SPC 0600Z Day 2 Outlook
DAY 2 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1233 AM CDT SAT MAY 25 2013 VALID 261200Z - 271200Z ...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE NRN HIGH PLAINS INTO THE MID MO RIVER VALLEY... ...SYNOPSIS... A WRN U.S. UPPER TROUGH CENTRALLY LOCATED OVER THE PACIFIC NW WILL MOVE EWD DURING THE DAY 2 PERIOD AS THE UPPER AIR PATTERN BECOMES MORE PROGRESSIVE AS A MID LEVEL LOW DEPARTS FROM NEW ENGLAND INTO THE CANADIAN MARITIME PROVINCES. MODEST BROAD SWLY MID LEVEL FLOW WILL SPILL DOWNSTREAM OVER THE HIGH PLAINS AS AN UPPER RIDGE WEAKENS OVER THE CNTRL U.S. A RESIDUAL FRONTAL ZONE OVER THE MIDWEST SEWD TO THE SRN APPALACHIANS WILL SLOWLY ADVANCE NWD WHILE A SURFACE LOW AND ATTENDANT DRYLINE/SURFACE TROUGH EXTEND NORTH-SOUTH OVER THE HIGH PLAINS. ...MID MO RIVER VALLEY INTO THE N-CNTRL AND NRN HIGH PLAINS... A MODERATE WARM ADVECTION REGIME WILL LIKELY BE ONGOING SUNDAY MORNING OVER THE N-CNTRL PLAINS NEAR A FRONTAL ZONE LOCATED OVER THE MID MO RIVER VALLEY. STEEP MID LEVEL LAPSE RATES IN EXCESS OF 8 DEG C PER KM MAY FACILITATE A MARGINAL HAIL THREAT WITH EARLY MORNING STORMS. THE NWD ADVANCE OF THE FRONTAL ZONE OVER THE MID MO VALLEY MAY BE HAMPERED BY THE EARLY DAY CONVECTION ACTING TO REINFORCE THIS EFFECTIVE OUTFLOW/FRONT INVOF THE MID MO RIVER VALLEY. LATER IN THE DAY...STRONG HEATING FARTHER W OVER THE HIGH PLAINS WILL LIKELY COINCIDE WITH GRADUAL MID LEVEL HEIGHT FALLS FROM KS/NEB NWD INTO ERN MT IN CONCERT WITH PERHAPS A FEW WEAK IMPULSES EJECTING INTO THE CNTRL-NRN HIGH PLAINS. A PLUME OF LOW LEVEL MOISTURE CHARACTERIZED BY DEWPOINTS IN THE 50S SHOULD ADVECT NWWD INTO THE WRN DAKOTAS INTO CNTRL-ERN MT WHILE RICHER MOISTURE WITH DEWPOINTS RANGING THROUGH THE 60S REMAIN FARTHER SE OVER NEB SWD E OF THE DRYLINE. FORECAST SOUNDINGS SHOW A MARGINAL TO MODERATELY UNSTABLE BOUNDARY LAYER OVER MT WITH MLCAPES RANGING FROM 500 J/KG W TO UPWARDS OF 2000 J/KG NEAR THE DAKOTAS BORDERS. OROGRAPHIC LIFT/UPSLOPE FLOW AND GENERAL CYCLONIC SWLY UPPER FLOW WOULD SEEMINGLY BE SUPPORTIVE OF ISOLD-WIDELY SCTD STORMS BY THE LATE AFTERNOON/EVENING HOURS. BACKED ELY FLOW N OF THE CNTRL HIGH PLAINS LOW FROM THE WRN DAKOTAS WWD INTO MT/WY WILL CONTRIBUTE SUFFICIENT DEEP LAYER SHEAR FOR ORGANIZED ISOLD STRONG-SEVERE STORMS...INCLUDING SUPERCELLS BY LATE AFTERNOON-EVENING...CAPABLE OF MAINLY A LARGE HAIL/SEVERE WIND GUST THREAT. FARTHER S IN CLOSER PROXIMITY TO THE SURFACE LOW...GREATER HEATING WILL BE NECESSARY TO OVERCOME A CAP OVER NEB/KS. MODEST SHEAR PROFILES WILL GENERALLY BE SUPPORTIVE OF ORGANIZED STRONG-SEVERE MULTICELLS AND PERHAPS A FEW SUPERCELLS BY THE AFTERNOON-EVENING. STORM MERGERS/COLD POOL CONSOLIDATION AND A STRENGTHENING LLJ AFTER DARK MAY FAVOR UPSCALE GROWTH AND A LINGERING LARGE HAIL/DMGG WIND THREAT INTO THE EVENING. ...WRN KS SWD INTO W TX... A SHARPENING DRYLINE DURING THE DAY MAY LEAD TO A FEW WIDELY-SPACED STORMS INVOF THE DRYLINE AS STRONG HEATING INTO THE 90S NEAR/WEST OF THE DRYLINE WEAKEN AND LOCALLY ERODE THE CAP BY LATE AFTERNOON. FORECAST SOUNDINGS ALONG THE DRYLINE SHOW A VERY STEEP LAPSE RATE PROFILE WITH DEWPOINTS MIXING INTO THE 50S. ALTHOUGH EFFECTIVE SHEAR VALUES WILL REMAIN MODEST /AOB 30 KT/...A FEW OF THE STRONGER STORMS WILL POTENTIALLY BE CAPABLE OF LARGE HAIL/DMGG WINDS BEFORE WEAKENING DURING THE EVENING. ..SMITH.. 05/25/2013
via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day2otlk_0600.html
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