Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 281816
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1216 PM CST FRI NOV 28 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CST FRI NOV 28 2014

MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR FREEZING RAIN
OR SLEET LATER TODAY AS A WEAK DISTURBANCE MOVES ALONG THE
MINNESOTA RIVER VALLEY. MEANWHILE TEMPERATURES WILL MODERATE INTO
THE 20S TODAY...AND REMAIN THEIR OVERNIGHT.

A BAND OF LIGHT TO MODERATE SNOW TIED TO THE H850-H700 WARM AIR
ADVECTION MOVED ACROSS THE NORTHERN HALF OF THE FORECAST AREA
OVERNIGHT AND PRODUCED ROUGHLY 1 TO 2 INCHES OF SNOW. BY EARLY
FRIDAY MORNING THIS BAND WAS LOCATED ACROSS EASTERN MN WESTERN
WI...AND AS A RESULT DROPPED THE UPSTREAM COUNTIES FROM THE WINTER
WEATHER ADVISORY.

LATER TODAY ANOTHER WEAK SHORTWAVE WILL SLIDE ACROSS THE REGION.
THIS SEEMS TO BE HANDLED BEST BY THE LAST FEW RUNS OF THE RAP13.
THE CONCERN WITH THIS FEATURE IS THE POTENTIAL FOR PRECIP
FALLING THROUGH A WARM LAYER WHICH BY 18Z IS FORECAST TO BE +3C AT
KMSP AND EVEN WARMER AT POINTS SOUTHWARD. THE SURFACE WILL STILL
BE IN THE 20S...SO THIS WOULD LEAD TO A BRIEF PERIOD OF
SLEET/FREEZING RAIN ROUGHLY ALONG A LINE JUST SOUTH OF THE I-94
CORRIDOR...REACHING EAU CLAIRE BY LATE AFTERNOON. ACCUMULATIONS
WOULD ONLY BE 1 OR 2 HUNDREDTHS...BUT EVEN THOSE MEAGER AMOUNTS
COULD LEAD TO SLICK ROADWAYS. FOR NOW INCREASED THE POPS AND
TRENDED TOWARDS THE LAST FEW RUNS OF THE HOPWRF AND HRRR WHICH
HAVE SLOWED THE ONSET OF THIS PRECIP. ONCE THIS MOVES THROUGH H850
AIR OF +5 TO +7 WILL REMAIN IN PLACE OVERNIGHT...AS SOUTHEASTERLY
WINDS GRADUALLY VEER TO A SOUTHERLY DIRECTION BY SATURDAY MORNING.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 357 AM CST FRI NOV 28 2014

STRONG WARM AIR ADVECTION WILL BE THE PREVAILING STORY SATURDAY
WITH A WMFNT WELL N OF THE WFO MPX CWFA AND AN INCOMING ARCTIC
HIGH PRES AIRMASS THAT LOOKS TO DROP THE HAMMER ON TEMPERATURES
GOING INTO SUNDAY. NOT LOOKING FOR MUCH OF ANYTHING IN TERMS OF
PRECIPITATION SO SATURDAY WILL RESULT IN MOSTLY CLOUDY SKIES DUE
TO INCREASED MOISTURE PROMOTING STRATUS DEVELOPMENT OVER A DECENT
SNOWPACK AND FAIRLY WIDESPREAD NVA KEEPING PRECIP N OF THE AREA.
DESPITE THE CLOUD COVER...THE STRONG WAA WILL FORCE HIGHS INTO THE
UPR 30S AND EVEN LWR 40S. BY LATE EVENING...A POTENT CDFNT WILL
DROP THRU THE CWFA...WHICH WILL HELP SCOUR OUT SOME OF THE CLOUD
COVER BUT IS NOT XPCTD TO PRODUCE MUCH...IF ANY...PRECIP FOR THE
CWFA. WINDS WILL KICK UP BUT THE MAIN EFFECT WILL BE TO
SIGNIFICANTLY DROP TEMPERATURES FOR SUNDAY...WITH HIGHS ONLY
REACHING THE LWR TEENS TO LWR 20S. THE ARCTIC HIGH PRES AIRMASS
WILL PERSIST THRU MON...PRODUCING HIGHS ONLY IN THE SINGLE DIGITS
ABOVE ZERO DESPITE PLENTY OF SUNSHINE. AS THE HIGH PRES AREA
SHIFTS OFF TO THE E FOR THE MIDDLE PORTION OF NEXT WEEK...A MORE
SOUTHERLY FLOW ON THE BACKSIDE WILL ALLOW SOME MODERATION IN
TEMPERATURES BUT STILL BELOW THE FREEZING MARK. HIGHS WILL CLIMB
INTO THE 20S...WITH VERY LITTLE CHANCES OF PRECIP GOING THROUGH
THE WEEK. THERE ARE STILL SOME INDICATIONS OF A MORE ORGANIZED LOW
PRES SYSTEM MOVING THRU THE CENTRAL CONUS MID-TO-LATE NEXT WEEK
BUT MODEL CONSENSUS...AND HENCE FORECAST CONFIDENCE...REMAINS LOW
IN THIS THINKING SO HAVE KEPT MUCH OF THE AREA DRY THRU NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1148 AM CST FRI NOV 28 2014

