DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 051604
SWODY1
SPC AC 051601

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1101 AM CDT TUE JUN 05 2012

VALID 051630Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT FOR
PARTS OF WRN AND CNTRL MT...

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING FOR
PORTIONS OF THE SERN U.S...

...SYNOPSIS...

AN OMEGA BLOCK WILL BE MAINTAINED OVER THE CONUS THROUGH THE DAY ONE
PERIOD...FEATURING AN AMPLIFIED RIDGE FROM THE CANADIAN PRAIRIE
PROVINCES SWD THROUGH THE GREAT PLAINS...BRACKETED BY TROUGHS ACROSS
THE INTERMOUNTAIN WEST AND E OF THE MS RIVER VALLEY. WITHIN THIS
BROAD-SCALE PATTERN...A SIGNIFICANT SHORTWAVE TROUGH AND ASSOCIATED
60-70 KT MIDLEVEL JET STREAK WILL TRANSLATE NEWD FROM THE GREAT
BASIN INTO NRN HIGH PLAINS WITH SYSTEM ASSUMING AN INCREASING
NEGATIVE TILT WITH TIME. ELSEWHERE...A SERIES OF WEAK VORTICITY
MAXIMA --SOME OF CONVECTIVE ORIGIN-- WILL AFFECT THE SERN U.S.
TODAY...EMBEDDED WITHIN A RIBBON OF 35-50 KT MIDLEVEL FLOW
ENCOMPASSING ERN CONUS TROUGH.

AT THE SURFACE...LEE CYCLONE OVER CNTRL MT WILL DEEPEN THROUGH THE
PERIOD WHILE SLOWLY DEVELOPING NNWWD INTO SRN PARTS OF
ALBERTA/SASKATCHEWAN LATE. THIS LOW PRESSURE WILL BE ATTENDED BY A
PACIFIC FRONT WHICH WILL ADVANCE EWD THROUGH THE NRN/CNTRL ROCKIES
INTO ADJACENT HIGH PLAINS. FARTHER SE...A COLD FRONT WILL SETTLE
STEADILY SWD THROUGH THE GULF COAST AND SERN ATLANTIC STATES. THE
WRN EXTENSION OF THIS WILL BOUNDARY REMAIN MORE QUASI-STATIONARY
OVER THE CNTRL HIGH PLAINS WHERE IT WILL LINK WITH A N-S ORIENTED
LEE TROUGH.

...MT...

ANOTHER ACTIVE SEVERE WEATHER DAY IS ANTICIPATED ALONG SURFACE
FRONTAL SYSTEM...AND AHEAD OF STRONG SHORTWAVE TROUGH APPROACHING
THE REGION. 12Z TFX SOUNDING EXHIBITED A STEEP MIDLEVEL LAPSE RATE
PROFILE ABOVE A MOIST BOUNDARY LAYER FOR THE ELEVATION WHICH WILL
SUPPORT MODERATE AFTERNOON INSTABILITY WITH MLCAPE VALUES
APPROACHING 1000-2000 J/KG. LATEST MODEL GUIDANCE IS SUGGESTIVE
THAT INITIAL STORM DEVELOPMENT WILL BE FOCUSED INVOF PACIFIC FRONT
AND HIGH TERRAIN OF SWRN MT/WRN WY BY MID AFTERNOON WITH STORMS
MOVING/DEVELOPING RAPIDLY NWD TOWARD THE INTERNATIONAL BORDER THIS
EVENING INTO TONIGHT.

FORECAST SOUNDINGS INVOF SURFACE LOW AND PACIFIC FRONT SHOW
PRONOUNCED VEERING OF WINDS WITH HEIGHT WITH 50-60 KT OF DEEP-LAYER
SHEAR. WHEN COUPLED WITH THE MODERATE INSTABILITY...SETUP WILL
FAVOR SUPERCELLS AND/OR SHORT BOWING SEGMENTS WITH A RISK FOR
DAMAGING WINDS AND LARGE HAIL. THE GREATEST POTENTIAL FOR A TORNADO
OR TWO WILL EXIST ACROSS PARTS OF N-CNTRL MT THIS EVENING WITHIN A
ZONE OF ENHANCED LOW-LEVEL SHEAR AND COMPARATIVELY LOWER T-TD
SPREADS TO THE N/NE OF SURFACE LOW TRACK.

...SERN ATLANTIC COAST TO CNTRL GULF COAST STATES...

12Z REGIONAL SOUNDINGS SAMPLED THE PRESENCE OF A RATHER MOIST
BOUNDARY LAYER /I.E. LOWEST 100-MB MEAN-MIXING RATIOS OF 14-15 G PER
KG/ AND A RELATIVELY WEAK CAP. AS TEMPERATURES WARM INTO THE
MID-UPPER 80S...EXPECT TSTMS TO INCREASE IN NUMBER ALONG AND AHEAD
OF COLD FRONT WITHIN A KINEMATIC ENVIRONMENT CHARACTERIZED BY
UNIDIRECTIONAL WLY TROPOSPHERIC FLOW WITH 30-40 KT OF DEEP-LAYER
SHEAR. GIVEN MLCAPE VALUES INCREASING TO 1500-3000 J/KG...POTENTIAL
WILL EXIST FOR ORGANIZED STORM MODES INCLUDING SUPERCELLS AND BOWING
STRUCTURES WITH THE PRIMARY HAZARDS BEING DAMAGING WINDS AND SEVERE
HAIL.

FOR ADDITIONAL NEAR-TERM GUIDANCE...SEE MCD 1069.

...TX...

MORNING RADAR/SATELLITE DATA INDICATE A WELL-DEFINED MCV OVER THE TX
SOUTH PLAINS INTO LOW ROLLING PLAINS WHICH WILL SERVE AS A FOCUS FOR
DIURNALLY ENHANCED TSTM DEVELOPMENT LATER TODAY. THE COMBINATION OF
STRONGER DAYTIME HEATING ALONG THE PERIPHERY OF DENSER CLOUDS NEAR
SYSTEM CORE...STEEP LAPSE RATES AND DEWPOINTS IN THE 60S WILL YIELD
A MODERATELY UNSTABLE AIR MASS BY AFTERNOON WITH MLCAPE OF 1500-2500
J/KG. MOREOVER...TIME-HEIGHT WIND OBSERVATIONS FROM LBB AND JAYTON
SHOW A BELT OF MODEST /20-30 KT/ WNWLY FLOW ALONG SRN FRINGE OF
PARENT CIRCULATION WHICH MAY BE SUFFICIENT FOR SOME STORM
ORGANIZATION GIVEN THE DEGREE OF INSTABILITY. AS SUCH...EXPECT THE
RISK FOR A FEW SEVERE STORMS TO INCREASE THIS AFTERNOON INTO EVENING
WITH DAMAGING WINDS AND LARGE HAIL BEING THE PRIMARY HAZARDS.

..MEAD/COHEN.. 06/05/2012

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