Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 162129
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
429 PM CDT WED APR 16 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CDT WED APR 16 2014

SFC ANALYSIS PUTS THE SFC LOW OVER BLUE
EARTH/LE SUEUR/WASECA COUNTIES IN MN WITH A WMFNT SNAKING NEWD
BETWEEN KLVN/KSYN ON TO EAU CLAIRE/CLARK COUNTIES IN WI. THE CDFNT
THEN SNAKES WSWWD THRU KJYG AND BETWEEN KOTG/KMJQ IN SWRN MN. PRECIP
CONTINUES TO SURGE NEWD IN ADVANCE OF THE LOW PRES CNTR...WITH LGT
RAIN S OF THE TWIN CITIES METRO WHILE MOD-HVY SNOW CONTINUES TO FALL
OVER MUCH OF NRN AND WRN PORTIONS OF THE WFO MPX CWFA. SNOWFALL
RATES OF 1-2 IN/HR CAN BE EXPECTED IN N-CENTRAL PORTIONS OF THE AREA
THRU THE NEXT COUPLE OF HRS AS THE LOW PRES CENTER ROTATES TO THE
ENE. NOT LOOKING FOR THAT MUCH WARMER AIR TO THE S TO MAKE MUCH MORE
OF A NWD PUNCH THAN IT HAS ALREADY MADE. THEREFORE...ANY AREAS
CURRENTLY HAVING SNOW WILL STAY AS SNOW THRU THE DURATION OF THIS
EVENT. AN AREAS EXPERIENCING RAIN OR A RAIN/SNOW MIX WILL THEN
GRADUALLY CHANGE OVER TO SNOW. THERE ARE A COUPLE OF OTHER KEY
FEATURES EVIDENT ON SATELLITE IMAGERY AND IN RAP/NAM MODELS THAT
WILL PLAY IMPORTANT ROLES IN THE PRECIP DEPICTION THRU THE EARLY
EVENING. A DRY SLOT THAT SHOWED UP NICELY IN ERN SD EARLY TDA HAS
SHOWN SIGNS OF CLOSING...ESPECIALLY NOW THAT IT SHOWS UP IN SWRN MN
ON KMPX RADAR. IT STILL IS THERE...BUT NOT AS LARGE AS
EARLIER...INDICATING THAT THE LOWER LEVELS OF THE ATMOS CONTINUE TO
SATURATE. THIS MEANS CONTINUED PRECIP DURATION WITH LITTLE BREAKS
THRU LATE EVENING. IN ADDITION...RAP/NAM SHOW THE UPPER LVL TROF
NUDGING THE SFC LOW ACRS SRN MN HAS TRYING TO PIVOT AS IT SWINGS
THRU TO A MORE NEGATIVE POSITION. THIS WOULD ENHANCE LIFT WITH
COLDER AIR SURGING IN ON THE BACKSIDE OF THE SYSTEM...WHILE MOISTURE
STILL REMAINS FAIRLY DEEP. THIS COMBINATION WOULD THEN POTENTIALLY
CREATE ADDITIONAL BANDS OF HEAVY SNOW THAT WILL SLOWLY TRAVERSE W TO
E ACRS MUCH OF THE MPX CWFA DURG THE EVE HRS...AGAIN POTENTIALLY
CREATING 1-2 IN/HR BANDS THAT MUCH OF THE CWFA WOULD EXPERIENCE.
DIFFICULT TO TIME IT BUT HAVE MAINTAIN HIGH-END POPS FOR CENTRAL-ERN
PORTIONS OF THE CWFA SINCE THE OVERALL PRECIP SHIELD WILL BE SLOW TO
EXIT THE AREA. ONCE THE TROF MOVES THRU LATE THIS EVE...THEN THE
PRECIP WILL GRADUALLY END FROM W TO E ACRS THE AREA...WITH THE VAST
MAJORITY SEEING SNOW IN VARYING INTENSITIES BY THAT POINT. IN
FACT...DUE TO THE ACCENTUATED INTENSITY SEEN EARLIER...HAVE ADDED A
FEW COUNTIES INTO THE WARNING AND SLIGHTLY NUDGED UP SNOWFALL TOTALS
IN THE WSW SEGMENTS TO ACCOUNT FOR THESE HIGH-INTENSITY SNOW BANDS.
HAVE ALSO ADJUSTED THE END TIMES OF THE ADVY/WRNG TO COINCIDE WITH
THE LOWERING OF POPS ACRS THE CWFA. TEMPS OVERALL WILL SETTLE INTO
THE LWR 20S INTO THE LWR 30S LATE TNGT WHILE WET SNOW ACCUMS WILL
GENERALLY TOP OUT IN THE 6-10 INCH RANGE IN NRN PORTIONS OF THE
CWFA...LOCALLY UPWARDS OF A FOOT NOT IMPOSSIBLE.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CDT WED APR 16 2014

