FXUS63 KMPX 261938
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
138 PM CST THU NOV 26 2009
.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.../18Z TAF ISSUANCE/
REGION SITS IN CYCLONIC FLOW AND CAA REGIME ON BACKSIDE OF GREAT
LAKES LOW. HAS RESULTED IN A STUBBORN STRATUS DECK THAT IS
BEGINNING TO SHOW BREAKS ACROSS MN AT 18Z...THOUGH ANOTHER SURGE
OF STRATUS FROM NW MN IS HEADING INTO THE AREA. ONCE THESE CLOUDS
CLEAR...VFR CONDITIONS WILL PREVAIL AND THIS BECOMES A WIND
FORECAST. WITH SFC RIDGE MOVING THROUGH DURING THIS PERIOD...WILL
SEE WINDS TURN TO THE WEST THIS AFTERNOON AND OVERNIGHT WILL
QUICKLY GO SW TO S TO SE IN RESPONSE TO ANOTHER COLD FRONT
DROPPING SOUTH THROUGH CANADA.
AXN/STC/RWF...GUIDANCE HAS A WEAK HANDEL ON CLOUDS OUT THIS
DIRECTION...ESPECIALLY AT AXN. THE SECONDARY SURGE ON SATELLITE
SHOWING LITTLE SIGNS OF BREAKING UP...SO GAVE THESE SITES AT
LEAST 3 HOURS OF MVFR CIGS BEFORE ALL CLEARS OUT.
MSP/RNH/EAU...AGAIN GUIDANCE STRUGGLING ON EVENTUAL DEMISE OF
STRATUS. STAYED WITH THE GFS/GFSLAMP GUIDANCE...WHICH WOULD BRING
ABOUT CLEARING AT MSP/RNH AT 20Z...BUT IT SHOULD BE NOTED THAT THE
RUC DOES NOT SCT OUT EAU AT ANY POINT...AND WAITS UNTIL 03Z TO DO
THE SAME AT MSP/RNH...SO WOULD NOT BE SURPRISED IF CIGS HOLD ON
LONGER AT THESE SITES THAN CURRENTLY FORECAST.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/MPG
