Jun 22, 2013 2000 UTC Day 1 Convective Outlook | |||||||||
Updated: Sat Jun 22 20:03:40 UTC 2013 | |||||||||
Probabilistic to Categorical Outlook Conversion Table |
Categorical Graphic | |||||||||
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Probabilistic Tornado Graphic | |||||||||
Probability of a tornado within 25 miles of a point. Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point. |
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Probabilistic Damaging Wind Graphic | |||||||||
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point. |
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Probabilistic Large Hail Graphic | |||||||||
Probability of hail 1" or larger within 25 miles of a point. Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point. |
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SPC AC 221959 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0259 PM CDT SAT JUN 22 2013 VALID 222000Z - 231200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NORTH CENTRAL ROCKIES...MUCH OF THE NORTHERN AND CENTRAL PLAINS...INTO PARTS OF THE UPPER MISSISSIPPI VALLEY... ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTHERN HIGH PLAINS... ...SOUTHERN HIGH PLAINS... PRIMARY OUTLOOK ADJUSTMENT IS THE ADDITION OF A CATEGORICAL SLIGHT RISK FOR HAIL/WIND POTENTIAL ACROSS PARTS OF WEST/NORTHWEST TX...WITH MORE ISOLATED STORMS ALSO ANTICIPATED ACROSS FAR SOUTHWEST TX. AIDED BY A WEAK MID-LEVEL IMPULSE APPROACHING FROM NM/SOUTHERN CO...AT LEAST ISOLATED INSTANCES OF HAIL/WIND ARE EXPECTED ESPECIALLY LATE THIS AFTERNOON/EARLY EVENING. ...ELSEWHERE... SEE PRIOR OUTLOOK DISCUSSION BELOW AND EXISTING/SUBSEQUENT MESOSCALE DISCUSSIONS FOR ADDITIONAL DETAILS. ..GUYER.. 06/22/2013 .PREV DISCUSSION... /ISSUED 1126 AM CDT SAT JUN 22 2013/ ...SYNOPSIS... TO THE SOUTH OF A REMNANT BLOCKING PATTERN OVER WESTERN AND CENTRAL CANADA...A MODEST BELT OF WESTERLIES CONTINUES TO CURVE ACROSS THE PACIFIC COAST THROUGH THE ROCKIES. A NUMBER OF SHORT WAVE TROUGHS ARE EMBEDDED WITHIN THE REGIME...INCLUDING ONE SIGNIFICANT IMPULSE NOW TURNING EASTWARD INTO THE NORTHERN/CENTRAL ROCKIES. THIS LATTER FEATURE IS EXPECTED TO PROGRESS NORTHEASTWARD ACROSS THE ROCKIES INTO THE NORTHERN HIGH PLAINS BY EARLY SUNDAY...PRECEDED BY AT LEAST A COUPLE OF SMALLER SCALE IMPULSES WITHIN INCREASINGLY CYCLONIC SOUTHWESTERLY MID/UPPER FLOW ACROSS THE NORTHERN AND CENTRAL PLAINS. MEANWHILE...A COUPLE OF PERTURBATIONS...NOW PROGRESSING INTO BROADER SCALE ANTICYCLONIC FLOW ACROSS THE UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES...WILL CONTINUE EASTWARD TODAY...AND THE TENDENCY MAY BE FOR MID-LEVEL HEIGHTS TO RISE ACROSS THE UPPER MIDWEST...BEFORE FALLING MORE SUBSTANTIVELY AGAIN LATE TONIGHT INTO SUNDAY. THIS EVOLVING PATTERN IS AGAIN EXPECTED TO SUPPORT CONSIDERABLE THUNDERSTORM ACTIVITY TODAY AND TONIGHT ACROSS THE NORTHERN ROCKIES INTO THE UPPER MIDWEST...WITH INCREASING CHANCES FOR THUNDERSTORM