000
FXUS63 KMPX 141826
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
126 PM CDT TUE MAY 14 2013

.UPDATE...
ISSUED AT 1241 PM CDT TUE MAY 14 2013

DECAYING CLOUDS AND SHOWERS NOW OVER WRN WI HAS GENERATED A STRONG
WARM FRONT ACROSS MN FROM ABOUT ABOUT DODGE CENTER...TO LE SEUR
AND UP TO ABOUT MORRIS...WHERE IT MEETS UP WITH A N-S ORIENTED
"COLD" FRONT THAT SITS JUST EAST OF FERGUS FALLS TO MARSHALL AT 1
PM. THIS WARM FRONT IS PROBABLY LEADING TO SOME COLD FEET FOR
FORECASTERS IN THE TWIN CITIES AND CENTRAL MN...WHERE AT 1 PM IT
WAS ONLY 81 AT MSP. HOWEVER...TO THOSE QUESTIONING 90S OCCURRING
IN THE TWIN CITIES...BE PATIENT...TEMPERATURES ON THE OTHER SIDE
OF THE WARM REALLY TAKE OFF. FOR INSTANCE...OLIVIA WENT FROM 81
TO 95 IN 90 MINUTES AND MANKATO WENT FROM 84 AT NOON TO 97 AT 1
PM. SO BE PATIENT...ALL IT WILL TAKE IS AN HOUR OR TWO IN THE WARM
SECTOR TO START PUSHING TEMPERATURES INTO THE MID 90S! STILL
CONFIDENT THAT THE RECORD OF 95 AT MSP IS VERY MUCH IN JEOPARDY
TODAY.

FINALLY...18Z AVIATION DISCUSSION ADDED BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM CDT TUE MAY 14 2013

THERE ARE MANY CONCERNS TODAY AS A LOW PRESSURE SYSTEM AND COLD
FRONT MOVE ACROSS THE FA DURING THE AFTERNOON AND EVENING. A SMALL
COMPLEX OF THUNDERSTORMS DID DEVELOP OVER NORTH DAKOTA OVERNIGHT AS
EXPECTED. THIS AREA OF PRECIPITATION WILL ADVANCE ACROSS NORTHERN
MN THIS MORNING. CONSENSUS FROM THE WRF MODELS WAS LITTLE
(SPRINKLES) OR NOTHING REACHING DOWN INTO CENTRAL MN OTHER THAN
SOME CLOUDS. BY LATE MORNING...THE LOW AND COLD FRONT SHOULD BE
INTO FAR WESTERN AREAS OF MN. SOUTH TO SOUTHWEST WINDS WILL INCREASE
AHEAD OF THE FRONT WHILE RATHER STRONG WEST/NORTHWEST WINDS OCCUR
IN THE WAKE OF THE FRONT. A LOW LEVEL THERMAL RIDGE WILL ADVANCE
NORTHEAST FROM THE CENTRAL PLAINS AND REACH INTO THE TWIN CITIES
BY LATE IN THE AFTERNOON. THE SHORT TERM MODELS REMAIN CONSISTENT
ON 23-26 DEG C AIR AT 850MB FROM THE TWIN CITIES ON SOUTHWEST INTO
NORTHERN IA RESPECTIVELY. HIGHS RECENTLY TO OUR WEST AND NORTHWEST
(CANADA) HAVE BEEN RUNNING REAL CLOSE TO 20 DEGREES ABOVE THESE
CONVERTED VALUES. THIS WOULD YIELD HIGHS FROM 93 TO 99 DEGREES.
AS A RESULT... OUR CURRENT FORECAST WAS RAISED A FEW DEGREES...
ESPECIALLY ACROSS SOUTH CENTRAL MN... WHERE THE RAP SOUNDINGS WERE
SHOWING HIGHS OF 100-103. THIS ALSO RESULTED IN A RECORD HIGH BEING
FORECAST FOR THE TWIN CITIES.

THE HEAT TODAY HAS LEAD TO THE ISSUANCE OF A HEAT ADVISORY FROM
THE TWIN CITIES ON SOUTH AND SOUTHWEST TO ALBERT LEA AND REDWOOD
FALLS. THIS IS A DRY HEAT BEING ACCOMPANIED BY 20 TO 25 MPH WINDS
DURING THE AFTERNOON... WHICH MAY LEAD TO DEHYDRATION ISSUES FOR
THOSE WORKING OUTSIDE. ANOTHER IMPORTANT ISSUE IS THAT THE TWIN
CITIES HAS ONLY BEEN IN THE 80S ONCE SO FAR THIS YEAR WITH 81
DEGREES ON APRIL 28TH. THIS BURST OF HEAT MAY LEAD TO HEALTH
ISSUES.

