OMG, ^^^^That's just absolutely incredible, possibly historic.
I've found that the 4km resolution NAM has had a tendency to deepen things too much too fast over the winter, and I certainly hope that is the case here. That said, the 990-ish versions on the 12km and 32km aren't really all that great, either.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 917 PM CST MON FEB 22 2016
.DISCUSSION... THE FRONTAL BOUNDARY HAS POSSIBLY STARTED DRIFTING NORTHWARD AT MID EVENING. AS THE LINE OF STORMS FORMING IN WEST TEXAS MOVES TOWARD SE TEXAS LATER TONIGHT...AM EXPECTING ADDITIONAL ACTIVITY TO FORM AHEAD OF THE MAIN LINE OF STORMS...ESPECIALLY OVER THE FRONTAL BOUNDARY THAT WILL BE OVER THE FORECAST AREA. THE LOCATION OF THIS BOUNDARY WILL HELP DICTATE THE TREK OF THE SURFACE LOW LATER TONIGHT AND ON TUESDAY.
LOOKING AT THE HIGH RESOLUTION MODELS...THE ARW AND NAM12 ARE CLOSE TO THE CURRENT TIMING OF THE MAIN LINE OF STORMS. THE HRRR AND RAP13 ARE A BIT FASTER. STILL THINK THAT THE MAIN LINE OF STORMS WILL BEGIN AFFECTING THE WESTERN COUNTIES BETWEEN 3 AND 6 AM AND THEN MOVE TO THE INTERSTATE 45 CORRIDOR BETWEEN 6 AND 9 AM. THE MAIN CONCERN FOR LATE TONIGHT AND TUESDAY WILL BE SEVERE THUNDERSTORMS...WITH THE MAIN HAZARDS ISOLATED TORNADOES... DAMAGING WINDS...AND LARGE HAIL. THERE IS ALSO THE POSSIBILITY OF LOCALLY HEAVY RAINFALL... ESPECIALLY WHERE THE SURFACE AND UPPER LEVEL LOW PRESSURE AREAS TRAVEL. STILL LOOKS LIKE THE HEAVIEST RAINFALL WILL BE NORTH OF INTERSTATE 10...ALTHOUGH THE RAP13 WAS FORECASTING A FURTHER SOUTHWARD TRACK FOR THE SURFACE LOW AND ASSOCIATED RAINFALL.