488 FXUS63 KMPX 161917 AFDMPX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 217 PM CDT THU MAY 16 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 207 PM CDT THU MAY 16 2013 TWO WEATHER CONCERNS FOR LATE TONIGHT...AND THRU FRIDAY AS INITIAL VERY DRY ATMOSPHERE WILL SUPPRESS CONVECTIVE TO THE SW THIS AFTN/EARLY EVENING. HOWEVER..A VERY POTENT DISTURBANCE NOTED ON SATELLITE MOVING ACROSS NEBRASKA WILL EVENTUALLY MOISTEN UP THE ATMOSPHERE...AND BASED ON THE AMOUNT OF ENERGY ASSOCIATED WITH THE COMPLEX OF TSRA/SHRA ACROSS NEBRASKA...PRECIPITATION WILL SPREAD ACROSS SW/SC MN BY MIDNIGHT. HOWEVER...DEPENDING UPON THE LOW LEVEL JET ORIENTATION TONIGHT...AND THE INTERACTION OF THE DISTURBANCE/PLUS HOW FAST THE ATMOSPHERE MOISTENS UP...WILL DEPEND ON HOW FAR N/NW THIS AREA OF PRECIPITATION SPREADS ACROSS OUR FA. BEST SCENARIO IS TO CONTINUE WITH HIGH POPS ALONG THE IA/MN BORDER...NORTHWARD TO MSP/WC WI WHERE THE BEST MOISTURE ADVECTION AND ENERGY WILL OCCUR. ELSEWHERE...PRECIPITATION WILL LIKELY OCCUR BUT RAINFALL AMTS WILL BE SUPPRESS AND LIKELY MUCH LOWER THAN EXPECTED. THIS AREA OF PRECIPITATION WILL LIKELY SPREAD NE OF THE FA BY LATE FRIDAY AFTN...WITH MAINLY AFTN ISOLD CONVECTION POSSIBLE IN SOUTHERN/CENTRAL MN DUE TO THE INCREASED INSTABILITY. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 253 AM CDT THU MAY 16 2013 A WET ACTIVE PATTERN WILL BE UPON THE AREA FROM THE END OF THIS WEEK THROUGH THE MIDDLE OF NEXT DUE TO THE ARRIVAL OF A HIGHLY AMPLIFIED RIDGE-TO-TROUGH PATTERN FOLLOWED BY THE DEVELOPMENT OF SEVERAL AREAS OF SFC LOW PRESSURE. ALL THIS WILL CULMINATE IN PLENTY OF RAIN THROUGH THE PERIOD...SEVERAL ROUNDS OF THUNDERSTORMS...AND A SMALL POTENTIAL OF SEVERE WX FOR SATURDAY. A BROAD UPPER RIDGE WILL SLOWLY GLIDE THROUGH THE REGION FRIDAY THROUGH SATURDAY NIGHT. HOWEVER...WITHIN THIS RIDGE WILL BE SEVERAL PROMINENT SHORTWAVE TROUGHS THAT WILL PROMOTE POCKETS OF LIFT ACRS THE AREA. AT THE SFC...A QUASI-STNRY SFC FRONT S OF THE REGION WILL TRANSITION TO A WMFNT AND LIFT N WITHIN THE INCRG H5 HEIGHTS. EVEN WITH THE RISING HEIGHTS...CAPPING IS NOWHERE NEAR IMPRESSIVE THUS ALLOWING FOR CONVECTION TO SPAWN NEAR AND ALONG THE NWD-MOVING FNT. PLENTY OF GULF OF MEXICO MOISTURE WILL BE ADVECTED WELL N INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION DUE TO A PROLONGED SLY FLOW...AND THIS WILL PUSH PWATS INTO THE 1.25-1.50 INCH RANGE. POPS REMAIN IN THE LIKELY CATEGORY WITH A CHC THUNDER MENTION SINCE LARGE-SCALE RIDGING WILL STILL BE THE GENERALIZED PATTERN. THERE WILL BE A BIT OF A LULL IN THE ACTION FRI NIGHT INTO SAT MRNG AS THE UPPER RIDGE BRIEFLY REASSERTS ITSELF...BUT THE RIDGE WILL QUICKLY SHIFT TO THE E ON SAT...ALLOWING A BROAD LONGWAVE TROUGH COMING ONSHORE THE WRN CONUS TO SHIFT INTO THE CENTRAL CONUS SAT-SUN. MUCH MORE BROADSCALE LIFT ALONG WITH MORE IMPRESSIVE UPPER JETTING WILL ALLOW MORE ORGANIZED CONVECTION TO DEVELOP FOR SAT NIGHT AND CONTINUING THROUGH TUE AS THE UPPER LEVEL TROUGH SETTLES OVER THE CENTRAL CONUS. UNDER THIS TROUGH...A SLOW-MOVING BUT WELL- DEVELOPED LOW PRES CENTER WILL MEANDER EWD...PROMOTING ENHANCED LOW-LEVEL JETTING MAINLY