Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 210440
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1040 PM CST THU NOV 20 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 320 PM CST THU NOV 20 2014

EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH 500MB HEIGHTS AND
WINDS IDENTIFIED THE 3 MAIN PLAYERS THAT WILL IMPACT THE UPPER
MIDWEST THIS WEEKEND AND EARLY NEXT WEEK. THE FIRST WAS A SHORTWAVE
OFF THE CALIFORNIA COAST...WHICH IS FORECAST TO TRANSLATE
SOUTHEASTWARD OVER THE NEXT 36 HOURS. THE NEXT IS A POWERFUL JET
OFF THE NORTHWEST COAST...WHICH WILL BEGIN TO COME ON SHORE BY 00Z
SATURDAY. THE THIRD IS THE SHORTWAVE IN THE LEFT EXIT REGION OF
THIS JET WHICH AGAIN WILL BE JUST OFF THE BRITISH COLUMBIA COAST
BY 00Z SATURDAY.

IN THE MEAN TIME...HIGH PRESSURE CURRENTLY IN PLACE ACROSS THE UPPER
MIDWEST WILL GRADUALLY SLIDE SOUTHEAST. THIS WILL SET THE STAGE
FOR AMPLE RADIATIONAL COOLING AND ANOTHER COLD NIGHT ACROSS THE
FORECAST AREA WITH MOST LOCATIONS DROPPING BELOW ZERO...ESPECIALLY
IN WESTERN WI. BY FRIDAY MORNING SOUTHERLY FLOW ON THE BACKSIDE OF
THIS DEPARTING HIGH PRESSURE WILL ADVECT MOISTURE ACROSS THE
REGION. FORECAST SOUNDINGS SHOW STRATUS DEVELOPING FROM SOUTHWEST
TO NORTHEAST. HIGH TEMPS WILL GENERALLY BE IN THE UPPER
20S...WHICH SHOULD BRING THE CONSECUTIVE DAYS OF SUB FREEZING
NOVEMBER HIGHS AT MSP TO 12...MAKING IT SECOND ONLY TO 15 BACK IN
1880.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 320 PM CST THU NOV 20 2014

LONG TERM (FRI NIGHT-THU)...NOT MUCH CHANGE IN FCST REASONING TODAY
AS MODEL SOLUTIONS ARE BECOMING AGREEABLE...WITH A SLIGHT EASTWARD
SHIFT ON SUN/MON. WITH THAT SAID...THERE ARE STILL MULTIPLE
CHALLENGING PERIODS AS A LARGE STORM SYSTEM TAKES SHAPE OVER THE
CENTRAL U.S.

HIGH PRESSURE WILL BE WELL TO OUR EAST BY FRI NIGHT WITH RETURN FLOW
ALREADY WELL ESTABLISHED. THERE IS A WEAK SHORTWAVE IN THE NORTHERN
STREAM THAT MAY PRODUCE A LITTLE LIGHT QPF OVERNIGHT FRI...AND WITH
TEMPS SLOWLY WARMING THROUGH THE 20S...THE FAVORED P-TYPE WOULD
LIKELY BE -FZDZ. THIS THREAT SHOULD BE CONFINED TO LOCATIONS ALONG
AND EAST OF INTERSTATE 35. WITH THE WARM AIR ADVECTING OVER THE
SNOWPACK...FOG IS ALSO A DISTINCT POSSIBILITY.

THERE LOOKS TO BE A BREAK IN PRECIP FOR MUCH OF THE DAY SAT AND THE
FIRST HALF OF SAT NITE AS LOW PRESSURE DEVELOPS IN TX IN ADVANCE OF
A DIGGING TROUGH. MEANWHILE...A SECOND (AND WEAKER) LOW WILL BE
MOVING ACROSS THE NORTHERN ROCKIES AT THE SAME TIME. TEMPS WILL WARM
CONSIDERABLY SAT/SAT NITE AS WARM AIR AND MOISTURE GETS DRAWN NORTH.
MODEL GUIDANCE IS SHOWING TEMPS INTO THE 40S ON SAT AND REMAINING
ABOVE FREEZING SAT NIGHT. SAT NITE (AT LEAST THE SECOND HALF) WILL
ONCE AGAIN FEATURE -RA/DZ AND PATCHY FOG MOST PREVALENT IN E MN/WI.
WE WILL CONTINUE TO SEE -SHRA AT LEAST IN E MN & WI FOR THE FIRST
HALF OF SUNDAY AS A CONSOLIDATION OF LOW PRESSURE CENTERS BEGINS TO
OCCUR OVER THE SOUTHERN GREAT LAKES.

