Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 251210
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
710 AM CDT MON MAY 25 2015

.UPDATE...
ISSUED AT 702 AM CDT MON MAY 25 2015

UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT MON MAY 25 2015

TODAY AND TONIGHT...SFC ANALYSIS SHOWS A PAIR OF LOW PRES
CENTERS...ONE OVER FAR S-CENTRAL MN AND A SECOND OVER SWRN
NEBRASKA...CONNECTED BY A WEAVING QUASI-STNRY FRONT. FLOW ALOFT
IS DECIDEDLY MERIDIONAL DUE TO A FAIRLY PERSISTENT SUBTROPICAL
RIDGE OVER THE SERN CONUS AND A DEEP UPR LVL LOW OVER THE
4-CORNERS REGION. WITH PLENTY OF MOISTURE BEING ADVECTED INTO THE
REGION DUE TO THIS UPR LVL SETUP...A LARGE AREA OF ISENTROPIC
ASCENT IN ADVANCE OF THE SFC FRONT ALLOWED PLENTY OF LIGHT-MOD
RAIN TO SPREAD N OVER THE WFO MPX CWFA OVERNIGHT. WITH THE FNT
ALSO LIFTING NWD...PRECIP BEHIND THE FRONT IS MORE SPARSE AND THIS
IS EXPECTED TO BE THE CASE THRU THE MRNG HRS. AM CONCERNED WITH
HOW MUCH DRY SLOTTING WILL OCCUR AS THE UPR LVL LOW LIFTS OFF TO
THE NNE IN CONCERT WITH THE SFC FEATURES... BUT IT IS OBVIOUSLY
DIFFICULT TO COMPLETELY RULE OUT PRECIP DEVELOPMENT WITH SUCH A
MOIST ENVIRONMENT IN PLACE /PWATS AROUND 1.50 INCHES/ WITHIN THE
BAROCLINIC SETUP OVER THE AREA. THAT SAID...HAVE TRIED TO DEPICT
THE DRY SLOTTING BY DROPPING POPS TO THE SLGT-LOW CHC RANGE OVER
SRN MN BY MIDDAY...THEN CONTINUING THAT TREND NWD INTO THIS AFTN.
THE FLIP SIDE OF HAVING A DRY SLOT AND POTENTIALLY ANY BREAKS IN
THE OVERCAST IS THAT THIS WOULD ALLOW ADDITIONAL INSOLATION TO
GROW ANY WORTHWHILE INSTABILITY FOR TSTMS. PREVAILING THINKING IS
THAT THE CLOUD SHIELD WITH OCNL SHWRS LOOKS TO BE ENOUGH TO
PREVENT ANY CONVECTIVE GROWTH SO HAVE CONFINED SLGT CHC TSTM
MENTION TO SRN PORTIONS OF THE CWFA. OVERALL...STILL SOME
UNCERTAINTY AS TO THE PRECIP COVERAGE BUT CONFIDENCE IS FAIRLY
HIGH THAT TSTMS WILL NOT BE AN ISSUE FOR THE VAST MAJORITY OF THE
CWFA...IF NOT THE ENTIRE AREA. PRECIP TAPERS OFF THIS EVENING AS
THE UPR LVL LOW LIFTS INTO NRN MN AND THE SFC FEATURES SLOWLY MOVE
EWD. IN TANDEM WITH THE UNCERTAINTY IN CLOUD COVER AND PRECIP
COVERAGE... TEMPS WILL BE AFFECTED DUE TO THE MORE PERSISTENT
CLOUD COVER REMAINING N AND SOME POTENTIAL BREAKS IN THE OVERCAST
S DUE TO THE DRY SLOTTING. THUS...THERE LOOKS TO BE A 10-DEGREE OR
SO GRADIENT OF HIGH TEMPS FROM N TO S ACRS THE CWFA TDA...WITH
CENTRAL MN HOLDING IN THE LWR 60S WHILE HIGHS HIT THE LWR 70S NEAR
THE IA BORDER.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CDT MON MAY 25 2015