LATE SAT INTO EARLY SUN. THERE IS SOME MODEL DISAGREEMENT AS TO THE PLACEMENT OF THE JETTING AND THE BEST INSTABILITY AXES. ATTM...BEST PLACEMENT FOR LARGE-SCALE ASCENT IS IN THE DAKOTAS...AND THIS IS HIGHLIGHTED IN THE SPC ASSESSMENT OF ITS SWODY3. THERE IS A SMALL CHC SOME ISOLD STRONG-TO-SEVERE STORMS COULD LAST SAT EVENING INTO SUN MRNG INTO FAR WRN MN...BUT THE DIURNALLY DRIVEN NATURE WOULD SEEM TO MITIGATE THIS POSSIBILITY DUE TO THE TIMING. BEYOND THE SEVERE WX THREAT...THE PERSISTENT RAIN EXPECTED FROM THIS MEANDERING SYSTEM WILL PRODUCE PERIODS OF STEADY RAIN...SOMETIMES MOD-HVY AT TIMES...SAT NIGHT THRU TUE. CUMULATIVE QPF FORECASTS ARE IN THE 1-2 INCH RANGE WITH ISOLATED AMOUNTS UP TO 3 INCHES...ESPECIALLY IN WRN MN. THE RAINFALL WILL SLOWLY TAPER OFF ACRS THE REGION TUE INTO WED AS THE UPPER LOW GRADUALLY LIFTS NE OUT OF THE REGION. THE FORECAST THEN INCLUDES A COUPLE DAYS OF DRYING OUT GOING INTO THE LATTER PORTION OF THE WEEK AS AN UPPER RIDGE AND BROAD SFC HIGH PRESSURE ARE EXPECTED TO MOVE ACRS THE REGION. AS FOR TEMPERATURES...THERE WILL BE GENERALLY LITTLE DAY-TO-DAY VARIATIONS THROUGH THE WEEKEND INTO EARLY NEXT WEEK SINCE THERE WILL BE PLENTY OF CLOUD/RAIN COMPLICATIONS ALONG WITH THE LACK OF PRONOUNCED AIR-MASS CHANGES. HIGHS WILL GENERALLY RUN IN THE 70S WITH LOWS IN THE 50S AND 60S. ONCE THE CDFNT FROM THE ORGANIZED LOW PRES SYSTEM SWINGS THRU BY EARLY TUE...TEMPS WILL BECOME A BIT COOLER AND DROP SLIGHTLY BELOW NORMAL. HIGHS WILL DROP TO THE 60S WITH LOWS AROUND 50 STARTING TUE AND GOING INTO THE MIDDLE OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1231 PM CDT THU MAY 16 2013 NO AVIATION CONCERNS THRU 00Z AS DRY EAST/EAST-SOUTHEASTERLY FLOW CONTINUES. COMPLEX OF TSRA/SHRA ACROSS THE DAKOTAS WILL BEGIN TO AFFECT THE WESTERN MPX TAF FORECAST AREA AFT 00-03Z WITH VSBYS INITIALLY DECREASE IN HEAVIER PRECIPITATION. EVENTUALLY CIGS WILL LOWER...WITH MVFR CIGS LIKELY BY MORNING. SFC WINDS WILL REMAIN FROM THE EAST-EAST-SOUTHEAST TODAY WITH SOME GUSTS AT AXN/STC/RNH BEFORE 00Z. GUSTY WINDS WILL ALSO ACCOMPANY ANY TSRA OVERNIGHT. THE BEST TIME FRAME FOR TSRA/SHRA WILL OCCUR AT AXN BETWEEN 4-10Z. AT STC BETWEEN 8-14Z...AT RWF BETWEEN 4 AND 10Z. RNH/EAU WILL LIKELY BE DRY UNTIL AFT 9Z. KMSP... VFR CONDS ALONG WITH EASTERLY WINDS WILL CONTINUE THRU 6Z WITH CIGS SLOWLY LOWERING TO LOW END VFR AFT 6Z AS SHRA BECOME TO DEVELOP ACROSS EASTERN MN. TSRA WILL BE POSSIBLE AFT 9Z...WITH A PERIOD OF MODERATE TO HEAVY RAINFALL DURING THE 10-14Z TIME FRAME. VSBYS WILL BE THE MAIN CONCERN WITH THE HEAVIER PRECIPITATION...EVENTUALLY CIGS WILL LOWER TO HIGH END MVFR AFT 12Z. THERE WILL LIKELY BE A BRIEF IN THE PRECIPITATION BY MID/LATE MORNING...WITH MORE PRECIPITATION LIKELY ON SATURDAY. GUSTY E/SE WINDS WILL LIKELY DEVELOP AFT MIDNIGHT AS THE BOUNDARY LAYER WINDS INCREASE TO OVER 20 KTS. /OUTLOOK FOR KMSP/ FRI NIGHT...VFR/MVFR CIGS. CHC IFR IN HEAVIER TSRA. E-SE WIND 10 KTS. SAT...VFR/MVFR CIGS. CHC IFR IN HEAVIER TSRA. SE-S WINDS 5-10 KTS. SUN...VFR/MVFR CIGS. CHC IFR IN HEAVIER TSRA. S-SE WINDS 8-12 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...JPC AVIATION...JLT