328
FXUS63 KMPX 161807 AAB
AFDMPX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
107 PM CDT WED OCT 16 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 304 AM CDT WED OCT 16 2013
SFC LOW THIS MORNING NOW OVER IN THE STRAITS OF MACKINAC. MOIST
CYCLONIC FLOW BETWEEN THIS LOW AND A SFC RIDGE SAGGING SOUTH ACROSS
NW MN HAS KEPT CLOUD COVER IN PLACE...ALONG WITH LIGHT RAIN AND
AREAS OF DRIZZLE ACROSS THE SOUTHEAST HALF OR SO OF THE MPX CWA. AS
THIS RIDGE AXIS WORKS SOUTHEAST ACROSS THE AREA TODAY...IT WILL
CLEAR THE LOW CLOUDS OUT FROM WEST TO EAST. FOR THAT CLEARING...
FOLLOWED THE SLOWER TIMING OF THE HRRR/RAP FOR CLEARING SKIES OUT
TODAY...WITH CLOUDS HOLDING TIGHT IN THE TWIN CITIES UNTIL ABOUT
NOON...WITH SKIES NOT CLEARING OVER IN THE EAU CLAIRE AREA UNTIL
ABOUT 5 PM. IR IMAGERY OVER THE LAST 2 HOURS HAS SHOWN CLOUD TOPS
OVER THE MPX AREA WARMING CONSIDERABLY...WHICH WILL START TO QUICKLY
PUT AN END TO THE PRECIP GENERATION...THOUGH EAU CLAIRE WILL LIKELY
SEE SOME LIGHT PRECIP LINGER THROUGH ABOUT 10 AM.
AFTER THIS MORNING...THE REST OF THE PERIOD WILL BE DRY AS SHORTWAVE
RIDGING AND ASSOCIATED HEIGHT RISES MOVE ACROSS THE AREA.
TONIGHT...A COLD FRONT CURRENTLY UP ACROSS THE CENTRAL CANADIAN
PRAIRIE PROVINCES WILL BE DROPPING INTO THE DAKOTAS AND NORTHWEST
MN. AS A RESULT...WINDS ARE EXPECTED TO BACK TOWARD THE SOUTHWEST
OVERNIGHT...USHERING IN WEAK WAA. THIS WILL LIKELY LEAD TO STEADY OR
SLIGHTLY RISING TEMPERATURES AFTER MIDNIGHT...ESPECIALLY ACROSS
WESTERN AND CENTRAL MN. THE SOUTHWEST WINDS WILL ALSO KEEP MOST
AREAS FROM FALLING BELOW FREEZING...THOUGH MORE SHELTERED LOW-LYING
AREAS OUT IN THE FAR ERN MPX CWA MAY SEE TEMPS DIP TO AROUND 30. IT
WAS DECIDED YESTERDAY TO SUSPEND THE FROST/FREEZE PROGRAM FOR THE
FALL DUE TO BOTH THE GROWING SEASON BASICALLY BEING DONE ACROSS THE
AREA. IN ADDITION...FROM A CLIMATOLOGY PERSPECTIVE...ALL AREAS ARE
NOW NEAR OR BEYOND A WEEK PAST THE MEDIAN DATE FOR THE FIRST FREEZE
OF THE FALL...SO NO FROST/FREEZE HEADLINES WERE CONSIDERED.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 304 AM CDT WED OCT 16 2013
THE EXTENDED PERIOD IS BASED ON THE LONG WAVE PATTERN BECOMING
MORE AMPLIFIED OVER THE WEEKEND AND INTO NEXT WEEK. THERE IS HIGH
CONFIDENCE FOR THIS PATTERN TO CONTINUE THROUGH THE EXTENDED
PERIOD WHICH MEANS A MUCH COLDER PATTERN THAN IT HAS BEEN IN THE
PAST MONTH. THE ENSEMBLE MEANS OF THE 50H PATTERN ARE FAIRLY
CONSISTENT WITH THE LONG WAVE TROUGH ACROSS THE EASTERN U.S. WITH
A LARGE UPPER RIDGE OFF THE WEST COAST. DIFFERENCES REMAIN IN THE
