Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 220858
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
358 AM CDT TUE APR 22 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM CDT TUE APR 22 2014

MAIN FORECAST CONCERNS THIS PACKAGE...TEMPERATURES.

06Z DATA ANALYSIS HAD COOLER AND DRY CANADIAN PRESSURE BUILDING INTO
MN EARLY THIS MORNING. THIS HIGH RESPONSIBLE FOR GENERALLY CLEAR
SKIES ACROSS THE UPPER MIDWEST...BUT FOR SOME STRATUS CLOUDS IN THE
VICINITY OF LK SUPERIOR. CONTINUING NORTHWEST WINDS EAST OF THE SFC
RIDGE AXIS ADVECTING MID 20S TO MID 30S DEWPOINTS INTO THE REGION...
WHILE CLEAR SKIES/DEEP DRY AIRMASS ALLOWS TEMPS TO FALL INTO THE
30S/40S ACROSS MUCH OF MN/IA/WI.

NO LARGE ERRORS NOTED WITH 22.00Z MODEL INITIALIZATIONS. SOLUTIONS
CONTINUE TO CONVERGE TOWARD A TIGHTER CONSENSUS FOR TODAY/TONIGHT AS
THE PATTERN PROGRESSES AND RIDGING ALOFT BUILDS ACROSS THE NORTH-
CENTRAL CONUS. ECMWF OFFERS THE BETTER RUN-TO-RUN CONSISTENCY. CHECK
OF OBS VS. MODEL DATA AT 06Z SHOWED ALL WERE GOOD WITH THE HIGH
BUILDING INTO MN. MODELS ALSO REASONABLE WITH THE DRIER AIR
SPREADING INTO THE REGION. PER WV IMAGERY...ALL APPEARED QUITE GOOD
WITH THE SHORTWAVE DETAILS ACROSS NOAM/EASTERN PAC. NO ONE MODEL
FAVORITE AND GIVEN THE TREND TOWARD THE TIGHTER CONSENSUS...FAVORED
THE MODEL/ENSEMBLE CONSENSUS. SHORT TERM FCST CONFIDENCE IS GOOD
THIS CYCLE.

IN THE SHORT TERM...A RATHER QUIET PERIOD AND FAVORING ANY ONE
DETERMINISTIC MODEL OVER THE OTHERS WOULD HAVE MINIMAL IMPACT ON THE
SENSIBLE WEATHER TODAY/TONIGHT. THE COOLER/DRY CAN HIGH DRIFTS EAST
ACROSS THE UPPER MIDWEST TODAY/TONIGHT AS MID LEVEL HGTS GRADUALLY
RISE/RIDGING BUILDS EAST INTO THE REGION. DAY TO START OFF SUNNY...
BUT FOR THE FAR NORTH END OF THE FCST AREA WHERE THE 850MB WINDS/
TRAJECTORIES SPREAD SOME OF THE LINGERING LOWER LEVEL MOISTURE/
CLOUDS INTO THE KMDZ AREA. MODELS SPREAD SOME INCREASED 850MB
MOISTURE SOUTHEAST INTO THE FCST AREA THIS AFTERNOON. SOME OF THIS
EVIDENT WITH SCT CLOUDS SPREADING INTO NORTHWEST MN EARLY THIS
MORNING. GIVEN THE COLD POOL ALOFT AND DIURNAL MIXING TO NEAR
850MB...FEW-SCT STRATO-CU SEEM REASONABLE FOR THE AFTERNOON HOURS.
MOSTLY CLEAR THIS EVENING WITH SOME INCREASE OF MID CLOUDS OVER THE
WEST END OF THE FCST AREA LATER TONIGHT AS 700MB MOISTURE TRANSPORT/
WARM ADVECTION AHEAD OF THE NEXT LOW/TROUGH BEGIN TO ARRIVE.  850MB
TEMPS IN THE -1C TO -6C RANGE THIS AFTERNOON/TONIGHT AROUND 1
STANDARD DEVIATION BELOW NORMAL. HIGHS/LOWS TODAY/TONIGHT SOME 3F TO
8F BELOW NORMAL. USED A BLEND OF THE GUIDANCE HIGHS/LOWS FOR TODAY/
TONIGHT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 358 AM CDT TUE APR 22 2014

MAIN FORECAST CONCERNS FOR WED THRU THU NIGHT...SHRA/TSRA CHANCES/
AMOUNTS AND TEMPERATURES THRU THE PERIOD.

