000
FXUS63 KMPX 162044
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
344 PM CDT SUN JUN 16 2013

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 344 PM CDT SUN JUN 16 2013

WARM...BREEZY AND DRY IS THE STORY THIS AFTERNOON WITH W-NW FLOW AND
QUASI-ZONAL FLOW ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI RIVER
VALLEY AND GREAT LAKES. THE 500 MB SHORTWAVE IS NOW APPROACHING THE
INTERNATIONAL BORDER ON THE SW SIDE OF LAKE WINNIPEG. THERE IS AN
E-W ORIENTATED SURFACE TROUGH STRETCHING ACROSS NORTHERN MINNESOTA
WITH A SUBTLE SOUTHWESTWARD EXTENSION ACROSS EASTERN ND/SD. WINDS
VEER TO THE NORTHWEST BEHIND THIS BOUNDARY. THIS IS VERY NEAR WHERE
THE CONVECTION HAS FIRED NEAR ABERDEEN. THE CUMULUS DEVELOPMENT IN
SD IS ALONG AN E-W LINE AND APPEARS TO BE FOCUSED ALONG THE OUTFLOW
BOUNDARY FROM THE CONVECTION THIS MORNING IN SD. NOT TO
MENTION...THE UPPER SUPPORT WITH THE RIGHT ENTRANCE REGION OF THE
JET AND DIFFERENTIAL VORTICITY ADVECTION. THERE IS A TONGUE OF 1500
J/KG SBCAPE AND GOOD MID LEVEL LAPSE RATES IN THE VICINITY OF THE
EASTERN SD CONVECTION /WHICH DID LOOK CAPABLE OF PRODUCING SEVERE
HAIL AROUND 315 PM/. THE INSTABILITY IS OVERLAPPED BY STRONG
WESTERLIES ASSOCIATED WITH THE JET...SO THERE IS ALSO NICE
UNIDIRECTIONAL SHEAR.

THE CLOUD BEARING WINDS WILL TAKE THESE STORMS INTO WESTERN MN AND
POSSIBLY ACROSS THE REST OF MN LATE THIS AFTERNOON AND INTO THE
EARLY EVENING HOURS. A LOT OF THE SHORT RANGE GUIDANCE SUPPORTS
THIS. THE POSITIVE NEWS IF YOU ARE NOT A THUNDERSTORM FAN...IS THAT
THE INSTABILITY DROPS WAY OFF BY THE TIME YOU GET 1-2 COUNTIES INTO
MN. HOWEVER...THERE IS STILL 500-100 J/KG IN FAR WEST CENTRAL MN.
EVEN IF WE LOSE THE THUNDER WE COULD STILL SEE SHOWERS LIMP ACROSS A
GOOD PORTION OF THE FORECAST AREA AS THEY WEAKEN WITH TIME. THESE
ARE HIGH BASE SHOWERS AND STORMS THAT MIGHT PACK A LITTLE WIND IF
THEY HOLD TOGETHER. WITH THE SUN TODAY AND DRY SOUNDING...LOW LEVEL
LAPSE RATES ARE ALSO QUITE HIGH. THIS IS A DOUBLE EDGED
SWORD...BECAUSE THE 20-30% SURFACE RELATIVE HUMIDITY /AND DRY AIR
ALOFT/ WILL KEEP SOME OF THE RAIN FROM ACTUALLY GETTING TO THE
SURFACE. WE THINK AFTER THESE DIMINISH DURING THE LATE
EVENING...THERE WILL BE NOTABLE BREAK IN RAIN COVERAGE TONIGHT AND
DURING THE MORNING HOURS TOMORROW. AS THAT UPPER TROUGH DROPS DOWN
OVERHEAD TOMORROW AND TEMPS COOL...WE SHOULD GET EARLY DIURNAL
CUMULUS AND EVENTUALLY SHOWERS/STORMS BEFORE THE NOON HOUR IN
WESTERN WI AND FAR EASTERN MN. THESE WILL DRIFT SOUTH WITH TIME AND
EVENTUALLY DIMINISH AROUND SUNSET TOMORROW. LOOK FOR COOLER TEMPS
TOMORROW DUE TO COLD ADVECTION AND ALSO INCREASED CLOUD
COVER...ESPECIALLY FOR EASTERN PORTIONS OF THE FORECAST AREA.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 PM CDT SUN JUN 16 2013

COMMON THEME DURING THE EXTENDED WILL BE THE BUILDING OF THE
SUBTROPICAL RIDGE. IT WILL BE BUILDING OVER THE SRN PLAINS DURING
THE COURSE OF THE UPCOMING WEEK...WITH THE ECMWF AND GFS BOTH
SLIDING IT OVER TO THE ROCKIES BY THE BEGINNING OF NEXT WEEK. MN/WI
WILL BE UNDER THE INFLUENCE OF THE UPPER RIDGING TUESDAY INTO
THURSDAY...BUT BY THE END OF THE WEEK INTO NEXT WEEKEND...MED RANGE
MODELS IN GOOD AGREEMENT IN KEEPING THE MPX AREA ON THE NRN EDGE OF
THIS RIDGE...LEAVING US SUSCEPTIBLE TO PERIODIC THUNDERSTORM
COMPLEXES RUNNING AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE.