RH FIELDS AND SFC PRESSURE...ESPECIALLY PAST THIS WEEKEND WHICH
WILL HAVE A LARGE IMPACT IF THE GFS BECOMES MORE IN LINE VS. THE
EC. ONE CONSIDERATION IS THE EC HAS THE UPPER RIDGE MOVING
EASTWARD ON THE WEST COAST AND INTO THE INTERIOR OF THE PACIFIC
NORTHWEST COMPARED TO THE GFS. AT THE SFC...THE DIFFERENCES ARE
MOST NOTICEABLE AS THE GFS DEVELOPS A STRONG SFC LOW ACROSS THE
GREAT LAKES BY TUE/WED...WHILE THE EC HAS A HIGH PRESSURE RIDGE
BUILDING ACROSS THE UPPER MIDWEST. ALTHOUGH BOTH OF THESE
SCENARIOS DO ALLOW FOR THICKNESS VALUES TO DROP SIGNIFICANTLY
BELOW THE 540M WHICH LEADS TO THE PRECIPITATION TYPE MORE SNOW
THAN RAIN IF PRECIPITATION DEVELOPS. LATER THIS WEEK... THICKNESS
VALUES REMAIN HIGH ENOUGH FOR MAINLY -RA WITH ONLY A SLIGHT CHC OF
A MIXTURE IN CENTRAL MN. ALTHOUGH MODELS TRY TO INTRODUCE -SN/-RA
ACROSS A LARGE PART OF THE CWA...IT DOESN/T SEEM REAL BASED ON THE
THE THERMAL PROFILE ALOFT AS PRECIPITATION IS FALLING.
HOWEVER...LATER IN THE WEEKEND...AND INTO NEXT WEEK...THESE
THERMAL PROFILE ARE CONDUCIVE FOR THE PRECIPITATION TYPE TO BE
MAINLY SNOW. THE ONLY FACTOR IS WHETHER A SYSTEM WILL BE STRONG
ENOUGH TO GENERATE -SN. SO...CONFIDENCE REMAINS HIGH FOR THE COLD
PERIOD TO DEVELOP AND REMAIN ACROSS THE CWA THRU NEXT WEEK. LOW
CONFIDENCE REMAINS ON PRECIPITATION TYPE/AMTS AND IF A SYSTEM CAN
GENERATE -SN NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1246 PM CDT WED OCT 16 2013
THE BACK EDGE OF MVFR CIGS IS CURRENTLY LOCATED ALONG A LINE FROM
ULM TO JUST WEST OF MSP AND RZN. STEADY PROGRESS OF CLEARING HAS
SLOWED SOMEWHAT WITH ADDITIONAL CU DEVELOPING BEHIND THE MASS OF
CLOUDS. STILL THINK DRIER AIR WILL ARRIVE THIS AFTERNOON...OR BY
EARLY THIS EVENING TOWARD EAU WITH MAINLY CLEAR SKIES TONIGHT.
CLOUDS WILL INCREASE AND LOWER LATE TONIGHT AND THURSDAY AHEAD OF
AN APPROACHING COLD FRONT WHICH MAY BRING RAIN LATE IN THE DAY AND
THURSDAY EVENING. FOG MAY BECOME AN ISSUE LATE TONIGHT IN
AREAS...ESPECIALLY OVER WESTERN WISCONSIN WHERE CLEAR SKIES WILL
PERSIST THE LONGEST.
KMSP...MSP CIGS HAVE FINALLY LIFTED ABOVE THE CRITICAL 017
THRESHOLD AND WILL REMAIN THERE FOR THE REST OF THE DAY. A GRADUAL
DECREASE IN CLOUDS CAN BE EXPECTED...WITH VFR CONDITIONS FORECAST
BY MID AFTERNOON.
/OUTLOOK FOR KMSP/
THU NIGHT...MVFR CIGS WITH -RA LIKELY EARLY...THEN VFR. WINDS NW
10-15 KTS.
FRI...VFR. MVFR CIGS LIKELY WITH CHC -RA OR -SN LATE FRIDAY NIGHT.
WINDS W 5 KTS.
SAT...VFR. CHC MVFR CIGS AND -RA. WINDS WNW 10-15 KTS.
SUN...VFR. CHC MVFR AND -RA/-SN TURNING TO -SN SUNDAY NIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...JLT
AVIATION...BORGHOFF