WHILE MOST OF THE FORECASTER ENERGY WAS SPENT ON THE SHORT TERM
WITH THE SNOW STORM...THERE ARE A COUPLE ITEMS OF NOTE IN THE LONG
TERM FORECAST. THE MAIN PRECIP EVENT IN THE EXTENDED IS A RAIN
EVENT THAT LOOKS TO LARGELY OCCUR SATURDAY OR SATURDAY NIGHT -
PERHAPS EVEN A RUMBLE OF THUNDER. THAT BEING SAID NO REALLY
SIGNIFICANT WEATHER IS ANTICIPATED THROUGH THE PERIOD...BUT A
PROGRESSIVE AND ACTIVE PATTERN IS EXPECTED. BEHIND THE CURRENT
SYSTEM...A SURFACE HIGH BUILDS IN AND TEMPS BUT TEMPS ALOFT
EITHER REMAIN STEADY OR SLOWLY MODERATE. WE`RE STILL LOOKING AT
DEPARTURES FROM NORMAL TOMORROW CLOSE TO 20 DEGREES. MORE SUNSHINE
AND WARM ADVECTION WILL ALLOW TEMPS TO REBOUND INTO THE 40S AND
LOWER 50S ON FRIDAY.

NEXT CHANCE FOR PRECIP ARRIVES ON SATURDAY WHEN WEAK ISENTROPIC
LIFT MOVES INTO MINNESOTA. MN/WI WILL BE FIGHTING DRIER AIR IN THE
WAKE OF THE HIGH...SO...AND IT LOOKS AS IF MOST OF THE MODEL
GUIDANCE HAS REDUCED THE QPF SINCE YESTERDAY`S RUNS - AT LEAST IN
SOUTHERN MN WHERE THE FORCING ISN`T AS STRONG. THE MORE ROBUST
TROUGH REMAINS NORTH AND THE RESULTING FORCING IS BETTER ACROSS
NORTHERN AND PORTIONS OF CENTRAL MN. NONETHELESS...A WEAK SHORT
WAVE AND FRONTAL BOUNDARY DROP ACROSS THE FORECAST AREA SATURDAY
NIGHT AND WITH THE HELP OF CONDITIONAL SYMMETRIC INSTABILITY OR
WEAK UPRIGHT INSTABILITY...WE COULD GENERATE SOME LIGHT SHOWERS.
DRYING IS THEN EXPECTED INTO EARLY NEXT WEEK WITH UPPER LEVEL
RIDGE BUILDING INTO THE UPPER MISSISSIPPI RIVER VALLEY.
TEMPERATURES WILL BE MILD AND ABOVE NORMAL WITH INCREASING
WARM/THETA-E ADVECTION RETURNING POPS TUESDAY NIGHT INTO
WEDNESDAY. LOOK FOR A WARMING TREND DURING THIS PERIOD...WITH
HIGHS IN THE 60S ON SUNDAY AND AND EVEN IN INTO THE LOWER 70S BY
TUESDAY. CONTINUED THE TREND OF BUMPING HIGHS SLIGHTLY ABOVE
GUIDANCE DURING THIS PERIOD WITH ALL MODELS INDICATING VERY WARM
LOW AND MID LEVEL TEMPERATURES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 106 PM CDT WED APR 16 2014

