Month: May 2013

Analyzed Severe Storm in Northern North Carolina Using MRMS

Posted in Live Blogs on by Kristin Calhoun.

Issued a severe thunderstorm warning for quarter sized hail for a storm that was moving out of Yadkin County NC and moving into Surry and Wilkes Counties. Started by analyzing storms with the suite of MRMS Data. We initially looked at the MESH product, which was indicating .25 in hail. Knowing that the storms had a history of producing quarters, we interrogated with the MRMS Height 50 dBZ echo Above -20 C. Noticing a lack of 50 dBz echos over -20C, we concluded that given the depth of the cold air under the cutoff low, severe hail was possible with lower cores than normally anticipated.

MESH overlapped on 0.5 deg Z
MESH overlapped on 0.5 deg Z

FRANK/KURTZ

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Using Hybrid Hydrometeor Classification to Warn on Large Hail

Posted in Live Blogs on by Kristin Calhoun.

Forecasters monitored several multicell storms over the southern Blacksburg CWA. Conditions were not optimal, but a few reports of quarter to golf ball sized hail were received in the county adjacent to the extreme southwest portions of the CWA. The attached image shows a four panel of base reflectivity, MESH trails, and HHC, which indicated large and giant hail in several pixels.
4-panel of reflecivity, MESH, and HHC

Austin/Hatzos

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EWP2013 – Mesoscale Outlook 2015 UTC

Posted in Outlooks on by Greg Stumpf.

Convection is ongoing across North-Central North Carolina westward into the Appalachians. The upper low is currently centered in eastern Tennessee. The most robust thunderstorms of the afternoon have developed across northwest Carolina along a a boundary extending from NW North Carolina into eastern Kentucky.

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Current radar imagery is overlayed with surface dewpoint. Storms are initiating along and north of the boundary.
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21z forecasted low-level lapse rates from the NAM

The environment is not overly robust to sustain severe convection. Surface-based CAPE values across Northern North Carolina  are roughly around 1000 J/Kg with 0-6 km shear 40-50 knots. Low-level lapse rates will be approaching 6-7.5 C/Km by 21z with mid-level lapse rates around 6-7 C/km. The main threat will be marginally severe hail, but 0-3 km helicity values between 150-200 m2/s2 could support a low-end tornado threat. However, as storms move away from the boundary, this threat will decrease.

The EFP has placed a 5% probability of severe storms for the previously mentioned area, while a slight risk of severe storms is forecasted by SPC in small area shown in the image below.

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Orange color represents a 5% probability of severe weather issued by the EFP.
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19z Day 1 Outlook from SPC.

As a lobe of energy wraps around the upper-low and moves northward into northern NC, the storms which have already initiated should be able to continue northward into the Blacksburg, VA CWA while some continuing activity is possible across the northwestern extent of the Raleigh, NC CWA.

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Simulated IR Satellite Imagery at 22z.

Hampshire/Guseman

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Welcome to the Experimental Warning Program 2013 spring experiment (EWP2013)

Posted in General on by Greg Stumpf.

Monday 6 May 2013 begins the first week of our three-week spring experiment of the 2013 NSSL-NWS Experimental Warning Program (EWP2013) in the NOAA Hazardous Weather Testbed at the National Weather Center in Norman, OK.  There will be five primary projects geared toward WFO applications, 1) the development of “best practices” for using Multiple-Radar/Multiple-Sensor (MRMS) severe weather products in warning operations, 2) an evaluation of a dual-polarization Hail Size Discrimination Algorithm (HSDA), 3) an evaluation of model performance and forecast utility of the OUN WRF when operations are expected in the Southern Plains, 4) an evaluation of the Local Analysis Prediction System (LAPS) Space and Time Multiscale Analysis System (STMAS), and 5) an evaluation of multiple CONUS GOES-R convective applications, including pseudo-geostationary lightning mapper products when operations are expected within the Lightning Mapping Array domains (OK, w-TX, AL, DC, FL, se-TX, ne-CO).  We will also be coordinating with and evaluating the EFP’s probabilistic severe weather outlooks as guidance for our warning operations.  Operational activities will take place during the week Monday through Friday.

For the week of 6-10 May, our distinguished NWS guests will be Marc Austin (WFO Norman, OK), Hayden Frank (WFO Boston, MA), Jonathan Guseman (WFO Lubbock, TX), Nick Hampshire(WFO Fort Worth, TX), Andy Hatzos (WFO Wilmington, OH), and Jonathan Kurtz (WFO Norman, OK).  The GOES-R program office, the NOAA Global Systems Divisions (GSD), and NWS WFO Huntsville’s Applications Integration Meteorologist (AIM) Program have generously provided travel stipends for our participants from NWS forecast offices nationwide.

Visiting scientists this week will include Lee Cronce (Univ. Wisconsin), Geoffrey Stano (NASA-SPoRT), Isidora Jankov (NOAA/GSD), and Amanda Terberg (NWS Air Weather Center GOES-R Liaison).

Gabe Garfield will be the weekly coordinator.  Clark Payne (WDTB) will be our “Tales from the Testbed” Webinar facilitator. Our support team also includes Darrel Kingfield, Kristin Calhoun, Travis Smith, Chris Karstens, Greg Stumpf, Kiel Ortega, Karen Cooper, Lans Rothfusz, Aaron Anderson, and David Andra.

Each Friday of the experiment (10 May, 17 May, 24 May), from 1200-1240pm CDT, the WDTB will be hosting a weekly Webinar called “Tales From the Testbed”.  These will be forecaster-led, and each forecaster will summarize their biggest takeaway from their week of participation in EWP2013.  The audience is for anyone with an interest in what we are doing to improve NWS severe weather warnings.  New for EWP2013, there will be pre-specified weekly topics.  This is meant to keep the material fresh for each subsequent week, and to maintain the audience participation levels throughout the experiment.  The weekly schedule:

Week 1:  GOES-R; pGLM

Week 2:  MRMS, HSDA

Week 3:  EFP outlooks, OUN WRF, LAPS

One final post-experiment Webinar will be delivered to the National Weather Association and the Research and Innovation Transition Team (RITT) in June.  This Webinar will be a combined effort of both sides of the Hazardous Weather Testbed (EFP and EWP).

Here are several links of interest:

You can learn more about the EWP here:

http://hwt.nssl.noaa.gov/ewp/

NOAA employees can access the internal EWP2013 page with their LDAP credentials.

https://secure.nssl.noaa.gov/projects/ewp2013/

Stay tuned on the blog for more information, daily outlooks and summaries, live blogging, and end-of-week summaries as we get underway on Monday 6 May!

Greg Stumpf, CIMMS/NWS-MDL, EWP2013 Operations Coordinator

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