A LATE-SEASON OUTBREAK OF ARCTIC AIR IS IN PROGRESS ACROSS THE U.S.

A LATE-SEASON OUTBREAK OF ARCTIC AIR IS IN PROGRESS ACROSS THE EASTERN U.S. WHILE MOISTURE FROM A LARGE PACIFIC STORM MOVES ACROSS THE CENTRAL ROCKIES AND OUT INTO THE PLAINS BY TUESDAY... A LATE-SEASON OUTBREAK OF ARCTIC AIR IS BEGINNING TO INVADE THE NORTHERN U.S. THIS EASTER SUNDAY. TEMPERATURES ARE EXPECTED TO DIP WELL BELOW NORMAL FOR NEXT FEW DAYS OVER THE EASTERN TWO-THIRDS OF THE COUNTRY. IN FACT...AREAS NEAR THE CANADIAN BORDER IN MINNESOTA AND NORTH DAKOTA CAN EXPERIENCE TEMPERATURES DIPPING BELOW ZERO BY TUESDAY MORNING. IN THE EASTERN U.S...RAIN AND THUNDERSTORMS WILL PRECEDE AN OLD FRONTAL BOUNDARY WHICH WILL STEADILY PUSH EASTWARD INTO THE ATLANTIC TONIGHT AND INTO MONDAY. SHOWERS AND SOME STRONG THUNDERSTORMS SHOULD ALSO ACCOMPANY THE TAIL END OF THIS FRONT WHICH WILL SLOWLY SINK SOUTHWARD INTO THE DEEP SOUTH ON MONDAY AND BEGINS TO WEAKEN AND DISSIPATE ON TUESDAY. THE ARCTIC COLD FRONT WILL QUICKLY ADVANCE ACROSS THE EASTERN U.S. IN THE WAKE OF THE OLD FRONTAL BOUNDARY...TRIGGERING SNOW SHOWERS IN THE GREAT LAKES AS WELL AS THE CENTRAL APPALACHIANS INTO NEW ENGLAND. OUT WEST...PRECIPITATION ASSOCIATED WITH A LARGE BUT WEAKENING OCEAN STORM HAS MOVED INTO A GOOD PORTION OF CALIFORNIA WITH SCATTERED MODERATE RAIN SHOWERS. THE UPPER-LEVEL FLOW WILL THEN CARRY THE MOISTURE EASTWARD THROUGH THE CENTRAL ROCKIES ON MONDAY. BY TUESDAY...THE UPPER-LEVEL ENERGY WILL BEGIN TO EXIT THE ROCKIES AND INTO THE PLAINS AS THE ARCTIC AIR MASS ARRIVES FROM THE NORTH AND EAST. THIS SETUP WILL RE-INVIGORATE THE SYSTEM...RESULTING IN A NEW ROUND OF SHOWERS AND THUNDERSTORMS TO DEVELOP IN THE CENTRAL PLAINS. IN ADDITION...TEMPERATURES WILL BE COLD ENOUGH FOR SNOW IN THE NORTHERN PART OF THE PRECIPITATION SHIELD.