ONCE THE WAVE MOVES OUT OF THE AREA BY TOMORROW MORNING...ANOTHER
SHORTWAVE WILL BE QUICKLY ADVANCING NORTHEAST FROM THE CO/KS AREA
AND BRING PRECIP FROM SOUTH CENTRAL MN THROUGH WEST CENTRAL WI AS
MID LEVEL OMEGA MAX BECOMES FOCUSED IN THAT REGION ALONG WITH DEEP
SATURATION. FURTHER WEST...DRY AIR AND DESCENT WILL KEEP
CONDITIONS DRY. FORCING IS NOT GREAT BUT THERE IS SOME LIMITED
ELEVATED INSTABILITY WHICH COULD HELP PRODUCE HIGHER PRECIP VALUES
THAN THE UNDER QUARTER INCH CURRENTLY FORECAST FOR
EASTERN/SOUTHERN MN AND WEST CENTRAL WI.

FOR WEDNESDAY...DRIER AIR AND UPPER LEVEL RIDGING PUSH IN FROM
THE WEST...SKIES WILL BEGIN TO CLEAR FROM WEST TO EAST TUESDAY
NIGHT AND WILL SET THE STAGE FOR A WARM DAY ON WEDNESDAY AS 850MB
TEMPS SURGE TO NEAR 16C. MIX DOWN FOR HIGHS WEDNESDAY GAVE TEMPS
IN THE AROUND 80 FOR JUST ABOUT THE ENTIRE FA. EXPECTING DEW
POINTS IN THE LOW TO MID 50S DURING THE DAY.

FOR THURSDAY THROUGH FRIDAY WE GET BACK IN THE SOUTHWEST FLOW
REGIME ON THE BACK SIDE OF THE UPPER RIDGE...WHICH TRANSLATES TO A
CONTINUOUS CHANCES FOR SCATTERED THUNDERSTORMS ACROSS THE
REGION...SO STILL CARRYING WIDESPREAD POPS IN THE FORECAST FOR
THIS PERIOD. ACTIVITY WILL BE FOCUSED ON THE WARM AND MOIST SIDE
OF A SLOW MOVING FRONTAL BOUNDARY THAT WILL EVENTUALLY MOVE SOUTH
OF THE AREA. FOR THE WEEKEND...CANADIAN HIGH STILL ON TRACK TO
DIVE SOUTH INTO OUR AREA BEHIND THE FRONT...AND BRING COOLER AND
DRIER CONDITIONS TO THE ENTIRE FA BY SATURDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 702 AM CDT MON MAY 25 2015

WIDESPREAD IFR-LIFR CEILINGS THIS MRNG WITH MVFR-IFR VSBY PLUS
SCATTERED RAIN SHOWERS...MAINLY OVER CENTRAL MN...MOVING NWD.
ANOTHER ROUND OF SHOWERS IS EXPECTED LATER THIS MRNG...HELPING
KEEP THE IFR CONDS IN PLACE. CONDS EXPECTED TO IMPROVE LATER THIS
MRNG WITH ENOUGH DRY SLOTTING TO DIMINISH RAIN COVERAGE AND ALLOW
CEILINGS TO RISE. HOWEVER...CONDS EXPECTED TO DETERIORATE TONIGHT
AS A FRONT SLOWLY CROSSES THE AREA...ALLOWING WINDS TO BECOME LGT
WITH PLENTY OF BLYR MOISTURE. IFR CEILINGS EXPECTED.

KMSP...CONDS ALREADY AT LIFR AND LIKELY TO REMAIN THERE FOR AT
LEAST A COUPLE HOURS INTO THE 25/12Z TAF. RAIN SHOWERS LATER THIS
MORNING WILL HELP ERODE THE LOW CLOUDS UP TO IFR LEVELS THEN CONDS
TO SLOWLY IMPROVE DURG THE DAY BEFORE DEGRADING AGAIN TNGT.

/OUTLOOK FOR KMSP/
WED...VFR. WINDS W 5-10 KTS.
THU...VFR. CHC P.M. -SHRA/-TSRA. WINDS SE AT 5-10 KTS.
FRI...MVFR IN SHWRS/TSMS. IFR POSSIBLE. WINDS SW 5-10 KTS BECOMING
N 10-15 KTS.

&&

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

$$

UPDATE...JPC
SHORT TERM...JPC
LONG TERM...SPD
AVIATION...JPC



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