FXUS63 KMPX 012111
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
311 PM CST TUE DEC 1 2009

.DISCUSSION...

WELL DEFINED WAVE WITH ASSOCIATED STRONG FGEN SIGNATURE MOVING
ACROSS N MN AND INITIAL COLD FRONT HAS MOVED INTO WESTERN MN.
STRONG SINKING MOVING ACROSS CWA OVERNIGHT SHOULD KEEP ANY
FLURRIES MAINLY NORTH OF THE AREA. INITIAL SURGE OF COLD ADVECTION
WAS BRINGING BAND OF SC INT THE AREA. THIS SHOULD CONTINUE ACROSS
AT LEAST THE CENTRAL AND WEST CENTRAL AREAS BUT MAY DECREASE
SOMEWHAT UNTIL THE BETTER CYCLONIC CURVATURE SWEEPS IN WEDNESDAY.
WILL PAINT IN SOME STRONGER WINDS/GUSTS THIS EVENING WITH THE
INITIAL COLD ADVECTION AND SINKING.

SECOND WAVE DROPPING SE THROUGH SASK CANADA WILL START AFFECTING
THE WESTERN AREAS LATER WEDNESDAY MORNING AND THEN INTO THE
EASTERN CWA BY WEDNESDAY NIGHT. BEST CHANCE OF MEASURABLE SNOW WILL
BE OVER WESTERN CWA INITIALLY WITH PVA. STEEPER LAPSE RATES WILL
MOVE INTO THE AREA WEDNESDAY AFTERNOON AND EVENING FOLLOWED BY
ANOTHER SPOKE IN THE COLD CYCLONIC FLOW THURSDAY NIGHT. MUCH OF
AVAILABLE MOISTURE WRUNG OUT IN LATER PERIODS SO CHANCE OF
WIDESPREAD MEASURABLE SLIP. WILL KEEP A SLIGHT CHANCE OR FLURRIES.
TEMP TRENDS FROM AVAILABLE GUIDANCE SEEMS CONSISTENT WITH ONLY
MINOR VARIATION FROM CURRENT FORECAST. 

LOOKING FARTHER DOWN THE ROAD...EARLY NEXT WEEK...BUILDING RIDGE
INT HE EASTERN PAC INTO AK AREA...ALLOWING LARGE SCALE TROUGHING
TO DEVELOP OVER THE NORTHERN ROCKIES. THIS WILL MEAN A STRONG JET
ACROSS THE PLAINS AND SOME POTENTIAL FOR LOW PRESSURE TO DEVELOP
TO OUR SOUTH. WILL CONTINUE THE TREND OF A CHANCE OF SNOW SOUTH
MONDAY NIGHT AND CONTINUE INTO TUESDAY. AFTERWARD..THERE IS A HINT
BY BOTH THE ECMWF AND GFS THAT THE UPPER RIDGE MAY BE UNDERCUT
KEEPING THE COLDEST AIR NORTH. WILL BE INTERESTING TO SEE HOW
THIS PANS OUT LATER NEXT WEEK.

&&

.AVIATION.../18Z TAF ISSUANCE/ 

TWO MAIN CONCERNS THIS FORECAST PERIOD ARE POTENTIAL ONSET OF MVFR
CIGS THIS AFTERNOON/TONIGHT AND WINDS. CULPRIT FOR ALL OF THIS IS
CLIPPER SYSTEM ZIPPING ACROSS NORTH CENTRAL MN THIS AFTERNOON.
MAIN COLD FRONT IS JUST NOW ON THE DOORSTEP OF RWF/AXN...WITH A
WARM FRONT JUST S/SW OF MSP. WILL SEE WINDS TURN FROM SE TO THE
WNW THIS AFTERNOON AT ALL BUT AXN/RWF...WHO ARE BASICALLY ALREADY
THERE. A FROPA A LITTLE BEFORE 00Z AT MSP STILL LOOKS TO BE ON
TRACK. AS FOR GUSTS...PRESSURE CHANGE PATTERN SHOWS BEST FORCING
FOR GUSTS GOING NORTH OF AREA...SO DIALED BACK ON SPEEDS
SOME...BUT BASED ON OBS ACROSS THE DAKOTAS...STILL LOOKS GOOD FOR
A FEW HOURS OF GUSTS AFTER FROPA. AS FOR CLOUDS...MAV/MET/GFSLAMP
GUIDANCE ALL NOT IN TUNE WITH WHAT PARENT MODELS SHOW FOR THE
STRATOCU OFF TO THE NORTH. AT MSP...MET IS ONLY GUIDANCE BRINGING
IN MVFR CIGS...BUT NOT UNTIL 12Z. SO...STUCK CLOSE TO WHAT RUC AND
NAM/GFS MODEL OUTPUT HAVE FOR CLOUDS. THIS WOULD RESULT IN THE
STRATOCU SURGING SOUTH SHORTLY AFTER 00Z AS FIST BLAST OF CAA SETS
IN. BASED ON UPSTREAM OBS...IF THE CLOUDS DO ROLL IN...SHOULD
EVENTUALLY SETTLE IN THE 015-020 RANGE BEFORE HEADING BACK TOWARD
030 BY WEDNESDAY AFTERNOON. SOME CONCERN THIS MAY NOT HAPPEN BASED
ON SHALLOWNESS OF MOISTURE AND SINKING MOTION COMING IN BEHIND THE
CLIPPER...BUT CLIMATOLOGY WITH A SYSTEM LIKE THIS CERTAINLY FAVORS
A MORE PESSIMISTIC FORECAST THAN GUIDANCE WOULD SUGGEST.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

JPR/MPG