Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 241804
AFDMPX

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

.UPDATE...FOR 18Z AVIATION DISCUSSION BELOW

&&

.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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 105 PM CDT FRI APR 24 2015

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO
AFFECT CENTRAL/SOUTH CENTRAL MN AND WEST CENTRAL WI INTO THE
EVENING HOURS...ALTHOUGH THE PRIMARY CONCERN WILL TRANSITION TO
CIG/VSBY REDUCTIONS AS STRATUS/DRIZZLE DEVELOPS ON THE
NORTHERN/EASTERN PERIPHERY OF THE SURFACE TROUGH. EXPECT CIGS TO
DEGRADE TO MVFR BETWEEN 20Z /WEST CENTRAL MN/ AND 03Z /WEST
CENTRAL WI/...WITH WIDESPREAD IFR CIGS BELOW 1500 FT FOR THE
OVERNIGHT HOURS. VSBYS IN BR/DZ SHOULD GENERALLY RANGE BETWEEN 3SM
AND 6SM...WITH POCKETS OF 2SM AT TIMES IN WEST CENTRAL MN.
SOUTHEAST WINDS WITH GUSTS TO AROUND 20 KTS GRADUALLY BACK TO EAST
TONIGHT AND DECREASE TO AROUND 10-12 KTS...AND THEN BACK MORE TO
THE NORTHEAST ON SATURDAY.

KMSP...
SHOWERS POSSIBLE INTO THE EVENING...WITH CIGS EXPECTED TO LOWER TO
MVFR AROUND 23Z AND -DZ/BR....THEN ADDITIONAL LOWERING TO BELOW
1500 FT AROUND 06Z. SHOULD SEE IMPROVEMENT ABOVE 1800FT BY 16Z
SATURDAY...WITH VFR DEVELOPING BETWEEN 19Z AND 21Z SATURDAY.

/OUTLOOK FOR KMSP/
SAT NIGHT...VFR. WINDS NE 5-10 KT.
SUN...VFR. WINDS NE 5-10 KT.
MON...VFR. WINDS NNE 5-10 KT.
TUE...VFR. WINDS NNW 5-10 KT.

&&

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

$$


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


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