain, and later further south in north central to central IA.  The beauty of these events is that this showcases how the UW-CTC product still does pretty well, even though the area has a lot of apparent cloud contamination within the scenes.  The below images are shown in chronological order with the original strong convection beginning in the MSPL area at 1515 UTC (Fig. 1).

Fig. 1

Later on at 1725 UTC, the UW-CTC captured good development in the MSPL area that later is an ongoing robust thunderstorm (Fig. 2).

Fig. 2

Some further strong convective development along the frontal boundary was noted in northern and central IA.  Figs. 3 (1932 UTC) and 4 (1955 UTC) capture this development unzipping further south along the boundary and still within areas of significant amounts of cloud debris.

Fig. 3

Fig. 4

CI mainly inland across FL peninsula

Forecaster comments from EWP blog...

Latest CI image shows moderately high probabilities for CI along ahead of the westward moving sea-breeze boundary.  Best chance for thunderstorms appears to be from the interior counties towards the west coast.  Some initiation is possible across Northern Brevard County…though the prospects for lightning are looking slim at this point.