259 
FXUS63 KMPX 031723
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1220 PM CDT MON MAY 3 2010

.UPDATE...

UPDATED FOR 18Z AVIATION DISCUSSION BELOW.

&&

.DISCUSSION...
/ISSUED 247 AM CDT MON MAY 3 2010/

THERE ARE SEVERAL FORECAST CONCERNS OVER THE NEXT SEVEN DAYS.
TEMPERATURES... PRECIPITATION CHANCES AND TIMING OF THE SHORT
WAVES...AND HOW COOL WILL IT GET OVER THE WEEKEND.

UPPER LOW THAT HAD DOMINATED THE WEATHER OVER THE WEEKEND...CONTINUES 
TO SPIN OVER ONTARIO CANADA THIS MORNING. THE UPPER LOW WILL BEGIN 
TO LIFT NORTHEAST AND WEAKEN AND BECOME ABSORBED INTO THE MEAN
UPPER AIRFLOW OVER NORTHEAST CANADA OVER THE NEXT COUPLE OF DAYS.
IN THE MEANTIME...WITH THE COOL POOL NEAR THE FORECAST
AREA...ANOTHER ROUND OF CUMULUS CLOUDS FORMING LATE MORNING AND
EARLY AFTERNOON. CONFINED SHOWERS OVER THE EASTERN SECTION OF MN
AND WESTERN WISCONSIN TODAY.

ANOTHER SHORTWAVE TROUGH AND UPPER LOW ARE FORECAST TO MOVE INTO THE 
UPPER MIDWEST TUESDAY AND TUESDAY NIGHT.  MODELS MAYBE A LITTLE TOO 
FAST ON MOVING THIS SYSTEM OVER THE WESTERN GREAT LAKES BY TUESDAY 
EVENING. SO HAVE CUT BACK ON POPS IN THE WEST ON TUESDAY WITH 
SURFACE TROUGH AND COLD FRONT AND THICKNESS RIDGE OVER THE EASTERN 
HALF OF MN BY 18Z TUESDAY. BEST POPS MAINLY EAST AND SOUTH OF THE 
TWIN CITIES. 

THICKNESS FIELDS BY MIDDAY THURSDAY...HAS THE 1000-500 MB THICKNESS 
OF 5400 - 5520 THICKNESS LINES ACRS THE CWA. MUCH COOLER AIR OVER 
THE NORTHERN PLAINS. THE LATEST GFS MODEL AND ECMWF MODELS ARE 
SIMILAR SHOWING STRONG COLD AIR ADVECTION CONTINUING INTO THE 
WEEKEND WITH SOME MIXED PRECIPITATION OR COLD RAIN INDICATED 
THURSDAY NIGHT INTO FRIDAY EVENING. 

HIGHS TODAY SHOULD WARM INTO THE UPPER 50S TO MIDDLE 60S...THEN WARM 
INTO THE UPPER 70S TO AROUND 80 DEGREES ON TUESDAY AHEAD OF THE COLD 
FRONT. BY FRIDAY...TEMPERATURES WILL STRUGGLE TO REACH THE UPPER 40S 
TO MIDDLE 50S BY FRIDAY. 

&&

.AVIATION.../18Z TAF ISSUANCE/ 
UPPER TROUGH TO MOVE ACROSS THE REGION THIS AFTERNOON/EVENING.  
WIDELY SCT -SHRA/SPRINKLES ASSOCIATED WITH THIS FEATURE AS IT MOVES 
THROUGH.  VFR CIGS GENERALLY ABOVE 4K FEET GRADUALLY LIFTING TO 
6-7K KT BY EARLY EVENING.  THEN SCT TO MID CLOUD/CIRRUS THEREAFTER.  
WEST WINDS A BIT GUSTY THIS AFTERNOON...THEN BECOMING LIGHT SOUTH OR 
SOUTHWEST AFTER 01Z.  INCREASING WINDS TUE MORNING AHEAD OF NEXT 
VIGOROUS TROUGH/SFC CDFNT WHICH SHOULD AFFECT WESTERN TAF SITES 
AFTER 18Z. 
 
KMSP...VFR CIGS 4-6K FT GRADUALLY LIFTING THIS AFTERNOON.  WIDELY 
SCT -SHRA/SPRINKLES EXPECTED AS WELL AS UPPER TROUGH MOVES THROUGH.  
THIS SHOULD ALL END BY 01Z OR SO...WITH GUSTY WEST WINDS BECOMING 
LIGHT SOUTHWEST/SOUTH.  EXPECT SCT CIRRUS/MID CLOUDS TO REDEVELOP 
OVERNIGHT AHEAD OF NEXT VIGOROUS TROUGH. SOUTH WINDS EXPECTED TO 
BECOME GUSTY AGAIN BY 17Z TUE WITH CDFNT PASSAGE SOMETIME AFTER 
21Z.  TIMING STILL IN QUESTION AND HOW WIDESPREAD ANY CONVECTIVE 
ACTIVITY WILL BE WHEN IT DEVELOPS.  BEST SHOT OF CONVECTION APPEARS 
TO BE IN WC WI LATE AFTERNOON/EVENING.

&&

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

$$
JVM/DWE