FXUS63 KMPX 270418 AAA
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1020 PM CST THU NOV 26 2009

.UPDATED FOR AVIATION DISCUSSION BELOW...

.DISCUSSION...
NOT TOO MUCH TO BE PARTICULARLY CONCERNED WITH OVER THE NEXT
SEVERAL DAYS... WITH GENERALLY QUIET AND SOMEWHAT WARMER THAN
NORMAL CONDITIONS CONTINUING. MAIN SHORT TERM PROBLEM IS CLOUD
COVER CURRENTLY OVER THE AREA... WHICH HAS BEEN SLOW TO ERODE
WHILE SIMULTANEOUSLY BEING REPLACED BY SOME ADDITIONAL MID-HIGH
CLOUDS STREAMING IN FROM THE NORTHWEST. AS LOW LEVEL RIDGING AND
WARMER TEMPERATURES PLOD EAST INTO THE AREA... WE SHOULD SEE A
CONTINUED EROSION OF THE LOWER CLOUDS... AND TREND TOWARD MORE IN
THE WAY OF PARTLY CLOUDY SKIES OWING TO MID-HIGH CLOUDS DESCENDING
THE UPPER RIDGE PARKED TO OUR WEST. FOLLOWED A BLEND OF THE
NAM/GFS THROUGH SATURDAY... THEN UTILIZED MORE OF THE ECMWF AND
GFS GUIDANCE.

EXPECT TO SEE THINGS BECOME CLEAR TO PARTLY CLOUDY FROM WEST TO
EAST AS WE HEAD THROUGH THE NIGHT TONIGHT... THEN PARTLY CLOUDY
SKIES LOOK LIKE A SAFE BET ON FRIDAY WITH DESCENT WARM ADVECTION
IN PLACE ACROSS THE AREA... BUT WITH LITTLE IN THE WAY OF DEEP
LAYER MOISTURE. WENT ABOVE GUIDANCE FOR HIGHS ON FRIDAY GIVEN
PROGGED 925-900MB TEMPERATURES AND A LITTLE BIT OF MIXING. A WEAK
SURFACE LOW WILL MOVE THROUGH LATE TOMORROW NIGHT AND SATURDAY...
BUT A LACK OF FORCING AND MOISTURE SHOULD KEEP ANY PCPN FROM
DEVELOPING. ONLY CHANCE FOR ANY PCPN THROUGH THE WEEKEND INTO THE
FIRST PART OF THE WEEK LOOKS TO BE SATURDAY NIGHT INTO SUNDAY AS A
SECONDARY COLD FRONT DROPS INTO THE AREA COINCIDENT WITH A MODEST
SHORTWAVE. MOISTURE WILL BE EXTREMELY LIMITED WITH THIS SYSTEM...
SO WILL ONLY INCLUDE A SLIGHT CHANCE FOR SNOW OR FLURRIES AT THIS
POINT... ESPECIALLY SINCE GUIDANCE HAS BEEN TRENDING DRIER WITH
TIME. 

THE LATER PERIODS... MONDAY THROUGH THURSDAY... LOOK TO BE 
INTERESTING AS THE UPPER AIR PATTERN WANTS TO MAKE A MAJOR SHIFT 
OVER NORTH AMERICA. THE GUIDANCE VARIES IN THE DETAILS... BUT 
GENERALLY AGREES ON THE OVERALL LONG WAVE PATTERN BY THE SECOND HALF 
OF NEXT WEEK. FOR THE FORECAST DETAILS... STUCK CLOSE TO THE HPC 
GUIDANCE WHICH APPEARS TO MIRROR A BLEND OF GFS... ECMWF... AND 
CANADIAN SOLUTIONS. A NORTHERN SHORTWAVE WILL BE KICKING OFF TO THE 
EAST ON MONDAY AS A SIGNIFICANT WAVE BEGINS TO ENTER WESTERN CANADA 
AND DROP SOUTHEASTWARD INTO THE CONUS. THIS FEATURE WILL BEGIN TO 
CARVE OUT A DEEP TROUGH OVER THE WESTERN US BY WEDNESDAY AS A 
VIGOROUS SOUTHERN STREAM WAVE STARTS TO LIFT NORTHEAST FROM NEAR THE 
GULF COAST. THE GFS AND ECMWF HANDLE THE EVOLUTION OF THINGS QUITE A 
BIT DIFFERENTLY DURING THIS TIME... PARTICULARLY WITH HOW THE 
SOUTHERN WAVE INTERACTS AND PHASES WITH THE NORTHERN STREAM. AT THIS 
POINT IT IS CERTAINLY TOO EARLY TO PUT MUCH STOCK IN THE SPECIFICS 
OF EITHER SOLUTION... BUT IT SEEMS LIKE A GOOD BET THAT A DECENT 
STORM COULD COME TOGETHER IN THE GREAT LAKES REGION TOWARD THE END 
OF THE WORKWEEK. BOTH SOLUTIONS WIND UP WITH A BROAD UPPER TROUGH 
ACROSS THE CONUS BY THURSDAY... ALTHOUGH THE ECMWF IS FARTHER WEST 
IN ITS POSITION OWING TO SOME DOWNSTREAM BLOCKING IT HAS DUE TO A 
CLOSED UPPER LOW OFF THE CANADIAN EAST COAST. ALTHOUGH THE OVERALL 
WEATHER PATTERN LOOKS INTERESTING... AT THIS POINT THERE IS NOTHING 
POINTING TOWARD SIGNIFICANT OBSERVABLE WEATHER IN OUR NECK OF THE 
WOODS THROUGH THE PERIOD. WILL INCLUDE SOME CHANCES FOR SNOW ACROSS 
PORTIONS OF THE AREA FROM WEDNESDAY INTO THURSDAY AS THE UPPER 
TROUGH TAKES OVER... BUT WILL KEEP POPS LOW SINCE MOST OF THE ACTION 
LOOKS LIKE IT WILL STAY OFF TO OUR EAST AT THIS POINT. CERTAINLY 
THINK THE FORECAST WILL SEE REFINEMENT OVER THE COMING DAYS GIVEN 
THE COMPLEXITY OF THE EVOLVING UPPER AIR PATTERN.

&&

.AVIATION.../06Z TAF ISSUANCE/ 

VFR CONDS EXPECTED FOR MUCH OF THE PERIOD AS SFC RDG LINE MOVES EAST 
ACROSS THE FA TONIGHT AND FRIDAY.  MID AND HIGH LEVEL CLOUDS MOVING 
ACROSS THE REGION OVERNIGHT.  KEAU REMAINS ON THE CUSP OF MVFR 
DECK...AND MAY CONTINUE THIS TREND DURING THE EARLY MORNING HOURS 
WITH FLOW OFF LK SUPERIOR.  WILL CONTINUE TEMPO GROUP FOR A FEW 
HOURS.  LIGHT WINDS WILL BECOME S-SELY DURING THE PERIOD AS THE RDG 
MOVES EAST.  DONT ANTICIPATE ANY GUSTS WITH BACKSIDE RIDGE FLOW 
DEVELOPING DURING THE DAY.  NEXT WEAK SFC TROUGH SAGS INTO NORTHWEST 
FA THROUGH 06Z SAT.  WILL BACK WINDS TO MORE NW AT KAXN DURING THE 
EVENING.  DONT SEE SIG CLOUD WITH THIS FEATURE WITH PERHAPS SOME 
MID/HIGH LEVEL CLOUDS AGAIN SAGGING SOUTHEAST. 

&&

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

$$

TRH/DWE