Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 111941
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
241 PM CDT FRI JUL 11 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 241 PM CDT FRI JUL 11 2014

LATEST VISIBLE IMAGERY SHOWS AN AREA OF EXTENSIVE LOW CLOUDS NEAR
AND DOWNWIND OF THE SURFACE FRONT/TROUGH AXIS WITH A MORE HEALTHY CU
FIELD TRYING TO DEVELOP NEAR ITS BACK EDGE AND POINTS UPSTREAM.
CLOUDS HAVE MANAGED TO BREAK UP SOUTHEAST OF THERE... INCLUDING THE
SOUTHERN AND EASTERN PORTION OF THE TWIN CITIES... IN THE WAKE OF
THIS MORNING/S CONVECTION. INSTABILITY HAS INCREASE ACROSS THE
WESTERN CWFA... WITH MLCAPE VALUES AOA 500 J/KG WITH NEAR 1500 J/KG
OVER THE FAR WEST. A SUBTLE SHORTWAVE FEATURE CAN BE SEEN IN THE
WATER VAPOR IMAGERY MOVING EAST THROUGH THE ZONAL FLOW ACROSS NORTH
DAKOTA AT THE CURRENT TIME. THIS COULD WORK WITH THE WEAK
CONVERGENCE PRESENT NEAR THE SURFACE TROUGH TO GENERATE SOME
ISOLATED/SCATTERED SHRA/TSRA LATE THIS AFTERNOON INTO EARLY THIS
EVENING. THE NAM IS NOT PARTICULARLY OPTIMISTIC ABOUT ANYTHING OVER
OUR AREA... WHILE THE GFS AND ECMWF MANAGE TO SHOW SOME LIGHT PCPN.
THE CAMS ARE A MIXED BAG... WITH MANY SUCH AS THE HRRR AND A COUPLE
HOPWRF MEMBERS KEEPING THINGS GENERALLY DRY... WHILE A COUPLE HOPWRF
MEMBERS AND THE HIRES WINDOW RUNS MANAGE TO SHOW A FEW CONVECTIVE
CELLS. ALLOWED FOR CHANCE POPS OVER THE AREA FROM LATE AFTERNOON
INTO EVENING TO ACCOUNT FOR THE POSSIBILITY OF A FEW SHRA/TSRA
GETTING GOING. OTHERWISE... THE MAIN LARGE SCALE SUPPORT FOR PCPN
THROUGH TOMORROW LOOKS TO SHIFT TO THE SOUTHERN PORTION OF THE AREA
AND EVEN MORE SO PERHAPS INTO IOWA WHERE THE BAROCLINIC ZONE LOOKS
TO STALL OUT AND THE BEST FRONTOGENESIS AND THETA-E ADVECTION IS
EXPECTED. ALLOWED FOR SOME OF THIS TO SPREAD NORTH DURING THE DAY ON
SATURDAY AS THE FLOW STARTS TO AMPLIFY AND WE SEE A SOMEWHAT
HEALTHIER SHORTWAVE ARRIVE FROM THE WEST.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 241 PM CDT FRI JUL 11 2014

THE LONG TERM PORTION OF THE FORECAST WILL BE GREATLY INFLUENCED BY
A HIGHLY AMPLIFIED LARGE SCALE PATTERN...WITH A DEEP TROUGH
DOMINATING EASTERN CANADA/CONUS...AND RIDGING PREVAILING OVER THE
WEST. SAID PATTERN WILL TRANSLATE TO BELOW NORMAL TEMPERATURES FOR
THE EASTERN TWO-THIRDS OF THE CONUS THROUGH MUCH OF NEXT WEEK.

SATURDAY EVENING SHOULD BRING THE EXIT OF ANY LINGERING SHOWERS
AND THUNDERSTORMS...WITH SKIES CLEARING OUT BY SUNDAY.
THUNDERSTORMS LOOK A BIT LESS LIKELY FOR SUNDAY PER THE 12Z MODEL
RUNS...WITH THE ONLY SLIM POTENTIAL APPEARING TO BE OVER FAR
SOUTHERN MN WHERE DIURNALLY-INDUCED ACTIVITY COULD DEVELOP IN THE
WANING BAROCLINIC ZONE.

MONDAY BRINGS THE ARRIVAL OF THE UPPER LOW OVERHEAD...MADE EVIDENT
BY SCATTERED SHOWERS AND TEMPERATURES NEARING 20 DEGREES BELOW
NORMAL. HIGHS IN THE LOW/MID 60S WILL COMBINE WITH BREEZY NORTHWEST
WINDS TO MAKE FOR A CHILLY DAY.

