DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 191217
SWODY1
SPC AC 191215

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0715 AM CDT MON APR 19 2010

VALID 191300Z - 201200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
PRIMARY FEATURE ASSOCIATED WITH STRONG THUNDERSTORM POTENTIAL TODAY
WILL BE LARGE MID/UPPER LEVEL RIDGE REMAINING ESTABLISHED OVER THE
ROCKIES AND ADJACENT HIGH PLAINS REGION. IN THE LOW LEVELS...A LEE
TROUGH WILL BECOME BETTER DEFINED OVER THE CNTRL AND SRN HIGH PLAINS
WHICH WILL PROVIDE THE FOCUS FOR ISOLATED TO SCATTERED...DIURNAL
STORMS.

...CNTRL/SRN HIGH PLAINS...
MORNING WV IMAGERY INDICATED A SERIES OF LOW AMPLITUDE SHORTWAVE
TROUGHS/VORT MAXIMA SHIFTING SLOWLY SEWD ACROSS THE NRN HIGH PLAINS
AND THE MID MO RIVER VALLEY ALONG DOWNSTREAM SIDE OF THE RIDGING
ALOFT. TRAILING IMPULSES SHOULD SUPPORT STORM FORMATION ALONG NRN
EXTENSION OF THE LEE TROUGH OVER PARTS OF ERN WY INTO WRN PORTIONS
OF SD AND NEB DURING THE AFTERNOON. IN ADDITION...CONVERGENCE ALONG
THE LEE TROUGH AND DIURNAL HEATING WILL INCREASE THE
POTENTIAL/COVERAGE OF LATE DAY TSTMS ACROSS MUCH OF THE HIGH PLAINS
REGION.

DESPITE ONLY MODEST LOW LEVEL MOISTURE...DAYTIME HEATING COUPLED
WITH COLD MID LEVEL AIR WILL SUPPORT LARGE LAPSE RATES AND MODEST
INSTABILITY WITH MLCAPE GENERALLY FROM 500-1000 J/KG EXPECTED. WHEN
COMBINED WITH VERTICAL WIND PROFILES EXHIBITING LIGHT SLY/SELY WINDS
VEERING TO 25-35 KT IN THE MIDLEVELS...ENVIRONMENT WILL BE
SUPPORTIVE OF ORGANIZED/ROTATING UPDRAFTS CAPABLE OF HAIL...SOME OF
WHICH MAY APPROACH SEVERE LEVELS.

IN ADDITION TO THE HAIL THREAT...THE RELATIVELY DRY SUB-CLOUD LAYER
INDICATES THE POTENTIAL FOR LOCALLY STRONG WIND GUSTS. THIS IS
ESPECIALLY THE CASE SHOULD INDIVIDUAL STORMS MERGE INTO A LARGER
CLUSTER. EXPECT THE HAIL/WIND THREAT TO PERSIST INTO MID/LATE
EVENING PRIOR TO THE COOLING AND RESULTANT STABILIZATION OF THE
BOUNDARY LAYER.

..EVANS/STOPPKOTTE/MEAD.. 04/19/2010

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