MODEL CONSENSUS CONTINUES TO TIGHTEN FOR THE WED THRU THU NIGHT
PERIOD AS STRONG TROUGHING OVER THE ROCKIES WED MOVES TO OVER THE
UPPER MIDWEST BY THU NIGHT. STILL SOME TIMING/STRENGTH DETAIL
DIFFERENCES THU/THU NIGHT AS THE TROUGH MOVES INTO/ACROSS THE REGION
BUT THESE LESS THAN EARLIER CYCLES...WITH MODELS TENDING TO FAVOR A
COMPROMISE OF THE EARLIER RUNS. WITH THE IMPROVING CONSENSUS...FCST
CONFIDENCE IN THE WED THRU THU NIGHT PORTION OF THE FCST IS GOOD.

BAND OF RATHER STRONG 850-700MB WARM ADVECTION/MOISTURE TRANSPORT
AND 295-310K ISENTROPIC LIFT ASSOCIATED WITH THE WARM FRONT AHEAD OF
LOW/TROUGH SPREADS NORTHEAST ACROSS THE AREA ON WED. RATHER STRONG
850-500MB FN CONVERGENCE SIGNAL SEEN AS WELL. THIS WITH PW VALUES
INCREASING INTO THE 0.75 TO 1 INCH RANGE BY LATE WED/WED EVENING.
GOOD CONSENSUS AMONG MODELS/ENSEMBLES FOR THIS FORCING/LIFT TO BE
STRONG ENOUGH TO PRODUCE PRECIP/OVERCOME THE DRIER SFC TO ROUGHLY
775MB AIRMASS. CONTINUED TO SPREAD 50-70 PERCENT -SHRA CHANCES
ACROSS MUCH OF THE FCST AREA BY WED AFTERNOON. GIVEN THE STRENGTH OF
THE 700-500MB FORCING/LIFT...INCLUDED AND ISOLATED TSRA MENTION FOR
THE AFTERNOON HOURS. THIS INITIAL FORCING/LIFT MOVES NORTHEAST OF
THE FCST AREA WED EVENING...WITH WHAT WOULD BE A 3 TO 6 HR BREAK
FROM THE SHRA/TSRA BEFORE THE NEXT STRONGER ROUND OF DEEP FORCING/
LIFT ARRIVES. JUST LOWERED PRECIP CHANCES A BIT FOR MOST LOCATIONS
IN THE 00-06Z THU PERIOD FOR NOW. LATER CYCLES WILL BE ABLE TO ADD
MORE DETAIL AS THE CONSENSUS TIGHTENS. DEEP LAYERED FORCING/LIFT
FROM 925-850MB WARM ADVECTION/MOISTURE TRANSPORT/THETA-E CONVERGENCE
THRU 400-200MB PV ADVECTION/DIVERGENCE ALOFT AHEAD OF THE MID LEVEL
SHORTWAVE/TROUGH. THIS WITH PW VALUES IN THE 1+ INCH RANGE...AROUND
200 PERCENT OF NORMAL. RAISED RAIN CHANCES TOWARD 90-100 PERCENT FOR
MUCH OF THE FCST AREA FOR LATER WED NIGHT/THU MORNING AS THE
STRONGEST LIFT AND SFC-700MB LOW/TROUGH APPROACH/LIFT ACROSS THE
AREA. CAPE CONTINUES TO APPEAR QUITE LIMITED OVER THE AREA OR IN THE
INFLOW AIRMASS LATER WED NIGHT/THU. GIVEN THE STRENGTH/DEPTH OF THE
FORCING/LIFT...CARRIED A TSRA CHANCE THESE PERIODS.

PRECIP CHANCES TREND DOWNWARD THU AFTERNOON/NIGHT AS THE SFC-500MB
TROUGH AXIS AND STRONGER FORCING/LIFT ROTATE/LIFT NORTHEAST OF THE
AREA AND DRIER AIR WRAPS IN AROUND THE SOUTH SIDE OF THE NEARLY
VERTICALLY STACKED SYSTEM BY FRI MORNING. SIDED WITH THE MODEL/
ENSEMBLE CONSENSUS FOR HIGHS/LOWS IN THE WED-THU NIGHT PERIOD. TEMPS
A CATEGORY OR 2 BELOW NORMAL THRU THE PERIOD QUITE REASONABLE GIVEN
ALL THE EXPECTED CLOUD COVER AND PRECIP AT LEAST WED AFTERNOON
THRU THU MORNING.

FOR FRIDAY THROUGH MONDAY.../DAYS 4 TO 7/...

MAIN FORECAST CONCERNS THIS PERIOD...LINGERING -SHRA CHANCES
FRI...RETURNING -RA/POTENTIAL -SN AT NIGHT CHANCES SAT NIGHT THRU
MON...MORE BELOW NORMAL TEMPERATURES.

