Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 241106
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
606 AM CDT FRI APR 24 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT FRI APR 24 2015

STRONG THETA-E ADVECTION IS ENSUING ACROSS THE AREA...WITH SKIES
MAINLY CLOUDY NOW ACROSS MN AS A RESULT. AS STRONG AS THIS FORCING
MAY BE...IT IS RUNNING INTO ONE HUGE PROBLEM...THE INCREDIBLY DRY
AIRMASS IN THE LOWER LEVELS IN PLACE ACROSS THE AREA EARLY THIS
MORNING. EVEN AT 3 AM THERE WERE SEVERAL LOCATIONS THAT STILL HAD
HUMIDITIES UNDER 25 PERCENT AND IN FACT...THERE ARE A FEW SITES OUT
IN WRN MN THAT ARE EVEN BORDERLINE RED FLAG CRITERIA WHERE SE WINDS
ARE STARTING TO GUST OUT OVER 20 MPH WITH HUMIDITIES UNDER 30
PERCENT. THE TRUE MAGNITUDE OF HOW DRY THIS AIRMASS IS COMES FROM
THE TWO SOUNDINGS RELEASED FROM MPX ON THURSDAY...BOTH OF WHICH
TALLIED PWATS UNDER A TENTH OF AN INCH. THIS IS COMMON WITH ARCTIC
OUTBREAKS IN THE DEAD OF WINTER...BUT IT IS EXCEEDINGLY RARE TO SEE
PWATS SO LOW AT THIS POINT IN APRIL.

WITHIN THIS WARM ADVECTION...THE MOISTURE CONVERGENCE AND
FRONTOGENESIS ARE REALLY CENTERED AROUND SE NODAK...WHERE RAIN IS
FINALLY STARTING TO MAKE INROADS TO THE SFC UP AROUND FARGO. FOR
THE REST OF TODAY...THEIR IS QUITE A BIT OF SPREAD AMONGST THE
SHORT TERM MODELS ON HOW THIS SYSTEM WILL SPREAD RAINFALL INTO
AREA...SO THERE IS LOW CONFIDENCE ON EXACT TIMING OF PRECIP AT ANY
ONE LOCATION. THIS IS LIKELY DUE TO THE LACK OF MUCH JET
SUPPORT...ALONG WITH NO REAL SHORT WAVE TO HELP FOCUS ACTIVITY.
INSTEAD...TODAY LOOKS TO BRING A GOOD 6-10 HOUR WINDOW TO MOST
LOCATIONS WHERE LIGHT RAIN WILL BE INTERMITTENT AS THE ZONE OF
THETA-E ADVECTION SWINGS THROUGH. DID CUT BACK SOME MORE ON QPF AS
WELL...WITH THIS LOOKING TO BE YET ANOTHER DISAPPOINTING SYSTEM IN
THE RAINFALL DEPARTMENT...WITH MOST FOLKS GETTING UNDER A TENTH OF
AN INCH OF RAIN. THE ONLY AREA THAT LOOKS LIKE THEY COULD DO
BETTER THAN THAT IS ACROSS CENTRAL MN...AS FRONTAL FORCING
CURRENTLY IN THE FARGO AREA PUSHES EAST THIS MORNING BEFORE
WEAKENING. FOR THE WEATHER GRIDS...MADE TWO CHANGES. ONE WAS TO
INTRODUCE ISOLATED THUNDER WORDING AS THE PLUME OF INSTABILITY
CURRENTLY UP INTO SE SODAK WILL PUSH INTO SW MN THIS
AFTERNOON...WITH THE NAM SHOWING A FEW HUNDRED J/KG OF MUCAPE
WORKING UP TO ABOUT A RED WING TO ALEXANDRIA LINE. ADDING FURTHER
SUPPORT TO BRINGING IN THE THUNDER MENTION WERE THE FACT THAT WE
HAVE SEEN INTERMITTENT LIGHTNING ACTIVITY ALL NIGHT WITH THE
SHOWERS WORKING ACROSS THE DAKOTAS...WITH THE SPC SREF
THUNDERSTORM PROBABILITIES GETTING UP ABOUT AS FAR NORTH AS I-94
AS WELL. THE SECOND CHANGE WAS TO REMOVE ANY MIXED PRECIP FROM THE
GRIDS THIS MORNING AS CLOUD COVER OVERNIGHT KEPT TEMPERATURES
HIGHER THAN WERE FORECAST...MEANING PRECIP MOVING IN WILL HAVE NO
PROBLEM MAINTAINING A LIQUID STATE.

TONIGHT WHAT LOOKS LIKE A CERTAINTY IS THE DEVELOPMENT OF LOW
STRATUS. AGAIN...THE FORCING FOR PRECIP DOES NOT LOOK ALL THAT GREAT
AS SFC ENERGY CONSOLIDATES INTO A SUB 1000 MB LOW THAT WILL BE
MOVING INTO THE KC AREA. THIS LOOKS TO KEEP THE BULK OF THE PRECIP
SOUTH OF THE MPX AREA...WITH THIS AREA LOOKING TO GET MORE LIGHT
RAIN/SPRINKLES TO GO ALONG WITH THE STRATUS. BASED ON WHAT WE SAW
WITH TEMPERATURES WITH THE CLOUDS TONIGHT...DID BOOST LOWS TONIGHT A
FEW DEGREES WITH THE CLOUDY SKIES EXPECTED. THIS RESULTED IN THE
BULK OF THE MIXED IN THE FORECAST FOR TONIGHT GETTING REMOVED AS
WELL.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 348 AM CDT FRI APR 24 2015

