000
FXUS63 KARX 131116
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
616 AM CDT THU MAR 13 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT THU MAR 13 2014

AT 3 AM...A WARM FRONT WAS LOCATED OVER WESTERN MINNESOTA.
THE COMBINATION OF 280 TO 290K ISENTROPIC LIFT AND STRONG 900 TO
800 MB FRONTOGENETIC LIFT WAS PRODUCING A 6 TO 8K DECK OF CLOUDS
ALONG AND WEST OF THE INTERSTATE 35 CORRIDOR. THERE WERE EVEN A
FEW REPORTS OF 2K FOOT CLOUDS BRIEFLY AT MASON CITY. THESE CLOUDS
WERE HELPING TO RISE TEMPERATURES INTO THE LOWER AND MID 30S.
MEANWHILE WHERE SKIES WERE STILL CLEAR...TEMPERATURES RANGE FROM
THE SINGLE DIGITS TO MID TEENS.

TODAY - THE WARM FRONT WILL MOVE EAST ACROSS THE FORECAST AREA.
AT MOST LOCATIONS...THE NAM AND GFS SOUNDINGS BECOME VERY
SATURATED BELOW 900 MB LATE THIS MORNING AND AFTERNOON. MEANWHILE
BOTH THE RAP HAS THIS LAYER DRY. NORMALLY...THE GFS AND NAM HAVE
PROBLEMS IN THIS SYNOPTIC SITUATION WHERE YOU HAVE STRONG WARM
AIR ADVECTION GOING UP AN OVER A SNOW PACK. WHILE THIS CAN
OCCUR...A SIMILAR SIGNAL IS SHOWING UP IN THE BUFKIT SOUNDINGS AT
BOTH FAIRMONT AND REDWOOD FALLS AND NEITHER LOCATION HAS ANY LOW
CLOUDS. DUE TO THE LOW LEVELS BEING DRIER THAN EXPECTED REMOVED
THE MENTION OF FREEZING DRIZZLE AND SNOW FOR MUCH OF THE AREA THIS
MORNING. THE ONLY PLACE THAT A MENTION OF FLURRIES WAS KEPT IN WAS
OVER IN CENTRAL WISCONSIN WHERE THE ARW HINTS THAT THERE MAY BE
SOME VERY LIGHT PRECIPITATION AROUND 13.15Z.

TONIGHT - THE 13.00Z MODELS ARE IN GOOD AGREEMENT THAT A SHORT
WAVE TROUGH AND COLD FRONT WILL MOVE SOUTHEAST THROUGH THE
REGION. THE AIR MASS AHEAD OF THIS FRONT IS VERY DRY DUE TO
THE DOWN SLOPED AIR BEING BROUGHT INTO THE AREA FROM THE NORTHERN
PLAINS. AS A RESULT...ONLY EXPECT SOME CLOUDS ASSOCIATED WITH
THIS SYSTEM.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 339 AM CDT THU MAR 13 2014

FROM FRIDAY INTO FRIDAY EVENING...THE 13.00Z MODELS ARE IN GOOD
AGREEMENT THAT A SECONDARY FRONT WILL REMAIN STATIONARY OVER
NORTHERN MINNESOTA AND NORTHERN WISCONSIN. AT THE SAME TIME...A
SERIES OF WEAK SHORT WAVES WILL BE MOVING ALONG THIS BOUNDARY. THE
COLD FRONT LOOKS CLOSE ENOUGH TO CLARK AND TAYLOR COUNTIES TO
WARRANT A SLIGHT CHANCE OF SNOW.

ON SATURDAY AND SATURDAY NIGHT...THE COLD FRONT WILL MOVE SOUTH
THROUGH THE FORECAST AREA. THE GFS HAS THE STRONGEST COLD AIR
ADVECTION IN THE WAKE OF THIS FRONT. MEANWHILE THE NAM HAS THE
WEAKEST COLD AIR ADVECTION. THE ECMWF WAS A NICE COMPROMISE
BETWEEN THE TWO...SO TRENDED TOWARD IT FOR TEMPERATURES. THERE
LOOKS TO BE ENOUGH LIFT AND MOISTURE NORTH OF INTERSTATE 94 FOR
A MENTION OF SOME LIGHT SNOW. MEANWHILE DURING THE AFTERNOON AND
EVENING...BOTH THE NAM AND ECMWF SUGGEST SOME WEAK TO MODERATE
CYCLOGENESIS TAKING PLACE ACROSS WESTERN AND SOUTHERN IOWA. THE
285 AND 290K ISENTROPIC SURFACES BECOME SATURATED ENOUGH TO
SUGGEST THE POSSIBILITY THAT A BAND OF SNOW COULD DEVELOP EITHER
ON THE INTERSTATE 90 CORRIDOR /ECMWF/ OR ACROSS NORTHEAST IOWA AND
SOUTHWEST WISCONSIN /GFS...GEM...AND NAM/. SINCE THIS IS A
RELATIVELY NEW DEVELOPMENT IN THE MODELS...OPTED TO GO WITH THE
BETTER SNOW CHANCES IN AREAS WHERE THERE WAS THE BEST MODEL
CONSENSUS.

FROM SUNDAY NIGHT INTO TUESDAY...THE MODELS CONTINUE TO STRUGGLE
ON TRACK AND TIMING OF A SERIES OF SYSTEMS MOVING THROUGH THE
REGION. SINCE THERE HAS BEEN VERY LITTLE RUN TO RUN
CONSISTENCY...JUST STAYED WITH THE MODEL CONSENSUS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 616 AM CDT THU MAR 13 2014

BAND OF VFR CLOUDS AHEAD OF THE APPROACHING FRONT WILL CONTINUE TO
MOVE EAST AND SHOULD CLEAR OUT OF BOTH TAF SITES BY MID MORNING.
EXPECT TO SEE SOUTH TO SOUTHWEST WINDS BETWEEN 10 AND 15 KNOTS
BEHIND THE WARM FRONT. AS THE WARM AIR COMES IN ALOFT...THE
INVERSION SHOULD REMAIN IN PLACE THROUGH THE DAY. THUS WITH VERY
LIMITED MIXING...NOT EXPECTING TO SEE MUCH IN THE WAY FOR GUSTS
TODAY. THE 13.06Z NAM CONTINUES TO SHOW THE POTENTIAL FOR SOME
WIND SHEAR TONIGHT AT KLSE. HOWEVER...THE 13.06Z GFS DOES NOT
INCREASE THE WINDS ALOFT QUITE AS MUCH AS THE NAM AND WOULD KEEP
THE SPEEDS JUST UNDER WIND SHEAR CRITERIA. CONFIDENCE THAT THIS
WILL OCCUR IS NOT VERY HIGH...ESPECIALLY WITH THE NAM HAVING A
BIAS OF BEING TOO STRONG WITH WIND SPEEDS...BUT SINCE IT WAS
ALREADY IN THE FORECAST...WILL LEAVE IT FOR NOW. THE WIND SHEAR
WILL END OVERNIGHT AS THE FIRST OF TWO COLD FRONT MOVES THROUGH
AND SWINGS THE SURFACE WINDS AROUND TO THE NORTHWEST WITH WIND
SPEEDS ALOFT DIMINISHING ENOUGH TO DROP THIS FROM THE FORECAST.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04