ZCZC SPCSWODY1 ALL ACUS01 KWNS 100554 SPC AC 100554 DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1254 AM CDT SUN AUG 10 2003 VALID 101200Z - 111200Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM ATY RWF 20 W LWD MKC UMN HOT TXK 45 NE DAL ADM END P28 RSL HLC 35 SSW BBW 45 WNW OFK MHE ATY GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 65 ESE YUM 70 NW GBN 45 N IGM 20 NNE P38 40 NE ELY 10 NE ENV 10 NE BYI 25 SW DLN 30 ENE MSO 35 NW 3TH 15 SW LWS 55 N BNO 30 NNE LMT 25 SSE MFR 40 NNW 4BK ...CONT... 55 N OLF 50 NNW REJ 50 ENE CDR 30 SSW VTN 45 SSE 9V9 25 SSE FAR 10 ENE RRT ...CONT... 10 SW ANJ MTW 35 NW STL 25 WSW UNO PBF 25 SSW MLU 30 E HEZ LUL 40 SSW TCL 15 NNE HSV 10 WSW CKV 15 NNE OWB 35 N FWA 35 NNE MTC GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 NNE FST 45 WSW BWD 20 NE SEP 55 ESE SPS 30 S LTS 45 W LBB 25 SE CNM 35 NNE FST ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTN AND TONIGHT ACROSS THE EASTERN PLAINS.... MODELS INDICATE SOME CHANGES TO LARGE-SCALE PATTERN BEGIN TO TAKE PLACE DURING THIS FORECAST PERIOD...BUT SUBTROPICAL RIDGES WILL REMAIN STRONG ACROSS THE INTERMOUNTAIN WEST/ROCKIES..AND WESTERN ATLANTIC...WHILE WEAK UPPER TROUGH PERSISTS ACROSS THE EASTERN STATES. NORTHEAST PACIFIC CLOSED IS PROGGED TO BEGIN LIFTING MORE RAPIDLY TOWARD THE PACIFIC NORTHWEST COAST...AS A SHORT WAVE TROUGH DIGS AROUND THE WESTERN PERIPHERY OF ANOTHER CLOSED LOW OVER NORTHERN BRITISH COLUMBIA. MOST PROMINENT FEATURE WITH REGARD TO CONVECTIVE DEVELOPMENT MAY BE SHORT WAVE TROUGH NOW DIGGING ACROSS THE NORTHERN PLAINS...EAST OF BUILDING/SHARPENING RIDGE AXIS IN THE LEE OF THE NORTHERN ROCKIES. THIS SHORT WAVE WILL TURN SOUTHWARD GENERALLY ALONG/WEST OF THE MISSISSIPPI RIVER...WITH ASSOCIATED STRONGER MID-LEVEL HEIGHT FALLS SHIFTING ROUGHLY FROM THE MID MISSOURI VALLEY REGION AT MID DAY INTO THE ARKLATEX REGION BY LATE TONIGHT. ...PLAINS... IN ASSOCIATION WITH SHORT WAVE TROUGH...MODERATELY STRONG NORTHERLY MID/UPPER JET WILL DEVELOP/SHIFT SOUTHWARD THROUGH THE PLAINS STATES...CONTRIBUTING TO FAVORABLY SHEARED ENVIRONMENT FOR ISOLATED SUPERCELLS AND SMALL CONVECTIVE CLUSTERS. INITIAL ACTIVITY APPEARS LIKELY TO DEVELOP BY EARLY AFTERNOON FROM PARTS OF SOUTHEASTERN SOUTH DAKOTA INTO EASTERN NEBRASKA/WESTERN IOWA...WHERE SUFFICIENT LOW-LEVEL MOISTURE WILL REMAIN IN PLACE FOR MEAN MIXED LAYER CAPE ON THE ORDER OF 2000 J/KG. DEEP MIXED BOUNDARY LAYER WITH SIZABLE SURFACE TEMPERATURE/DEW POINT SPREADS BY PEAK HEATING...IN CONJUNCTION WITH STEEP MID-LEVEL LAPSE RATES AND RELATIVELY DRY AIR ALOFT...WILL CONTRIBUTE TO FAVORABLE ENVIRONMENT FOR LARGE HAIL/DAMAGING DOWNBURSTS IN MORE INTENSE CELLS. ALTHOUGH LONG-LIVED CLUSTER OF STORMS DOES NOT APPEAR LIKELY...STRONGER STORMS AND SMALL CLUSTERS OF CONVECTION ARE EXPECTED TO GRADUALLY DEVELOP SOUTHWARD WITH LARGE-SCALE FORCING ...ACROSS CENTRAL/EASTERN KANSAS BY LATE AFTERNOON...AND PARTS OF EASTERN OKLAHOMA BY LATE THIS EVENING. CLUSTER OF STORMS MAY SPREAD SOUTHEASTWARD OUT OF OKLAHOMA INTO NORTHEAST TEXAS/WESTERN LOUISIANA OVERNIGHT...BUT WITH LOSS OF DAYTIME HEATING... STABILIZATION OF BOUNDARY LAYER ACROSS THE EASTERN PLAINS MAY MINIMIZE CONTINUING HAIL/WIND THREAT. ...WASHINGTON/OREGON... STRONG MID/UPPER JET NOW ROUNDING SOUTHERN PERIPHERY OF CLOSED LOW OFF THE PACIFIC COAST WILL OVERSPREAD THE PACIFIC NORTHWEST COAST STATES DURING THE DAY...AS CLOSED LOW BEGINS TO ACCELERATE NORTHEASTWARD. THIS WILL CONTRIBUTE TO FAVORABLE SHEAR PROFILES FOR UPDRAFT ROTATION IN THE LEE OF THE CASCADES...BUT LACK OF BETTER MOISTURE APPEARS LIKELY TO LIMIT EXTENT OF DESTABILIZATION AND IS EXPECTED TO MARGINALIZE SEVERE THREAT. HOWEVER...NEAR/SHORTLY AFTER PEAK HEATING...AS MEAN MIXED LAYER CAPE INCREASES TO AROUND 500 J/KG OR SO...ISOLATED STORMS WITH HAIL AND GUSTY WINDS WILL BE POSSIBLE. ...MONTANA... SHORT WAVE TROUGH ALREADY PROGRESSING INTO THE NORTHERN INTERMOUNTAIN REGION WILL CONTINUE NORTHEASTWARD INTO CREST OF AMPLIFYING UPPER RIDGE IN THE LEE OF THE CANADIAN ROCKIES. FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED WITH THIS FEATURE MAY SUPPORT ISOLATED STRONG CONVECTION ACROSS PARTS OF NORTH CENTRAL MONTANA BY MID DAY...BUT STRONGER LIFT/MAIN CONVECTIVE ACTIVITY APPEARS LIKELY ACROSS SOUTHERN/CENTRAL ALBERTA AND SASKATCHEWAN. ...EASTERN STATES... ALTHOUGH HIGHER MOISTURE CONTENT AIR WILL BEGIN TO SHIFT EAST OF ALL BUT THE SOUTHERN FLORIDA PENINSULA EARLY IN THE DAY...AIR MASS AHEAD OF UPPER TROUGH AXIS...STILL WEST OF THE APPALACHIANS... REMAINS SUFFICIENTLY MOIST FOR SCATTERED THUNDERSTORM ACTIVITY. ..KERR/BRIGHT.. 08/10/2003 ...NOTICE... FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3. THE INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED. $$ |