PRIMARY CONCERN IS THE NEXT 6 HOURS DEALING WITH FREEZING DRIZZLE
POTENTIAL ACROSS THE AREA.

LOW CONFIDENCE IN THE FORECAST OVERALL..ESPECIALLY TONIGHT AND
TOMORROW MORNING. THE NAM HAS OVERDONE ITS MOISTURE ANALYSIS AND
IS AFFECTING ITS PROFILES THROUGH TONIGHT. STARTING OFF...A BATCH
OF MOSTLY FREEZING DRIZZLE/RAIN IS MOVING WEST TO EAST ACROSS THE
FA EARLY THIS AFTERNOON. THANKFULLY...THE REFLECTIVITY RETURNS
CURRENTLY ON RADAR SHOW A DECENT AMOUNT OF VIRGA IN SOME
SPOTS...ESPECIALLY FAR SOUTHERN MN. IN ADDITION...THE PRECIP THAT
IS REACHING THE GROUND WILL NOT LAST VERY LONG...SO AMOUNTS SHOULD
BE VERY LIGHT. THIS AREA WILL CONTINUE WORKING EAST ACROSS THE
AREA.

IN TERMS OF CLOUD COVER AND FOG POTENTIAL...I QUESTION NAM
SOUNDING MOISTURE SIMILAR TO THE PREVIOUS SHIFT. CONSIDERING THE
SUITE OF GUIDANCE AT HAND HOWEVER...ITS CLEAR THAT LOW LEVEL
SOUTHWESTERLY FLOW WILL CONTINUE TO USHER IN WARMER AND DRIER AIR
TO THE FA. THE BIG QUESTION IS WHAT HAPPENS NEAR THE SURFACE AS
THE INVERSION STRENGTHENS. CURRENT FORECAST CALLS FOR ENOUGH
MOISTURE TRAPPING TO ALLOW MVFR OR IFR CIGS TO REMAIN IN PLACE.
HRRR INDICATES LOW STRATUS BECOMING TRAPPED UNDER THE DRYING
OCCURRING ABOVE 900-850H...SO INDICATED THE POTENTIAL FOR
RESTRICTIONS THROUGH MUCH OF TOMORROW.

KMSP...THIS IS AN EVOLVING FORECAST SITUATION. BOUTS OF FZDZ
APPEAR MORE LIKELY FROM 19-21Z HAS AS BEEN OBSERVED UPSTREAM OF
MSP. OTHERWISE...WE CONTINUE TO LINGER ON THE EDGE OF VFR TO THE
WEST. STILL...EXPECTING THE CIGS TO PERSIST THROUGH THE AFTERNOON.
CONFIDENCE IN THE CEILING FORECAST BEYOND 00Z IS QUITE LOW.
SOUTHWESTERLY DRY AIR ADVECTION COULD PREVENT RESTRICTIONS
TONIGHT...BUT WENT WITH A MORE PESSIMISTIC FORECAST BECAUSE THE
STRENGTH OF THE INVERSION LENDS ME TO BELIEVE WE`LL GET ENOUGH
MOISTURE TRAPPED BELOW IT TO CAUSE PROBLEMS.

/OUTLOOK FOR KMSP/
SUN NIGHT...VFR. WINDS NW AT 15G25KTS.
MON...VFR. WINDS NW AT 5-10KTS...BECOMING S LATE.
TUE...VFR. WINDS S AT 15G20KTS...BECOMING W.

&&

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

$$

SHORT TERM...JRB
LONG TERM...JPC
AVIATION...SPD





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