Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 021740
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1240 PM CDT THU JUL 2 2015

.UPDATED FOR 18Z AVIATION DISCUSSION...
ISSUED AT 1234 PM CDT THU JUL 2 2015

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM CDT THU JUL 2 2015

WE ARE LOOKING AT A FAIRLY QUIET SHORT TERM WITH JUST A FEW PASSING
HIGH CLOUDS AND CONTINUED MILD TEMPERATURES.

THERE IS A PRONOUNCED SHORTWAVE CURRENTLY MOVING ACROSS THE NORTHERN
PLAINS AND EVER CLOSER TO WESTERN MN EARLY THIS MORNING. THERE IS
ALSO A DECENT 500MB JET ORIENTATED FROM NW-SE ACROSS MT/WY/SD AND
NOSING INTO NORTHERN NE. THESE FEATURES COMBINED WITH 500-1000 J/KG
OF MLCAPE ARE PRODUCING THE TWO-THREE CLUSTERS OF THUNDERSTORMS IN
ND/SD/NE. THIS ACTIVITY IS EXPECTED TO CONTINUE MOVING EAST-
SOUTHEAST THROUGHOUT THE MORNING WITH A GRADUALLY WEAKENING TREND AS
THE STORMS ENCOUNTER MORE STABLE AIR ACROSS THE FAR EASTERN DAKOTAS
AND IN WESTERN MN. THAT IS NOT TO SAY SOME OF THIS ACTIVITY WONT
LIMP INTO WEST CENTRAL AND SOUTHWEST MN...BUT THE CURRENT THINKING
IS THAT THE ACTIVITY DOESNT WARRANT LIKELY WORDING. THE SHORTWAVE
SHOULD DRIVE MOST OF THE ACTIVITY SOUTHWEST OF THE FORECAST. WE
INCLUDED A FEW HOURS OF 20-40% RAIN WITH THUNDERSTORMS FOR THE
POTENTIAL THAT THIS ACTIVITY IMPACTS OUR WESTERN FORECAST AREA LATER
ON THIS MORNING...PERHAPS INTO THE EARLY AFTERNOON. OTHERWISE...WE
ARE ONCE AGAIN SEEING A LITTLE LIGHT FOG OUT THERE THIS MORNING
GIVEN THE CALM WIND AND NEARLY CLOUD FREE SKIES. THERE WILL BE MORE
SUN TODAY AS COMPARED TO YESTERDAY...SO UPPER 70S FOR HIGHS SHOULD
BE ATTAINABLE. LOW TO MID 70S ARE MORE LIKELY IF WE HOLD ONTO MORE
MID CLOUDS THROUGH THE DAY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 416 AM CDT THU JUL 2 2015

CONCERNS IN THE LONG TERM ARE FOCUSED ON PRECIPITATION EVENTS FOR
TWO PERIODS...FRIDAY/FRIDAY NIGHT AND THEN FROM SUNDAY INTO MONDAY.
MODEL SOLUTIONS ARE CONSISTENT ON DRIVING ONE FINAL SHORT WAVE
ACROSS US IN THE NORTHWEST FLOW FRIDAY AFTERNOON AND EVENING.
ASSOCIATED WITH THIS IS A BACK DOOR COLD FRONT THAT SAGS INTO THE
NORTH METRO LATE IN THE DAY AND THEN BECOMES STATIONARY OVERNIGHT.
ARW/NMM AND THE NAMNEST SHOW WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS DEVELOPING ALONG THE FRONT IN NORTHERN MN LATE
FRIDAY MORNING AND THEN DROPPING SLOWLY INTO CENTRAL MN AND
NORTHERN WI DURING THE AFTERNOON...PERHAPS REACHING AT LEAST THE
NORTH METRO OF THE TWIN CITIES BY EVENING. THEREFORE...BROUGHT
SOME SMALL POPS SOUTHWARD ALONG THE FRONT THROUGH THE DAY ON
FRIDAY WITH SMALL POPS LINGERING FRIDAY EVENING FROM WEST OF THE
METRO THROUGH MUCH OF OUR WEST CENTRAL WI COUNTIES.

