FXUS63 KMPX 262317
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
517 PM CST SAT DEC 26 2009
.UPDATE...
UPDATED TO INCLUDE 00Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
OCCLUDED UPPER LOW NICELY WRAPPED UP AND DRIFTING NW ACROSS WI.
PERSISTENT AREA OF -SN IN AREA OF CONTINUED WEAK ISENTROPIC LIFT
WELL NW OF UPPER LOW ACROSS N MN INTO THE DAKOTAS HAS BEEN BRUSHING
WC MN WITH SCT -SN. LIFT DECREASES SLOWLY THRU THE EVENING...AND
WILL KEEP LIKELY POPS IN THRU 06Z. LOBE OF VORTICITY HAS BEEN
ROTATING AROUND PARENT UPPER LOW AND NOW ACRS W LAKE SUPERIOR WITH
SOME ENHANCED CLOUDS AHEAD OF IT ACROSS NE INTO EC MN. WIDESRPEAD
VSBYS IN 1-2SM RANGE ACROSS NE MN ASSOCIATED WITH THIS FEATURE WITH
A FEW VSBYS BLO 1SM. UPPED POPS AND SNW AMOUNTS A BIT THRU 06Z FOR
E MN CWA AS THIS FEATURE MOVES THRU. MAY SEE A FEW 1 INCH SNOW
AMOUNTS FROM THIS FEATURE.
UPPER LOW BEGINS TO KICK OUT ON SUNDAY WITH REMAINING PRECIPITATION
AS FEW SPITS OF --SN.
QUIET PATTERN THEN FOR A COUPLE DAYS IN NWLY FLOW. UPPER AIR PATTERN
THEN FLATTENS ALLOWING A COUPLE OF WEAK WAVES TO MOVE THRU AREA.
RETAINED SOME SLIGHT CHANCE POPS FOR WEDNESDAY. A BIT OF A
DIFFERENCE ON TIMING ON WHAT APPEARS TO BE A BIT STRONGER WAVE
BEHIND IT. GFS MOVES IT THRU ON THURSDAY/THURSDAY NIGHT WITH ECMWF A
BIT SLOWER. KEPT OUR SLIGHT CHANCE POPS FOR NE CWA ON THURS FOR NOW
AND DIDN'T DO ANY FURTHER EXPANSION ON IT UNTIL BETTER RESOLVED.
&&
.AVIATION.../00Z TAF ISSUANCE/
CUTOFF UPPER LOW CURRENTLY SPINNING OVER WISCONSIN WILL ROTATE IN
PLACE FOR A BIT TONIGHT BEFORE FINALLY DRIFTING EAST. SURFACE LOW
NEAR THE WISCONSIN ILLINOIS BORDER WILL DO PRETTY MUCH THE SAME...
WHILE SMALLER MESOLOW FEATURE OVER MINNESOTA WHICH IS CURRENTLY
CAUSING SOME DIRECTIONAL HAVOC WITH THE WINDS DRIFTS OUT OF THE
AREA AND WEAKENS. AREA OF SNOW CURRENTLY MOVING SOUTHWARD ACROSS
THE AREA IS IN ASSOCIATION WITH ANOTHER SPOKE OF VORTICITY
ROTATING AROUND THE UPPER LOW... AND WILL BRING CEILINGS AND
VISIBILITIES INTO THE IFR-MVFR RANGE FOR THE FIRST FEW HOURS OF
THE FORECAST ACROSS THE WESTERN SITES. THEN LOOK FOR IMPROVING
LATER TONIGHT... WITH MOST LOCATIONS BECOMING VFR INTO THE DAY ON
SUNDAY BEFORE SOME LOWER CLOUDS MOVE BACK IN LATER IN THE DAY.
KMPX... MAIN POINTS OF UNCERTAINTY IN THE FORECAST ARE THE
POTENTIAL FOR SOME MVFR CEILINGS AND VISIBILITIES IN THE FIRST FEW
HOURS AS KMSP FINDS ITSELF ON THE EASTERN EDGE OF THE AREA OF
SNOWFALL. WINDS ARE ALSO A BIT OF AN UNKNOWN THIS EVENING DUE TO
INFLUENCE OF MESOLOW OVER CENTRAL MINNESOTA. OTHERWISE... FEEL
FAIRLY CONFIDENT IN VFR CONDITIONS OVERNIGHT INTO SUNDAY AND
GENERAL TREND TOWARD NORTHERLY WINDS AS LARGE SCALE FLOW REASSERTS
ITSELF. WILL SEE DEVELOPMENT OF A LOWER DECK OF CLOUDS AGAIN
MONDAY AFTERNOON... BUT FOR NOW WILL STAY HIGHER THAN MOST
GUIDANCE AND GO AROUND 2K FEET... BUT INCLUDED A SCATTERED LOWER
DECK TO ACCOUNT FOR SOME POSSIBILITY OF LOWER VALUES.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/BAP
