DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 271931
SWODY1
SPC AC 271929

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 PM CDT WED JUN 27 2012

VALID 272000Z - 281200Z

...NO SVR TSTM AREAS FORECAST...

HAVE MADE MINOR CHANGES TO UPPER MS VALLEY SEVERE RISK...NAMELY TO
LOWER SEVERE PROBS ALONG THE U.S./CANADIAN BORDER. LATEST OA FIELDS
SUGGEST VERY WARM EML REMAINS ACROSS THIS REGION WITH 700MB
TEMPERATURES ON THE ORDER OF 16-18C. SFC HEATING ALONE WILL NOT
ALLOW BOUNDARY LAYER PARCELS TO REACH THEIR LFC AND ANY ACTIVITY
THAT DEVELOPS ACROSS THIS REGION WILL BE ELEVATED AND LESS ROBUST
THAN A LOWER ROOTED UPDRAFT. WILL MAINTAIN 5% SEVERE PROBS TO
ACCOUNT FOR A FEW STRONG ELEVATED STORMS BUT OVERALL TRENDS DO NOT
LOOK FAVORABLE FOR ORGANIZED SEVERE.

HAVE REMOVED 5% SEVERE PROBS ACROSS SOUTH FL WHERE CONVECTION HAS
STRUGGLED TO ATTAIN LEVELS NECESSARY FOR LIGHTNING DISCHARGE. IN
ALL LIKELIHOOD ANY STORMS THAT FORM WILL REMAIN QUITE SPARSE AND
SUB-SEVERE.

OTHERWISE...GREATEST CONCENTRATION OF CONVECTION IS NOW OCCURRING
ACROSS THE 4-CORNERS REGION INTO THE NRN FRONT RANGE OF CO. ROBUST
UPDRAFTS SHOULD GRADUALLY INCREASE IN AREAL COVERAGE ACROSS THE
HIGHER TERRAIN AND THIS ACTIVITY SHOULD MOVE NEWD TOWARD THE HIGH
PLAINS OF NERN CO WHERE UPSLOPE FLOW MAY ENHANCE THE PROSPECT FOR
SUSTAINED STORMS CAPABLE OF PRODUCING GUSTY WINDS NEAR SEVERE
LEVELS. REF MCD1295 FOR FURTHER DETAILS.

..DARROW.. 06/27/2012

.PREV DISCUSSION... /ISSUED 1125 AM CDT WED JUN 27 2012/

...NRN/CNTRL MN...
WATER VAPOR IMAGERY SHOWS AN INTENSE UPPER LOW OVER SRN SASKATCHEWAN
THAT IS FORECAST TO MOVE MAINLY EWD ACROSS THE CANADIAN PRAIRIE
PROVINCES THROUGH TONIGHT. AS THE SYSTEM MOVES EWD...WEAK MID LEVEL
HEIGHT FALLS ARE EXPECTED ACROSS EXTREME NRN MN WITH THE BULK OF THE
DYNAMIC FORCING FOR LARGE SCALE ASCENT REMAINING NORTH OF THE
US/CANADA BORDER. 12Z REGIONAL RAOBS INDICATED AN EXPANSIVE AREA OF
VERY WARM 700 MB TEMPERATURES OF 16-18C ASSOCIATED WITH AN
EML/CAPPING INVERSION THAT HAS SPREAD OVER THE UPPER MS VALLEY AND
TOWARD THE UPPER GREAT LAKES. THIS WILL LIKELY INHIBIT
SURFACE-BASED CONVECTION ALONG A COLD FRONT MOVING INTO THE UPPER MS
VALLEY DESPITE A GRADUAL INCREASE IN LOW LEVEL MOISTURE INTO THE MN
AREA.

MODEL GUIDANCE INDICATES CONSIDERABLE UNCERTAINTY IN THE LIKELIHOOD
OF CONVECTIVE DEVELOPMENT NEAR THE FRONT OVER NRN/CNTRL MN LATER
THIS AFTERNOON AND EVENING...BUT THE PRESENCE OF STEEP LAPSE
RATES/MODERATE INSTABILITY AND FAVORABLE DEEP LAYER SHEAR SUPPORTS A
CONDITIONAL RISK OF SEVERE STORMS FOR ANY SUSTAINED UPDRAFTS THAT
DEVELOP. RELATIVE PROXIMITY OF THE CANADIAN UPPER LOW SUGGESTS THE
PROBABILITY OF DEEP CONVECTION MAY BE HIGHER CLOSER TO THE NRN MN
BORDER...AND HAVE MAINTAINED CURRENT SLIGHT RISK AREA IN THIS REGION
WITH LOWER /5%/ HAIL AND WIND PROBABILITY VALUES SWD INTO CENTRAL
MN.

...CENTRAL ROCKIES INTO HIGH PLAINS
A RELATIVELY NARROW PLUME OF MID LEVEL MOISTURE IS EVIDENT IN WATER
VAPOR IMAGERY AND SOUNDER/GPS PW DATA FROM SERN AZ INTO THE CENTRAL
ROCKIES WHERE SCATTERED HIGH-BASED CONVECTION IS OCCURRING THIS
MORNING. ADDITIONAL CONVECTION IS EXPECTED TO DEVELOP OVER THE
HIGHER TERRAIN OF CENTRAL CO THIS AFTERNOON. THIS ACTIVITY IS
EXPECTED TO SPREAD EWD INTO PARTS OF THE CENTRAL HIGH PLAINS LATE
THIS AFTERNOON AND EVENING ALONG/NORTH OF A COLD FRONT MOVING SWD
OVER THE AREA. SWLY MID LEVEL WINDS OF 25-30 KT WILL CONTRIBUTE TO
SUFFICIENT VERTICAL SHEAR FOR A FEW MULTICELL CLUSTERS TO FORM.
SOME STORMS MAY BE CAPABLE OF PRODUCING STRONG WIND GUSTS GIVEN THE
PRESENCE OF A DEEP WELL-MIXED BOUNDARY LAYER.

...SRN FL...
IN THE WAKE OF TD DEBBY NOW OFF THE NERN FL COAST...WSWLY DEEP LAYER
WINDS ARE EVIDENT IN RAOB AND LOCAL VAD PROFILES OVER SRN FL. 12Z
MFL RAOB EXHIBITED POTENTIAL INSTABILITY AND CONTINUED HEATING SOUTH
OF A BAND OF CONVECTION ALONG A FMY-PBI LINE MAY PROMOTE DEVELOPMENT
OF A FEW THUNDERSTORMS THIS AFTERNOON. INCREASING MID/UPPER LEVEL
DRYING AS SEEN IN WATER VAPOR IMAGERY AND MODERATELY STRONG
UNIDIRECTIONAL WSWLY FLOW ALOFT SUGGEST RISK OF ISOLATED STRONG WIND
GUSTS WITH MORE INTENSE CONVECTIVE CELLS INTO THE EVENING.

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