FXUS63 KMPX 022139
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
339 PM CST WED DEC 2 2009

.DISCUSSION...

NEXT WEATHER MAKER OF SIGNIFICANCE IS THE UPPER LOW DROPPING SE
OUT OF NORTH DAKOTA. AHEAD OF THIS CIRCULATION...THERE IS AN AREA
OF PV ADVECTION DEVELOPING FROM EASTERN SD INTO SW MN. THE RUC
CONTINUES TO DEVELOP THIS FORCING OVERNIGHT BUT THE MAIN FORCING
FROM THE UPPER LOW MOVES IN THURSDAY MORNING. IT LOOKS LIKE THE
NAM REFLEC SIMULATION IS A LITTLE TOO FAR EAST INTO NW MN THIS
AFTERNOON. THE WWD ESTIMATE OF SNOWFALL A TOUCH FARTHER WEST OVER
SW MN LOOK REASONABLE. H5 HEIGHT FALLS MAINLY OVER SE SD INTO
CENTRAL IA WOULD SUPPORT THIS AS WELL. WILL UP POPS A BIT AND RUN
THE BEST AREA FROM WEST CENTRAL INTO SOUTH CENTRAL MN. GENERAL
COLD CYCLONIC FLOW WILL DOMINATE THROUGH FRIDAY WITH AT LEAST
FLURRIES THE REMAINDER OF THURSDAY INTO THURSDAY NIGHT.
ANOTHER WEAK WAVE WILL DROP DOWN IN THE CYCLONIC FLOW ON FRIDAY
WITH A SMALL CHANCE OF MEASURABLE SNOW OVER THE NORTH AND EAST
PART OF THE CWA. CLOUDS MAY HOLD UP OVERNIGHT TEMPS A BIT ABOVE
GUIDANCE TONIGHT BUT THEN CLOSER TO GUIDANCE BEHIND THE DEPARTING
WAVE ON THURSDAY.

OTHERWISE THE SLIDE IN TEMPS SHOULD LAST INTO FRIDAY...AND THEN
A BIT OF MODERATION IN MAX TEMPS INTO THE WEEKEND AHEAD OF SOME
SURFACE DEVELOPMENT IN THE PLAINS. PRECIP CHANCES APPEAR TO BE ON
THE LOW SIDE WITH THE GENERAL WEST TO EAST UPPER JET THROUGH THE
CENTRAL PLAINS. WILL CONTINUE THE LOW CHANCE OF SNOW FOR SOUTHERN
MN. THE GFS ENSEMBLE POPS FOR FAR SOUTHERN MN DO NOT SHOW MUCH
VARIATION AMONG THE MEMBERS AND ARE STILL ONLY IN THE 20 RANGE ON
AVERAGE. 

&&

.AVIATION... /18Z TAF ISSUANCE/ 

LOW PRESSURE ALOFT OVER NORTH DAKOTA WILL MOVE SOUTHEAST TO
SOUTHERN MN DURING THE TAF PERIOD. THIS FEATURE WILL AID IN LIGHT
SNOW OR SNOW SHOWERS SPREADING ACROSS THE MN TAF SITES TONIGHT AND
THURSDAY AND ACROSS WEST CENTRAL WI DURING THE DAY TOMORROW WITH
MVFR CONDITIONS. HOWEVER...CEILINGS/VISIBILITIES QUITE VARIABLE RIGHT
NOW AT THE TAF SITES WITH KRNH SCT AND KAXN AT 4SM BR OVC005. THE
LOW CONDITIONS AT KAXN IS STRETCHES NW TO KGFK AND SE TO KULM. THIS
IS WHERE A LOW LEVEL THERMAL RIDGE RESIDES ALONG WITH AN AXIS OF
HIGHER DEW POINTS. THIS STRUCTURE WILL MOVE SLOWLY SE DURING THE
PERIOD AND IS ALSO WHERE THE BEST CHANCE FOR SN0W EXISTS TONIGHT
AND EARLY THURSDAY. WINDS WILL BE N TO NW AT 8 TO 12 KNOTS THROUGH
THE PD. ADDITIONAL DETAILS FOR EACH SITE BELOW.

KAXN...LIFR CONDITIONS ARE EXPECTED TO IMPROVE TO AT LEAST IFR
THIS AFTERNOON. THIS IS SUPPORTED BY CLIMATOLOGY WITH SHOWS
CONDITIONS BETTER THAN 500 FEET BY 22Z. ALSO MOS GUIDANCE SUGGEST
HIGHER CONDITIONS. SNOW SHOWERS EXPECTED INTO KAXN THIS EVENING AS
FORCING AND DEEPER LAYER MOISTURE ARRIVES AHEAD OF THE UPPER LOW.
EXPECT 2-4 MILES DURING THE NIGHT WITH CEILINGS IFR/LOW MVFR.
GRADUAL IMPROVEMENT TO MVFR ON THURSDAY IN THE WAKE OF THE UPPER LOW.

KRWF...CLEARING JUST WEST OF KRWF ATTM BUT IT IS EXPECTED TO STAY
TO THE WEST WITH VFR CEILINGS SLOWLY BECOMING MVFR BY LATE THIS
AFTERNOON AND CONTINUING TONIGHT AND THURSDAY. FLURRIES EXPECTED
AROUND MIDNIGHT WITH 3-5 MILE VISIBILITY IN SNOW LATE IN THE
NIGHT AND THURSDAY MORNING.

KSTC...VFR CEILINGS WILL GIVE WAY TO MVFR EARLY TONIGHT. FLURRIES
EXPECTED LATE IN THE EVENING WITH 4-6 MILE VISIBILITY IN SNOW LATE
IN THE NIGHT AND THURSDAY MORNING.

KMSP...MVFR CEILINGS PREVAIL ATTM...BUT CLEARING IS JUST NORTH
AND EAST OF KMSP. BACK EDGE IS MOVING SLOWLY SW WITH POTENTIAL
FOR BKN035 AROUND 21Z. INDICATED THIS IN THE TAF WITH VFR CEILINGS
EXPECTED THIS EVENING. MVFR CEILINGS EXPECTED TO DEVELOP BY
MIDNIGHT WITH FLURRIES POSSIBLE BY DAYBREAK. BEST SNOW SHOWER
POTENTIAL IN THE 03/18 TO 04/00Z TIME FRAME WITH 3-5 MILE
VISIBILITY POSSIBLE. 

KRNH...MAINLY CLEAR SKIES OVER THE SITE WILL SLOWLY FILL IN THIS
AFTERNOON WITH SCT-BKN CU AROUND THE 030 FOOT LEVEL. MVFR CEILINGS
THEN FORECAST FOR TONIGHT AND THURSDAY. FLURRIES EXPECTED AT
03/12Z WITH MVFR VISIBILITIES POSSIBLE AFTER 03/18Z. 

KEAU...BKN-OVC MVFR CEILINGS EXPECTED THROUGH THE TAF PERIOD.
FLURRIES POSSIBLE AT 03/15Z WITH BETTER POTENTIAL FOR MVFR
VISIBILITIES IN SNOW SHOWERS AFTER 03/21Z. 

&&

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

$$

JPR/RAH