310  
FXUS63 KARX 132323  
AFDARX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LA CROSSE WI  
623 PM CDT THU JUN 13 2024  
   
KEY MESSAGES
 
 
- LINGERING SHOWERS WILL DIMINISH BY LATE THIS AFTERNOON WITH A  
DRY, SEASONABLE END TO THE WORK WEEK.  
 
- TRENDING HOTTER AND HUMID LATE THIS WEEKEND INTO NEXT WEEK  
WITH HIGH TEMPS NEAR OR ABOVE 90F FOR SOME AREAS SUNDAY INTO  
EARLY NEXT WEEK.  
 
- INTERMITTENT SHOWERS/STORMS POSSIBLE SATURDAY INTO NEXT WEEK.  
CONFIDENCE IN COVERAGE/TIMING IS LOWER, BUT HEAVY  
RAIN/STRONGER STORMS WOULD BE POSSIBLE. RIGHT NOW THE HIGHEST  
RAIN CHANCES LOOK TO BE LATER SATURDAY/SATURDAY NIGHT.  
 

 
   
DISCUSSION
 
 
ISSUED AT 205 PM CDT THU JUN 13 2024  
 
THIS EVENING-FRIDAY:  
 
A COLD FRONT CONTINUES TO SWEEP SOUTH OF THE AREA THIS AFTERNOON.  
MID-LEVEL FRONTOGENESIS ON THE COOL SIDE OF THE SURFACE BOUNDARY HAS  
BEEN AIDING IN A BAND OF SHOWERS ACROSS THE REGION TODAY WITH GUSTY  
WINDS OF 40 TO 55 MPH, GIVEN DRY LOW-LEVEL PROFILES, BUT THESE  
WILL DIMINISH THROUGH LATE AFTERNOON AS DRIER AIR WORKS IN. THE  
SEVERE WEATHER THREAT STILL LOOKS TO HOLD FARTHER SOUTH ACROSS  
SOUTHEAST IOWA AND ILLINOIS LATE TODAY CLOSER TO THE SURFACE  
FRONT AND GREATER INSTABILITY. AS OF 2 PM, SPC MESOANALYSIS  
INDICATED THE SURFACE-BASED CAPE GRADIENT HAD ALREADY SHIFTED  
SOUTH OF THE AREA. CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE  
GREAT LAKES FRIDAY INTO FRIDAY NIGHT PROVIDING A SEASONABLE, DRY  
MID-JUNE AIRMASS WITH SOME DIURNAL CUMULUS DEVELOPMENT THROUGH  
THE DAY.  
 
SATURDAY-THURSDAY:  
 
A PATTERN CHANGE WILL OCCUR OVER THE WEEKEND INTO NEXT WEEK AS RIDGE  
BUILDING OCCURS ACROSS THE CENTRAL US, EVENTUALLY AMPLIFYING OVER  
THE GREAT LAKES INTO THE NORTHEAST NEXT WEEK. THIS WILL USHER IN A  
HOTTER, MORE HUMID AIRMASS.  
 
MORE UNSETTLED WEATHER IS EXPECTED TO START THE WEEKEND AS A FEW  
SHORTWAVES EJECT FROM THE PLAINS AND BROAD WARM ADVECTION/MOISTURE  
TRANSPORT INCREASES. THE THUNDER THREAT LOOKS LOW DURING THE DAY ON  
SATURDAY WITH THE HIGHER INSTABILITY OUT TO THE WEST. A MORE HUMID,  
UNSTABLE AIRMASS MOVES IN BY SUNDAY, BUT DEEP LAYER SHEAR LOOKS  
MODEST, SO CONFIDENCE IN ORGANIZED SEVERE WEATHER IS LOW. HOWEVER,  
INCREASING PRECIPITABLE WATER VALUES AND DEEPENING WARM CLOUD DEPTHS  
COULD RESULT IN LOCALIZED HEAVY RAIN POTENTIAL, ESPECIALLY BY  
SATURDAY NIGHT AS INSTABILITY ADVECTS EASTWARD AND INTERACTS WITH  
THE PASSING SHORTWAVE AND STRONGER MOISTURE TRANSPORT. THE HIGHER  
RAIN CHANCES (70-80%) CURRENTLY EXTEND FROM SOUTHEAST MINNESOTA  
THROUGH NORTH-CENTRAL WISCONSIN LATER SATURDAY/SATURDAY, AND WPC HAS  
INCLUDED A LEVEL 2 OF 4 RISK FOR EXCESSIVE RAINFALL FOR THIS AREA  
DURING THIS TIME. A NOTICEABLE AIRMASS CHANGE IS EXPECTED HEADING  
FROM SATURDAY INTO SUNDAY AS DEW POINTS CLIMB AND TEMPS LIKELY RISE  
TO NEAR 90 IN SOME AREAS BY SUNDAY, PENDING COVERAGE OF  
SHOWERS/STORMS.  
 
