Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 210457 AAA
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1059 PM CST FRI NOV 20 2009

.UPDATED FOR AVIATION DISCUSSION BELOW...

.DISCUSSION...

AREAS OF DENSE FOG EXPECTED CONTINUE TO DEVELOP OVER MAINLY WC WI
DURING THE NIGHT. TEMPS CONTINUE TO COOL WITH LIGHT WINDS AND
CLEAR SKY. SHOULD SEE FOG BURN OFF QUICKLY SATURDAY MORNING AS
GRADIENT BUILDS EAST INTO THE AREA AND SFC RDG EXITS THE REGION.
ISSUED DENSE FOG ADV THROUGH 16Z SAT MORNING.

&&

.AVIATION.../06Z TAF ISSUANCE/

EXPECTING IFR/LIFR CIG/FOG DEVELOPMENT INTO THE KEAU/KRNH AREA
THROUGH ABOUT 15Z SAT.  OTHER MVFR VSBY/FOG IN THE KSTC/KMSP REGION.
OTHERWISE...VFR CONDS OVER THE REMAINDER OF THE REGION AS SFC RDG
MOVES EAST AND GRADIENT DEVELOPS EAST AS LOW PRESSURE TROUGH
DEVELOPS OVER THE DAKOTAS.  THIS SHOULD INCREASE SOUTHERLY WINDS
INTO THE GUSTY CATEGORY OVER MN FA...DEVELOPING THROUGH 18Z SAT.
THEN CIRRUS EXPECTED TO CONTINUE TO DEVELOP EAST AND THICKEN DURING
THE DAY.  GUSTINESS SHOULD SUBSIDE AS TROUGH MOVES INTO THE AREA SAT
EVENING.  MODELS CONTINUE TREND OF DEVELOPING STRATUS SATURDAY
NIGHT.  TIMING IN QUESTION AGAIN WITH THE NAM_WRF PROBABLY A BIT
SLOWER THAN THE GFS THIS RUN.  WILL HINT AT SOME SCT015 LIFTING INTO
THE KRWF/KMSP THROUGH 05Z SUN...AND THEN BKN015 AT KMSP AFTER 09Z.

&&

.PREV DISCUSSION...
/ISSUED 537 PM CST FRI NOV 20 2009/
FORECAST ISSUE IN THE SHORT TERM IS THE POTENTIAL OF FOG...THIS
TIME IN EASTERN SECTIONS OF CWA. METARS STILL SHOWING SOME HZ IN
THE AIR FROM THE TWIN CITIES METRO AREA ON EAST WITH MID CLOUDS ON
THEIR WAY OUT. OVERNIGHT LOWS TONIGHT WILL GENERALLY BE A BIT
COOLER THAN LAST NIGHT WITH LITTLE OR NO CLOUD COVER.

MAX TEMPS TODAY REACHED INTO THE UPPER 40S TO MID 50S ACROSS AREA
THIS AFTERNOON. WITH AIRMASS WARMING TOMORROW IN ESTABLISHED
SOUTHERLY FLOW AND MOSTLY SUNNY SKIES...WILL BE ADD A FEW MORE
DEGREES.  A BIT BREEZY WESTERN MINNESOTA WITH 850 MB WINDS UP INTO
THE 40 KNOT RANGE.

VIGOROUS TROUGH COMING ONSHORE ONTO WEST COAST WITH 12Z 500 MB
HEIGHT FALLS IN 100 METER RANGE.  THIS FEATURE GETS DAMPENED OUT A
BIT AS IT APPROACHES OUR AREA SUNDAY WITH STRONGER TROUGH COMING IN
BEHIND IT. THE CONCERN FOR SATURDAY NIGHT/SUNDAY IS FOR STRATUS TO
IMPACT AREA IN CONTINUED SOUTH FLOW.  EXPANDED AREA OF DRIZZLE
NORTHWARD SOMEWHAT FOR LATE SATURDAY NIGHT. ALSO BUMPED UP MIN TEMPS
JUST A BIT SATURDAY NIGHT WITH SOUTH WINDS AND CLOUDS.

WEAK ISENTROPIC LIFT FOR SUNDAY MAINLY ACROSS EASTERN AREA STILL
GOOD ENOUGH FOR CHANCE POPS AS AIRMASS MOISTENS UP.

SOME DIFFERENCES BETWEEN GFS/ECMWF ON SYSTEM FOR MID WEEK WITH ECMWF
BIT SLOWER WITH SOMEWHAT MORE SOUTHERLY TRACK ON DEEP UPPER LOW.
MAINTAINED HIGH CHANCE POPS...ESPECIALLY SOUTHERN CWA. MAY BE ENOUGH
COLD AIR VICINITY UPPER LOW FOR AT LEAST A MIX...BASED ON GFS
TIMING. ENUF COLD AIR IN PLACE BY LATER TUESDAY NIGHT/WED FOR ANY
PCPN TO BE -SN. INCREASED CLOUD COVER INTO THURSDAY WITH
COOL..CYCLONIC FLOW ACROSS AREA WITH TEMPERATURES CLOSER TO SEASONAL
NORMALS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 10 AM CST SATURDAY FOR GOODHUE.

WI...DENSE FOG ADVISORY UNTIL 10 AM CST SATURDAY FOR BARRON-CHIPPEWA-
     DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX.

&&

$$

DWE/MTF








  • National Weather Service
  • Twin Cities, MN Weather Forecast Office
  • 1733 Lake Drive West
  • Chanhassen, MN 55317-8581
  • 952-361-6670
  • Page Author: MPX Webmaster
  • Web Master's E-mail: w-mpx.webmaster@noaa.gov
  • Page last modified: Nov 10th, 2009 17:50 UTC
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