Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 120403
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1103 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 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1103 PM CDT FRI JUL 11 2014

LOW CONFIDENCE FORECAST OVERNIGHT WITH RESPECT TO THE IFR
CEILING/VSBY POTENTIAL AT KRNH AND KEAU. THE COLD FRONT NEAR AN KAXN
TO KHON LINE HAS HARDLY MOVED THIS EVENING IN RESPONSE TO A WAVE
OF LOW PRESSURE DEVELOPING ON THE TAIL END OF THE FRONT. A FEW
TSRA CONTINUE TO MOVE SE OF KJMR. THESE SHOULD DISSIPATE WHILE
PASSING JUST NE OF KRNH. WITH THE FRONT NEARLY STALLING...THIS HAS
KEPT LOW VFR CLOUDINESS FROM SE MN THROUGH WEST CENTRAL WI FROM
BEING PUSHED EAST. THERE IS STILL A WINDOW OF OPPORTUNITY LATE IN
THE NIGHT FOR THIS CLOUDINESS TO BREAK UP SOME...ALLOWING FOG AND
STRATUS CEILINGS TO FORM. HOWEVER...MORE MID/HIGH LEVEL CLOUDS ARE
ALREADY FILTERING INTO WESTERN MN FROM CONVECTION IN THE WESTERN
HIGH PLAINS. THEREFORE...MODIFIED MAINLY THE LOW VISIBILITY
FORECAST AT KRNH AND KEAU DUE TO MORE HIGHER LEVEL CLOUDINESS BUT
HELD ON TO THE LOW CEILING FORECAST. KMSP...KSTC AND KRWF ARE BETTER
SUITED FOR MVFR FOG ALMOST RIGHT OUT THE GATE...BUT AGAIN...THE
INCREASING MID/HIGH LEVEL CLOUDS SHOULD TEMPER ON HOW LOW VSBYS
GO. HELD ON TO MVFR CIGS FOR A TIME SATURDAY MORNING AT KRNH AND
KEAU AS THE WAVE OF LOW PRESSURE RIDES NORTHEAST ALONG THE FRONT.
SHOWERS AND ISOLATED THUNDERSTORM WILL SPREAD INTO WEST CENTRAL
AND SOUTHERN MN BEFORE DAYBREAK SATURDAY AND PERSIST THROUGH MUCH
OF THE DAY. KRWF SHOULD SEE SCATTERED SHOWERS BUT MVFR CONDITIONS
ARE FORECAST TO REMAIN SOUTH OF THIS SITE. LIGHT WINDS OVERNIGHT
TONIGHT WITH NORTHWEST TO WEST WINDS LESS THAN 10 KNOTS ON
SATURDAY.

KMSP...CONFIDENCE LOW ON THE CEILING/VSBY FORECAST OVERNIGHT.
CERTAINLY SEEMS TO BE HIGH POTENTIAL FOR LOW CONDITIONS DEVELOPING
WITH A VERY MOIST LOW LEVEL PROFILE IN PLACE. THE QUESTION IS
WHETHER THE INCREASING MID/HIGH LEVEL CLOUDS FROM THE WEST
OVERRULE AND KEEP THINGS VFR. IN KEEPING WITH THE LOW CEILINGS...HELD
ON TO MVFR CEILINGS INTO MID MORNING AS THE COLD FRONT MOVES
THROUGH. A RATHER ORGANIZED AREA OF SHOWERS WILL BE JUST SOUTH OF
THE AIRFIELD BY MIDDAY SATURDAY AND PERSIST THROUGH THE AFTERNOON.
VCSH USED AT THIS POINT.

/OUTLOOK FOR KMSP/

SATURDAY NIGHT...VFR. WEST WINDS LESS THAN 10 KTS BECOMING NORTHWEST.
SUNDAY...VFR. NORTHWEST WINDS 10 TO 15 KTS.
SUNDAY NIGHT. MVFR POSSIBLE WITH A CHANCE OF SHRA/TSRA. NORTHWEST
WINDS 5 TO 10 KTS.
MONDAY...MVFR POSSIBLE WITH A CHANCE OF SHRA/TSRA. NORTHWEST
WINDS 15 TO 25 KTS.
MONDAY NIGHT...MVFR POSSIBLE. NORTHWEST WINDS 10 TO 15 KTS.
TUESDAY...VFR. NORTHWEST WINDS 10 TO 15 KTS.

&&

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

$$

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





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