Friday 2/12: The Latest NWS Discussion

Forecast Discussion for our area:

A LOT OF MOVING PARTS IN REGARDS TO THE EARLY WEEK SYSTEM POISED
TO AFFECT THE EASTERN U S AND THE 00Z MODEL SUITE DID LITTLE TO
INCREASE THE LOW CONFIDENCE IN HIGHLIGHTING SPECIFIC IMPACTS TO
CENTRAL INDIANA. THE EXTENDED PERIOD WILL BE ACTIVE WITH VARIOUS
SNOW THREATS THROUGH MIDWEEK BEFORE A WARMING TREND COMMENCES FOR
THE SECOND HALF OF THE WEEK.

NORTHERN STREAM CLIPPER SYSTEM WILL SWING THROUGH THE LOWER GREAT
LAKES LATE SUNDAY AND EARLY MONDAY AND WILL PRESENT CHANCES FOR
SNOW. AT THE SAME TIME...LOW PRESSURE ORGANIZING OVER THE LOWER
MISSISSIPPI VALLEY WILL TRACK NORTHEAST INTO THE LOWER APPALACHIANS
BY TUESDAY. ADDITIONALLY...OP GFS AND ECMWF BOTH TRACK ANOTHER
CLIPPER INTO THE MID MISSISSIPPI VALLEY. THE 00Z RUNS OF THE
OPERATIONAL MODELS ARE TRACKING THE MAIN SYSTEM EAST OF THE
APPALACHIANS AND ARE SUGGESTIVE OF LESS OF AN IMPACT TO THE REGION
WITH NO PHASING WITH THE CLIPPER TO THE NORTHWEST. GFS ENSEMBLE
MEMBERS ON THE OTHER HAND ARE ALL OVER THE PLACE WITH THE SURFACE
LOW TRACK DUE TO VARYING DEGREES OF PHASING IN THE UPPER LEVELS.
FURTHER MUDDYING THE WATERS IS THE MARGINAL TEMPS IN THE NEAR
SURFACE LAYER WHICH ARGUES FOR EVEN THE POSSIBILITY FOR OTHER PRECIP
TYPES TO MIX IN WITH SNOW FOR A TIME ON MONDAY AND TUESDAY.

THE UPPER LEVEL FLOW AND TELECONNECTION PATTERN SUGGESTS
POTENTIAL IS THERE FOR SOME SHIFT NORTH AND WEST TO THE MAIN
SYSTEM. WITH THE PRIMARY UPPER WAVE STILL OUT OVER THE PACIFIC AND
NOT FULLY SAMPLED YET...FUTURE MODEL RUNS TODAY AND SATURDAY WILL
BE CRITICAL IN DETERMINING IF THE MAIN STORM SHIFTS LEFT AND
PRESENTS A GREATER IMPACT TO PARTS OF THE FORECAST AREA FOR EARLY
WEEK. AT THIS TIME HOWEVER...ATTEMPTING TO EMPLOY ANY DETAIL
INCLUDING POTENTIAL SNOWFALL AMOUNTS IS POINTLESS. WILL CARRY
CHANCES OF SNOW MONDAY AND TUESDAY WITH A POSSIBILITY FOR RAIN TO
MIX IN ACROSS THE SOUTH TUESDAY AS CRITICAL LOW LEVEL THICKNESSES