ACTIVITY ALSO EASTWARD ACROSS THE GREAT LAKES REGION INTO PARTS OF THE NORTHEAST. STRONG HEATING MAY ALSO AGAIN CONTRIBUTE TO SCATTERED STORM DEVELOPMENT LATE THIS AFTERNOON AND EVENING ACROSS PARTS OF THE SOUTHERN HIGH PLAINS OTHERWISE...WITH MID-LEVEL INHIBITION REMAINING RELATIVELY WEAK EAST OF THE MISSISSIPPI VALLEY...SCATTERED THUNDERSTORM ACTIVITY IS ALSO EXPECTED AROUND THE PERIPHERY OF A LINGERING WEAK UPPER LOW CENTERED NEAR THE SOUTHERN APPALACHIANS...ACROSS PARTS OF THE LOWER OHIO VALLEY INTO THE OZARK PLATEAU...AND ACROSS THE GULF AND SOUTH ATLANTIC COASTS. ...NRN/CNTRL ROCKIES EASTWARD TO UPPER MIDWEST... THE DETAILS OF POTENTIAL CONVECTIVE DEVELOPMENT FOR TODAY REMAIN A BIT UNCLEAR. THE PRIMARY SURFACE BOUNDARY OF INTEREST APPEARS TO BE A COMPOSITE OUTFLOW BOUNDARY GENERATED BY STORM CLUSTERS OF THE PAST COUPLE OF DAYS...WHICH NOW GENERALLY EXTENDS ACROSS LOWER MICHIGAN...NORTHERN INDIANA AND ILLINOIS...THROUGH SOUTHERN IOWA...AND THE VICINITY OF THE KANSAS/NEBRASKA BORDER...INTO THE COLORADO FRONT RANGE. MODIFICATION AND NORTHWARD RETREAT OF THIS BOUNDARY IS UNCERTAIN...BUT STEEPEST MID-LEVEL LAPSE RATES...EAST OF THE HIGH PLAINS...HAVE GENERALLY BECOME FOCUSED IN A CORRIDOR ALONG AND TO ITS NORTH. MID-LEVEL LAPSE RATES REMAIN MODESTLY STEEP NORTHWARD THROUGH MUCH OF THE DAKOTAS...BUT CONSIDERABLE OVERTURNING HAS STABILIZED A SIGNIFICANT PORTION OF THE UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES REGION. WHERE MID-LEVEL LAPSE RATES REMAIN STEEP...THE BOUNDARY LAYER ALSO REMAINS MOIST TO THE NORTH OF THE FRONT...BENEATH MODEST SOUTHWESTERLY MID-LEVEL FLOW...WHICH WILL CONTRIBUTE TO SUFFICIENT SHEAR FOR ORGANIZED STORM DEVELOPMENT ACROSS A BROAD AREA OF THE NORTH CENTRAL U.S. BY LATE AFTERNOON. IN ADDITION TO THE OUTFLOW BOUNDARY...THE LOW-LEVEL UPSLOPE FLOW REGIME ACROSS THE NORTH CENTRAL HIGH PLAINS IS EXPECTED TO PROVIDE ANOTHER FOCUS FOR RELATIVELY HIGHER SEVERE STORM PROBABILITIES. AIDED BY FORCING ASSOCIATED WITH THE UPPER IMPULSE...DISCRETE STORM DEVELOPMENT IS EXPECTED TO INCREASE THROUGH THE AFTERNOON ACROSS PARTS OF CENTRAL INTO EASTERN WYOMING/NORTHEAST COLORADO AND ADJACENT WESTERN NEBRASKA AND THE WESTERN DAKOTAS. STRONGEST STORMS WILL BE CAPABLE OF PRODUCING VERY LARGE HAIL...PERHAPS A COUPLE OF TORNADOES...BEFORE ACTIVITY GROWS UPSCALE WITH A MORE PROMINENT RISK FOR DAMAGING WIND GUSTS AS IT SPREADS EASTWARD INTO THE PLAINS THIS EVENING. ...SOUTHERN GREAT LAKES REGION/OHIO VALLEY... MODERATE BOUNDARY LAYER DESTABILIZATION DOES APPEAR PROBABLE WITH DAYTIME HEATING...ALONG AND SOUTH OF THE OUTFLOW BOUNDARY ACROSS THE SOUTHERN GREAT LAKES REGION INTO THE OHIO VALLEY. THIS MAY BE ENOUGH TO SUPPORT SMALL CLUSTERS OF STORMS WITH AT LEAST LOW PROBABILITIES FOR SEVERE WIND/HAIL. HOWEVER...DUE TO THE WEAK NATURE OF THE FLOW FIELDS...SEVERE POTENTIAL STILL APPEARS TOO LOW FOR A SLIGHT RISK AT THE PRESENT TIME. CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z |