Tornado Alley Forecasts, Nowcasting and Reports

[debris74]

ah, un consiglio x tutti. se postate delle carte, fatelo come faccio io in allegato. perchè poi dopo 6 ore si aggiornano e chi viene magari a leggere il 3d dopo quelle 6 ore, trovandosi carte diverse, non capisce più nulla del senso della discussione.

[Ben]

ah, un consiglio x tutti. se postate delle carte, fatelo come faccio io in allegato. perchè poi dopo 6 ore si aggiornano e chi viene magari a leggere il 3d dopo quelle 6 ore, trovandosi carte diverse, non capisce più nulla del senso della discussione.

[Andrerus]

Io mi butto in TX per ora e attendo..

[debris74]

le ETA 12z sono migliorate e infatti SPC mette subito fuori il primo moderate risk della stagione:

...THERE IS A MDT RISK OF SVR TSTMS FROM NWRN TX THROUGH THE EXTREME
ERN TX PANHANDLE...WRN OK AND A PORTION OF SWRN KS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN AND
CNTRL PLAINS...

...SYNOPSIS...

UPPER TROUGH NOW MOVING ONTO THE PACIFIC COAST WILL CONTINUE EAST
INTO THE SWRN U.S. FRIDAY...THEN INTO THE SRN PLAINS OVERNIGHT. LEAD
SRN STREAM SHORTWAVE TROUGH NOW MOVING INTO NWRN MEXICO WILL EJECT
NE THROUGH THE SRN PLAINS DURING THE DAY. MODELS SUGGEST A SECONDARY
IMPULSE COULD EJECT NE THROUGH THE SRN HIGH PLAINS IN ADVANCE OF
UPPER TROUGH LATE FRIDAY AFTERNOON. LEE CYCLONE WILL CONSOLIDATE AND
DEEPEN OVER THE CNTRL HIGH PLAINS LATER IN THE DAY AS UPPER TROUGH
APPROACHES. THE DRYLINE WILL BECOME BETTER DEFINED ACROSS WRN KS
THROUGH WRN TX AS THE SURFACE LOW DEEPENS. A PACIFIC FRONT WILL
ADVANCE EAST AND MERGE WITH THE DRYLINE FRIDAY NIGHT.


...CNTRL THROUGH SRN PLAINS...

MODIFIED CP AIR WITH DEWPOINTS IN THE MID TO UPPER 50S WILL ADVECT
NWD THROUGH THE WARM SECTOR AS THE LOW LEVEL JET STRENGTHENS IN
RESPONSE TO LEE CYCLOGENESIS. PLUME OF STEEP MID LEVEL LAPSE RATES
WILL ADVECT EWD THROUGH THE CNTRL AND SRN HIGH PLAINS AND OVERTAKE
THE MOIST AXIS ACROSS WRN KS THROUGH WRN OK AND WRN TX. NARROW AXIS
OF MODERATE INSTABILITY WITH MLCAPE FROM 1000 TO 1500 J/KG WILL BE
POSSIBLE FRIDAY AFTERNOON JUST E OF DRYLINE. BUT...INSTABILITY
FARTHER EAST ACROSS CNTRL KS THROUGH CNTRL OK IS EXPECTED TO REMAIN
LIMITED DURING THE DAY DUE TO POTENTIAL FOR AREAS OF CLOUDS AND RAIN
ASSOCIATED WITH EJECTING LEAD SHORTWAVE TROUGH.

VERTICAL SHEAR PROFILES WILL BECOME INCREASINGLY FAVORABLE FOR
SUPERCELLS AS THE MID LEVEL JET ADVANCES EAST AND OVERLAPS THE
STRENGTHENING 50+ KT LOW LEVEL JET. WIND PROFILES WITH LARGE LOW
LEVEL HODOGRAPHS WILL EXIST IN WARM SECTOR. PRIMARY CONCERN WILL BE
INITIATION POTENTIAL IN VICINITY OF DRYLINE WHERE NARROW CORRIDOR OF
BETTER INSTABILITY IS EXPECTED DURING THE AFTERNOON. THE INSTABILITY
AXIS IS EXPECTED TO REMAIN CAPPED TO SURFACE BASED STORMS MUCH OF
THE DAY. HOWEVER...MIXING AND CONVERGENCE IN VICINITY OF DRYLINE AND
POSSIBLY SOME LARGE SCALE ASCENT ACCOMPANYING A LEAD SUBTLE
SHORTWAVE TROUGH COULD CONTRIBUTE TO DEVELOPMENT OF ISOLATED STORMS
BY LATE AFTERNOON FROM NWRN TX THROUGH WRN KS. STORM MODE WOULD BE
DISCRETE SUPERCELLS CAPABLE OF PRODUCING VERY LARGE HAIL AND
ISOLATED TORNADOES. HOWEVER...CONFIDENCE IN LATE AFTERNOON
INITIATION IS NOT PARTICULARLY HIGH AT THIS TIME.

OVERNIGHT...FORCING FOR ASCENT WILL INCREASE AS THE MAIN UPPER
TROUGH ADVANCES EAST INTO THE SRN PLAINS AND AS THE PACIFIC FRONT
MERGES WITH THE DRYLINE. MUCAPE OVER THE WRN PORTION OF WARM SECTOR
WILL BE MAINTAINED INTO THE EVENING AS MID LEVEL LAPSE RATES
CONTINUE TO STEEPEN WITH THE APPROACH OF THE THERMAL TROUGH.
STORMS WILL LIKELY DEVELOP AND INCREASE IN COVERAGE ALONG AND IN
ADVANCE OF THE EWD ADVANCING FRONT FROM PARTS OF WRN TX THROUGH WRN
OK INTO WRN KS AND SPREAD EAST. INITIAL MODE MAY BE
SUPERCELLULAR...BUT WITH A GRADUAL EVOLUTION TO AN MCS CONTAINING
MIXED MODES INCLUDING LINES AND SUPERCELLS. THROUGH SOME THREAT FOR
ISOLATED TORNADOES WILL REMAIN...THE PRIMARY THREAT WILL TRANSITION
TO LARGE HAIL AND DAMAGING WIND WITH GREATEST SEVERE COVERAGE
EXPECTED IN MODERATE RISK AREA.