Friday, February 22, 2013

UPDATE: UPPER MIDWEST WINTER STORM

WX UNIT UPDATE 1020Z 2/22/2013 .....WISCONSIN AND SURROUNDING STATES....

SEE NOAA NWS BULLETINS FOR OFFICIAL STATEMENTS VIA WWW.NWS.NOAA.GOV

WX UNIT DISCUSSION

STORM SYSTEM CONTINUES TO LIFT NEWD THROUGH THE UPPER MIDWEST, CORNBELT, AND GLAKES REGIONS.   SFC LOW RIGHT AROUND IRK MO AT ABOUT 1010MB AND VIRTUALLY STATIONARY AND RATHER BROAD AND NOT WELL DEFINED WITH A WARM FRONT EXTNDG EWWRD INTO CTRL IL.

SYSTEM IS BECOMING INCREASINGLY STACKED AND HAS SLOWED ITS NRN PROGRESSION SLIGHTLY.  PER LATEST RADAR IMAGERY AND SFC DATA THE HEAVIEST SNOW IS CONFINED GENERALLY ACROSS SWRN LWR MICH, EXTREME NRN IN, SERN AND ECTNRL WI, EXTNDNG ACRS CENTRL WI INTO ERN AND CENTRL PTNS OF MN.  

AN AREA OF DRY MID LEVEL FETCH AT H700 IS NOTED AS SYSTEM STACKS AND WEAKENS.  SNOWFALL SHOULD NOT BE AS HEAVY EXCEPT FOR A FEW CONCENTRATED SNOW BANDS IN THE DEFORMATION ZONE INDICATED ABOVE.

SEE WWW.SPC.NOAA.GOV FOR LATEST MESO DISCUSSIONS AND UPDATES

SYSTEM SHOULD WIND DOWN BUT THERE WILL BE PERSISTENT LIGHT TO MODERATE SNOW BANDS THAT SHOULD LINGER ACRSS MUCH OF WI AND ADJOINING STATES DURG NEXT 12 TO 18 HR PERIOD.

AM NOT EXPECTING SFC WINDS TO INCREASE WITH A STACKED SYSTEM AS THIS USUALLY INDICATES PROGRESSIVE WEAKENING WITH TIME HOWEVER A STRONG UPPER FLOW CONTINUES WITH NEGATIVE TILT ALLOWING SECONDARY SNOW BAND TO PERSIST FROM WRN IN ACROSS CHI AREA AND NRN IL INTO SRN IA.  

SLGT BREAK IN PCPN NOTED BETWEEN THIS AREA OF SNOW AND THE ONE TO THE NORTH.  

THIS SYSTEM HAS A FEW COMPLICATED DYNAMICS THAT WILL CAUSE IT TO BE A PESKY PERSISTENT BUT WEAKENING STORM THAT MAY ACTUALLY LINGER ACROSS THE REGION AND WILL BE A RATHER DIFFICULT FORECAST WITH VARIOUS SHORT TERM UPDATES AND ADVISORIES IN LOCAL AREAS OF CONCERN OVER THE NEXT 12 to 18 HOURS.

KEEP UP WITH THE FORECAST

EXTENDED OUTLOOK:  WATCHING UPSTREAM AS UPPER FLOW INDICATES ANOTHER SYSTEM PER 06Z GFS RUN FOR MONDAY THROUGH TUESDAY.  LOOKS LIKE A CLASSIC PANHANDLE HOOK TYPE SYSTEM WHICH COULD BE ON THE ORDER OF AT LEAST 4 TO 8 INCHES OF SNOW OR MORE WITH SUBSTANTIAL GULF MOISTURE FLOW.

WX UNIT STORM TEAM

STORM CHASERS: CASPER/MOEN