Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 232029
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
329 PM CDT SAT APR 23 2016

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 329 PM CDT SAT APR 23 2016

DEVELOPING LOW PRESSURE SYSTEM TO OUR WEST IS THE MAIN CONCERN IN
THE SHORT TERM.  UPPER LEVEL TROUGH WITH A SLIGHT NEGATIVE TILT IS
PUSHING EAST THROUGH THE WESTERN CONUS AT THIS TIME. AT THE
SURFACE...A DEFINED LOW IS DEVELOPING NEAR THE MT/WY/SD BORDER
INTERSECTION AND WILL ADVANCE EASTWARD TONIGHT.  STRONG THETA-E
ADVECTION HAS ENSUED ACROSS THE MIDWEST THANKS TO STRONG SOUTHERLY
LOW LEVEL FLOW...AND TEMPERATURES AND DEW POINTS ALIKE HAVE BEEN ON
THE RISE.  THE POSITION OF THE MAIN WARM FRONT ASSOCIATED WITH THIS
SURFACE LOW WILL BE CRITICAL IN THE TYPE OF WEATHER YOU CAN EXPECT
THROUGH TOMORROW.  AT THIS TIME...WE EXPECT THE WARM FRONT TO LIFT
NORTH THROUGH MOST OF SOUTHERN MN TONIGHT BEFORE BECOMING QUASI-
STATIONARY THROUGH CENTRAL MN /ORIENTED WEST TO EAST/ WITH THE
SURFACE LOW REACHING CENTRAL SOUTH DAKOTA BY TOMORROW MORNING.

THE LOW LEVELS ARE DRY OUT THERE THIS AFTERNOON...BUT HIGHER UP
STEEP LAPSE RATES AND NEGATIVE ADIABATIC OMEGA ARE WORKING TOGETHER
TO PRODUCE A FEW ISOLATED SHOWERS WITH A FEW STRIKES OF THUNDER
ACROSS CENTRAL MN.  SEEING THIS AREA EXPAND INTO THE METRO THE NEXT
FEW HOURS IS NOT OUT OF THE QUESTION.

FOR TONIGHT...PRIMARY AREA OF PRECIP STILL REMAINS ON TRACK TO GET
GOING ACROSS NORTHERN MN AS THE BEST FORCING IS THERE.  STRONG F-GEN
NORTH OF THE SURFACE COMBINED WITH DECENT UPPER LEVEL JET DYNAMICS
WILL GENERALLY BE NORTH OF OUR FORECAST AREA...BUT MAINTAINED LIKELY
POPS FROM NEAR ALEXANDRIA TO MILLE LACS LAKE.  FARTHER SOUTH...COULD
STILL SEE A FEW SHOWERS POP UP BUT NOT EXPECTING MUCH IN TERMS OF
COVERAGE.

FOR SUNDAY...THE FRONT WILL BE DRAPED JUST NORTH OF THE TWIN CITIES.
FORECAST HIGHS DIFFER BY 20-30 DEGREES ACROSS SHORT DISTANCES NEAR
THE FRONTAL BOUNDARY. HIGHS SOUTH OF THE FRONT WILL LIKELY BE IN THE
70S WITH DEW POINTS NEAR 60 DEGREES. IN TERMS OF SEVERE WEATHER
POTENTIAL...THERE IS A MARGINAL RISK OF SEVERE WEATHER LATE TOMORROW
AFTERNOON SOUTH OF THE FRONTAL BOUNDARY.  CAMS INDICATE STORMS
FIRING IN THE WARM SECTOR AHEAD OF THE COLD FRONT IN EASTERN
NEBRASKA/WESTERN IOWA AND FAR SOUTHERN MN...WITH STORM MOTION MOVING
NORTHEAST. CAPE VALUES NEAR 1000 J/KG IN FAR SOUTHERN MN ARE
EXPECTED...BUT STEEP LAPSE RATES IN THE MID LEVELS WILL AID IN
THUNDERSTORM STRENGTH.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 329 PM CDT SAT APR 23 2016

