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 020610
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
110 AM CDT THU OCT 2 2014

.UPDATE...
ISSUED AT 1049 PM CDT WED OCT 1 2014

ISSUED A DENSE FOG ADVY FOR THE ERN HALF OF OUR MN AND MOST OF
OUR WI CWA. COLD FRONT IS MAKING LITTLE IF ANY PROGRESS EAST AND
AT 11 PM WAS ONLY TO A REDWOOD FALLS TO LONG PRAIRIE LINE...WITH
WIDESPREAD IFR/LIFR STRATUS ALREADY IN PLACE. WITH LIGHT
WINDS AND MOIST BOUNDARY LAYER FROM RAINS YESTERDAY...EXPECT THIS
STRATUS TO DESCEND TO THE GROUND AND BECOME DENSE FOG TONIGHT.
INITIAL AREA ISSUED FOR WAS BASED ON WHERE THE HRRR SHOWS DENSE
FOG FORMING...ALONG WITH WHERE THE 21Z HOPWRF SHOWS 75% OR GREATER
PROBABILITIES FOR VISIBILITIES LESS THAN A HALF MILE. WILL WATCH
VISIBILITY TRENDS THE NEXT COUPLE OF HOURS...BUT THINKING WE WILL
PROBABLY HAVE TO FILL IN RUSK/CHIP/EAU CLAIRE COUNTIES AS WELL. IF
FRONT DOES NOT MAKE MUCH MORE PROGRESS EAST IN THE NEXT COUPLE OF
HOURS...MAY HAVE TO ADD A ROW OR TWO OF COUNTIES ON THE WEST END
AS WELL...BUT FOR NOW...AREA WITH HIGHEST CONFIDENCE FOR SEEING
DENSE FOG IS HIGHLIGHTED IN THE ADVY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 316 PM CDT WED OCT 1 2014

AFTERNOON ANALYSIS SHOWS A STACKED LOW OVER MANITOBA...WITH THE
ASSOCIATED BOUNDARY STRADDLING THE MN/DAKOTAS BORDER. THE FIRST
RELATED WAVE OF LIFT GENERATED A HEALTHY AREA OF SHOWERS THAT WILL
CONTINUE TO LIFT FROM EAST CENTRAL MN AND WEST CENTRAL WI TOWARD
LAKE SUPERIOR. IN ITS WAKE...RESIDUAL LOW LEVEL MOISTURE AND LIGHT
WINDS WILL CONTRIBUTE TO PESKY STRATUS AND FOG DEVELOPMENT TONIGHT
INTO THURSDAY. WILL NEED TO WATCH WEST CENTRAL WISCONSIN WHERE
CONDITIONS COULD LEAD TO DENSE FOG OVERNIGHT...PARTICULARLY NEAR EAU
CLAIRE.

ON THURSDAY...THE NEXT WAVE EJECTS NORTHEAST ACROSS THE AREA FROM
THE SOUTHERN STREAM SYSTEM. EXPECT ANOTHER ROUND OF RAIN WITH A FEW
THUNDERSTORMS TO BLOSSOM OVER SOUTH/EAST CENTRAL MN AND WEST CENTRAL
WI THURSDAY AFTERNOON. THE PRIMARY UNCERTAINTY IS HOW FAR WEST THE
PRECIPITATION SHIELD WILL EXTEND. HAVE LEANED TOWARD THE NAM/ECMWF
WHICH RESTRICT THE CATEGORICAL POPS EAST OF A REDWOOD FALLS TO ST
CLOUD MN LINE. HAVE INCLUDED 70-80 POPS ALONG AND EAST OF THE
INTERSTATE 35 CORRIDOR FOR THURSDAY AFTERNOON.