AXN/STC/RWF CONTINUE TO BE MOST AFFECTED BY MOD/HVY SNOW THIS AFTN
AS THE SWATH OF PRECIPITATION WITHIN AIR COLD ENOUGH TO PRODUCE
SNOW RATHER THAN RAIN LINGERS FROM SWRN MN INTO N-CENTRAL MN.
MSP/RNH/EAU HAVE EMERGED TO HAVE LITTLE-TO-NO PRECIP AT 16/18Z
INITIALIZATION...BUT WITHIN A FEW HOURS TIME THE PRECIPITATION
AREA WILL GRADUALLY SHIFT EWD...BRINGING PRECIP BACK TO THE ERN
TAFS. PRECIP LOOKS TO RETURN AS -RA FOR A FEW HRS BEFORE A BRIEF
TRANSITION TO -RASN BEFORE ALL -SN. THE CONCERN THEN BECOMES
MESOSCALE BANDING OF PRECIP FOR THESE ERN SITES AS THE UPR LEVEL
TROF PIVOTS ALOFT OVER SRN MN THIS EVENING...SETTING THE STAGE FOR
ENHANCED LOCALIZED LIFT WHICH COULD PRODUCE PERIODS OF IFR-WORTHY
HVY SNOW THIS EVENING. HAVE USED TEMPO GROUPS TO ADVERTISED THIS
ATTM. THE PRECIP LOOKS TO BE LARGELY AWAY FROM THE TERMINALS BY
06Z THIS EVE...A LITTLE LATER FOR THE WI SITES. THE OTHER CONCERN
IS THE POTENTIAL FOR LLVL STRATUS OVERNIGHT WITH THE DEEP MOISTURE
WITHIN THE BLYR...BUT AM NOT ENTIRELY SOLD ON THIS IDEA DUE TO THE
STRONG LLVL NW WINDS XPCTD SO ASIDE FROM MVFR CIGS...HAVE LEFT
VSBY AS IMPROVING TO VFR.

KMSP...DEFINITIVE BREAK IN THE PRECIP HAS DEVELOP OVER MSP...
GOING MAINLY S AND E FROM THERE...WHILE PRECIP IS NOT FAR OFF AT
ALL GOING N AND W. AS THE AFTN PROGRESSES...THIS DRY PERIOD WILL
COME TO AN END WITH -RA RETURNING FROM THE W BY MID-AFTN. TEMPS IN
THE MID-30S WILL ALLOW FOR A P-TYPE OF SHOWERY -RA WHEN IT
RESUMES. AS COLDER AIR WRAPS AROUND THE BACKSIDE OF THE LOW PRES
CENTER SHIFTING EWD OVER SRN MN LATE THIS AFTN...PRECIP WILL MIX
WITH AND EVENTUALLY CHANGE BACK OVER TO -SN. SOME MINOR SNOW
ACCUMULATION IS POSSIBLE...ALONG WITH POTENTIAL BANDS OF MOD-HVY
SNOW...DUE TO MESOSCALE EFFECTS BUT ITS POTENTIAL IS ENOUGH TO
CARRY A TEMPO GROUP THIS EVENING. CONDS IMPROVE LATE OVERNIGHT
THRU THE DAY TMRW TO VFR WHILE WINDS TAKE ON A DRIER NW FLOW.

/OUTLOOK FOR KMSP/
THU...MAINLY VFR. SOME MVFR CIGS EARLY. WINDS NNE 10-15 KTS.
FRI...MAINLY VFR. CHC MVFR FRI NIGHT WITH -RA/-SN. WINDS NE 5-10
KTS.
SAT...MAINLY VFR. CHC MVFR WITH -RA/-SN. WINDS E-SE 10-15 KTS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ041-
     047-048-054>057-064-065-073.

     WINTER STORM WARNING UNTIL 1 AM CDT THURSDAY FOR MNZ042-043-
     049>051-058-059.

     WINTER STORM WARNING UNTIL 4 AM CDT THURSDAY FOR MNZ044-045-052-
     053-061.

     WINTER WEATHER ADVISORY UNTIL 4 AM CDT THURSDAY FOR MNZ060-062-
     063.

     WINTER WEATHER ADVISORY UNTIL 1 AM CDT THURSDAY FOR MNZ066-068.

WI...WINTER STORM WARNING UNTIL 4 AM CDT THURSDAY FOR WIZ014.

     WINTER WEATHER ADVISORY UNTIL 4 AM CDT THURSDAY FOR WIZ023.

     WINTER STORM WARNING UNTIL 7 AM CDT THURSDAY FOR WIZ015-016.

     WINTER WEATHER ADVISORY UNTIL 7 AM CDT THURSDAY FOR WIZ025-027.

&&

$$

SHORT TERM...JPC
LONG TERM...CLF
AVIATION...JPC







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