Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 110935
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
435 AM CDT FRI APR 11 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT FRI APR 11 2014

SCATTERED SHOWERS MOVING ACROSS THE FA THIS MORNING CONTINUE TO BE
HINDERED BY PRESENCE OF LOW LEVEL DRY AIR.  SOME RAIN IS MAKING IT
TO THE SURFACE...BUT MUCH OF THE REFLECTIVITY ON RADAR THIS MORNING
IS VIRGA...WITH JUST A FEW SITES REPORTING VERY LIGHT RAIN.  THE
VIRGA/SCATTERED SHOWERS WILL QUICKLY MOVE EAST THROUGH THE MORNING
AND GIVE WAY TO CLEARING SKIES TODAY. TEMPERATURES WILL EXCEED
YESTERDAYS HIGHS BY A FEW DEGREES GIVEN THE VERY GRADUAL WARMING
TREND EVIDENT AT 850H ON THE RAP THROUGH THIS EVENING.

FOR TONIGHT...AN UPPER LEVEL SHORTWAVE TROUGH WILL PUSH ACROSS
CENTRAL MINNESOTA INTO WISCONSIN. BOTH FORCING AND AVAILABLE
MOISTURE LEND HIGHER CONFIDENCE TO PRECIPITATION FORMING AND
EXPANDING DURING THE OVERNIGHT HOURS.  A 100+ KT JET STREAK TO THE
NE OF THE FA PLACES US SOLIDLY IN THE RIGHT-ENTRANCE REGION
INDICATING STRONG UPPER LEVEL DIVERGENCE.  IN THE LOW LEVELS...A LOW
LEVEL JET WILL GATHER STRENGTH OVERNIGHT AND WILL POKE INTO SOUTHERN
MINNESOTA.  NOT ONLY WILL THIS JET SUPPLY THIS AREA WITH INCREASING
MOISTURE...STRONG WARM AIR ADVECTION WILL ALSO BE OCCURRING
PROVIDING STRONG LOW LEVEL LIFT TO THIS REGION.  THE LOW LEVEL
CONVERGENCE AT THE NOSE OF THE JET COUPLED WITH THE UPPER LEVEL
DIVERGENCE FROM THE UPPER LEVEL JET INDICATES STRONG DIFFERENTIAL
DIVERGENCE ONGOING OVERNIGHT ACROSS EAST CENTRAL MINNESOTA INTO FAR
WESTERN WISCONSIN. LIKELY TO CATEGORICAL POPS HAVE BEEN ADDED TO
THESE AREAS AFTER 09Z WHEN THE LOW LEVEL JET STRENGTHENS.  THE NAM
INDICATED A MUCH DRIER SOLUTION...PREFERRED A BLEND OF THE GFS/ECMWF
GIVEN THE STRONG FORCING AND MOISTURE TRANSPORT OCCURRING WITH THE
STRENGTHENING LOW LEVEL JET OVERNIGHT.  LOW LEVEL DRY AIR SHOULD BE
QUICKLY OVERCOME IN THIS CASE.  NEGATIVE LIFTED INDEX VALUES AND
WEAK MOST UNSTABLE CAPE DO PUSH INTO FAR SOUTHERN MINNESOTA AFTER
09Z...SO THUNDERSTORMS WILL BE A POSSIBILITY EARLY TOMORROW MORNING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 400 AM CDT FRI APR 11 2014

MAIN POINTS:

1) PRECIP EVENT IS STILL ON TRACK FOR SATURDAY WITH MOST
OF THE RAIN EXPECTED IN THE MORNING.

2) THERE ARE NOTABLE MODEL DIFFERENCES ON THE LOCATION OF THE QPF
AXIS ON SUNDAY.

3) THE GFS HAS TRENDED TOWARD THE ECMWF AND IS NOW GOING COLDER
WITH TEMPERATURES MON-WED.