TEMPERATURES TONIGHT WILL HANG IN THE UPPER 40S TO MID 50S UNDER THE
EXTENSIVE CLOUD COVER...WITH LOW/MID 60S ANTICIPATED FOR THURSDAY.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 PM CDT WED OCT 1 2014

THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE LONG TERM FORECAST PICKS UP
DURING QUITE AN ACTIVE PERIOD OF WEATHER.  AN IMPRESSIVE FALL LOW
PRESSURE SYSTEM WILL BE COMING TOGETHER ACROSS THE MIDWEST BY
THURSDAY EVENING...AND WILL SPREAD MODERATE TO HEAVY RAIN AT TIMES
INTO SOUTHEASTERN MINNESOTA THROUGH WESTERN WISCONSIN.  AT THIS
TIME...AN UPPER LEVEL TROUGH THAT IS POSITIONED OVER THE FOUR
CORNERS REGION TODAY...WILL LIFT NORTHEAST AS IT BEGINS TO PHASE
WITH A DEEPLY AMPLIFIED NORTHERN TROUGH DROPPING SOUTHEAST FROM
ALBERTA THROUGH SASKATCHEWAN. STRONG FRONTOGENESIS...ACCOMPANIED BY
DECENT DIFFERENTIAL DIVERGENCE AND STRONG ISENTROPIC LIFT WILL BE
FOCUSED FROM A LINE NEAR FAIRMONT...THROUGH THE EAST METRO TOWARD
TAYLORS FALLS AND AREAS TO THE EAST.  THE SURFACE LOW WILL ADVANCE
NORTHEAST FROM MISSOURI TO NEAR GREEN BAY BY MIDNIGHT THURSDAY
NIGHT...AND WILL RAPIDLY DEEPEN OVERNIGHT THROUGH MUCH OF FRIDAY AS
THE NORTHERN AND SOUTHERN TROUGHS PHASE TOGETHER.  FOR MUCH OF
CENTRAL AND ESPECIALLY WESTERN MINNESOTA...FRIDAY WILL BE MOSTLY
DRY.  HOWEVER...THE DEEPENING SURFACE LOW WILL CREATE VERY WINDY
CONDITIONS AS A 1030MB SURFACE HIGH MOVE IN TO MONTANA...MEANING
QUITE A TIGHT PRESSURE GRADIENT IS EXPECTED ACROSS THE UPPER MIDWEST
THROUGH THE DAY.  THE CENTER OF THE UPPER TROUGH WILL BE OVERHEAD BY
MID DAY...AND STRONG COLD AIR ADVECTION WILL HOLD DAYTIME
TEMPERATURES ABOUT 20 DEGREES BELOW SEASONAL NORMALS.  COLD AIR
ADVECTION LOOKS STRONGER AT THIS POINT WITH 850H TEMPS OF -4 TO
-6...SO COOLED HIGH TEMPS FRIDAY BY ABOUT TWO TO THREE DEGREES
EVERYWHERE...MEANING MOST WILL SEE HIGHS IN THE 40S...WITH WIND
CHILL VALUES LOWER THAN THAT.  ON FRIDAY NIGHT...MODELS INDICATE AN
AREA OF DECENT THETA-E ADVECTION MOVING THROUGH ON THE BACKSIDE OF
THE SYSTEM WHICH MAY PRODUCE LIGHT PRECIP ACROSS THE EASTERN HALF OF
THE CWA.  TEMPERATURES LOOK TO BE COLD ENOUGH FOR MIXING IN SOME
SNOWFLAKES OVERNIGHT...ESPECIALLY ACROSS WESTERN WISCONSIN...BUT AT
THIS TIME NO ACCUMULATION IS EXPECTED.

SATURDAY THROUGH MONDAY...DURING THIS PERIOD...THE AFOREMENTIONED
FALL SYSTEM WILL ADVANCE NORTH TOWARD HUDSON BAY AND CONTINUE
DEEPENING INITIALLY.  MAINLY DRY CONDITIONS ARE IN THE FORECAST FOR
OUR AREA.  THE UPPER TROUGH WILL KEEP THE STRONG NORTHWEST WIND
FLOWING OVER OUR AREA DURING THIS TIME...MEANING QUITE A COLD
WEEKEND IS IN STORE.  EARLY SATURDAY MORNING...TEMPERATURES IN THE
30S WILL BE COMMON...WITH AREAS IN THE NORTHWEST POTENTIALLY
DROPPING BELOW FREEZING. FROM SUNDAY THROUGH MONDAY...THE STRONG
SYSTEM WILL RETROGRADE TO JUST SOUTHWEST OF THE HUDSON BAY AND
BECOME VERTICALLY STACKED.

