Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 060007
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
607 PM CST THU MAR 5 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 402 PM CST THU MAR 5 2015

TONIGHT-FRIDAY...SFC ANALYSIS SHOWS THE CENTER OF A 1040MB HIGH OVER
THE IA/MO BORDER WITH PRONOUNCED NW FLOW ALOFT. FURTHER W OVER THE
WRN DAKOTAS INTO THE CENTRAL PLAINS...A SNAKING WARM FRONT WILL
GRADUALLY PUSH EWRD...ON THE HEELS OF THE DEPARTING HIGH PRESSURE
AREA...THRU TOMORROW AFTERNOON. THIS SHIFT WILL ALLOW A MORE
PRONOUNCED SLY WIND COMPONENT TONIGHT INTO TOMORROW. IN
ADDITION...A WEAK MID LEVEL TROF DISTURBANCE ALOFT WILL PASS OVER
THE REGION OVERNIGHT. WITH A CONTINUED DRY BOUNDARY LAYER...AND
MEAGER DEEP MOISTURE AND LIFT...THIS TROF WILL PRODUCE NOTHING
MORE THAN AN INCREASE IN CLOUDS OVERNIGHT THRU DAYBREAK. ONCE THIS
TROF MOVES THRU...NW FLOW ALOFT WILL RESUME BUT WITH A MORE
PACIFIC COMPONENT RATHER THAN ARCTIC. IN ADDITION...SFC FLOW WILL
REMAIN W TO SW THRU THE DAY TMRW. THUS...PARTIAL CLEARING IS
EXPECTED WITH ENHANCED WAA TONIGHT THRU TOMORROW AS THE WARM FRONT
IS EXPECTED TO ENTER MN. THIS COMBINATION OF EVENTS WILL SPELL
RISING TEMPS OVERNIGHT FOLLOWED BY HIGHS ON FRI THAT WILL BE ABOUT
20 DEGREES WARMER THAN TODAY.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 402 PM CST THU MAR 5 2015

MAIN CHANGE WE HAVE SEEN IN THE EXTENDED IS SOME BETTER AGREEMENT
BETWEEN THE GFS/ECMWF FOR THE SECOND HALF OF NEXT WEEK...WITH THE
GFS TRENDING MORE TOWARD THE ECMWF /AS OPPOSED TO THE OTHER WAY
AROUND/. OTHERWISE...THE REST OF THE FORECAST STILL LOOKS
SIMILAR...WITH A COUPLE OF MINOR PRECIP CHANCES OVER THE WEEKEND
FOLLOWED BY HIGHS 10 TO 20 DEGREES ABOVE NORMAL FOR A CHANGE FOR THE
FIRST HALF OF NEXT WEEK.

RIGHT NOW...THE UPPER PATTERN LOOKS LIKE IT DID ALL OF
FEBRUARY...WITH A RIDGE OVER THE WEST COAST AND A TROUGH OVER ERN
NOAM...WITH AN IMPRESSIVE WINTER STORM STILL ONGOING TO THE EAST OF
THE TROUGH ALONG THE ERN SEABOARD. OVER THE WEEKEND...THE WRN RIDGE
WILL REMAIN...BUT THE ERN TROUGH WILL BE LIFTING NORTH...ALLOWING
FOR A MODIFICATION IN THE AIRMASS. AS WE WORK THROUGH NEXT
WEEK...THE RIDGE STARTS WORKING EAST...WHICH WILL ALLOW FOR A
SIGNIFICANT INCREASE IN HEIGHTS...A MORE ZONAL FLOW...AND
SIGNIFICANTLY WARMER AIR TO ENTER THE REGION.