THE MERGING OF THESE TWO LOWS WILL CAUSE A RAPID INTENSIFICATION OF
A SINGULAR LOW SOMEWHERE IN THE GREAT LAKES EARLY MON. IF NOTHING
ELSE...THIS RAPID DEEPENING OF THE LOW WILL PRODUCE STRONG WINDS FOR
OUR AREA. COLD AIR WILL QUICKLY WRAP AROUND THE SYSTEM BY MON WITH
ANY PRECIP CHANGING TO SNOW. IN TERMS OF PRECIP...THERE WILL BE A
DEFORMATION AREA OF PRECIP STRETCHING BEHIND THE LOW ENHANCED BY THE
UPPER LEVEL LOW MOVING DIRECTLY OVER THE STATE OF MN ON MON. AT THIS
TIME IT LOOKS LIKE THE MAJORITY OF (SIGNIFICANT) SNOWFALL WILL BE
CONFINED TO THE NORTHERN HALF OF MN...BUT THERE REMAINS A DECENT
CHANCE FOR SNOW OVER THE ENTIRE REGION. POPS AT THIS JUNCTURE WILL
REMAIN IN THE CHANCE CATEGORY WITH SNOWFALL AMOUNTS JUST TOO
DIFFICULT TO NAIL DOWN. AS MENTIONED EARLIER...WIND WILL BE THE MAIN
IMPACT FROM THIS SYSTEM WITH SUSTAINED WINDS GREATER THAN 20KT WITH
GUSTS POTENTIALLY EXCEEDING 35KT. DEPENDING ON THE COMPOSITION AND
AMOUNT OF SNOW...BLOWING AND DRIFTING SNOW MAY BECOME A SIGNIFICANT
FACTOR. PLEASE STAY TUNED TO FUTURE FORECASTS AS WE REFINE SNOW
CHANCES/AMOUNTS.

THIS SYSTEM WINDS DOWN FOR US BY TUE AFTN WITH MORE BELOW AVERAGE
TEMPS AND MINIMAL PRECIP CHANCES THRU WED. THERE IS THE THREAT FOR
MORE -SN ON THANKSGIVING...BUT AT THIS POINT MODEL SPREAD IS PRETTY
SIGNIFICANT SO ONLY SMALL CHANCES ARE WARRANTED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1020 PM CST THU NOV 20 2014

VFR CONDITIONS WILL PREVAIL OVERNIGHT UNDER CLEAR SKIES. LIGHT
SOUTHWESTERLY WINDS WILL BECOME SOUTHERLY BY FRIDAY MORNING AND
INCREASE TO 10-15 KT BY THE AFTERNOON...WHEN GUSTS EXCEEDING 20KT
ARE POSSIBLE AT AXN AND RWF. MVFR CIGS ARE ALSO EXPECTED TO
DEVELOP OVER SW MINNESOTA IN THE LATE MORNING DUE TO A LOW CLOUD
DECK WHICH WILL SPREAD NORTHEASTWARD THROUGH THE AFTERNOON. A LOW
STRATUS DECK WILL LIKELY OVERSPREAD THE ENTIRE REGION BY FRIDAY
EVENING...WHICH WILL RESULT IN MVFR/IFR CIGS AT ALL TERMINALS
DURING THIS TIME. SOME PATCHY FREEZING DRIZZLE IS ALSO POSSIBLE
FRIDAY NIGHT...ALTHOUGH CONFIDENCE IS TOO LOW TO INCLUDE IN TAFS
AT THIS TIME.

KMSP...VFR CONDITIONS OVERNIGHT AND FRIDAY MORNING WILL GRADUALLY
GIVE WAY TO MVFR/IFR CONDITIONS UNDER INCREASING CLOUDS DURING THE
LATE AFTERNOON AND EVENING. SOME PATCHY FREEZING DRIZZLE IS
POSSIBLE LATE FRIDAY EVENING...BUT CHANCES ARE LOW AT THIS TIME.

/OUTLOOK FOR KMSP/
SAT...MVFR POSSIBLE.  WINDS SSW 10G20 KT.
SUN...MVFR/IFR WITH FZDZ/RA POSSIBLE. WINDS SE 10 KT.
MON...MVFR/IFR WITH -SN/BLSN POSSIBLE. WINDS NW 25G30 KT.

&&

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

$$

SHORT TERM...JRB
LONG TERM...JCA
AVIATION...ADL






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