HEADING INTO NEXT WEEK, THE RIDGE WILL AMPLIFY ACROSS THE GREAT  
LAKES WITH THE UPPER MISSISSIPPI VALLEY RESIDING ON THE WESTERN  
PERIPHERY OF THE RIDGE IN A VERY WARM/HOT, HUMID SOUTHWEST FLOW.  
NAEFS 850 MB TEMP AND PRECIPITABLE WATER VALUES EXCEED THE 90%  
PERCENTILE RELATIVE TO CLIMO DURING THIS STRETCH. THE STRONGER MID-  
LEVEL SOUTHWEST FLOW IS EXPECTED TO BE ORIENTED ACROSS THE NORTHERN  
PLAINS, WHICH MAY KEEP THE GREATEST FOCUS FOR SEVERE WEATHER TO THE  
WEST. HOWEVER, THERE IS SOME UNCERTAINTY IN THE AMPLITUDE IN THE  
AMPLITUDE/POSITION OF THE RIDGE. A FLATTER/EASTWARD DISPLACED RIDGE  
ORIENTATION (~40% OF EC/GEFS/CPC MEMBERS) WOULD SUPPORT INCREASED  
CHANCES FOR INTERMITTENT SHOWERS/STORMS (INCLUDING STRONG/SEVERE  
STORMS AND HEAVY RAINS) AS EMBEDDED SHORTWAVE TROUGHS PROGRESS  
THROUGH THE FLOW WHILE A MORE AMPLIFIED RIDGE WOULD LIKELY  
RESULT IN DRIER CONDITIONS WITH THE HIGHER SHOWER/STORM  
POTENTIAL FARTHER NORTHWEST. BROAD NBM RAIN CHANCES IN THE  
20-40% RANGE SEEM REASONABLE AT THIS TIME SUNDAY INTO NEXT WEEK  
GIVEN THE UNCERTAINTY. LIKEWISE, TEMPS COULD BE IMPACTED BY  
CLOUDS/RAIN, DEPENDENT ON RIDGE POSITION, WITH SPREAD INCREASING  
BY LATER IN THE WEEK DUE TO UNCERTAINTY IN THE LONGWAVE  
EVOLUTION.  
 

 
   
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
 
 
ISSUED AT 623 PM CDT THU JUN 13 2024  
 
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH MOSTLY CLEAR  
SKIES. WINDS WILL REMAIN LIGHT AT AROUND 5 KTS OR LESS OVERNIGHT  
FROM THE NORTHWEST BEFORE GRADUALLY SHIFTING NORTH AND INCREASING  
SLIGHTLY DURING THE AFTERNOON. FEW TO SCT MID-LEVEL CLOUDS ARE  
POSSIBLE LATER INTO THE DAY FRIDAY ACROSS WESTERN WISCONSIN.  
HOWEVER, FAIRLY DRY MODEL SOUNDINGS GIVE LITTLE CONFIDENCE IN  
THIS POSSIBILITY DURING THE AFTERNOON.  
 

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

 
 

 
 
DISCUSSION...JM  
AVIATION...NAYLOR  
 
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