Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 011707
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1207 PM CDT FRI AUG 1 2014

.UPDATE...FOR 18Z AVIATION DISCUSSION

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI AUG 1 2014

SHORT TERM CONCERNS REMAIN TIMING OF THUNDER THREAT TODAY INTO THIS
EVENING.

A WEAK SHORT WAVE EXITING THE EASTERN CWA EARLY THIS MORNING PER
WATER VAPOR IMAGERY AND LATEST SPC MESOSCALE ANALYSIS. STEEP MID
LEVEL LAPSE RATES AROUND 7.5 C/KM AND MUCAPE AROUND 500 J/KG
CONTINUE TO GENERATE ISOLATED PULSE TYPE CONVECTION IN WEST
CENTRAL WI WITH SMALL HAIL INDICATED. THIS SHOULD EXIT BEFORE 12Z.

ATMOSPHERE REMAINS RIPE FOR CONVECTION TO DEVELOP AHEAD OF THE NEXT
SHORT WAVE WHICH APPEARS TO BE MOVING INTO FAR NORTHERN MN AT THIS
TIME. THIS IS PROGGED TO DROP SOUTH AND EAST...AND WE SHOULD SEE
CONVECTION DEVELOP INTO CENTRAL MN BY 15Z...AND INTO EAST CENTRAL MN
AND MOST OF WC WISCONSIN AROUND 18Z OR SO.  WILL MENTION HIGH CHANCE
POPS FOR NOW...MUCH OF THIS AREA.  BULK LAYER SHEAR WILL BE LIMITED
BUT MUCAPE IS PROGGED TO INCREASE TO AROUND 2K J/KG DURING THE
AFTERNOON...WITH CONTINUED STEEP MID LEVEL LAPSE RATES.  LARGE HAIL
WILL BE POSSIBLE WITH THE STRONGER CELLS THAT DEVELOP...MAINLY
ACROSS THE EASTERN PORTION OF THE AREA.  MAX TEMPERATURES ARE
EXPECTED TO WARM CLOSE TO YESTERDAYS VALUES AS THE TROUGH MOVE
ACROSS THE REGION.

THIS SHORT WAVE SHOULD EXIT TO THE SOUTH OF THE AREA DURING THE
EVENING WITH A MORE DIURNAL TREND IN THE CONVECTION.  WITH GENERAL
CLEARING AND LIGHT WINDS...PATCHY FOG WILL BE POSSIBLE AFTER
MIDNIGHT ACROSS MUCH OF THE AREA.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI AUG 1 2014

SATURDAY LOOKS DRY WITH THE FRIDAY SHORT WAVE WELL TO THE SOUTH.
THE NEXT WAVE TO WATCH WILL BE DROPPING INTO MINNESOTA SATURDAY
AFTERNOON AND EVENING. THIS WILL ALSO BE ACCOMPANIED BY SHOWER AND
THUNDERSTORM ACTIVITY...BUT THIS ACTIVITY SHOULD NOT BE TOO
WIDESPREAD GIVEN IT/S NOCTURNAL ARRIVAL. COVERAGE MAY INCREASE A
BIT SUNDAY AFTERNOON AS THE TAIL END LINGERS OVER ERN MN AND WRN
WI AND FORECAST SOUNDINGS INDICATE AT LEAST SOME INSTABILITY.

UNCERTAINTY HAS BEGUN TO INCREASE AGAIN FOR NEXT WEEK...PARTICULARLY
FOR TUESDAY AND BEYOND. THE ECMWF HAD BEEN STABLE FOR MULTIPLE
RUNS BUT THE 01.00Z EDITION NOW FEATURES A MUCH DEEPER TROUGH OVER
NEW ENGLAND AND A SLIGHTLY BEEFIER RIDGE INTO SOUTH CENTRAL
CANADA. THIS ESSENTIALLY LEADS TO THE STATIONARY FRONT THAT HAD
BEEN DRAPED NICELY FROM NODAK TO CENTRAL/SRN MN AND SRN WI...TO BE
POSITIONED FURTHER SOUTH FROM SODAK TO CENTRAL IA AND NRN IL. THIS
WOULD MEAN A DRIER FORECAST FOR THE MAJORITY OF THE CWA...EXCEPT
PERHAPS FAR SRN MN WHERE IT COULD ACTUALLY BE WETTER. NOT ONLY
DOES THE DEEPER TROUGH IN THE NORTHEAST RESULT IN A FURTHER SOUTH
FRONTAL POSITION...BUT IT WOULD ALSO DELAY THE MAIN WAVE FROM
EJECTING EASTWARD AS QUICKLY AND WOULD RESULT IN REPEATED SHOWER/STORM
DEVELOPMENT THROUGH DAY 7. THE GFS ENSEMBLES DID SUPPORT A
SOUTHWARD TREND TO SOME DEGREE...BUT NOT A FAR SOUTH AS THE ECMWF.
BECAUSE THIS IS A VERY RECENT DEVELOPMENT...OPTED TO STAY THE
COURSE FOR NOW AND AWAIT BETTER CONTINUITY WITH FUTURE SOLUTIONS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1208 PM CDT FRI AUG 1 2014

THE CUMULUS DECK WILL BECOME MORE EXTENSIVE THIS AFTERNOON...WITH
SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP GENERALLY
ALONG/NORTH OF INTERSTATE 94 FROM CENTRAL MN INTO WEST CENTRAL WI.
THE MOST-AFFECTED SITES WILL BE KSTC-KRNH-KEAU...WITH KMSP AND
KAXN BEING ON THE SOUTHERN/WESTERN FRINGES OF THE ACTIVITY. HAVE
MAINTAINED TEMPOS AT WI SITES...AND VC MENTIONS AT MN SITES /WITH
THE EXCEPTION OF KEEPING KRWF DRY/. SKIES CLEAR THIS EVE AND WINDS
DECREASE TO AOB 5 KTS...WITH BR POSSIBLE AT WEST CENTRAL WI
SITES...ESPECIALLY WHERE PRECIP OCCURS. HAVE INCLUDED MVFR/IFR VSBY
RESTRICTIONS AT KRNH/KEAU...BUT THAT COULD BE EVENTUALLY LOWERED
TO LIFR. SCT-BKN MID LEVEL CLOUDS ARE EXPECTED AGAIN
SATURDAY...WITH WINDS VEERING TO SOUTH-SOUTHWEST AS A TROUGH NOSES
INTO WEST CENTRAL MN.

KMSP...
KMSP IS EXPECTED TO BE ON THE SRN/WRN FRINGES OF THE MAIN AREA OF
SHRA/TS THIS AFTERNOON...SO HAVE HELD ONTO THE VCTS MENTION VERSUS INCLUDING
A TEMPO AT THIS POINT. CUMULUS CLOUDS CLEAR OUT THIS EVE AND
NORTHWEST WINDS DECLINE BELOW 5 KTS AND GRADUALLY VEER TO
SOUTHERLY IN DIRECTION. BKN MID CLOUDS EXPECTED AGAIN BY LATE
MORNING.

/OUTLOOK FOR KMSP/
SAT NIGHT...VFR. SLIGHT CHANCE TSRA. WINDS VARIABLE 5 KTS.
SUN...VFR. SLIGHT CHANCE TSRA. WINDS SW 5-10 KTS.
MON...VFR. CHANCE TSRA. WINDS ESE 5-10 KTS.
TUE...VFR. CHANCE MVFR IN TSRA. WINDS EAST 5-7KTS.

&&

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

$$


SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...LS





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