ANOTHER CONCERN TODAY IS THE POTENTIAL FOR WIND ADVISORY CRITERIA
BEING MET IN THE NORTHWEST CWA IN THE MID TO LATE AFTERNOON HOURS.
THE RAP LOW LEVEL WINDS IN THE 200-300 FOOT RANGE ARE FORECAST IN
THE UPPER 20 KNOT RANGE. THIS IS THE HIGHEST OF ALL THE GUIDANCE.
THE NAM WINDS WERE MORE IN THE 23-24 KNOT RANGE WHICH BLENDED WELL
WITH THE LAMP GUIDANCE. CRITERIA FOR A WIND ADVISORY HAS A BETTER
CHANCE OF BEGIN MET OVER NORTH DAKOTA. AT THIS POINT WE HELD OFF
ON ISSUING AN ADVISORY.

FINALLY...ALTHOUGH A STRONG CAP EXISTS IN THE 700-750MB RANGE
TODAY...THERE REMAINS SOME POTENTIAL FOR CONVECTION TO BREACH THE
CAP AND DEVELOP DURING THE LATE AFTERNOON/EVENING ALONG THE
FRONT... MAINLY TO THE EAST AND SOUTH OF THE TWIN CITIES. WE KEPT
THE SMALL CHANCES FOR THUNDERSTORMS AS IS. OUR LOCAL WRF WAS THE
MOST AGGRESSIVE WITH ACTIVITY DEVELOPING FROM JUST SOUTH OF THE
TWIN CITIES TO OMAHA AROUND 21Z...WHILE THE NMM WRF HAS SOME
STORMS JUST EAST OF US. MOST OF THE SOLUTIONS SHOW A HIGHER CHANCE
FOR STORMS OVER IA TONIGHT AS WELL AS IN NORTHEAST WI. GIVEN THE
SHEAR FORECAST...STORMS THAT DO DEVELOP COULD BECOME SEVERE WITH
LARGE HAIL AND DAMAGING WINDS... ESPECIALLY WITH THE INVERTED V
SOUNDING. NAM DOWNDRAFT CAPE VALUES ARE ON THE ORDER OF 1000 J/KG
OVER WEST CENTRAL WI AND SE MN LATE THIS AFTERNOON AND EVENING.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 415 AM CDT TUE MAY 14 2013

WEDNESDAY THROUGH MONDAY...QUIET AND SEASONABLE WEATHER WILL GIVE
WAY TO A WETTER PATTERN AT THE END OF THE PERIOD. SEVERE WEATHER IS
ALSO POSSIBLE FOR THE WEEKEND. EARLY MORNING NORTHERN HEMISPHERIC IR
IMAGERY TOGETHER WITH THE ECMWF 250MB HEIGHTS AND WINDS IDENTIFIED
ZONAL FLOW ACROSS THE WESTERN CONUS...WITH A LOW AMPLITUDE PATTERN
ACROSS THE PACIFIC. FOR WEDNESDAY AND THURSDAY THIS ZONAL FLOW WILL
SET UP ACROSS INTERNATIONAL BORDER...WITH NEGATIVE VORTICITY
ADVECTION AND WEAK SUBSIDENCE ACROSS THE UPPER MIDWEST. THIS WILL
RESULT IN TWO DRY DAYS WITH LIGHT WINDS AND TEMPERATURES 5 TO 10
DEGREES ABOVE THE SEASONAL AVERAGE FOR MID MAY.

BY THURSDAY NIGHT THE AFOREMENTIONED LOW AMPLITUDE JET ACROSS THE
PACIFIC WILL BEGIN TO DIG ACROSS THE WESTERN US...WITH A BROAD AREA
OF LEE SIDE TROUGHING ALONG THE EASTERN SPINE OF THE ROCKIES. THIS
WILL INDUCE SOUTHERLY FLOW WITH GULF MOISTURE TRANSPORT ACROSS THE
CENTRAL CONUS...AND GRADUALLY BUILD AN UPPER LEVEL RIDGE THURSDAY
NIGHT INTO FRIDAY. MEANWHILE THE COLD FRONT THAT WILL HAVE PASSED
THROUGH THE AREA ON TUESDAY AND STALL OUT ACROSS SOUTHERN IOWA WILL
LIFT NORTHWARD AS A WARM FRONT. LOW LEVEL THETA_E ADVECTION AS SEEN
IN THE H925-850 LAYER SHOULD PROMOTE THUNDERSTORM DEVELOPMENT ALONG
THE WARM FRONT...WHILE THE UPPER LEVEL ANTICYCLONIC FLOW ALOFT
ALLOWS EVACUATES THE OUTFLOW FROM THESES STORMS AND ALLOWS THEM TO
PERSIST. DIFFICULT TO QUANTIFY THE CONVECTIVE POTENTIAL SINCE THE
LOW LEVEL MOISTURE HAS BEEN UNRELIABLE LATELY. HOWEVER...THE
SYNOPTIC SETUP WITH GULF MOISTURE ADVECTION INCREASES CONFIDENCE
THAT THESE MOISTURE DEPENDENT VARIABLES...A.K.A. CAPE...ARE
REASONABLY REPRESENTED. DEEP LAYER SHEAR PROFILES VARY DEPENDING ON
THE TIMING AND PLACEMENT OF THE WARM FRONT...BUT BOTH THE 14.12 GFS
AND ECMWF ARE IN GOOD AGREEMENT AND LIFT THE FRONT THROUGH THE CWA
ON FRIDAY. MEANWHILE THE UPPER LEVEL JET WILL CONTINUE TO CARVE OUT
A TROUGH OVER THE FOUR CORNERS REGION. THE GFS...GEM...AND ECMWF ALL
DEVELOP A SURFACE LOW AND TRACK IT ACROSS THE UPPER MIDWEST FOR THE
WEEKEND...BRINGING CONTINUED CHANCES FOR PRECIP. THE RUN TOTAL
PRECIP FROM THE GFS AND ECMWF INDICATE THAT OVER 3 INCHES OF RAIN
ARE POSSIBLE. WITH THIS PROLONGED PERIOD OF PRECIP. IN
SUMMATION...EXPECT AN MCS TO DEVELOP THURSDAY NIGHT AND MOVE ACROSS
THE REGION FRIDAY AS THE WARM FRONT LIFTS NORTHWARD. THEN WILL SEE
CONTINUES CHANCES FOR THUNDERSTORMS SATURDAY AND SUNDAY AS THE UPPER
LEVEL DYNAMICS BECOME MORE FAVORABLE FOR ASCENT. SEVERE WEATHER
REMAINS POSSIBLE...BUT CONFIDENCE IN THE EXACT PLACEMENT OF THE
MESOSCALE FEATURES IS LOW AT THIS TIME.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1241 PM CDT TUE MAY 14 2013