THE FRONT WILL WASH OUT ON SATURDAY AS THE LOW LEVEL FLOW BECOMES
MORE SOUTHERLY WHILE SHORTWAVE RIDGING PASSES BY ALOFT. THIS LEADS
INTO SUNDAY WHEN A CHANGE IN THE UPPER AIR PATTERN BEGINS WITH
MORE OF A WESTERLY FLOW AS A LARGE UPPER LOW BEGINS MOVING ACROSS
CENTRAL CANADA. THIS FEATURE RIGHT NOW IS MOVING NORTHEAST FROM
THE GULF OF ALASKA AND IS QUITE IMPRESSIVE IN WV IMAGERY. AN
ASSOCIATED COLD FRONT IS STILL ON TRACK TO MOVE INTO NORTHWEST
MINNESOTA SUNDAY AFTERNOON. THE EASTWARD PROGRESSION OF THE FRONT
HAS BECOME A LITTLE SLOWER ON THE 00Z ECMWF VERSUS THE 12Z RUN.
THE GFS HAS REMAINED QUITE CONSISTENT WITH THE FRONT REACHING THE
TWIN CITIES BY MONDAY MORNING AND PASSING EAST OF EAU CLAIRE
MONDAY AFTERNOON. THE SLOWER MOVEMENT BY THE ECMWF IS A LITTLE
TROUBLESOME AND NEEDS TO BE WATCHED. IT/S A REFLECTION OF SMALL
WAVES MOVING NORTHEAST ALONG THE FRONT SUNDAY NIGHT AND MONDAY.
MOST TIMES IT WOULDN/T BE A BIG ISSUE...BUT ONCE AGAIN PW VALUES
ARE FORECAST TO CLIMB TO A LITTLE OVER 2 INCHES SUNDAY NIGHT AND
MONDAY ACROSS EASTERN/SOUTHERN MN AND WESTERN WI. THIS IS NEARLY
AT THE TOP OF OUR SOUNDING CLIMATOLOGY AND WELL ABOVE THE 90TH
PERCENTILE. HENCE...HEAVY RAIN IS BECOMING A CONCERN WITH THE
SHOWERS AND THUNDERSTORMS SUNDAY NIGHT AND MONDAY. A CHECK OF THE
CIPS ANALOG GUIDANCE FOR THIS PERIOD SHOWS SOME SMALL PROBABILITIES
NEAR THE TWIN CITIES FOR MORE THAN 2 INCHES OF RAIN.

ONCE THE WAVE CLEARS THE REGION LATE MONDAY...AN AREA OF HIGH
PRESSURE WILL MOVE IN FOR TUESDAY AND WEDNESDAY WITH DRY WEATHER
AND MUCH LESS HUMID AIR.

HIGH TEMPERATURES REMAIN PROBLEMATIC OVER THE WEEKEND. BLENDED
GUIDANCE SEEMED TOO COOL GIVEN THE 850MB TEMPERATURE PATTERN.
MIX-DOWN WAS MUCH WARMER AND WAS BLENDED IN TO KEEP FORECAST HIGHS
IN THE MIDDLE 80S FOR MOST LOCATIONS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1234 PM CDT THU JUL 2 2015

VFR CONDITIONS THROUGHOUT. LIGHT SOUTHEASTERLY WINDS WILL BECOME
LIGHT SOUTHWESTERLY FRIDAY MORNING.

KMSP...
ONLY THING NOTEWORTHY IS POTENTIAL FOR AFTERNOON SHOWERS...AND
EVEN A THUNDERSTORM FRIDAY AFTERNOON. COVERAGE WILL BE
SCARCE...AND PROBABILITY IS LOW...SO DID NOT MENTION IN THE TAF.
THE BEST TIME PERIOD WOULD BE FROM 21 TO 03Z FRIDAY EVENING.

/OUTLOOK FOR KMSP/

SAT...VFR. WINDS SW 5-10 KTS.
SUN...VFR. WITH MVFR/-TSRA LATE. WINDS S 10-15 KTS.
MON...MVFR/IFR WITH TSRA EARLY. THEN VFR. WINDS NW 10-15 KTS.

&&

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

$$

SHORT TERM...CLF
LONG TERM...RAH
AVIATION...JRB



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