Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 242106
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
406 PM CDT FRI OCT 24 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 322 PM CDT FRI OCT 24 2014

SFC TROUGH WAS JUST EAST OF I-35 AT 3PM. 20-30 KT LLJ HAS DEVELOPED
OUT AHEAD OF THIS TROUGH. HOWEVER...THIS HAS DEVELOPED BENEATH THE
RIGHT EXIT REGION OF A 150 KT JET UP ALONG THE INTERNATIONAL BORDER.
FORECAST SOUNDINGS EAST OF THE TROUGH SHOW THE SUBSIDENCE INVERSION
THAT HAS DEVELOPED WITHIN THE RIGHT EXIT REGION. BECAUSE OF THIS
INVERSION...WE ARE SEEING NO PRECIP GENERATION...BUT ARE SEEING A
STRATUS DECK EXPAND BENEATH THE INVERSION. THESE CLOUDS WILL SLOWLY
WORK EAST WITH THE THROUGH...CLEARING THE ERN CWA BY MIDNIGHT. A
1020MB HIGH WILL BE WORKING ACROSS THE DAKOTAS TONIGHT IN THE WAKE
OF THE THROUGH...WHICH WILL HELP KEEP ANY ADDITIONAL FOG/STRATUS AT
BAY. WITH THE HIGH COMING IN...CUT BACK A FEW DEGREES ON LOWS FOR
TONIGHT...THOUGH AM CONCERNED WE MAY HAVE CUT THINGS BACK A LITTLE
TOO MUCH AS SFC DEWPOINTS HAVE REMAINED IN THE 40S/50S...INDICATING
WE MAY NOT SEE TEMPS DROP AS AGGRESSIVELY AS WE CURRENTLY HAVE.

NOT MANY CONCERNS FOR SATURDAY AS HIGH PRESSURE GOES FROM THE
DAKOTAS AND INTO MN. WILL SEE BREEZY CONDITIONS STILL ALONG AND
NORTH OF I-94 AS GRADIENT REMAINS TIGHT TO THE NE. ONLY CHANGE FOR
SATURDAY WAS TO BOOST HIGHS A FEW DEGREES...CLOSER TO WHAT THE
WEIGHTED MODEL AND BIAS CORRECTED GUIDANCE ARE SHOWING...WHICH HAVE
BEEN THE STRONGEST PERFORMERS IN THESE SORTS OF AIRMASSES THE LAST
COUPLE OF WEEKS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 322 PM CDT FRI OCT 24 2014

FOLLOWED THE LEAD OF THE SHORT TERM FORECASTER AND ALSO BOOSTED
HIGH TEMPS ON SUNDAY DUE TO THE STRONG WARM ADVECTION AND
HIGH LIKELIHOOD OF PARTIALLY CLEAR SKIES THROUGH THE EARLY
AFTERNOON. BY SUNDAY EVENING THE MAIN OCCLUDED FRONT SHOULD BE
PASSING INTO WESTERN MN FROM THE DAKOTAS AND THE 800-600MB FGEN
WILL BE STRONGEST OVER FAR EASTERN MN AND WESTERN WI. OF THE 12Z
GUIDANCE...THE GFS WAS THE FASTEST IN MOISTENING THE LOWER
ATMOSPHERE AND GENERATING LIGHT RAIN ACROSS THE EASTERN HALF OF
THE FORECAST AREA. THE REST OF THE GUIDANCE - NAM/ECMWF/GEM ARE
ALL IN RELATIVELY GOOD AGREEMENT IN TAKING MOST OF THE RAIN EAST
OF THE FORECAST AREA INTO CENTRAL AND EASTERN WI. IT ALSO APPEARS
THERE WILL BE A FEW HUNDRED JOULES OF ELEVATED INSTABILITY SUNDAY
NIGHT AND MONDAY MORNING IN SOUTHERN MN AND WESTERN WI...SO WE HAVE
INCLUDED ISOLATED THUNDER IN THE FORECAST. THERE IS A LARGE
DIFFERENCE IN THE DEGREE OF MOISTENING IN THE FORECAST SOUNDINGS
BETWEEN KMSP AND KEAU...SO THE METRO MAY IN FACT MISS OUT ON THE
SUNDAY EVENING/NIGHT RAIN. EVENTUALLY...THE SURFACE FRONT AND
TROUGH SWING THROUGH MONDAY NIGHT /ABOUT 18 HOURS AFTER THE
INITIAL ISENTROPIC BAND OF PRECIP/...SO THIS LOOKS LIKE A BETTER
WINDOW FOR MORE WIDESPREAD /ALBEIT STILL LIGHT/ PRECIP ACROSS THE
FORECAST AREA. BREEZY NORTHWEST FLOW IS EXPECTED ON TUESDAY BEHIND
THIS SYSTEM AND WILL KNOCK TEMPERATURES BACK INTO THE LOWER 50S
FOR HIGHS...WHICH IS CLOSE TO CLIMATE NORMALS IN MN/WI FOR LATE
OCTOBER. THE COOLER AIR MASS EXPECTED NEXT WEEK IS STILL NOT AS
COLD AS WHAT WE SAW IN EARLY OCTOBER WHEN MANY LOCATIONS REMAINED
IN THE 40S FOR A COUPLE DAYS IN A ROW. THE 12Z ECMWF IS MUCH MORE
AGGRESSIVE WITH THE WARMING LATE NEXT WEEK COMPARED TO THE GFS.
ACTUALLY...THE PREVIOUS 24.06Z GFS WAS MUCH MORE AGREEABLE WITH
THE WARMER ECMWF...BUT BACKED OFF WITH THE MORNING RUN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM CDT FRI OCT 24 2014

SFC TROUGH AT 18Z WAS NEAR A MKT/MSP/RZN LINE WITH A TONGUE OF
MVFR CIGS RACING NORTH TO THE EAST OF IT. RAP/HRRR HAVE HAD A GOOD
HANDLE ON THESE CIGS THIS MORNING...SO THIS FORECAST FAVORS TRENDS
FROM THOSE MODELS CLOSELY. IN THE WAKE OF THE SFC TROUGH...DRIER
AIR IS MOVING IN...SO THAT WILL KEEP ANY STRATUS/FOG OUT OF THE
AREA IN ITS WAKE THE REST OF THIS TAF PERIOD. WINDS WILL BE
STRONGEST ALONG/NORTH OF I-94 SATURDAY AS A SFC HIGH GOES FROM SW
MN INTO IA.

KMSP...MVFR CLOUDS SHOWED UP AT THE SAME TIME AS THE SFC
TROUGH...SO CONFIDENCE IS HIGH THAT MSP WILL BE BACK TO VFR AND
VFR FOR GOOD BY 20Z.

/OUTLOOK FOR KMSP/
SUN...VFR EARLY. CHC MVFR/SHRA IN EVENING. WINDS SE 10 KTS.
MON...MVFR CIGS LIKELY. CHC SHRA. WINDS BCMG WNW 5-10 KTS.
TUE...CHC MVFR/SHRA. WINDS W 15G25 KTS.


&&

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

$$

SHORT TERM...MPG
LONG TERM...CLF
AVIATION...MPG







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