EWP Blog

MPX decided to move to AMA for the last hour of the experiment. MPX storms mainly just big rain producers with FF a problem. Went with a warning for Potter without much radar data yet mainly due to strong updraft, strong upper diverergence and MESH of 1.75 inch. Nice inflow into the storm as well.

KOAX 88D appears to have a poor viewing angle to detect the strong winds behind a bow echo/gust front over Lancaster county, NE. This likely negatively impacted the ability of 3DVAR to see the strong winds.  The line moved through the Lincoln, NE area and produced 60 to 65 mph gusts, yet the 2310 UTC 3DVAR 1km winds only show north winds of 17 m/s. On Monday, 3DVAR 1km winds did very well handling the damaging winds associated with the MCS that moved through the Memphis (MEG) CWA.  Just need to install more radars to minimize this problem. 🙂

0600 PM     TSTM WND GST     CERESCO                 41.06N 96.65W
06/14/2012  E65 MPH          SAUNDERS           NE   TRAINED SPOTTER
0608 PM     TSTM WND GST     LINCOLN                 40.82N 96.69W
06/14/2012  M60 MPH          LANCASTER          NE   ASOS
SNELSON/TMT
		
			

The storm that had steady updraft strength around 25 ms over Harrison County gave some lead time before low level mesocyclone tightened north of Magnolia on KOAX 0.5 deg SRM. But 3DVAR did not show strong increase in updraft helicity with max value reaching 50 m/s at 2300z. Low level meso has weakened but strong mid level circulation remains at 2312z.

TMT/SN

22Z OUNWRF forecasting storms to fire along outflow from current storms and consolidate severe threat across the southern zones by 7 PM.  It really starts to hit the hail threat across the southern zones by that time.

In the very near term, OUNWRF did a decent job getting the intensification of the Furnace and Harlan storms, taking the furnace storm southeast out of the CWA briefly, and weakening the Harlan storm completely.

Here is the current warning/radar situation…

Garmon/Skov

Just got -27c/15min in the CTC product in Brown County — just west of MPX CWFA. This corresponds well to a developing echo in central Brown County. Perhaps a sign of more severe weather shortly?

The 3DVAR products are showing an intensification with the line of storms north of Omaha.  Updraft strength has increased to around 20 m/s Washington and Burt Counties. MESH increased to 2.2 inches in southern Burt County.

Latest updraft strength up to 21 m/s over southeast Burt County.

UPDATE…3DVAR shows an increase in updraft strength with a strong increase in max divergence above 8 km in northern Harrison County. Maybe see an increase in hail size in the next 15 minutes.

Continuing to increase…to 27 m/s at 2250z.

TMT/SN

Looks like 3-4 inches of rain has fallen over the past several hours SE of the Twin Cities. With another inch or two possible from training storms…opted to go with a FFW.

Line of severe thunderstorms has developed over the southeast MPX CWA. Small circulations have developed along the southern half of the line, which may locally enhance wind gusts (>65 mph). MESH with this line has averaged around 1″, and we did get one severe report of quarter size hail. Updraft strength and upper divergence have been somewhat marginal, which verifies our thinking that this is probably more of a wind bag than a large hail producer.

Velocity image at 2222z:

Issued another SVR for the La Sueur County Storm. Did see some weakening in the 3dvar fields, but the last volume scan suggested a renewed updraft and increased storm top divergence. However, MESH has decreased so it is unclear if the storm is just reorganizing or if there is a diminishing trend going on. MRD/TY

Ping-pong ball size hail jusr reported from Wilsonville area in SW Furnace county.  MESH up to around 2 inches and we have increased the hail size in the warning to around 2 inches.

The 3DVAR shows updrafts increasing downstream of the main large dominant updraft at this time.

Garmon/Skov