MEDIUM RANGE MODEL RUNS OF 22.00Z IN DECENT AGREEMENT FOR THE TROUGH
TO BE PROGRESSIVE FRI AND HGTS OVER THE UPPER MIDWEST TO RISE FRI
NIGHT/SAT. LESSER BETWEEN MODEL AND RUN-TO-RUN CONSISTENCY BY
SUN/MON AS THE PATTERN REMAINS ACTIVE AND ANOTHER STRONG TROUGH
MOVES THRU THE ROCKIES SUN AND INTO THE CENTRAL CONUS FOR EARLY NEXT
WEEK. FCST CONFIDENCE AVERAGE FOR FRI/SAT THEN BELOW AVERAGE FOR
SUN/MON.

NOT A LOT OF TIME SPENT IN THE DAY 4-7 PERIOD THIS CYCLE. BETTER
SIGNAL FOR A SECONDARY SHORTWAVE TO ROTATE DOWN THRU THE BACK SIDE
OF THE TROUGH AND ACROSS MN/WI ON FRI. WITH DEEPER CYCLONIC FLOW...
LINGERING -SHRA CHANCES...MAINLY ACROSS THE NORTHEAST THIRD OF THE
FCST AREA ON FRI APPEAR REASONABLE FOR NOW. ONCE THIS SHORTWAVE
PASSES...HGTS START TO RISE WITH ANOTHER RIDGE OF COOL CAN HIGH
PRESSURE NOSING INTO THE REGION FOR FRI NIGHT/SAT. MODELS THEN TRY
TO SPREAD MOISTURE AHEAD OF THE LEE LOW/TROUGHING INTO/OVER THIS
HIGH PRESSURE/SFC RIDGING SAT NIGHT INTO MON. WITH THE MID LEVEL
PATTERN LOOKING RATHER OMEGA-BLOCKY OVER CENTRAL/EASTERN NOAM FOR
SUN/MON...GFS APPEARS TO SPREAD MOISTURE/PRECIP TOO FAR NORTHEAST
INTO THE RIDGING ON DAYS 6/7. HOWEVER...MADE ONLY MINOR CHANGES TO
THE MODEL/ENSEMBLE CONSENSUS -RA /SOME -SN CHANCES DURING THE LATE
NIGHT/EARLY MORNING HOURS/ CHANCES IN THE SAT NIGHT THRU MON FCST
GRIDS. TEMPS LOOKING TO REMAIN BELOW NORMAL IN THE FRI-MON PERIOD
GIVEN WHAT WOULD BE EAST/NORTHEAST LOW LEVEL FLOW OUT OF A LARGE CAN
HIGH PARKED NORTHEAST OF THE GREAT LAKES. MODEL CONSENSUS HIGHS/LOWS
FOR DAYS 4-7 LOOK TO HAVE THIS WELL TRENDED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1129 PM CDT MON APR 21 2014

VFR EXPECTED THROUGH THE PERIOD.

&&

.HYDROLOGY...
ISSUED AT 358 AM CDT TUE APR 22 2014

MINOR FLOODING CONTINUES ON THE MISSISSIPPI RIVER AT MCGREGOR IA.
ALONG THE MISSISSIPPI RIVER...RIVER LEVELS ARE EXPECTED TO GRADUALLY
FALL THROUGH MID WEEK BUT THEN WILL LEVEL OFF OR RISE SLIGHTLY AS
RUNOFF FROM SNOWMELT OVER NORTHWEST WISCONSIN AND CENTRAL INTO
PORTIONS OF NORTHERN MINNESOTA MAKES ITS WAY INTO THE LOCAL AREA.
RIVER LEVELS ARE EXPECTED TO REMAIN ELEVATED INTO NEXT WEEK.

&&

.CLIMATE...
ISSUED AT 358 AM CDT TUE APR 22 2014

KRST HAS GONE 192 DAYS WITHOUT REACHING 70F...SINCE OCT 11. GIVEN
THE FCST FOR THE NEXT 7 DAYS...THIS STRING LOOKS TO REMAIN INTACT
INTO AT LEAST THE END OF APRIL. THE LAST TIME A STRING OF DAYS
WITHOUT REACHING 70F WENT THIS LONG WAS THE WINTER SEASON OF
1996-97...194 DAYS. THE RECORD STRING OF DAYS BETWEEN REACHING 70F
AT KRST IS 209...SET IN THE WINTER SEASON OF 1959-60.

&&

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

$$

SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....BAUMGARDT
HYDROLOGY....RRS
CLIMATE......RRS



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