390 
FXUS63 KMPX 072008
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
308 PM CDT TUE SEP 7 2010

.DISCUSSION...

THINGS QUIETING DOWN THIS AFTERNOON AS POWERFUL SYSTEM THAT CAME 
ACROSS THE AREA OVERNIGHT SPINS EAST ACROSS THE GREAT LAKES. IN ITS 
WAKE...LARGE H5 HEIGHT RISES /OVER 150 M 12 HOUR RISES/ ARE WORKING 
ACROSS THE NRN PLAINS IN ITS WAKE...WHICH WILL LEAD TO AT LEAST ONE 
QUIET NIGHT TONIGHT AND DAY TOMORROW. NEXT CHANCES FOR RAIN STILL 
LOOK TO COME INTO WRN MN WEDNESDAY NIGHT...WITH A BREAK IN THE 
ACTION THURSDAY AND MOST OF FRIDAY BEFORE ANOTHER COLD BRINGS 
SHOWERS AND THUNDERSTORMS TO THE ENTIRE AREA FRIDAY AFTERNOON 
THROUGH FRIDAY NIGHT. AT THIS POINT...THE WEEKEND IS LOOK 
PLEASANT...BEFORE ANOTHER COLD FRONT BRINGS ABOUT ANOTHER CHANCE FOR 
RAIN THE BEGINNING OF NEXT WEEK.

FOR TONIGHT...ONLY POTENTIAL ISSUE WILL BE WITH FOG IN WESTERN AND 
CENTRAL MN. SFC RIDGE CURRENTLY OVER THE DAKOTAS WILL BE CENTERED 
OVER MN BY TOMORROW MORNING...WITH THE SKIES CLEARING OUT AND WINDS 
CALMING DOWN IN RESPONSE. THOUGH HAVE SEEN A GOOD BOUT OF CAA DURING 
THE DAY ON THE BACKSIDE OF THE GREAT LAKES LOW...DRY AIR ADVECTION 
HAS ONLY BEEN MODEST...WITH MOST OF THE AREA STILL SEEING DEWPS IN 
THE MID 40S. WITH A CROSS OVER TEMPERATURE IN THE MID 40S...HIGHEST 
PROBABILITY FOR FOG WILL BE IN WESTERN AND CENTRAL MN...WHERE 
COMBINATION OF HEAVY RAINS LAST NIGHT AND LOWS IN THE UPPER 30S AND 
LOWER 40S WILL SET UP THE POTENTIAL FOR SOME FOG THERE...SO HAVE A 
MENTION OF IT IN GRIDS. THOUGH WITH MOS GUIDANCE AND SREF PROBS NOT 
REALLY PLAYING UP FOG POTENTIAL...NOT ENOUGH SUPPORT FOR A FOG 
ADVISORY AT THIS TIME.

FOR WEDNESDAY...UPPER RIDGE WILL BE MOVING OVERHEAD...BUT A 
SHORTWAVE CURRENTLY NEAR LAS VEGAS WILL BE HEADING NORTHEAST ACROSS 
THE PLAINS. MODELS STARTING TO COME INTO BETTER AGREEMENT ON THIS 
SYSTEM...WHICH LOOKS TO BRING A RETURN TO WET CONDITIONS FOR W/SW MN 
WEDNESDAY NIGHT. THIS WAVE WILL BE ASSOCIATED WITH STRONG AREAS OF 
MID LEVEL WAA AND FGEN...WHICH SHOULD HELP PRODUCE A SHIELD OF 
MAINLY RAIN WITH EMBEDDED THUNDERSTORMS. THIS AREA COMES INTO WRN 
AND SW PORTIONS OF CWA AFTER MIDNIGHT WEDNESDAY NIGHT...SO HAVE 
FAVORED POPS/QPF THERE. DURING THE DAY ON THURSDAY HOWEVER...MODELS 
CONSISTENT WITH DISSOLVING THIS AREA OF FORCING...AS FGEN AND WAA 
BECOME CONCENTRATED TO THE NW OVER NODAK/SRN CANADA AS A STRONG SFC 
LOW SPINS UP IN THE NRN HIGH PLAINS IN RESPONSE TO ANOTHER STRONG 
SHORTWAVE EMANATING FROM THE PAC NW AND MOISTURE GETS ABSORBED BY 
THE REMNANTS OF TS HERMINE MOVING INTO THE MID MS VALLEY. THIS SPLIT 
NATURE OF MOISTURE AND FORCING LOOKS TO KEEP THE AREA PRIMARILY DRY 
FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING...SO HAVE FURTHER CUT 
BACK ON POPS IN THIS TIME PERIOD. BY LATE FRIDAY AFTERNOON...COLD 
FRONT ASSOCIATED WITH HIGH PLAINS LOW WILL BE MOVING INTO THE ERN 
DAKOTAS. SIGNAL FROM MODELS AGAIN FAIRLY STRONG FOR PRECIP ALONG THE 
FRONT FROM LATE FRIDAY AFTERNOON THROUGH FRIDAY NIGHT...SO HAVE 
INCREASED POPS TO LIKELY DURING THIS PERIOD...AS THE REST OF THE CWA 
LOOKS TO GET INTO SOME PRECIP. AS FOR SEVERE POTENTIAL...IT LOOKS 
RATHER MINIMAL...AS DEWPS LOOKS TO ONLY CREEP UP INTO THE MID 50S TO 
NEAR 60 AHEAD OF THE FRONT. THIS LEADS TO RATHER MARGINAL 
INSTABILITY...THOUGH ENOUGH WILL BE PRESENT TO AT LEAST GENERATE A 
FEW RUMBLES OF THUNDER WITH THE PASSING SHOWERS.

FOR THE WEEKEND...CAA BEHIND THIS FRONT LOOKS TO KEEP HIGHS SATURDAY 
ABOUT 5 TO 10 DEGREES BELOW NORMAL WITH WAA AHEAD OF NEXT WEEKS 
SYSTEM RETURNING TEMPERATURES TO NEAR NORMAL FOR SUNDAY. AS FOR NEXT 
WEEK...THE ECMWF HAS BEEN CONSISTENT THE LAST COUPLE OF RUNS WITH 
TAKING ANOTHER SHORTWAVE ACROSS NRN MN MONDAY...WITH A COLD FRONT 
COMING THROUGH THE MPX CWA...WARRANTING THE INTRODUCTION OF POPS FOR 
THEN.

&&

.AVIATION.../18Z TAF ISSUANCE/ 

CYCLONIC CURVATURE AROUND STRONG LOW PRESSURE OVER THE GREAT
LAKES WILL GRADUALLY WEAKEN THIS AFTERNOON FOLLOWED BY BUILDING
HIGH PRESSURE OVERNIGHT. MVFR CIGS LIFTING TO LOW VFR FROM WEST TO
EAST DURING THE AFTERNOON AND THEN CLEARING AS HIGH PRESSURE MOVES
IN TONIGHT. THERE IS A RISK OF PATCHY FOG LOWERING VSBYS TO LIFR
AT THE FAVORED TAF SITES...INCLUDING KSTC...KAXN...AND KEAU.

KMSP..LOW VFR CIGS BECOMING SCT LATE AFTERNOON AND THEN CLEAR
OVERNIGHT. STILL GUSTY NW WINDS UP TO 28 KNOTS. WIND DECREASING
TO LESS THAN 10 KNOTS AFTER 02Z. 



&&

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

$$

MPG/JPR