SPC AC 062000
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT TUE APR 06 2010
VALID 062000Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS LOWER MI TO IA TO
CENTRAL/ERN OK...
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS WRN NY...NERN
PA...EXTREME NRN NJ...
--- UPDATES ---
...CENTRAL/SRN PLAINS TO IA...
MINOR ADJUSTMENTS TO OUTLOOK LINES IN THESE AREAS TO REFLECT
MESOBETA AND SMALLER SCALE OBSERVATIONAL/SATELLITE/RADAR TRENDS.
TSTMS DEVELOPING IN BAND OF CONVERGENCE ACROSS KS...WITH INCREASING
POTENTIAL FOR SVR HAIL AND GUSTS THROUGH REMAINDER AFTERNOON. REF
GUIDANCE IN THAT AREA...AND MESOSCALE DISCUSSION 271 FOR W-CENTRAL
TO N-CENTRAL OK NEAR-TERM POTENTIAL. RELATIVE MAX IN UNCONDITIONAL
TORNADO PROBABILITIES IS BEING FOCUSED MORE TIGHTLY INVOF SFC WARM
FRONT ACROSS IA...WHERE 0-1 KM SRH SHOULD REMAIN GREATEST FOR ANY
SUPERCELLS THAT CAN FORM FARTHER SW AND INTERACT WITH THIS BOUNDARY.
...NERN CONUS...
SMALL BUT LONG-LIVED TSTM COMPLEX -- ANCHORED BY SUPERCELL THAT
APPEARS SLIGHTLY ELEVATED BASED ON MODIFIED SOUNDINGS -- IS FCST TO
CONTINUE MOVING GENERALLY EWD ALONG AND JUST N OF SFC WARM
FRONT...WITH POTENTIAL FOR ANCHORING STORM OR ANY NEWER DEVELOPMENT
TO BECOME SFC-BASED WITH SVR WIND THREAT. SPATIAL FOCUS OF
MAXIMIZED SVR PROBABILITIES IS BEING NARROWED ACCORDINGLY.
..EDWARDS.. 04/06/2010
.PREV DISCUSSION... /ISSUED 1129 AM CDT TUE APR 06 2010/
A SHORTWAVE TROUGH CURRENTLY DIGGING ACROSS CO/NM WILL TRACK
EASTWARD INTO THE PLAINS TODAY...AND ACROSS THE MS VALLEY TONIGHT.
AS IT DOES SO...SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG A SURFACE COLD FRONT/DRYLINE FROM IA INTO OK.
...IA/MO/KS...
16Z SURFACE ANALYSIS SHOWS A LOW NEAR OMA WITH WARM FRONT EXTENDING
EASTWARD ACROSS CENTRAL IA...AND COLD FRONT EXTENDING SOUTHWESTWARD
INTO CENTRAL KS. THIS LOW IS EXPECTED TO BE JUST WEST OF DSM BY
LATE THIS AFTERNOON...AND WILL LIKELY BE THE FOCUS FOR RAPID
THUNDERSTORM DEVELOPMENT. FORECAST SOUNDINGS SHOW STRONG EFFECTIVE
SHEAR SUGGESTING SUPERCELL STRUCTURES WILL BE DOMINANT.
THERMODYNAMIC PROFILES ARE ALSO QUITE FAVORABLE FOR LARGE HAIL DUE
TO STEEP MID LEVEL LAPSE RATES AND AMPLE CAPE. STORMS WILL LIKELY
SPREAD INTO EASTERN IA AND NORTHERN IL DURING THE EVENING WITH A
CONTINUED SEVERE THREAT. DUE TO ENHANCED LOW LEVEL SHEAR IN
PROXIMITY OF SURFACE LOW AND WARM FRONT...PARTS OF CENTRAL IA AND
NORTHERN MO HAVE BEEN HIGHLIGHTED WITH 10% PROBABILITY OF TORNADOES.
FARTHER SOUTH...STORMS WILL DEVELOP LATER THIS AFTERNOON ALONG THE
SURFACE COLD FRONT INTO EASTERN KS/WESTERN MO. THESE STORMS WILL
ALSO LIKELY BE SUPERCELLULAR AND TRACK NORTHEASTWARD ACROSS OUTLOOK
REGION WITH A THREAT OF RELATIVELY WIDESPREAD LARGE HAIL. IF
DISCRETE EVOLUTION CAN BE SUSTAINED...ISOLATED TORNADOES WILL BE
POSSIBLE ACROSS THIS REGION AS WELL THROUGH THE EVENING.
...OK...
ALL MODEL GUIDANCE SUGGESTS CONVECTIVE INITIATION WILL BE RETARDED
UNTIL NEAR/AFTER DARK ACROSS OK DUE TO STRONG CAPPING INVERSION.
HOWEVER...LOW LEVEL AND DEEP LAYER VERTICAL SHEAR WILL BE QUITE
FAVORABLE FOR SUPERCELL STRUCTURES ONCE STORMS FORM. STRENGTH OF
CAP SUGGESTS STORMS WILL BE FOCUSED ALONG FRONT/DRYLINE WITH A QLCS
EVOLUTION LIKELY THROUGH THE NIGHT INTO EASTERN OK.
...PA/NY...
A FAST-MOVING MCS OVER LOWER MI HAS BECOME VERY ORGANIZED AT THE
MESOSCALE...AND IS LIKELY TO PERSIST THROUGH THE DAY. THESE STORMS
WILL TRACK EASTWARD ALONG WARM FRONT AND BEGIN AFFECTING WESTERN NEW
YORK BY MID AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS CAN
FORM...THESE STORMS MAY POSE A THREAT OF LARGE HAIL AND DAMAGING
WINDS.
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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