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