MESO: Mesoscale Discussion 1442

ACUS11 KWNS 291942
SWOMCD
SPC MCD 291941
WYZ000-COZ000-UTZ000-IDZ000-292145-

MESOSCALE DISCUSSION 1442
NWS STORM PREDICTION CENTER NORMAN OK
0241 PM CDT WED JUN 29 2011

AREAS AFFECTED...MUCH OF UT...FAR WRN CO...SWRN WY...SERN ID

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 291941Z - 292145Z

A FEW STORMS MAY PRODUCE SVR WIND GUSTS THIS AFTERNOON.

A PLUME OF MID/UPPER-LEVEL MOISTURE EMANATING FROM THE EAST PACIFIC
EXTENDS NWD ACROSS ERN SECTIONS OF THE GREAT BASIN PER RECENT GPS PW
DATA -- I.E. PWAT VALUES OF 0.65 TO 0.80 INCH. STEEP LOW-LEVEL LAPSE
RATES OWING TO STRONG HEATING OVER THE MOUNTAINS COUPLED WITH STEEP
MID-LEVEL LAPSE RATES AND OROGRAPHIC EFFECTS WILL FOSTER THE
DEVELOPMENT OF SCATTERED TO NUMEROUS CONVECTION THROUGH THE
AFTERNOON. SBCAPE VALUES OF 500 TO 1500 J/KG WILL LIKELY PROMOTE
VIGOROUS UPDRAFTS...WHICH WILL BE FURTHER ENHANCED BY MODERATE TO
STRONG VERTICAL SHEAR. THE STEEPENING LAPSE RATES SUPPORTIVE OF
DCAPE VALUES OF 1200 TO 1500 J/KG WILL PROMOTE INTENSE MICROBURSTS
CAPABLE OF PRODUCING SVR SFC WINDS. THIS THREAT WILL BE EXACERBATED
BY DOWNWARD TRANSPORT OF STRONG LOW/MID-LEVEL FLOW WITHIN
DOWNDRAFTS...AS THE SALT LAKE CITY AREA VWP DEPICTS 40 TO 65 KT OF
AMBIENT FLOW IN THE 2-5-KM AGL LAYER. THIS STRONGER FLOW ALOFT IS
ALREADY BEING MANIFESTED AT THE SFC OUTSIDE OF DEEP/MOIST CONVECTION
AS GUSTS OF 30 TO 40 KT PER MESOWEST OBSERVATIONS. HOWEVER...WITH
THE DISCUSSION AREA LOCATED WELL TO THE EAST OF A MID-LEVEL VORT MAX
CENTERED OVER CNTRL CA AND ATTENDANT HEIGHT FALLS...SYNOPTIC-SCALE
FORCING FOR ASCENT WILL BE LIMITED. THIS WILL MINIMIZE THE COVERAGE
OF THE SVR STORM THREAT SUCH THAT THE ISSUANCE OF A WW IS NOT
NECESSARY.

..COHEN.. 06/29/2011

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

ATTN...WFO...CYS...RIW...GJT...SLC...PIH...

LAT...LON 39031292 40251299 41541270 42571204 43291121 43591018
43360850 42330774 40910780 39530861 38820910 38190985
37791082 37851205 38281265 39031292

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