Consider these excerpts from its write-up (bold text indicates my added emphasis) discussing the severe weather potential:
* SEVERE POTENTIAL THE FIRST DAY OF JUNE WILL GENERALLY BE TIED TO THE EAST-NORTHEASTWARD ADVANCEMENT OF A POTENT UPPER TROUGH OVER THE EASTERN THIRD OF THE CONTINENTAL U.S.
* AS THE PARENT UPPER SYSTEM TRENDS TOWARD A SLIGHT NEGATIVE TILT ON FRIDAY...AMPLE FORCING FOR ASCENT/VERTICAL SHEAR WILL CONTRIBUTE TO SUSTAINED STRONG/SEVERE THUNDERSTORMS
* DAMAGING WINDS /POTENTIALLY WIDESPREAD/ AND SEVERE HAIL WILL BE THE PRIMARY HAZARDS FROM WHAT SHOULD MAINLY BE A MULTICELLULAR/LINEAR CONVECTIVE MODE. SOME SUPERCELLS...PERHAPS EVEN A TORNADO THREAT...COULD OCCUR PROVIDED SUFFICIENT DESTABILIZATION NEAR THE AFOREMENTIONED WARM FRONT.
SPC indicates a “slight risk” of severe storms but a 30% probability of severe weather within 25 miles of a point for the entire D.C. metro region - which is quite high for a 3-day outlook.
The NWS office in Sterling also supports the storm threat idea. Here are excerpts from its latest discussion:
* EXPECT HEAVY THUNDERSTORMS AND POTENTIAL FLASH FLOODING
* THE LOW LEVEL SHEAR /IN BOTH 12Z NAM AND GFS FORECAST SOUNDINGS/ IS FAVORABLE FOR TORNADOES
Severe weather is not a given. For severe weather to materialize, the timing and spacing of certain features will have to come together just right. But, at the moment, this appears to be the most favorable set up for severe weather so far this year.
We will keep you updated on this potential and provide additional analysis Thursday into Friday.