AIR TAXI DEV WX PENETRATES ARSA WITHOUT CLRNC.

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I WAS SEBOUND FROM PIR TO OMA; AND ENCOUNTERED TSTMS WHICH CAUSED ME TO DEV ALMOST 100 MI W AND APCH OMA FROM THE W INSTEAD OF N. WHEN I LAST CHKED MY POS FROM THE LNK VOR; I WAS 40 DME ON THE 300 DEG RADIAL; AND JUST WSW OF COLUMBUS; NE. AT THAT POINT FLYING STRAIGHT E TO OMA WOULD PASS ME 15-20 MI N OF THE LNK ARSA. I THEN TUNED MY VOR RADIOS INTO OMA AND COLUMBUS. I PROGRESSED E; HOWEVER; I ENCOUNTERED MORE SEVERE WX; MODERATE TURB WITH OCCASIONAL SEVERE CHOP; LIGHTENING; MODERATE RAIN. I ENDED UP TURNING MORE SE THAN I REALIZED WHILE DEVIATING FROM THIS WX AND ENTERED THE LNK ARSA. ACCORDING TO MY NAV OFF THE OMA VOR I STILL BELIEVED MYSELF TO BE WELL N OF THE LNK ARSA. HOWEVER; WHEN I CALLED OMA APCH AND OBTAINED A SQUAWK CODE; HE INFORMED ME I WAS IN THE LNK ARSA. HE HANDED ME OVER TO LNK APCH. I EXPLAINED MY PROBLEM WITH THE WX WHICH KEPT ME TOO BUSY TO NAV FOR A SHORT WHILE; AND HE HANDED ME BACK TO OMA APCH. CAUSES: MINDSET; 'I'M WELL N OF THE LNK ARSA; IT'S NOT A FACTOR.' FAILURE TO KEEP TRACK OF POS FROM LNK ARSA; INSTEAD RELYING ON VISUAL PERCEPTION OF WHERE I WAS. DEALING WITH THE WX PUT ME BEHIND IN NAV; NAV BECAME SECONDARY. HOW TO PREVENT A RECURRENCE: IF ANYWHERE NEAR TCA'S; ARSA'S; ETC; MONITOR POS IN RELATION TO THAT AIRSPACE. USE RADAR SVC IF AVAILABLE IF VFR; OR FLY IFR IF CAPABLE. PS; I HAD OBTAINED A FULL WX BRIEFING BEFORE DEPARTING; AND AN UPDATE SHORTLY AFTER DEPARTING; AND THESE STORMS WERE MUCH MORE WIDESPREAD AND INTENSE THAN FORECAST.