SPC AC 061609
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1109 AM CDT TUE MAY 06 2008
VALID 061630Z - 071200Z
...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER
MUCH OF CENTRAL/EASTERN NEB AND NORTHWEST KS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE SOUTHERN AND
CENTRAL PLAINS REGION...EXTENDING INTO PARTS OF THE UPPER MS
VALLEY....
MORNING WATER VAPOR IMAGERY SHOWS AN UPPER LOW OVER THE NORTHERN
GULF OF CALIFORNIA...WITH ASSOCIATED SOUTHWESTERLY MID LEVEL JET
BEGINNING TO NOSE OUT OF NORTHERN MEXICO INTO SOUTHERN NM/SOUTHWEST
TX. MEANWHILE...RELATIVELY FAST WEST-NORTHWESTERLY MID LEVEL FLOW
EXTENDS FROM THE NORTHERN ROCKIES INTO THE MID MS VALLEY. CURRENT
INDICATIONS ARE FOR AN ACTIVE SEVERE WEATHER EPISODE THIS AFTERNOON
AND EVENING ACROSS THE CENTRAL AND SOUTHERN PLAINS. THIS ACTIVITY
APPEARS LIKELY TO BE FOCUSED INTO TWO AREAS: NEB/KS AND WEST TX.
UNFORTUNATELY...MODEL GUIDANCE VARIES SIGNIFICANTLY REGARDING
CONVECTIVE EVOLUTION AND TIMING ACROSS THE PLAINS STATES TODAY AND
LESSENS OVERALL CONFIDENCE IN FORECAST SCENARIO.
...NEB/KS...
SATELLITE IMAGERY SHOWS SHORTWAVE TROUGH EMBEDDED IN
WEST-NORTHWESTLY MID LEVEL FLOW OVER EASTERN MT/WESTERN DAKOTAS.
THIS FEATURE WILL TRACK ACROSS THE NORTHERN PLAINS TODAY...PROVIDING
INCREASINGLY STRONG LARGE SCALE FORCING FOR ASCENT. MORNING
SOUNDINGS SHOWED VERY STEEP LAPSE RATES AND THE POTENTIAL FOR LARGE
CAPE VALUES DESPITE RATHER LIMITED LOW LEVEL MOISTURE. A
COMBINATION OF SURFACE DEWPOINTS IN THE MID 50S AND TEMPERATURES IN
THE 70S WILL YIELD MLCAPE VALUES OVER 2000 J/KG AND LITTLE
INHIBITION. CURRENT CONVECTION OVER SOUTHERN SD MAY INTENSIFY THIS
AFTERNOON...WHILE OTHER STORMS FORM SOUTHWESTWARD ACROSS WESTERN
NEB/NORTHWEST KS. ALL OF THESE STORMS WILL TRACK SOUTHEASTWARD
ACROSS THE MDT RISK AREA /MUCH OF NEB AND NORTHWEST KS/ WITH LARGE
HAIL LIKELY...INCLUDING THE POTENTIAL FOR VERY LARGE AND DAMAGING
HAIL. CONVECTION IS LIKELY TO GROW UPSCALE INTO AN ORGANIZED MCS
DURING THE EVENING AND POSE AN ENHANCED THREAT OF DAMAGING WINDS
ACROSS SOUTHEAST NEB INTO EASTERN/CENTRAL KS.
...EASTERN NM/WEST TX...
LATEST SURFACE ANALYSIS SHOWS REMNANT OUTFLOW BOUNDARY FROM
OVERNIGHT CONVECTION EXTENDING FROM NEAR MAF EASTWARD INTO CENTRAL
TX. THIS BOUNDARY IS LIKELY TO WASH OUT AND LIFT NORTHWARD
TODAY...ALLOWING MOIST LOW LEVEL AIR MASS TO ADVECT NORTHWESTWARD
INTO MUCH OF WEST TX AND SOUTHEAST NM. THIS AREA IS UNDER SHORTWAVE
RIDGING THIS MORNING...BUT HEIGHT FALLS WILL COMMENCE BY MID
AFTERNOON WHILE STRONG SURFACE HEATING RESULTS IN MLCAPE VALUES OF
2000-2500 J/KG. AS INFLUENCE OF UPPER LOW BEGINS TO APPROACH THE
DRYLINE LATE THIS AFTERNOON...ISOLATED THUNDERSTORMS ARE LIKELY TO
DEVELOP NEAR THE NM/TX BORDER WEST OF LBB-MAF. THESE STORMS ARE
EXPECTED TO BE SUPERCELLULAR WITH A RISK OF VERY LARGE HAIL AND A
FEW TORNADOES. STORMS WILL BECOME MORE NUMEROUS THROUGH THE EVENING
AND SURGE EASTWARD ACROSS WEST CENTRAL TX OVERNIGHT AS LARGE SCALE
FORCING OVERSPREADS REGION.
..HART/JEWELL.. 05/06/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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