WARM FRONT MENTIONED IN UPDATE LEADING TO BIGGEST AVIATION ISSUE
THIS PERIOD...WIND DIRECTIONS. NORTH OF THE WARM FRONT...WINDS
HAVE BACKED CONSIDERABLY MORE THAN EXPECTED...WITH STC/MSP/RNH/EAU
ALL EXPERIENCING ESE WINDS. COLD FRONT IN THE AREA OF AXN RIGHT
NOW AND 12Z TAFS STILL HAD FROPA AND WIND SHIFT TIMED WELL...SO
MADE FEW CHANGES TO THE TIMING OF THE FROPA WITH THESE TAFS. WARM
SECTOR JUST TO HOT/DRY TO THINK THERE IS EVEN A REMOTE CHANCE FOR
A TSRA...SO DID NOT CONTINUE MENTION OF TS AT EAU. REST OF TAF
LOOKS GOOD...WITH WEAKER NW WINDS AND MAINLY CLEAR SKIES EXPECTED
FROM TONIGHT THROUGH WEDNESDAY.

KMSP...OUTSIDE OF TWEAKING WIND DIRECTION TO BE MORE SE AT THE
BEGINNING...FEW CHANGES WERE NEEDED FOR THE TAF. EXPECT A FAIRLY
RAPID VEERING OF WINDS THIS AFTERNOON AS THE COLD FRONT MOVES
THROUGH BETWEEN 21 AND 22Z. DURING THIS HOUR WIND SPEEDS WILL
LIKELY BACK OFF SOME..BUT EXPECT 270-300 WINDS TO QUICKLY PICK UP
IN STRENGTH AND GUSTINESS IN ITS WAKE. LOOKS LIKE THE WIND SHIFT
SHOULD COME IN JUST BEFORE THE EVENING PUSH STARTS...SO SHOULD BE
ABLE TO GET RUNWAYS TURNED AROUND BEFORE PEAK VOLUME HITS.

/OUTLOOK FOR KMSP/
THU...VFR. LGT AND VRBL WINDS.
FRI...VFR WITH MVFR/-TSRA LIKELY. SE WINDS 10 KTS.
SAT...MVFR OR LOWER WITH -TSRA LIKELY. SE WINDS 5-10 KTS.

&&

.FIRE WEATHER...
ISSUED AT 440 AM CDT TUE MAY 14 2013

A RED FLAG WARNING NOW COVERS ALL OF OUR MN COUNTIES FOR THIS
AFTERNOON AND EARLY EVENING. A DRY SURGE OF HEAT WILL OCCUR TODAY
WITH AFTERNOON HUMIDITY VALUES LOWERING TO A FEW PERCENT ABOVE AND
BELOW 20. THE VERY LOW HUMIDITY COUPLED WITH SOUTHWEST TO WEST
WINDS FROM 20 TO 25 MPH ...WITH GUSTS TO 35 MPH... COULD LEAD TO
DANGEROUS WILDFIRE CONDITIONS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR MNZ041>045-
     047>070-073>078-082>085-091>093.

     HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR MNZ059>063-065>070-
     073>077-082>085-091>093.

WI...NONE.
&&

$$

UPDATE...MPG
SHORT TERM...RAH
LONG TERM...JRB
AVIATION...MPG
FIRE WEATHER...RAH