GOOD CONTINUITY CONTINUES BETWEEN THE GFS AND ECMWF FOR MUCH OF
THE LONG TERM...LEADING TO HIGHER CONFIDENCE WITH THE SENSIBLE
WEATHER. RAIN WILL DIMINISH FROM NORTH TO SOUTH ON SATURDAY AS A
WAVE OF LOW PRESSURE DROPS SOUTHEAST ACROSS THE MIDDLE MISSISSIPPI
VALLEY. LIKELY TO CATEGORICAL POPS CONTINUE IN FAR SOUTHERN MN
FOR THE MORNING WITH CHANCE POPS IN THE AFTERNOON. A RIDGE OF HIGH
PRESSURE WILL BUILD OVER THE LOCAL AREA FOR SUNDAY AND MONDAY WITH
SOME FINE SPRING WEATHER OCCURRING. AFTER HIGHS IN THE LOWER 50S
ON SATURDAY...TEMPERATURES WILL WARM TO AROUND 60 FOR SUNDAY WITH
LOWER TO MIDDLE 60S FOR TUESDAY...WHICH IS ACTUALLY NORMAL FOR
LATE APRIL.

THERE REMAINS A SHORT WAVE AND WEAK COOL FRONT THAT WILL PUSH
ACROSS THE FORECAST AREA FROM MONDAY NIGHT THROUGH TUESDAY NIGHT.
THIS SYSTEM IS WEAKENING WITH TIME WITH ONLY SMALL POPS INDICATED
TO THE WEST AND NORTH OF THE TWIN CITIES FOR MONDAY NIGHT AND
TUESDAY. A MUCH LARGER RIDGE OF HIGH PRESSURE WILL FOLLOW AND EXPAND
OUT ACROSS THE NORTHERN ROCKIES AND PLAINS FOR WEDNESDAY AND
THURSDAY. DRY WEATHER IS IN STORE FOR THE REGION WITH HIGH
TEMPERATURES TRENDING ABOVE NORMAL WITH UPPER 60S TO LOWER 70S
LIKELY. EVEN WARMER TEMPERATURES ARE POSSIBLE FOR THE END OF THE
WEEK (FRIDAY AND SATURDAY) AS RIDGING ALOFT DOMINATES THE CENTRAL
THIRD OF THE CONUS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 606 AM CDT FRI APR 24 2015

LLJ WORKING INTO WRN MN THIS MORNING HAS SHOWERS WITH EMBEDDED
TSTRMS FROM OMAHA TO FARGO. HOWEVER...WE ARE STILL DEALING WITH A
VERY DRY AIRMASS IN THE LOW LEVELS WHICH IS MAKING EWRD PROGRESS
INTO THE MPX AREA DIFFICULT. FELT TIMING FROM INHERITED TAFS
LOOKED GOOD BASED ON LATEST HRRR/HOPWRF FORECASTS SO MADE MINIMAL
CHANGES THERE. GIVEN THE DRY AIR...ALSO FAVORED THE SLOWER SREF
FOR BRINGING MVFR AND LOWER CIGS INTO THE AREA. IN FACT...SREF CIG
PROBABILITIES PAINT THE POSSIBILITY THAT DRY ERLY FLOW WILL KEEP
THE WI TERMINALS VFR THROUGH THIS TAF PERIOD. AT THE VERY
LEAST...LOWEST CLOUDS LOOK TO BE OUT IN WRN MN TONIGHT...WITH IFR
OR LOWER CIGS LIKELY WEST OF I-35.

KMSP...UNCERTAINTY EXISTS ON TWO FRONT FOR THIS TAF...TIMING ON
WHEN OR EVEN IF MSP SEES RAIN ALONG WITH HOW LOW DO CIGS GO. FOR
THE RAIN...ONE BAND OF VIRGA ALREADY MOVED THROUGH THIS
MORNING...BUT MAIN BATCH OF FORCING LOOKS TO ARRIVE CLOSER TO 18Z.
FOR MUCH OF THE AFTERNOON...EXPECT INTERMITTENT PERIODS OF -RA
THAT MAY CONTINUE INTO MUCH OF TONIGHT. HRRR AND LAMP WOULD SAY
MVFR CIGS MOVE IN WITH THE RAIN CHANCES...BUT GIVEN HOW DRY WE ARE
IN THE LOW LEVELS...FAVORED THE SLOWER TIMING OF THE SREF.
CONFIDENCE ON CIGS GOING BELOW 018 TONIGHT IS MEDIUM AS LOWER
CIGS AND BETTER MOISTURE LOOK TO REMAIN OFF TO THE WEST...WITH
CONTINUED DRY ERLY SFC WINDS PLAYING HAVOC ON CLOUD HEIGHTS
THROUGH TONIGHT.

/OUTLOOK FOR KMSP/
SAT...BCMG VFR. WINDS E 10-15 KT.
SUN...VFR. WINDS NE 5-10 KT.
MON...VFR. WINDS NNE 5 KT.

&&

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

$$

SHORT TERM...MPG
LONG TERM...RAH
AVIATION...MPG



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