Here is a portion of this morning’s Area Forecast Discussion from the NWS in the Quad Cities discussing the possible Winter Storm this weekend.

OPERATIONAL MODELS COMING AROUND TO A SIMILAR SOLUTION AND LOOKING MORE AND MORE OMINOUS FOR A WINTER STORM TO IMPACT THE REGION… BEGINNING FRIDAY NIGHT AND LASTING INTO SATURDAY NIGHT OR SUNDAY. LATEST MODEL RUNS…INCLUDING THE 00Z ECM…NOW TRENDING TOWARD PHASING AND A SLOWER AND DEEPER SYSTEM. AS COLDER AIR ARRIVES FROM THE NORTHWEST PHASING OCCURS WITH THE MODELS DEVELOPING AN IMPRESSIVE SURFACE AND 500 MB LOW. NICE SOUTHERLY FLOW OF GULF MOISTURE AHEAD OF THE SYSTEM BRINGS SPECIFIC HUMIDITIES TO 3-4 G/KG INTO THE DVN CWA. THERE WILL BE A TIGHT THERMAL GRADIENT SETTING UP ACROSS THE REGION SO QUITE A RANGE OF TEMPERATURES EXPECTED…WHICH WILL MAKE FOR A TRICKY FORECAST INCLUDING PRECIPITATION TYPE. RAIN FRIDAY NIGHT WILL GRADUALLY TRANSITION TO SNOW FROM WEST TO EAST. HAVE RAISED POPS TO LIKELY FRIDAY NIGHT AND SATURDAY.

BOTH THE GFS AND ECM NOW REMARKABLY SIMILAR IN TRACKING A DEEPENING SURFACE TO 500 MB LOW FROM ABOUT ST. LOUIS TO NORTHERN INDIANA SATURDAY NIGHT INTO SUNDAY. THIS IS A FAVORABLE PATTERN FOR HEAVY SNOW IN PORTIONS OF THE DVN CWA AS STRONG LIFT WILL BE OCCURRING AND A DEFORMATION ZONE APPEARS TO SET UP. EXACTLY WHERE THE FRONTAL BOUNDARY SETS UP IS RATHER TRICKY AT THIS POINT BUT SIGNALS POINT TO THE POTENTIAL FOR A BAND OF HEAVY SNOWS OF AT LEAST 6 INCHES. THE WARM GROUND WILL BE ABLE TO MELT SOME OF THIS SNOW BUT A RAPID RATE OF FALL WILL ACCUMULATE NO MATTER THE GROUND TEMPERATURE. THIS IS ESPECIALLY TRUE AT NIGHT. THERE IS ALSO THE POTENTIAL FOR A NARROW BAND OF VERY HEAVY SNOW IF CONVECTION DEVELOPS IN THIS TIGHT BAROCLINIC ZONE…BUT MARCH IS KNOWN FOR EXTREMES. BASED ON THE CURRENT MODEL RUNS THE FAVORED AREA FOR THE AXIS OF HEAVIEST SNOWS WOULD BE ACROSS PORTIONS OF EASTERN IA POSSIBLY AS FAR EAST AS ALONG THE MS RIVER. BUT THIS COULD CHANGE SO STAY TUNED. OF COURSE ANY ACCUMULATIONS WILL PLAY AN IMPORTANT ROLE IN TEMPERATURES LATER ON. THIS WOULD ALSO BE A TYPICAL MARCH HEAVY WET SNOW WITH HIGH MOISTURE CONTENT. RAISED POPS SATURDAY NIGHT BUT DID NOT CHANGE SUNDAY. LATER SHIFTS WILL NEED TO RE-EVALUATE THIS SITUATION.