Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KARX 151108
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
508 AM CST MON DEC 15 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 229 AM CST MON DEC 15 2014

FOG STILL PRIMARY CONCERN INITIALLY...BUT A CHANGE IS COMING AS
THE LARGE CLOSED SYSTEM EJECTS NORTHEAST THROUGH THE REGION. FOG
WILL GIVE WAY TO RAIN...AND THEN A TRANSITION TO SNOW AS THE
COOLER AIR SURGES IN BEHIND THE SYSTEM.

08Z SURFACE ANALYSIS SHOWS CENTER OF THE LOW PRESSURE SYSTEM OVER
KS...WITH AN INVERTED TROUGH STRETCHING NORTH THROUGH OMAHA AND
INTO WESTERN IA/MN AND WESTERN ONTARIO. EXTENSIVE LOW CLOUD AND
FOG CONTINUES TO PLAGUE THE AREA EAST OF THE SYSTEM AND DENSE FOG
ADVISORIES CONTINUE THROUGH NOON. SHIELD OF RAIN ROTATING AROUND
THE SYSTEM AND AS IT MOVES IN...SHOULD HELP TO IMPROVE THE FOG
SITUATION. THUS THE PLAN IS TO LET THE ADVISORY RUN UNTIL NOON.

SYSTEM TRACKS SLOWLY NORTHEAST ACROSS IA TODAY...AND TO NEAR
CHICAGO BY TUESDAY MORNING. DEFORMATION AREA WITH MOST
SIGNIFICANT PRECIPITATION LOOKS TO BE FROM THE SIOUX FALLS
AREA...UP TOWARD THE TWIN CITIES AND DULUTH. ENOUGH COLD AIR
AVAILABLE FOR SOME OF THAT TO FALL IN THE FORM OF SNOW. FOR OUR
FORECAST AREA...APPEARS THAT THE HEAVIEST PRECIPITATION WILL BE
OVER BEFORE THE COLD AIR ARRIVES. SO WHILE THERE WILL LIKELY BE
SOME WINTRY PRECIPITATION... IT SHOULDN`T AMOUNT TO TOO MUCH THIS
TIME. LAST ITEM TO DIAGNOSE IS THE POTENTIAL FOR A MIX AS THE COLD
AIR SURGES IN TO CHANGE THE RAIN OVER TO SNOW. COULD BE A SHORT
PERIOD OF SLEET OR EVEN FREEZING RAIN AS THE TRANSITION OCCURS.
FOR NOW DO NOT FORESEE THE NEED FOR AN ADVISORY...BUT WE WILL HAVE
TO KEEP AND EYE ON THE TIMING OF THE COLD AIR ARRIVAL.

THE WARM TEMPERATURES OF THE PAST FEW DAYS WILL BE DISAPPEARING
BEHIND THE SYSTEM AS WELL. TEMPERATURES WILL HOVER IN THE 40S
TODAY...BUT LOOK TO DIVE BELOW THE FREEZING MARK BY MORNING.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 229 AM CST MON DEC 15 2014

SYSTEM PULLS AWAY ON TUESDAY...BUT ANOTHER TROUGH DROPS SOUTH OUT
OF ONTARIO BEHIND IT...HELPING TO DIG A LARGER TROUGH. DYNAMIC
LIFT AHEAD OF THIS SECOND SYSTEM WILL ACT ON RESIDUAL MOISTURE AND
LOOKS TO GENERATE SOME FLURRIES TUESDAY NIGHT. ADDED TO THE
FORECAST. THIS ONE ALSO HAS ANOTHER REINFORCING SHOT OF COLD AIR
WITH IT...SO EXPECT A RETURN TO MORE TYPICAL DECEMBER TEMPERATURES
FOR THE REMAINDER OF THE WEEK. HIGH PRESSURE THEN SETTLES IN FOR
THURSDAY INTO EARLY FRIDAY...PROVIDING TRANQUIL BUT COOL WEATHER.
THE NEXT WEATHER DISTURBANCE MOVES THROUGH THE SOUTHERN PORTION OF
THE COUNTRY FRIDAY INTO SATURDAY. ECMWF KEEPS THE SYSTEM WELL
SOUTH OF OUR AREA...BUT THE GFS IS A BIT FURTHER NORTH. SIDING
WITH THE ECMWF AT THIS POINT BUT BEARS WATCHING WITH MANY PEOPLE
HAVING WEEKEND TRAVEL PLANS. BEYOND THAT...THE UPPER LEVEL FLOW
PATTERN LOOKS TO KEEP THE MAIN STORM TRACKS EITHER NORTH OR SOUTH
OF THE LOCAL AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 508 AM CST MON DEC 15 2014

FOG CONTINUES TO REDUCE THE VISIBILITY TO MILE OR LESS AT BOTH TAF
SITES...ALTHOUGH THERE HAVE BEEN SOME TEMPORARY IMPROVEMENTS. NO
SIGNIFICANT AIRMASS CHANGE WILL OCCUR FOR MUCH OF THE MORNING SO
THE IFR CONDITIONS WILL CONTINUE. LOW PRESSURE OVER KANSAS WILL
PUSH INTO SOUTHERN IOWA TODAY. THE RAIN THAT IS FALLING NORTH OF
THE LOW WILL WORK INTO THE REGION AND IS EXPECTED TO OVERSPREAD
THE AREA DURING THE LATE MORNING. AS THIS HAPPENS...IT SHOULD
ALLOW SOME IMPROVEMENTS IN THE VISIBILITY TO OCCUR...BUT STILL
EXPECT IFR CONDITIONS TO PREVAIL. THE RAIN SHOULD CONTINUE ON AND
OFF FOR MUCH OF THE DAY AND NIGHT UNTIL THE LOW MOVES PAST THE
AREA SWINGING THE WINDS AROUND TO THE NORTH. THIS WILL ALLOW
COLDER AIR TO START SPREADING IN WHICH COULD PRODUCE A PERIOD OF
SLEET BEFORE GOING OVER COMPLETELY TO LIGHT SNOW LATE TONIGHT AT
KRST. IT LOOKS LIKE THE COLDER AIR WILL NOT REACH KLSE UNTIL
16.12Z OR LATER SO HAVE NOT INCLUDED ANY MIXED PRECIPITATION
THERE. IT ALSO LOOKS LIKE IFR CONDITIONS WILL REMAIN THROUGH THE
ENTIRE PERIOD WITH VERY LITTLE CHANGE IN THE CEILINGS EXPECTED.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ017-029-032>034-
     041>044-053>055-061.

MN...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR MNZ079-086>088-
     094>096.

IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ008>011-018-019-
     029-030.

&&

$$

SHORT TERM...MW
LONG TERM...MW
AVIATION...04


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.