Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 030448
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1148 PM CDT TUE JUN 2 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 247 PM CDT TUE JUN 2 2015

THE MAIN CONCERN WITH THE FORECAST IS WITH THE RAIN CHANCES
THROUGH THE PERIOD.

THE UPPER LEVEL RIDGE OVER THE CENTRAL CONUS WILL START TO GET
FLATTENED TONIGHT AS A SHORT WAVE TROUGH COMES OUT OF THE ROCKIES.
THE GENERAL MODEL CONSENSUS FROM THE 02.12Z MODELS IS FOR THIS
WAVE TO COME ACROSS THE DAKOTAS LATE TONIGHT AND THEN MOVE ACROSS
MINNESOTA INTO NORTHERN WISCONSIN THROUGH WEDNESDAY EVENING. THIS
WAVE DOES NOT LOOK TO BE ALL THE STRONG WITH ONLY SOME WEAK PV
ADVECTION IN THE 500-300 MB LAYER. IN THE LOW LEVELS...THE COLD
FRONT OVER THE DAKOTAS WILL MOVE STEADILY EAST AND IS EXPECTED TO
GRADUALLY WEAKEN AS IT APPROACHES. WHAT FRONTOGENESIS THERE IS
WITH THE FRONT IS VERY WEAK AND LOOKS TO BE LIMITED TO THE
1000-850 MB LAYER. THE WARM AIR ADVECTION AHEAD OF THE FRONT IS
NOT VERY STRONG EITHER AND LOOKS TO GENERATE 1-2 UBAR/S OF UP
GLIDE ON THE 305K ISENTROPIC SURFACE. THE MOISTURE TRANSPORT IS
RATHER WEAK WEDNESDAY AS WELL SO WOULD ONLY EXPECT SCATTERED
CONVECTION TO FORM ALONG AND AHEAD OF THE FRONT. THE 02.12Z NAM
HAS COME IN WITH MUCH LESS ACTIVITY ALONG THE FRONT THAN ITS
PREVIOUS RUNS AND THE 02.12Z HI-RES MESO MODELS ARE SOMEWHAT
SIMILAR.

THIS FIRST WAVE WILL MOVE OFF INTO CANADA LATE WEDNESDAY NIGHT AND
THEN WILL BE QUICKLY FOLLOWED BY ANOTHER WAVE COMING UP FROM THE
SOUTHWEST AND TOPPING WHAT REMAINS OF THE UPPER LEVEL RIDGE AXIS.
THE 02.12Z MODELS HAVE BACK OFF ON THE INTENSITY OF THIS WAVE FROM
PREVIOUS RUNS AND THE OVERALL FORCING NOW LOOKS TO BE VERY SIMILAR
TO WHAT IS EXPECTED WITH THE WEDNESDAY WAVE WITH ONLY WEAK PV
ADVECTION IN THE 500-300 MB LAYER. WHAT REMAINS OF THE SURFACE
BOUNDARY WILL BE PUSHED IN THE AREA BUT THE FRONTOGENESIS
CONTINUES TO BE VERY WEAK AND LIMITED TO THE 1000-850 MB LAYER.
THE ISENTROPIC UP GLIDE LOOKS TO BE EVEN WEAKER THURSDAY WITH AT
MOST 1 UBAR/S ON THE 305K SURFACE. THE SIGNAL WITH THE MOISTURE
TRANSPORT IS TO ALSO BE WEAKER THAN WEDNESDAY SO AGAIN WOULD
EXPECT ONLY SCATTERED CONVECTION TO OCCUR WITH THE BOUNDARY IN THE
AREA.

THE MAIN CAPE AXIS LOOKS TO REMAIN TO THE WEST OF THE FORECAST
AREA WITH THE POSSIBILITY OF MAYBE 1000 J/KG OF ML CAPE ACROSS
OUR FAR WEST WEDNESDAY AFTERNOON. FOR THURSDAY...THERE COULD BE
BETWEEN 1000 AND 1500 J/KG OF ML CAPE MAINLY SOUTH OF INTERSTATE
90. HOWEVER...THE SHEAR LOOKS VERY WEAK BOTH DAYS WITH 20 TO 25
KNOTS IN THE 0-6 KM LAYER WEDNESDAY AND 20 KNOTS OR LESS THURSDAY.
THE CAPE PROFILE BOTH DAYS LOOKS TO BE TALL AND SKINNY WHICH
SHOULD NOT BE ABLE TO SUPPORT STRONG UP DRAFTS. CANNOT RULE OUT
MAYBE SOME STRONG STORMS BOTH DAYS BUT THE CHANCES FOR SEVERE
LOOKS TO BE PRETTY MINIMAL.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 247 PM CDT TUE JUN 2 2015

THE WAVE FROM THURSDAY WILL NOT BE FAST MOVING AND WILL STILL BE
CLOSE ENOUGH FRIDAY TO POSSIBLY PRODUCE SOME CONVECTION OVER THE
AREA. THE CHANCES WILL RAPIDLY DIMINISH AFTER THAT AS THE WAVE
MOVES AWAY WITH HIGH PRESSURE MOVING IN FOR SATURDAY. AFTER THIS
POINT...THE MODELS START TO DIVERGE ON HOW QUICKLY THE MOISTURE
AND NEXT SYSTEM WILL START TO RETURN TO THE UPPER MIDWEST. THE
02.12Z ECMWF IS QUICKER TO DROP A SHORT WAVE TROUGH OUT OF THE
NORTHERN STREAM INTO THE UPPER MIDWEST THAN WHAT THE 02.12Z GFS
IS...BUT THESE SOLUTIONS ARE CLOSER IN TIMING THAN WHAT THE 02.00Z
RUNS WERE. THIS SYSTEM WILL RETURN THE RAIN CHANCES BACK TO THE
AREA FOR PRIMARILY SATURDAY NIGHT AND SUNDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1148 PM CDT TUE JUN 2 2015

STILL WATCHING TIMING AND COVERAGE OF SHOWERS AND THUNDERSTORMS
FOR WEDNESDAY AT KRST/KLSE AS A COLD FRONT MOVES INTO THE REGION.
WILL CONTINUE VCSH/VCTS MENTION AS UNCERTAINTY PRECLUDES GREATER
DETAIL AT THIS TIME...ALTHOUGH BEST TIMING FOR ANY THUNDER WILL BE
LATE AFTERNOON/EARLY EVENING. MVFR/IFR CEILINGS/VISIBILITY
POSSIBLE WITH ANY STRONGER STORMS...BUT OTHERWISE EXPECT VFR
CONDITIONS THROUGH THE TAF PERIOD. SOUTHERLY WINDS TO PERSIST FROM
8 TO 12 KTS WITH OCCASIONAL GUSTS INTO THE LOW 20 KT RANGE AT
KRST.

&&

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

$$

SHORT TERM...04
LONG TERM...04
AVIATION...ROGERS


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