000
FXUS63 KARX 262148
AFDARX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
348 PM CST THU FEB 26 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 348 PM CST THU FEB 26 2015

WITH DIURNAL HEATING...A SCATTERED TO BROKEN DECK 4K FOOT CLOUDS
DEVELOPED ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. MODEL
SOUNDINGS SHOW THAT WITH THE LOSS OF DIURNAL HEATING LATE THIS
AFTERNOON AND EVENING THAT CLOUDS WILL GRADUALLY DISSIPATE ACROSS
THE AREA...AND BY MID TO LATE EVENING SKIES WILL BE CLEAR.

FOR LATE TONIGHT AND EARLY FRIDAY MORNING...A 1039 MB
HIGH...CENTERED OVER THE EASTERN DAKOTAS...WILL MOVE SOUTHEAST
INTO WESTERN IOWA TONIGHT. THIS HIGH SHOULD BE CLOSE ENOUGH TO THE
UPPER MISSISSIPPI RIVER VALLEY THAT OUR SURFACE GRADIENT WILL ONLY
SUPPORT 5 KNOTS OR LESS OF WINDS. THE COMBINATION OF THE LIGHT
WEST WINDS AND CLEAR SKIES WILL ALLOW THE TEMPERATURES TO FALL
INTO THE -10 TO -30 DEGREE RANGE. THE COLDEST TEMPERATURES WILL
FOUND IN CENTRAL WISCONSIN. BLACK RIVER FALLS COULD POTENTIALLY
SEE THEIR THIRD DAY IN THE PAST WEEK WHERE THEIR TEMPERATURE HAS
FALLEN TO -29F OR COLDER. WITH TEMPERATURES THIS COLD...ANY WIND
AT ALL WILL PRODUCE WINDS IN THE -20 TO -35 DEGREE RANGE. HOWEVER
IF THE WIND IS A BIT STRONGER THAN FORECAST...THE LOW TEMPERATURES
WOULD BE A BIT WARMER THAN FORECAST AND WE WOULD SEE SLIGHTLY
WARMER WIND CHILLS. DUE TO THIS...THINKING THAT IN EITHER
SCENARIO...THE WINDS CHILLS WILL ONLY BE TEMPORARILY IN THE -20 TO
-35 DEGREE RANGE. DUE TO THIS...THE CONSENSUS WAS TO JUST ISSUE A
SPECIAL WEATHER STATEMENT TO COVER THIS SITUATION.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 348 PM CST THU FEB 26 2015

FROM SATURDAY NIGHT INTO SUNDAY...THE 26.12Z MODELS CONTINUE TO
STRUGGLE WITH INTERACTION BETWEEN A SOUTHERN AND NORTHERN STREAM
SHORT WAVE TROUGH. THE ECMWF CONTINUES TO THE FURTHEST NORTH AND
PRODUCES SNOW ACROSS THE ENTIRE FORECAST AREA. THE HIGHEST TOTALS
OF 1 TO 2 INCHES WILL BE FOUND SOUTH OF INTERSTATE 90. THE 26.12Z
NAM WAS IN GENERAL AGREEMENT WITH THE ECMWF...BUT ITS 26.18Z RUN
SHIFTED IT SOUTH TOWARD THE GFS AND GEM SOLUTIONS WHICH EITHER
MISSES OUR AREA COMPLETELY OR JUST BRUSHES NORTHEAST IOWA AND
SOUTHEAST MINNESOTA. DUE TO THESE DISCREPANCIES...STAYED CLOSE TO
THE MODEL CONSENSUS.

FROM MONDAY NIGHT INTO TUESDAY NIGHT...THE MODELS SHOW THAT
ANOTHER A SHORT WAVE IN THE SOUTHERN STREAM WILL BRING ANOTHER
BOUT OF WINTER PRECIPITATION TO THE AREA. THE GFS CONTINUES TO
HAVE THE DEEPEST LOW AND IT IS ALSO THE FASTEST WITH ITS SURFACE
LOW. IN THIS SCENARIO...THERE WOULD BE A WINTRY MIX SOUTH OF
INTERSTATE 90 AND ACCUMULATING SNOW NORTH OF INTERSTATE 90. WHILE
THE ECMWF HAS A WEAKER SURFACE LOW AND IT IS SLOWER AT MOVING INTO
THE AREA...IT RESULTS IN THE SAME SCENARIO AND THE GFS. MEANWHILE
THE GEM IS THE FARTHEST SOUTH OF THE SOLUTIONS AND HAS A SIMILAR
TIMING TO THE ECMWF. WITH THIS SCENARIO...THE ENTIRE AREA WOULD
SEE ACCUMULATING SNOW. STILL A BIT TOO FAR OUT TO MENTION
AMOUNTS.

IN THE WAKES OF THIS SYSTEM...ANOTHER ROUND OF COLD AIR MOVES INTO
THE REGION. BOTH THE GFS AND ECMWF HAVE HIGH TEMPERATURES IN THE
TEENS FOR WEDNESDAY. ON THURSDAY...THE GFS ONLY HAS HIGH
TEMPERATURES IN THE SINGLE DIGITS AND THE ECMWF IS IN THE TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1129 AM CST THU FEB 26 2015

HIGH PRESSURE WILL BUILD INTO WESTERN IOWA THIS AFTERNOON INTO
TONIGHT AND PROVIDE VFR CONDITIONS AT BOTH RST AND LSE TAF SITES
THROUGH THE TAF PERIOD. DAYTIME HEATING WILL ALLOW FOR
DEVELOPMENT OF SCATTERED CUMULUS CLOUDS ACROSS THE AREA THIS
AFTERNOON. CLOUD HEIGHTS ARE EXPECTED TO BE IN THE 2500-3500 FEET
RANGE. INTRODUCED SCATTERED CLOUDS AT BOTH TAF SITES FOR THIS
AFTERNOON. NORTHWEST WINDS WILL DIMINISH TO AROUND 5 KNOTS OR
LESS AFTER 02Z FRIDAY AT BOTH TAF SITES.


&&

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

$$

SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