Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 141803
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
103 PM CDT SUN SEP 14 2014

.UPDATE...

18Z AVIATION DISCUSSION ADDED BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SUN SEP 14 2014

PRECIPITATION CHANCES TONIGHT WERE THE MAIN CONCENTRATION IN THE
SHORT TERM PORTION OF THE FORECAST...WITH AN OTHERWISE BENIGN
24-HOUR PERIOD.

A SURFACE TROUGH WILL PASS ACROSS THE AREA TODAY WHILE A SHORTWAVE
ALONG THE SOUTHERN PERIPHERY OF THE MEAN CANADIAN TROUGH MOVES OVER
THE AREA. MOISTURE IS LACKING...BUT A POCKET OF DECENT 700-600MB
FRONTOGENESIS AND PV ADVECTION NOSE INTO SOUTHERN MN
TONIGHT...PRIMARILY BETWEEN 06Z AND 12Z MONDAY. HAVE INCLUDED CHANCE
POPS GENERALLY ALONG AND SOUTH OF A REDWOOD FALLS TO EAU CLAIRE
LINE...WITH LIKELY POPS CONFINED TO THE INTERSTATE 90 CORRIDOR.

IN THE MEANTIME...WEAK COLD AIR ADVECTION IN THE WAKE OF THE TROUGH
WILL YIELD TEMPERATURES ON THE COOL SIDE OF NORMAL FOR
MID-SEPTEMBER. SHOULD SEE HIGHS TOP OUT FROM AROUND 60 DEGREES IN
CENTRAL MN TO NEAR 65 ALONG THE IOWA BORDER. EXTENSIVE CLOUD COVER
SHOULD ACT AS A SUFFICIENT BLANKET TONIGHT AND INHIBIT FROST
CONCERNS...WITH LOWS IN THE 40S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 253 AM CDT SUN SEP 14 2014

SUNDAY NIGHTS SHRTWV ENERGY AND ASSOCIATED AREA OF SHRA WILL
QUICKLY MOVE OFF TO THE SE BY MONDAY MORNING...AS STRONG
SUBSIDENCE DEVELOPS.

HIGH PRESSURE WILL DOMINATE THE UPPER MIDWEST THRU MOST OF THE
UPCOMING WEEK WITH SLIGHTLY BELOW NORMAL TEMPS AND DRY CONDS.
THERE WILL BE A BIG PATTERN CHG DEVELOPING ACROSS THE GULF OF
ALASKA WITH A MEAN TROUGH SETTING UP IN THIS REGION. DOWNSTREAM
ACROSS THE UPPER MIDWEST A STRONG FRONTAL BOUNDARY WILL MOVE
ACROSS THE AREA...INCREASING THE CHC/S OF SHRA/TSRA BY FRI/SAT.
THICKNESS VALUES RISE SIGNIFICANTLY AHEAD OF THIS FEATURE...BUT
QUICKLY DECREASES FOR A SHORT PERIOD NEXT WEEKEND.

AS MENTION BEFORE...A BIG PATTERN CHG IS EXPECTED IN THE GULF OF
ALASKA WHICH WILL LEAD TO THE UPPER JET MOVING FURTHER NORTHWARD
ACROSS CANADA. THIS WILL TRANSLATE TO A WARMER PATTERN FOR OUR
REGION. THIS IS ALSO ADVERTISED IN THE LATEST GFS ENSEMBLE 50H
MEAN AND ANALOG COMPOSITE FOR THE WEEK OF SEPT 21ST. THESE ANALOGS
INDICATED THAT THERE WAS A STRONG UPPER RIDGE BUILDING ACROSS
CENTRAL CANADA...WITH A STRONG TROUGH IN THE GULF OF ALASKA.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1249 PM CDT SUN SEP 14 2014

COLD FRONT IN THE PROCESS OF CLEARING EAU...WITH POST FRONTAL
STRATOCU SNEAKING DOWN INTO CENTRAL MN. AXN WILL HAVE AT LEAST
A COUPLE OF HOURS OF MVFR CIGS. THESE CLOUDS MAY GET AS FAR SOUTH
AS STC...BUT NOT EXPECTING THEM ANY FARTHER SOUTH THAN THAT. BIG
QUESTION FOR TONIGHT IS HOW FAR NORTH WILL PRECIP MAKE IT. THE
COMPLICATING FACTOR IS THE DRY AIR THAT WILL EXIST BELOW THE
FORCING...BUT THE RAP/HRRR/NAM SHOW SOME LIGHT RAIN GETTING UP TO
RWF/MSP/EAU. DID INTRODUCE SOME -RA TO RWF...BUT FEEL DRY AIR WILL
BE STOUT ENOUGH WITH SFC HIGH DROPPING SOUTH TO KEEP MSP/EAU TO
REPORTING VIRGA.

KMSP...BEGINNING TO SEE INDICATIONS WITH SOME OF THE SHORT TERM
MODELS THAT RAIN MAY GET AS FAR NORTH AS MSP...BUT WE WILL HAVE A
PRETTY STRONG AND DEEP LAYER OF DRY AIR BELOW THE PRECIP THAT
SHOULD ALLOW FOR NOTHING MORE THAN VIRGA. EVEN IF PRECIP DOES
REACH THE GROUND...SAID DRY AIR WILL KEEP CIGS VFR...WHILE RATES
WILL NOT BE STRONG ENOUGH TO DROP VSBYS. OTHER THAN
THAT...CONFIDENCE IS HIGH WITH THE REMAINING ASPECTS OF THE TAF.

/OUTLOOK FOR KMSP/
TUE...VFR. WINDS SW AT 10 KTS.
WED...VFR. WINDS SSE AT 5 KTS.
THU...VFR. WINDS SE AT 10 KTS.

&&

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

$$

SHORT TERM...LS
LONG TERM...JLT
AVIATION...MPG





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