Area Forecast Discussion
Issued by NWS Twin Cities, MN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KMPX 041816
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
116 PM CDT FRI SEP 4 2015

.SHORT TERM...(THIS EVENING AND SATURDAY)
ISSUED AT 117 PM CDT FRI SEP 4 2015

ALTHOUGH WE HAVE PLENTY OF INSTABILITY IN PLACE TODAY WITH
DEWPOINTS IN THE LOW/MID 70S...SHEAR/FORCING ARE CURRENTLY
LACKING. HOWEVER...A SHORTWAVE PUSHING IN FROM THE DAKOTAS SHOULD
HELP DRIVE AT LEAST LIGHT SHOWERS INTO WEST/NORTH CENTRAL MN THIS
AFTERNOON AND EVENING. SEEMINGLY BETTER CHANCES ARRIVE TONIGHT AS
A 30-40KT LLJ DEVELOPS AND A WEAK PV ADVECTION SIGNATURE MOVES
OVERHEAD. THESE MECHANISMS ARE SOMEWHAT DISJOINTED HOWEVER...AND
CAMS MODELS ARE MORE DRY THAN WET. THEREFORE CONFIDENCE IS RATHER
LOW...SO HAVE MAINTAINED 20-30 POPS. LOW TEMPS WILL REMAIN QUITE
MILD GIVEN THE ELEVATED DEWPOINTS AND CLOUD COVER. ANTICIPATE LOWS
SIMILAR TO THURSDAY NIGHT...RANGING FROM THE UPPER 60S TO MID 70S.

AN EVEN WARMER AND MORE HUMID DAY IS EXPECTED FOR SATURDAY...WITH
LITTLE TO NO CHANGE IN DEWPOINTS OR WINDS...AND EVEN SLIGHTLY
WARMER TEMPS NOSING INTO EAST/SOUTH CENTRAL MN. WILL HAVE SOME
AREAS NEARING HEAT ADVISORY CRITERIA...PARTICULARLY THE TWIN
CITIES METRO AREA WHERE HEAT INDICES ARE FORECAST IN THE MID 90S.
INSTABILITY WILL REMAIN HIGH...WITH EVEN GREATER PWAT VALUES
APPROACHING 2 INCHES. HAVE MAINTAINED 20-30 POPS FOR THE
AFTERNOON HOURS...BUT HIGHER CHANCES WILL ARRIVE ON SATURDAY
EVENING AS A STRONGER MID LEVEL SHORTWAVE APPROACHES.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 249 AM CDT FRI SEP 4 2015

SATURDAY AND SUNDAY...MAIN UPR LVL RIDGE AXIS WILL LOCATE ITSELF
OVER THE ERN SEABOARD COME SAT MRNG BUT A TRAILING SECONDARY RIDGE
WILL ALLOW FOR HIGH HEAT AND HUMIDITY TO REMAIN OVER THE AREA FOR
SATURDAY. HIGHS WILL AGAIN HIT THE MID-UPR 80S FOR THE ENTIRE CWFA
WITH DEWPOINTS IN THE LWR 70S DUE TO A CONTINUED DEEP PLUME OF
MOISTURE FROM THE DEEP SOUTH. THIS WILL CREATE HEAT INDEX VALUES
INTO THE MID 90S FOR MUCH OF THE AREA. RELATED TO THE MOISTURE
SURGE WILL BE PWATS INCRG TO ARND 1.75 INCHES...POSSIBLY AS HIGH
AS 2.0 INCHES. THIS WILL BE A LARGE FACTOR IN CONJUNCTION WITH A
SHORTWAVE DISTURBANCE RIDING ATOP THE SECONDARY RIDGE THRU THE
CENTRAL PLAINS ON INTO THE UPR MISS RIVER VALLEY SAT NIGHT INTO
SUN MRNG. THIS WILL HELP PROMOTE SCTD SHWRS/TSTMS STARTING IN WRN
MN DURG THE DAY ON SAT...GRADUALLY PUSHING EWD SAT NIGHT INTO SUN
WITH STEADILY INCRG COVERAGE. THE HIGH PWATS COMBINED WITH WEAK
STORM MOTIONS AND STORM TRAINING MAY WELL LEAD TO PERIODS OF HEAVY
RAIN...PARTICULARLY SAT NIGHT INTO SUN. THERE LOOKS TO BE MODEST
0-6KM SHEAR IN THE 25-30KT AREA WHICH...WITH PROFILES SHOWING
VEERING WITH HEIGHT...COULD PROMOTE ISOLD STRONG/SEVERE TSTMS SAT
NIGHT BUT THE POTENTIAL IS ONLY MARGINAL. A DEVELOPING CDFNT OVER
THE PLAINS SAT NIGHT INTO SUN MRNG...IN ADVANCE OF A CUTOFF LOW
SHIFTING NEWD INTO WRN CANADA...WILL STEADILY PUSH THRU THE REGION
SUN AND HELP PUSH THE PRECIPITATION OFF TO THE E LATE DAY SUN THRU
SUN NIGHT. IN ADDITION...THE INCREASED CLOUD/RAIN COMPLICATIONS ON
SUNDAY WILL MAKE FOR SLIGHTLY LOWER MAX TEMPS AND HEAT INDEX
VALUES /ALTHOUGH HEAT INDICES IN THE LWR 90S CANNOT BE RULED OUT
AT ALL/.