FOR TUESDAY AND WEDNESDAY...THE UPPER RIDGE WILL BEGIN BUILDING UP
THE PLAINS. THIS SHOULD PROMOTE A COUPLE OF DRY DAYS ACROSS THE
AREA...BUT THERE IS STILL SOME POTENTIAL FOR ISO SHRA/TSRA GOING
INTO TUESDAY DEPENDING ON HOW QUICKLY A STRONG UPPER WAVE WORKS
ACROSS THE AREA AHEAD OF THE BUILDING HEIGHTS. 16.12 ECMWF/NAM STILL
SHOW THIS WAVE BEING OVER SRN MN AT 18Z TUESDAY...SO ITS NOT OUT OF
THE REALM OF POSSIBILITY TUESDAY AFTERNOON COULD FEATURE A FEW
STORMS OVER SRN MN.

ONLY SIGNIFICANT CHANGE MADE TO THE GRIDS THESE TWO DAYS WAS TO
START THE PROCESS OF UNDERCUTTING GUIDANCE DEWPOINTS BOTH
AFTERNOONS. HIGH PRESSURE THESE TWO DAYS WILL BE CENTERED OVER
MICH...AND MIXING DURING THE AFTERNOONS SHOULD PROMOTE SOME
DIURNALLY DRIVEN DEWP DROPS...ESPECIALLY IN ERN AREAS. MIXING LIKELY
WILL NOT BE AGGRESSIVE AS WE HAVE SEEN TODAY...BUT ALL GUIDANCE IS
LIKELY UNDERPLAYING THE DEGREE OF DRY AIR MIXING THAT WILL BE SEEN.

FOR THURSDAY THROUGH THE WEEKEND...THE BIG ISSUE HERE IS WHEN DO
PERIODIC THUNDERSTORM CHANCES OCCUR. WITH BUILDING HEIGHTS...WE WILL
ALSO SEE TEMPERATURES SLOWLY INCREASE...WITH HIGHS GENERALLY
EXPECTED TO BE IN THE 80S WITH LOWS IN THE 60S. ALONG WITH
TEMPERATURES...MOISTURE WILL BE ON THE INCREASE AS WELL...WITH PWATS
FROM THE GFS FORECAST TO GET BACK ABOVE 1.5 INCHES /OR 150% OF
NORMAL/ BY THE END OF THE WEEK.

THIS TYPE OF PATTERN TENDS TO YIELD QUITE A BIT OF UNCERTAINTY...AS
EXACT EVOLUTION OF CONVECTION ONE DAY WILL PLAY A LARGE ROLL IN
WHERE CONVECTION FIRES UP THE NEXT DAY AND SO ON. AT THIS TIME
THOUGH LLJ SUPPORT FOR MORE WIDESPREAD CONVECTION DOES NOT LOOK TO
INCREASE UNTIL AT LEAST THURSDAY NIGHT FROM THE GFS/GEM OR FRIDAY
WITH THE ECMWF. BASED ON THE LLJ FORECAST...CHANCES FOR
THUNDERSTORMS LOOK GOOD FRI/FRI NIGHT...WITH A POSSIBLE LULL IN
ACTIVITY LATER SAT/SAT NIGHT...BEFORE THE LLJ BRINGS RENEWED STORM
CHANCES BACK SUN INTO MON.

THIS TYPE OF WEATHER PATTERN IS ONCE CONDUCIVE FOR GENERATING
MCS/S...SO DOES LOOK LIKE BY THE END OF THE WEEK INTO NEXT WEEKEND
THE THREAT FOR STORMS WITH DAMAGING WINDS ALONG WITH HEAVY RAINS
WILL BE ON THE INCREASE. ENJOY THE COUPLE OF DRY DAYS THIS WEEK
WHILE THEY LAST!

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1244 PM CDT SUN JUN 16 2013

DRY AND BREEZY WESTERLY WINDS WILL CONTINUE TODAY WITH VFR
CONDITIONS THROUGH TONIGHT AND MOST LIKELY ON MONDAY AS WELL.
THERE ARE A COUPLE PERIODS WHERE SHOWERS AND/OR WEAK STORMS ARE
POSSIBLE. THE FIRST IS LATE THIS AFTERNOON AND EVENING. WE ARE NOT
HIGHLY CONFIDENT IN SHOWER DEVELOPMENT TODAY GIVEN THE DRY AIR IN
PLACE...BUT WE ARE KEEPING AN EYE OUT NEAR THE MN/SD BORDER
BETWEEN 3-4 PM THIS AFTERNOON. ANYTHING THAT FORMS WILL MOVE EAST
DURING THE EVENING. SCATTERED SHOWERS AND WEAK STORMS ARE ALSO
POSSIBLE TOMORROW AFTERNOON /ESPECIALLY IN EASTERN MN AND WESTERN
WI/ AFTER THE SUN HEATS UP THE ATMOSPHERE.

KMSP...

NO MAJOR WEATHER CONCERN OVER THE NEXT 30 HOURS. WE COULD SEE A
FEW SHOWERS IN EASTERN MN EARLY THIS EVENING...BUT COVERAGE WILL
NOT BE GREAT EVEN IF THE SHOWERS MATERIALIZE. A LITTLE BETTER
CHANCE TOMORROW AFTERNOON. TAKE A LOOK AT THE RADAR COVERAGE IN
NORTHERN MINNESOTA THIS AFTERNOON...THIS MIGHT BE SIMILAR TO HOW
IT LOOK CLOSER TO THE AIRPORT MONDAY AFTERNOON /MAYBE NOT QUITE AS
MANY SHOWERS/.

/OUTLOOK FOR KMSP/

MON NIGHT...VFR NNE WINDS 5-10KTS.
TUE...VFR. ESE WINDS.
WED...VFR. S WINDS 5 KTS.


&&

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

$$

SHORT TERM...CLF
LONG TERM...MPG
AVIATION...CLF