UAHCI along cold front in Kansas

Over the past several hours, several storms have fired along the cold front in Kansas and subsequently moved off towards the northeast. This area continues to be defined by a thin line of convergence at 2255 UTC (see Figure 1). The UAHCI product continues to indicate the storms will continue to fire along this portion of the front with a stronger strength of signal on the northern end. Subsequent visible imagery shows that the northern end of this line segment did indeed generate more convection as can be seen at 2345 UTC with the mature cumulonimbus in Figure 2. The southern end of the line continues to show strong strengths of signal, with future development likely in the unstable environment.

Figure 1

Figure 2

Sea breeze along W-coast of Florida

Forecaster comments from EWP blog...

The synthetic IR/WV forecast did a good job in placing strongest activity over Florida along the W coast, where eastward moving sea breeze probably caused strongest convergence in easterly wind regime. Pulsating storms featured reflectivity peaks in excess of 50 dBz.

Harrison County MO CTC Lead Time

Forecaster comments from EWP blog...

The following CTC image led to the issuance of a warning at 2028Z.   Severe hail signatures were noted with storm at 2112Z and severe hail was reported at 2130Z.

RSO mimics GOES-R temporal resolution for UAHCI

Away from the main activity occurring in the Upper Midwest (previous blog posts), thunderstorms are also developing in association with the upper low. The UAHCI algorithm has captured this development over Nebraska. Severe weather is not anticipated with this activity. GOES is currently in Rapid Scan Operations, so this will closely mimic the temporal resolution of GOES-R. The first image is from 2032 UTC with SOS values over 70.

This second image is from 2040 UTC, with a strength of signal over 80.

The last image is from 2045 with a strength of signal continued over 80. The storms went onto initiate over central Nebraska!  The temporal resolution of GOES-R will surely help convective initiation algorithms.

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.