TUESDAY THE TROUGH CENTER WILL HAVE SHIFTED EAST OF THE AREA...SO
SHOWER CHANCES WILL BE MAINLY CONFINED TO WEST CENTRAL WI
COUNTIES. HIGHS WILL MODERATE A TAD...BUT WILL LIKELY STILL TOP
OUT IN THE MID/UPPER 60S.

WEDNESDAY AND THURSDAY THE LOW LIFTS INTO QUEBEC AND HEIGHTS RISE
A BIT. THIS WILL MEAN GRADUALLY MODERATING TEMPERATURES AND DRY
WEATHER...WITH HIGHS IN THE LOW/MID 70S ON WEDNESDAY...AND
MID/UPPER 70S FOR THURSDAY.

BY FRIDAY THE FLOW TRANSITIONS TO NEARLY ZONAL ACROSS THE
CONUS...AS WEAK MID LEVEL TROUGHING OVER SOUTHERN
SASKATCHEWAN/MANITOBA INDUCES HIGH PLAINS SURFACE CYCLOGENESIS.
SOUTHERLY FLOW AHEAD OF THIS FEATURE WILL AID IN FURTHER TEMPERATURE
MODERATION ON FRIDAY...WITH HIGHS IN THE UPPER 70S AND LOWER 80S.
STILL LOOKS TO BE DRY ON FRIDAY...ALTHOUGH THE AFOREMENTIONED
TROUGH SHOULD FACILITATE SHOWER AND THUNDERSTORM CHANCES AT SOME
POINT NEXT WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 156 PM CDT FRI JUL 11 2014

WILL HAVE VARIOUS ISSUES THROUGH THE PERIOD. LINGERING CEILINGS
ACROSS THE AREA SHOULD GENERALLY IMPROVE THROUGH THE AFTERNOON...
WHILE REMAINING MOST FOCUS NEAR AND DOWNSTREAM OF THE FRONT/TROUGH
WHERE SOME MVFR REMAINS. THERE IS A CHANCE FOR A FEW SHRA/TSRA
FROM 21Z THROUGH 03Z AT MOST SITES... BUT COVERAGE IS EXPECTED TO
BE LOW IF THINGS OCCUR... SO LEFT ANY MENTION OUT OF THE FORECAST
FOR NOW. LATER TONIGHT WE COULD SEE SOME FOG AT MOST SITES... AND
IT COULD BE WORSE THAN FORECAST IF WINDS DIE AND WE HAVE LESS IN
THE WAY OF MID-HIGH CLOUDS THAN EXPECTED. HINTED AT SOME LOWER
VISIBILITIES... BUT DID NOT GO AS LOW AS WHAT IS POSSIBLE GIVEN
THE UNCERTAINTY. SHRA/TSRA WILL BE POSSIBLE AGAIN ON SATURDAY...
BUT THERE REMAINS UNCERTAINTY ON HOW FAR NORTH ACROSS THE AREA IT
WILL EXTEND... SO PLAYED THINGS OPTIMISTIC FOR NOW AND DID NOT
INCLUDE TOO MUCH OF A MENTION.

KMSP...CONFIDENCE IN FORECAST SPECIFICS IS LOW GIVEN SLOWLY MOVING
FRONT/TROUGH AND LINGERING BAROCLINIC ZONE WITHOUT ANY SIGNIFICANT
FORCING FEATURE OVER THE AREA. FOG ISSUES AND PERHAPS SOME STRATUS
COULD BE WORSE THAN INDICATED LATER TONIGHT... AND PCPN COULD BE
MORE WIDESPREAD INTO THE AREA LATER TONIGHT.

/OUTLOOK FOR KMSP/
SATURDAY NIGHT...VFR. WEST WIND LESS THAN 10 KT BECOMING NORTH.
SUNDAY...VFR. NORTHWEST WIND 5 TO 15 KT.
SUNDAY NIGHT. MVFR POSSIBLE WITH A CHANCE OF SHRA/TSRA. NORTHWEST
WIND 5 TO 15 KT. MONDAY...MVFR POSSIBLE WITH A CHANCE OF
SHRA/TSRA. NORTHWEST WIND 10 TO 20 KT. MONDAY NIGHT...MVFR
POSSIBLE. NORTHWEST WIND 5 TO 10 KT. TUESDAY...VFR. NORTHWEST WIND
LESS THAN 10 KT.

&&

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

$$

SHORT TERM...TRH
LONG TERM...LS
AVIATION...TRH






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