Area Forecast Discussion
Issued by NWS La Crosse, WI

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000
FXUS63 KARX 280816
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
316 AM CDT MON JUL 28 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 316 AM CDT MON JUL 28 2014

MAIN FORECAST CONCERNS ARE CLOUD TRENDS TODAY.

LATEST INFRARED SATELLITE IMAGERY INDICATING STRATOCUMULUS CLOUDS
OVER MUCH OF MINNESOTA/EASTERN DAKOTAS AND MOSTLY CLEAR SKIES OVER
MUCH OF WISCONSIN. THIS CORRELATES WELL WITH THE LATEST 28.03Z RAP
850MB RELATIVE HUMIDITY FIELD AND THE 850MB 28.00Z UPPER AIR
ANALYSIS.

TODAY THE 28.00Z NAM/GFS AND 28.03Z RAP DIFFER ON THE EXTENT OF THE
850MB MOISTURE...WHERE THE NAM IS MORE WIDESPREAD AND THE GFS IS
LESS EXTENSIVE. THE LATEST 28.03Z RAP APPEARS TO HANDLE THE EXTENT
OF THE CLOUDS/MOISTURE BETTER AND HAVE TRENDED SKY COVER CLOSER TO
THIS FOR TODAY. THIS SUGGEST THE CLOUDS WILL DIMINISH ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON.

SKIES SHOULD BE MOSTLY CLEAR TONIGHT ACROSS MUCH OF THE FORECAST AREA
...AS MODELS SHOW 850MB MOISTURE ERODES/ADVECTS SOUTH OF FORECAST
AREA.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 316 AM CDT MON JUL 28 2014

TUESDAY AND WEDNESDAY...REGION REMAINS UNDER THE INFLUENCE OF THE
UPPER LEVEL TROUGH OVER THE EASTERN UNITED STATES. THE 28.00Z
GFS/NAM/ECMWF SHOW A COUPLE OF WEAK IMPULSES TO TRACK OVER THE
EASTERN PARTS OF THE FORECAST AREA. THE 28.00Z GFS/NAM BUFKIT
SOUNDINGS EAST OF THE MISSISSIPPI RIVER INDICATE CAPE OF 300 TO
AROUND 350 J/KG BY 21Z TUESDAY AND COMBINED WITH STEEP LOW LEVEL
RATES OF 8-9 C/KM AND ATMOSPHERE COLUMN UNCAPPED...EXPECT SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP EAST OF THE
MISSISSIPPI RIVER LATE TUESDAY MORNING INTO THE AFTERNOON HOURS.

WITH LESS MOISTURE AND MUCH OF THE FORECAST AREA REMAINS CAPPED
PER BUFKIT SOUNDINGS...ANY SHOWERS AND ISOLATED THUNDERSTORMS
WILL BE FOCUSED OVER THE EXTREME EASTERN PARTS OF THE FORECAST
AREA WEDNESDAY AFTERNOON.

THURSDAY INTO SUNDAY...MAIN FORECAST CONCERNS ARE THE DIURNALLY
DRIVEN SHOWERS/ISOLATED THUNDERSTORM POSSIBILITIES THROUGH THE
PERIOD. THE 28.00Z GFS/ECMWF/GEM CONTINUE TO DIFFER ON STRENGTH OF
WEAK SHORTWAVE TROUGHS EMBEDDED IN THE NORTHERLY FLOW ALOFT. THE
28.00Z GEM/GFS IS MORE AMPLIFIED WITH SHORTWAVE TROUGH ON FRIDAY
THAN THE ECMWF. HENCE...PRODUCE HIGHER AMOUNTS OF QPF ACROSS MUCH OF
THE FORECAST AREA. DUE TO THE STRENGTH ISSUES WITH WEAK
IMPULSES...CONFIDENCE IN FORECAST WITH PRECIPITATION CHANCES
THURSDAY INTO SATURDAY REMAIN LOW. TEMPERATURES THROUGH MUCH OF
THIS PERIOD WILL REMAIN SLIGHTLY BELOW NORMAL...AS THE AREA
REMAINS UNDER COOL NORTHERLY FLOW ALOFT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1146 PM CDT SUN JUL 27 2014

WHILE THE CLOUD FORECAST IS CHALLENGING FOR THIS TAF CYCLE...IT
APPEARS THE CLOUDS WILL BE VFR FOR THE PERIOD. CYCLONIC FLOW
AROUND A LARGE SCALE LOW WILL KEEP CLOUDS POSSIBLE ACROSS THE TAF
SITES THROUGH THE PERIOD IN NORTHERLY FLOW OUT OF CANADA.
SOUNDINGS AT 00Z ACROSS THE REGION SHOW MOIST CONDITIONS WITH
DEWPOINT DEPRESSIONS AT 4C OR LESS. SATELLITE SHOWING MN MUCH MORE
CLOUDY THAN WI AND THE MODEL GUIDANCE SEEMS TO HOLD ONTO THAT
TREND THROUGH THE FORECAST. THUS...HAVE KEPT KRST MORE CLOUDY THAN
KLSE THIS CYCLE. DETAILS ON THE CLOUDS ARE TOUGH AND CONFIDENCE IS
LOW. HOWEVER...CONFIDENCE IS HIGHER THAT THE CLOUDS WILL REMAIN
VFR FOR THE MOST PART.

&&

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

$$

SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...BAUMGARDT



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