MONDAY THROUGH THURSDAY...WITH THE CDFNT E OF THE AREA BY MON
MRNG...MUCH COOLER/DRIER AND MORE STABLE AIR WILL MOVE INTO THE
AREA MON WITH THE ARRIVAL OF HIGH PRES. HOWEVER...THIS HIGH PRES
AIRMASS WILL BE SHORT-LIVED DUE TO PROGRESSIVE ZONAL FLOW ALOFT.
ANOTHER AREA OF LOW PRES LOOKS TO SKIRT THE REGION TO THE
SOUTH...SPREADING ISOLD/SCTD SHWRS AND TSTMS ACRS THE AREA...
MAINLY OVER SRN PORTIONS. THIS SYSTEM THEN EXITS TO THE E ON
TUE...FOLLOWED BY HIGH PRES THAT WILL LAST THROUGH THE MIDDLE OF
THE WEEK AND ALLOWING FOR A DRY FCST. AS ALLUDED TO ABOVE... MUCH
COOLER TEMPERATURES WILL TAKE HOLD OF THE REGION STARTING MON.
HIGHS WILL DROP BACK TO THE UPR 60S TO MID 70S WITH LOWS FALLING
TO THE UPR 50S TO MID 50S ALONG WITH MUCH LOWER HUMIDITY LEVELS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 117 PM CDT FRI SEP 4 2015

LIGHT SHOWERS WILL BE IN THE VICINITY OF THE WESTERN SITES /KAXN
AND KRWF/ THIS AFTERNOON/EVE...BUT VFR CONDITIONS ARE EXPECTED
THROUGH TONIGHT. THE ONE EXCEPTION WILL BE WITH LIGHT FOG
FORMATION THAT IS EXPECTED DURING THE EARLY MORNING HOURS.
ASSOCIATED VSBYS SHOULD GENERALLY BE MVFR OR BETTER. AFTER
THAT...SCT-BKN MID CLOUDS PREVAIL. SHOWER AND THUNDERSTORM CHANCES
INCREASE EARLY IN THE NEXT PERIOD /AFTER 00Z SAT/. WINDS REMAIN
SOUTH/SOUTHEAST THROUGH THE PERIOD WITH GUSTS INTO THE MID/UPPER
TEENS /KNOTS/ DURING THE DAYTIME HOURS.

KMSP...
COULD SEE SOME SHOWERS IN THE VICINITY OF THE AIRPORT THIS
EVE...BUT OVERALL DRY CONDITIONS EXPECTED THROUGH THIS PERIOD.
ALSO ANOTHER CHANCE FOR MINOR VSBY REDUCTIONS TO 5SM-6SM AROUND
DAYBREAK SATURDAY DUE TO BR. SOUTHEAST WINDS LOSE THE GUSTS THIS
EVE...BUT PICKUP AGAIN AND MORE FROM THE DUE SOUTH AROUND/AFTER
15Z SAT.

/OUTLOOK FOR KMSP/
SUN...VFR WITH MVFR/TSRA LIKELY AT TIMES. WIND SW AT 15G20KT.
MON...MVFR/TSRA POSSIBLE EARLY. THEN VFR. WIND NE AT 5-10KT.
TUE...VFR. WIND NNW AT 10KT.

&&

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

$$

SHORT TERM...LS
LONG TERM...JPC
AVIATION...LS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.