SPC MD 1446


MD 1446 Image

Mesoscale Discussion 1446
NWS Storm Prediction Center Norman OK
0715 PM CDT Fri Jul 12 2019

Areas affected...Portions of western/central NE into far
northeastern CO

Concerning...Severe potential...Watch possible 

Valid 130015Z - 130215Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated large hail may occur with storms over the western
Nebraska Panhandle early this evening, with a severe wind gust
threat potentially increasing into western/central Nebraska over the
next couple of hours. Watch issuance is possible.

DISCUSSION...Surface observations and visible satellite show a
quasi-stationary front extending from the western NE Panhandle into
far northeastern CO and southwestern NE at 00Z. Weak low-level
convergence along this boundary in addition to outflow from
high-based, generally disorganized storms across eastern CO/WY have
recently initiated additional storms across the western NE
Panhandle. The airmass along and north of the front has become
strongly to extremely unstable early this evening owing to steep
mid-level lapse rates of 7.5 to near 9 C/km overlying upper 60s to
lower 70s surface dewpoints. Also, the 00Z sounding from North
Platte NE indicates MLCAPE in excess of 3300 J/kg is present across
western NE.

Primary uncertainty regarding a greater severe weather threat this
evening across western/central NE and far northeastern CO is the
lack of stronger low to mid-level flow. The main belt of enhanced
mid-level westerlies will remain displaced to the north of this
region, with only 10-20 kt of west-northwesterly flow estimated on
various RAP forecast soundings and the 00Z observed sounding from
LBF. Even so, initial robust storm development across the western NE
Panhandle will be capable of producing isolated large hail based on
current radar trends and MRMS hail size estimates. It remains
unclear if storms will congeal into a loosely organized multicell
cluster as they develop eastward across western/central NE this
evening. Severe wind gusts would potentially become the main threat
if this upscale growth were to occur. Severe Thunderstorm Watch
issuance this evening will be dependent on convective trends across
the western NE Panhandle and far northeastern CO over the next
couple of hours.

..Gleason/Hart.. 07/13/2019

...Please see www.spc.noaa.gov for graphic product...


LAT...LON   42480399 42800359 42960306 42970113 42830031 42449961
            41919926 41109926 40130027 40120248 40560313 41000358
            41440377 42480399 

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