MONDAY NIGHT THROUGH WEDNESDAY...THE WEAKENING SYSTEM WILL BEGIN
PUSHING EAST AND 850H TEMPS WILL BE ON THE RISE. TEMPERATURES ARE
EXPECTED TO RETURN TO THE 60S FOR HIGHS ON TUESDAY. DISAGREEMENT
REMAINS BETWEEN THE GFS/EC ABOUT THE UPPER PATTERN TOWARD THE MIDDLE
AND END OF NEXT WEEK...WHICH WILL DICTATE TEMPERATURES ACROSS THE
MIDWEST.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1254 AM CDT THU OCT 2 2014

TWO CONCERNS THE TAF PERIOD ARE THE DENSE FOG IN THE PROCESS OF
FORMING AND THE TIMING OF RAIN LATE THIS MORNING INTO THE
AFTERNOON. AT 6Z...THE FRONT IS ONLY TO ABOUT A RWF TO LONG
PRAIRIE LINE. EAST OF THE FRONT IT IS UGLY...WITH LIFR CIGS
QUICKLY BECOMING 1/4SM OR LESS FG. AXN WILL REMAIN WEST OF THE
FOG...AM HOPING THE FRONT WILL WORK THROUGH RWF ENOUGH TO KEEP
THEM OUT OF THE FOG...BUT WILL BE CLOSE. FOR STC/MSP/RNH/EAU...
CONFIDENCE IS HIGH THAT DENSE FOG WILL BE A SIGNIFICANT ISSUE
THROUGH 15Z. ONLY QUESTION REALLY IS WHEN DOES IT HAPPEN. HAVE IT
HAPPENING AT MSP THE LATEST. AREA OF RAIN CURRENTLY IN CENTRAL NEB
WILL BE HEADING THIS WAY THIS MORNING. STUCK CLOSE TO A
GFS/HRRR/RAP/HOPWRF BLEND FOR BRINGING RAIN ACROSS ALL MN
TERMINALS THIS MORNING AND WI TERMINALS THIS AFTERNOON. WINDS WILL
REMAIN FAIRLY LIGHT THROUGH TODAY...BUT THU EVENING...WE WILL
FINALLY START TO GET SOME PRESSURE RISES INTO WRN MN...MARKING THE
BEGINNING OF WHAT WILL BE A BREEZY THU NIGHT AND FRIDAY.

KMSP...HAVE HIGH CONFIDENCE IN DENSE FOG SIGNIFICANTLY IMPACTING
THE MORNING PUSH THIS MORNING AT MSP. GIVEN HOW WIDESPREAD THE
DENSE FOG IS AROUND THE CITIES AT 6Z...MSP WILL NOT BE ESCAPING
THE FOG. THE MAIN QUESTION IS HOW LOW TO GO WITH VSBYS...BUT
CURRENT TAF MAY NOT BE LOW ENOUGH. THERE IS A HIGH CHANCE THAT
VISIBILITIES THIS MORNING WILL DROP BELOW AIRPORT MINIMUMS...WITH
SIGNIFICANT IMPACTS TO AIRPORT ARRIVAL RATES LIKELY BETWEEN 10Z
AND 14Z. AFTER THAT...STUCK CLOSE TO WHAT THE PREVIOUS TAF HAD
FOR THE TIMING OF RAIN INTO THE FIELD...AND LOOKS LIKE WE WILL SEE
ANOTHER SEVERAL HOUR ROUND OF RAIN THIS AFTERNOON...MUCH LIKE WE
SAW YESTERDAY. BY THE END OF THE TAF...MSP WILL START FEELING THE
STRONGER WINDS...BUT THE MORE SIGNIFICANT NW WINDS AND GUSTS WILL
NOT NEED TO SHOW UP UNTIL THE LAST 6 HOURS OF THE 12Z TAF PACKAGE.

/OUTLOOK FOR KMSP/
FRI...MAINLY MVFR WITH CHC -SHRA. WINDS WNW 20G30 KTS.
SAT...VFR. WINDS NW 10-15 KTS.
SUN...VFR. WINDS NW 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ043>045-
     050>053-059>063-066>070-074>078-082>085-091>093.

WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ014-015-
     023>026.

&&

$$

UPDATE...MPG
SHORT TERM...LS
LONG TERM...SPD
AVIATION...MPG






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