FOR THE WEEKEND...THE TWO WAVES OF INTEREST ARE COMING DOWN FRIDAY
NIGHT AND SATURDAY NIGHT. IN BOTH CASES...THEY WILL BE FAST MOVING
AND LIMITED ON MOISTURE. THE FIRST WAVE WILL HAVE AN ATTENDANT SFC
LOW GOING ACROSS THE INTERNATIONAL BORDER AND LAKE SUPERIOR...SO
EXPECT ANY PRECIP WITH THIS TO REMAIN PRIMARILY NORTH OF I-94...SO
LIMITED POPS FRIDAY NIGHT INTO SATURDAY MORNING TO AREAS MAINLY
ALONG AND NORTH OF I-94. WE WILL HAVE A BRIEF COOL DOWN IN THE WAKE
OF THIS SYSTEM FOR SATURDAY...THOUGH HIGHS WILL ONLY BE A FEW DEGS
COOLER THAN FRIDAY AND RIGHT NEAR SEASONAL NORMS. THE SATURDAY NIGHT
WAVE LOOKS TO BE THE STRONGER OF THE TWO...THOUGH WE ARE SEEING TWO
CAMPS WHEN IN COMES TO PRECIP POTENTIAL ACROSS THE MPX AREA. THE
NCEP MODELS /INCLUDING THE SREF/ KEEP THE MPX AREA MAINLY
DRY...WHILE THE ECMWF AND CANADIAN SHOW A NICE BURST OF SNOW TO THE
TUNE OF 1-3 INCHES. THE DIFFERENCES LOOK TO STEM FROM HOW FAR SOUTH
ENERGY FROM A WAVE GOING ACROSS THE ARROWHEAD WILL EXTEND...WITH THE
MORE BULLISH MODELS BRINING THE SHORTWAVE ENERGY FARTHER SOUTH. FOR
SUNDAY NIGHT...KEPT POPS AT 30S OR LESS IN PLACE...JUST ORIENTED THE
CHANCE POPS AREA TO BE MORE IN LINE WITH WHERE THE ECMWF SHOWS THE
SNOW FALLING.

FOR NEXT WEEK...AS THE WRN RIDGE BEGINS TO SLIDE EAST...WE WILL SEE
THE UPPER JET AND ATTENDANT STORM TRACK LIFTING NORTH INTO
CANADA...WHICH LOOKS TO KEEP US DRY MOST OF THE WEEK. AS THE RIDGE
BUILDS IN WE WILL SEE A SIGNIFICANT INCREASE IN LOW LEVEL
TEMPS...WITH THE ECMWF SHOWING 925 TEMPS BUILDING TO BETWEEN 10C AND
14C TUESDAY AND WEDNESDAY. THE QUESTION MONDAY THROUGH WEDNESDAY IS
HOW DEEP WILL WE MIX. THE ECMWF CONTINUES TO SHOW THAT MIXING
EXTENDING UP TO AT LEAST 925MB...WITH THAT RESULTING IN HIGHS IN THE
UPPER 50S TO MID 60S. THE GFS KEEPS MIXING PRETTY SHALLOW /LIKE
AROUND 950 MB/. THIS WOULD MEAN MUCH OF THIS WARMING GOES INTO
BUILDING A STRONG INVERSION...WITH HIGHS HOLDING ABOUT 10 DEGS
COOLER THAN WHAT THE ECMWF HAS. WITH BLENDED FORECAST USED...THE
ECMWF IS OUT ON ITS OWN...SO CURRENT FORECAST IS MORE IN LINE WITH
THE GFS. BESIDE THOSE WARM HIGHS...SW WINDS THROUGH THE OVERNIGHT
HOURS WILL LIKELY HOLD TEMPERATURES UP NEAR OR ABOVE 30 MON AND TUE
NIGHTS...SO WE WILL BE STARTING THE MELT NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 607 PM CST THU MAR 5 2015

HIGH CONFIDENCE IN VFR WITH NO AVIATION WEATHER CONCERNS.

KMSP...

HIGH CONFIDENCE IN VFR WITH A LIGHT WIND OUT OF THE SOUTH-
SOUTHWEST.

/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NW 10 KTS.
SUN...MAINLY VFR. MVFR CEILINGS POSSIBLE WITH SLGT CHC -RASN.
WINDS W 10 KTS.
MON...VFR. WINDS SW 10 KTS.

&&

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

$$

SHORT TERM...JPC
LONG TERM...MPG
AVIATION...CLF



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