Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 180439
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1139 PM CDT SUN AUG 17 2014

.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 230 PM CDT SUN AUG 17 2014

LATEST WATERVAPOR IMAGERY POINTED TO A SHORTWAVE TROUGH MOVING
SLOWLY EAST ACROSS WESTERN MN...RESPONSIBLE FOR AN AREA OF
SHOWERS/STORMS ACROSS MID/EASTERN SECTIONS OF THE GOPHER STATE.
ANOTHER UPPER LEVEL SHORTWAVE TROUGH WAS SWINGING INTO THE NORTHERN
PLAINS.

THIS FIRST SYSTEM WILL CONTINUE TO MAKE SLOW PROGRESS EAST
TONIGHT...GRADUALLY TRACKING INTO NORTHERN WI. MODELS SUGGEST THAT
THIS FEATURE WILL WEAKEN AND/OR GET PULLED INTO THE NEXT
SHORTWAVE...WHICH WILL TAKE A SPEEDIER PATH ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY ON MONDAY. 25 KT 850 MB JET WILL PROVIDE A
PUSH OF LOW LEVEL MOISTURE FOR THE SYSTEM TO WORK ON MONDAY.
ALTHOUGH WARM CLOUD DEPTHS AREN/T AS DEEP AS RECENT DAYS - ITS STILL
FORECAST TO BE AROUND 3.5 KFT WITH PWS AROUND 1.6. SO...HEAVY RAIN
STILL A GOOD BET WITH ANY OF THE STRONGER STORMS. MUCAPES BUILD IN
EXCESS OF 2000 J/KG BY 00 TUE...WITH THE BULK OF THE SHEAR IN THE 0-
3KM LAYER NEAR 25 KTS. FAIRLY SKINNY CAPE PROFILES ACROSS THE
FORECAST AREA FOR THE MOST PART - PER BUFKIT SOUNDINGS - ALTHOUGH A
BIT MORE FAVORABLE FOR STORM DEVELOPMENT ACROSS NORTHEAST IA.
OVERALL...DON/T SEE AN ORGANIZED SEVERE WEATHER THREAT AT THIS TIME.
BELIEVE HEAVY RAIN AND A CHANCE FOR SMALL HAIL THE MORE LIKELY
OUTCOMES.

ON THE WHOLE...WILL HAVE SOME SCATTERED SHOWERS/STORMS INTO THE
EVENING HOURS FOR SOUTHEAST MN...WITH CHANCES MOSTLY ALONG AND NORTH
OF I-90 THROUGH THE OVERNIGHT. THE GREATER THREAT FOR RAIN WILL COME
LATER IN THE DAY ON MONDAY...AND MOST LOCATIONS CAN EXPECT TO GET
WET.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 230 PM CDT SUN AUG 17 2014

DECENT AGREEMENT IN THE MODELS WITH THE OVERALL PATTERN FOR THE
LATER PART OF THE NEW WEEK. THE GFS/ECMWF POINT TO A FAIRLY
PROGRESSIVE PATTERN WITH SOME MINOR RIDGE BUILDING FRI. BOTH SLIDE
AN UPPER LEVEL SHORTWAVE TROUGH ACROSS THE NORTHERN PLAINS
WED...TRACKING NORTH OF THE REGION ON THU. AN ASSOCIATED SFC WARM
FRONT WILL LIFT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY...WITH
FRONTOGENETIC LIFT AND WARM AIR ADVECTION ALONG IT LIKELY
RESULTING IN A BAND OF SHOWERS/STORMS.

ANOTHER SHORTWAVE TROUGH IS SLATTED TO MOVE OUT OF THE SOUTHERN
ROCKIES AND TAKE AIM ON THE UPPER MISSISSIPPI RIVER VALLEY FRI/SAT.
SOME DISAGREEMENTS BETWEEN THE MODELS ON
TIMING/POSITIONING/STRENGTH...WITH THE GFS THE QUICKER OF THE TWO.
OVERALL...BOTH SOLUTIONS POINT TO ANOTHER ROUND OF SHOWERS/STORMS.
WILL SIDE WITH CONSENSUS FOR RAIN CHANCES FOR NOW.

LOOKING AT A SLOW WARM UP THIS WEEK...WITH SOME MID-UPPER 80 DEGREE
READINGS LIKELY BEFORE THE WORK WEEK IS DONE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1139 PM CDT SUN AUG 17 2014

SHOWERS AND STORMS CONTINUE TO REDEVELOP OVER SOUTHEAST MINNESOTA
LATE THIS EVENING IN AN AREA OF WEAK MOISTURE TRANSPORT AND
VERTICAL LIFT AHEAD OF A SHORT WAVE TROUGH COMING ACROSS
MINNESOTA. EXPECT THIS ACTIVITY TO CONTINUE FOR A FEW MORE HOURS
UNTIL THE SHORT WAVE TROUGH MOVES PAST THE AREA AND WILL INITIALLY
HAVE TEMPO GROUPS AND THE VCTS WHEN IT IS SHOULD BE MOVING OUT OF
THE AREA. CONFIDENCE IS HIGHEST THAT KRST WILL CONTINUE TO BE
IMPACTED AS THAT IS WHERE THE NOSE OF THE MOISTURE TRANSPORT IS.
THE RADAR SHOWS THE ACTIVITY WEAKENING AS IT APPROACHES THE
MISSISSIPPI RIVER AND WITH THE MOISTURE TRANSPORT NOT MOVING
MUCH...KLSE MAY NOT SEE A WHOLE LOT OF ACTIVITY SO WILL STAY WITH
VCTS THERE. THE 18.03Z RAP STILL INDICATES THAT LOW STRATUS AND
SOME FOG SHOULD FORM LATE TONIGHT ONCE THE RAIN ENDS...BUT
CONCERNED THAT THE WINDS MAY STAY UP A LITTLE TOO MUCH TO ALLOW
MORE THAN MVFR VISIBILITIES TO DEVELOP. STRATUS EXPECTED TO START
LIFTING LATE MONDAY MORNING WHICH IS WHEN THE NEXT SHORT WAVE
TROUGH WILL BE APPROACHING FROM THE WEST TO START THE NEXT ROUND
OF SHOWERS AND STORMS. FEEL THERE WILL NEED TO BE A PERIOD OF
CATEGORICAL THUNDER FOR BOTH TAF SITES...BUT CONFIDENCE ON WHEN
THIS WILL OCCUR IS TOO LOW TO INCLUDE IT RIGHT NOW. THE 18.00Z NAM
AND 17.12Z HI-RES ARW WOULD SUGGEST LATE AFTERNOON INTO THE
EVENING BUT WHAT IS IN OF THE 18.00Z HI-RES ARW SUGGESTS AS EARLY
AS 18Z MONDAY. WILL CONTINUE WITH VCTS UNTIL THE TRENDS BECOME
CLEARER.

&&

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

$$

SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04



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