Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 222019
SWOMCD
SPC MCD 222019
MTZ000-222245-

MESOSCALE DISCUSSION 1361
NWS STORM PREDICTION CENTER NORMAN OK
0319 PM CDT FRI JUL 22 2016

AREAS AFFECTED...PORTIONS OF MONTANA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 222019Z - 222245Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...AN ISOLATED SVR-TSTM RISK WILL BE DEVELOPING THIS
AFTERNOON...DURING THE NEXT FEW HOURS. HOWEVER...WW ISSUANCE IS
UNLIKELY.

DISCUSSION...VISIBLE SATELLITE AND RADAR TRENDS SUGGEST THAT
CONVECTION IS DEVELOPING IN RESPONSE TO DIURNALLY ENHANCED
OROGRAPHIC CIRCULATIONS IN PROXIMITY TO THE ROCKY MOUNTAIN FRONT AND
TOWARD THE SWRN MT MOUNTAINS. THE GLANCING INFLUENCE OF DCVA
ACCOMPANYING A SHORTWAVE TROUGH PROGRESSING ACROSS THE NRN GREAT
BASIN...AND ASCENT RELATED TO SMALL-SCALE PERTURBATIONS EMBEDDED
WITHIN BROADER ANTICYCLONIC FLOW FARTHER SE...ARE ALSO ENCOURAGING
THE UPTICK IN CONVECTION. SUFFICIENT LOW-LEVEL MOISTURE -- DEWPOINTS
IN THE UPPER 40S TO THE 50S -- EXISTS ACROSS THE HIGH PLAINS OF MT
TO SUPPORT MARGINAL/MODERATE INSTABILITY IN THESE AREAS. CONVECTION
MAY INCREASE IN INTENSITY AS IT SPREADS ACROSS THE HIGH PLAINS
DURING THE NEXT SEVERAL HOURS. GIVEN THE OVERALL MODEST NATURE OF
LARGE-SCALE ASCENT...THE OVERALL SVR RISK WILL REMAIN ISOLATED.
HOWEVER...THE H7-H5 LAPSE RATE AROUND 8.9 C/KM SAMPLED BY THE 12Z
GREAT FALLS MT RAOB SUPPORTS THE POTENTIAL FOR SUBSTANTIAL UPDRAFT
ACCELERATIONS. THESE ACCELERATIONS...COMBINED WITH AROUND 35-55 KT
OF EFFECTIVE SHEAR...SUGGEST A FEW ORGANIZED CONVECTIVE ELEMENTS
CAPABLE OF ISOLATED SVR WIND/HAIL MAY OCCUR.

..COHEN/WEISS.. 07/22/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BYZ...GGW...TFX...

LAT...LON   45520810 45530940 46411015 47571103 48481204 48861195
            48991082 49020991 48880785 48040711 46090695 45520810




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