NOW THAT WE`RE 24-36 HOURS OUT FROM THE RAIN EVENT ON
SATURDAY...IT`S NO SURPRISE THERE IS BETTER MODEL AGREEMENT ON THE
PLACEMENT OF RAIN AND EXPECTED AMOUNTS. THE GFS AND ECMWF ARE IN
BETTER AGREEMENT WHEN COMPARED TO THE NAM...WHICH IS FARTHER NORTH
WITH THE MOISTURE ADVECTION AND PLACEMENT OF THE 800-600MB FGEN.
THE NAM THEREFORE HAS MORE WARMTH FARTHER NORTH AND THE PRECIP
PLACEMENT ACROSS NORTHERN MN...WHERE THE GFS AND ECMWF DEVELOP
MORE RAIN OVER CENTRAL AND PORTIONS OF SOUTHERN MN. TRENDS IN THE
ISENTROPIC LIFT AND SATURATION SUGGEST WESTERN MN...ESPECIALLY SW
MN COULD MISS OUT ON A LOT OF THE PRECIP WITH DEVELOPMENT MORE
LIKELY THE FARTHER EAST YOU GO IN MN. FOR THE EASTERN HALF OF THE
FORECAST AREA...IT LOOKS LIKE A GOOD 0.10"-0.40" EVENT WITH THE
HIGHER TOTALS OCCURRING WHERE THERE IS EMBEDDED CONVECTION. THAT
IS LIKELY GIVEN THE TONGUE OF 500-1000 J/KG OF MUCAPE AND BEST LI
NEAR 0. WE TRIED TO REMAIN STEADFAST IN KEEPING THE CONVECTION
CONFINED TO THE WARM SECTOR OR NEAR THE SURFACE WARM FRONT DURING
THE DAY ON SATURDAY. BY SATURDAY EVENING THE SURFACE LOW/TROUGH
SHOULD HAVE MADE ENOUGH PROGRESS TO THE EAST THAT THE CONVECTION
SHOULD BE SOUTH AND EAST OF THE FORECAST AREA. THEREFORE...AFTER
THE RAIN CLEARS SATURDAY MORNING...WE ARE MUCH MORE CONFIDENT IN
A MAINLY DRY AFTERNOON THAN WE WERE A DAY OR TWO AGO.

THE AMOUNT OF PRECIP AND SNOW CHANCES ON SUNDAY ALL DEPEND ON
WHERE THE BAROCLINIC ZONE SETS UP. AS OF RIGHT NOW...MODEL
CONSENSUS KEEPS THE BEST FORCING ACROSS IA...FAR SOUTHEAST MN AND
WI. THIS WILL BE MODERATE RAIN EVENT WITH AN INCH OR TWO OF QPF
BEING FORECAST. AT THIS POINT...SOUTHERN MN AND WEST CENTRAL WI
MISS OUT ON MUCH OF THE RAIN. THE 11.00/06 NAM SEEMS TOO FAR TO
THE NORTH AND THE TRACK RECORD THIS WINTER HASN`T BEEN GREAT FOR
THE NAM OUTSIDE OF IT`S 0-24HR FORECAST. WE SIDED WITH MORE OF A
ECMWF/GEM/GFS BLEND AND UNLESS WE SEE THESE THREE MODELING SYSTEMS
TREND ANOTHER 100-150 MILES NORTH...SUNDAY LOOKS DRY /CLOUDY/ FOR
MUCH OF THE FORECAST AREA. THIS SEEMS LIKELY GIVEN THE RUN-TO-RUN
CONSISTENCY OVER THE PAST 3-4 CYCLES.

SUNDAY-WEDNESDAY STILL LOOKS COLD AND AS MENTIONED ABOVE. THE
THERMAL PROFILE OFF THE GFS NOW MATCHES THE PREVIOUS ECMWF RUNS
THAT SHOW A SLOWER/DEEPER TROUGH AND A NICE 850MB COLD POCKET.
SO...JUST AS WE GET APRIL`S MONTHLY TEMPERATURE BACK UP NEAR
NORMAL...WE SHOULD DROP IT BACK DOWN WITH 20S FOR LOWS AND 40S FOR
HIGHS. BELIEVE IT OR NOT...ANOTHER NEAR ZERO NIGHT CAN NOT BE
RULED OUT IN SOME OF THE COLD SPOTS IN NORTHERN MN TUESDAY MORNING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1158 PM CDT THU APR 10 2014

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A FEW SHOWERS MAY
PUSH ACROSS THE REGION LATE TONIGHT AND EARLY FRIDAY...BUT ARE NOT
EXPECTED TO BE HEAVY OR IMPACT MUCH GIVEN THE AMOUNT OF DRY AIR
NEAR THE SURFACE. WEST WINDS WILL INCREASE AGAIN BY LATE FRIDAY
MORNING BEFORE SHIFTING QUICKLY SOUTHEAST DURING THE EARLY
EVENING.

KMSP...VFR. DESPITE A FEW SHOWERS OR SPRINKLES TONIGHT...NO MAJOR
CONCERNS.

/OUTLOOK FOR KMSP/
SAT...MVFR CIGS WITH SHRA LIKELY. CHANCE TSRA. WINDS S 10-15 KTS
BCMG N 5-10 KT.
SUN...MAINLY VFR. CHC MVFR CIGS/SHRA. WINDS N 10-15 KT.
MON...VFR. WINDS NW 5-10 KT.


&&

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

$$

SHORT TERM...SPD
LONG TERM...CLF
AVIATION...BORGHOFF







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