THERE ARE TWO THEMES IN THE LONG TERM...WET AND COOL. WE WILL BE
DEALING WITH THREE RATHER VIGOROUS LOW PRESSURE SYSTEMS MOVING
THROUGH THE REGION DURING THE FORECAST PERIOD. THE FIRST IS
SUNDAY NIGHT THROUGH MONDAY NIGHT...THE SECOND IS WEDNESDAY
THROUGH THURSDAY WITH THE LAST ARRIVING SATURDAY AND LASTING INTO
NEXT MONDAY. THIS LEAVES US WITH TWO DRY DAYS NEXT WEEK...TUESDAY
AND FRIDAY. RUN TOTAL QPF IS RATHER IMPRESSIVE FROM BOTH THE GFS
AND ECMWF WITH AMOUNTS FOR THE NEXT 7 DAYS TOTALING IN THE 2 TO 3
INCH RANGE ACROSS CENTRAL MN AND WEST CENTRAL WI WITH 3 TO 4
INCHES ACROSS SOUTHERN MN. FORTUNATELY THE RAIN COMES IN PIECES
AND WE HAVE BEEN RATHER DRY OVER THE PAST MONTH WHICH SHOULD HELP
MITIGATE FLOOD CONCERNS. HOWEVER...THE PERIOD OF INTEREST AT THIS
POINT IS SUNDAY NIGHT AND EARLY MONDAY TO THE NORTH AND EAST OF
THE TWIN CITIES. THIS AREA IS IN THE RIGHT ENTRANCE REGION OF A
140+ KNOT JET...MID LEVEL FRONTOGENESIS AND AT THE NOSE OF THE LOW
LEVEL MOISTURE TRANSPORT. THIS AREA ALSO LIES ALONG A RIBBON OF
ELEVATED CONVECTIVE INSTABILITY. NEEDLESS TO SAY THE LAYER
Q-VECTOR CONVERGENCE IS VERY STRONG. THE CONCERN IS THAT 1 TO 2
INCHES OF RAIN COULD FALL IN THE AFOREMENTIONED AREAS SUNDAY NIGHT
AND EARLY MONDAY...IN ADDITION TO THE RAIN TONIGHT AND SUNDAY...IF
CONVECTION BECOME THE DOMINATE WEATHER TYPE. THIS SCENARIO WAS
EVIDENT IN A FEW MEMBERS OF THE SREF AND GEFS PLUMES BETWEEN THE
TWIN CITIES AND DULUTH. ANOTHER CONCERN IS THE THREAT EARLY SUNDAY
NIGHT FOR A FEW SEVERE STORMS ACROSS SOUTHERN MN WHICH DEVELOP
LATE SUNDAY AFTERNOON. VARIOUS CAMS SUGGEST THAT THERE MAY BE
ACTIVITY IN TWO AREAS EARLY SUNDAY EVENING...ONE IN SOUTHWEST MN
AHEAD OF THE COLD FRONT AND A SECOND LINE IN THE WARM SECTOR NEAR
THE NOSE OF A 40 KNOT LOW LEVEL JET ALONG THE I-35 CORRIDOR FROM
THE TWIN CITES ON SOUTHWARD.

THE OTHER THEME THIS WEEK IS HIGH TEMPERATURES AVERAGING FROM 5
TO 10 DEGREES BELOW NORMAL. THE EXCEPTION IS SATURDAY WITH HIGHS
TRENDING BACK TO NEAR NORMAL. FOR AGRICULTURAL CONCERNS...FROST
AND OR FREEZE CONDITIONS ARE LIKELY ACROSS CENTRAL MN AND
ADJOINING AREAS OF WEST CENTRAL WI TUESDAY MORNING WITH FROST
POSSIBLE IN THESE SAME AREAS FRIDAY MORNING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1259 PM CDT SAT APR 23 2016

VFR IS EXPECTED FOR THE REMAINDER OF THE AFTERNOON.
TONIGHT...CLOUD COVER WILL INCREASE AHEAD OF THE APPROACHING
SYSTEM...AND SHOWERS COULD BREAK OUT ACROSS CENTRAL MN THROUGH
WESTERN WI. CONFIDENCE IS LOW IN COVERAGE AND PLACEMENT OF
THOSE...BUT GENERALLY EXPECT VFR CIGS THROUGH THE EVENING.
EXPECTING TO SEE MVFR CEILINGS DEVELOP OVERNIGHT NORTH OF THE
SAGGING FRONTAL BOUNDARY...SO AFFECTING STC AND AXN. IFR STRATUS
APPEARS LIKELY NORTH OF THAT FRONT THROUGH TOMORROW. CONFIDENCE
IS LOW IN AREAS LIKE MSP AND RNH IN TERMS OF SEEING MVFR CIGS
TOMORROW...WHICH IS HIGHLY DEPENDENT ON THE EXACT FRONTAL
POSITION. OVERALL PRECIP THROUGH THE PERIOD IS SCATTERED AND
UNFOCUSED MAKING IT TOUGH TO NAIL DOWN WHERE AND WHEN A SPECIFIC
AIRFIELD WILL SEE SHOWERS MOVING THROUGH.

KMSP...INCREASING CHANCES OF TSRA TOMORROW AFTERNOON AFFECTING THE
METRO AREA. FRONTAL BOUNDARY THROUGH THE METRO DURING THE DAY WILL
BE KEY AND WHERE IT ENDS UP BY THE TIME STORMS GET GOING IN
SOUTHERN MN.

/OUTLOOK FOR KMSP/
SUN NITE...MVFR/IFR WITH -SHRA/TS. WIND ESE 10-15KTS.
MON...MVFR/IFR WITH -SHRA. WIND NE 10-15KTS.
TUE...VFR. WINDS E 10-15KTS.


&&

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

$$

SHORT TERM...SPD
LONG TERM...RAH
AVIATION...SPD



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