Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 240541 AAA
AFDDLH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DULUTH MN
1241 AM CDT THU APR 24 2014

.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW...



UPDATE ISSUED AT 912 PM CDT WED APR 23 2014

SPOTTERS/OBSERVATIONS REVEAL MORE SLEET/SNOW OCCURRING THIS
EVENING THAN WHAT WAS EARLIER EXPECTED. WE HAVE UPDATED GRIDS TO
ADD MORE SLEET SNOW TO PORTIONS OF NORTHERN MINNESOTA...ESPECIALLY
ALONG AND NORTH OF LINE FROM PINE RIVER TO MOOSE LAKE AND ACROSS
FAR NORTHERN WISCONSIN. AN AREA OF MID LEVEL FGEN CONTINUES TO
IMPACT THE NORTHLAND WITH BOTH DYNAMIC/EVAPORATIVE COOLING LEADING
TO COOLER COLUMN TEMPERATURES. WE UPPED SNOW AMOUNTS SOME...AND
COULD SEE SOME AREAS GET AN INCH OR TWO OVERNIGHT.

UPDATE ISSUED AT 700 PM CDT WED APR 23 2014

RAIN WAS OCCURRING ACROSS OUR SOUTHWEST CWA INTO OUR SOUTHERN
AREAS...AND WILL MOVE SLOWLY NORTH. DRY AIR OVER THE REST OF THE
CWA WAS SLOWING THE ADVANCEMENT OF THE PRECIPITATION. SOME SLEET WAS
ALSO REPORTED OVER OUR SOUTHWEST ZONES. STRONG FGEN FORCING WAS
AIDING IN THE DEVELOPMENT OF THE PRECIPITATION. THE NAM SHOWS THE
FGEN WEAKENING SOME AS IT MOVES NORTHEAST. WE WILL HAVE TO KEEP A
CLOSE EYE ON THE PRECIP TYPE THIS EVENING...AS SOUNDINGS ARE CLOSE
TO BEING RAIN OR SNOW. THIS COULD LEAD TO SOME MORE SNOW
ACCUMULATIONS IN SPOTS TONIGHT.

WE WILL ALSO UPDATE TO ADD SOME THUNDER TO OUR SOUTHWEST ZONES
WHERE SOME LIGHTNING STRIKES HAVE RECENTLY BEEN DETECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED APR 23 2014

AT 330 PM...LIGHT RAIN HAD FINALLY SPREAD INTO THE BRAINERD LAKES
AREA...AS A NW TO SE BAND OF RAIN SLOWLY MIGRATED TO THE NE. THE
REMAINDER OF THE CWA SAW TEMPERATURES GENERALLY IN LOW TO MID 50S.
WINDS WERE A BIT GUSTY FROM THE SE WITH SOME GUSTS INTO THE 20 MPH
RANGE IN THE BRAINERD LAKES AREA.

THE MAIN FOCUS FOR THE SHORT TERM IS THE EVOLUTION OF THE STORM
SYSTEM THAT WILL LIKELY BRING SNOW ACCUMULATION TO AT LEAST THE
NORTHERN PORTION OF THE CWA. RAIN WILL CONTINUE TO SPREAD
NORTHEASTWARD ACROSS THE CWA OVERNIGHT...AND MAY BEGIN TO MIX WITH
SOME SNOW...ESPECIALLY FURTHER NORTH AND EAST AS THE COLUMN STARTS
TO COOL. FORECAST SOUNDINGS SHOW THE GFS AS THE WARMEST
MODEL...WITH THE ECMWF AND NAM BEING SIMILAR AND COLDER. THINK ANY
SNOW ACCUMULATION OVERNIGHT WILL BE NEGLIGIBLE. EAST WINDS
WILL BEGIN TO INCREASE ACROSS THE AREA OVERNIGHT AS WELL. THE
MODELS ARE IN A BIT BETTER AGREEMENT IN TERMS OF EVENTUAL SNOW
ACCUMULATION AND TIMING OF COOLING. THE NAM...ECMWF AND GFS ALL
SHOW MORE THAN 6 INCHES OF RUN TOTAL SNOW ACCUMULATION IN THE TIP
OF THE ARROWHEAD WITH LESSER AMOUNTS FURTHER SOUTH. IN FACT...THE
NAM AND ECMWF SUPPORT ABOUT A FOOT OF SNOW IN THE HIGHER TERRAIN
OF MAINLY COOK COUNTY. HAVE DECIDED TO ISSUE A WINTER STORM WATCH
FOR THE ENTIRE ARROWHEAD REGION FOR THE POTENTIAL OF SEEING 6
INCHES OF SNOW OR GREATER. AM A BIT CONCERNED THAT SOME OF THE
INITIAL SNOW WILL GO INTO MELTING...ESPECIALLY ON ROADWAYS SO WILL
BE A LITTLE CAREFUL ABOUT GOING TOO HIGH AT THIS POINT ON
SNOWFALL. NONETHELESS...IT LOOKS LIKE A PERIOD OF POTENTIALLY
HEAVY SNOW ACCUMULATION FROM THURSDAY AFTERNOON THROUGH FRIDAY
MORNING. MORE THAN 6 INCHES OF SNOW NOW APPEARS LIKELY FOR THE
ARROWHEAD WITH LESSER AMOUNTS TO THE WEST AND SOUTH OF THE WATCH
AREA. THERE COULD ALSO BE A PERIOD OF SOME ICE...FREEZING RAIN OR
SLEET...BUT THINK THE MAIN SHOW WILL BE RAIN CHANGING TO SNOW.

WILL GO WITH HIGH POPS ACROSS THE BOARD TONIGHT AND THURSDAY. HIGH
RESOLUTION MODELS HAVE LATCHED ONTO CURRENT TRENDS FAIRLY WELL AND
WILL USE A COMBINATION OF THE HRRR/RAP AND 4 KM NMM WRF FOR THE
SHORT TERM TRENDS. CURRENT THOUGHT IS AN INCH OR TWO IN
DULUTH...AND MAYBE ADVISORY TYPE SNOW JUST OUTSIDE OF THE WATCH
AREA.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED APR 23 2014

THE FOCUS IS ON THE LOW PRESSURE SYSTEM THAT WILL CONTINUE MOVING
THROUGH THE UPPER MIDWEST AND GREAT LAKES REGION THURSDAY NIGHT AND
FRIDAY. THIS SYSTEM IS DIFFICULT TO FORECAST DUE TO THE POTENTIAL
FOR MULTIPLE PCPN TYPES...SPECIFICALLY RAIN AND SNOW AND A MIXTURE
OF BOTH. COMPLEXITY IS ADDED BY THE TIME OF THE YEAR AND SURFACE AND
LOW TEMPERATURES WITH THIS SYSTEM. BASICALLY...THE ARROWHEAD AND
NORTHERN FORECAST AREA HAVE THE THREAT OF SEEING SIGNIFICANT SNOW.
THERE ARE CONCERNS THOUGH THAT THERE COULD BE QUITE A BIT OF MELTING
AND COMPACTING OF THE SNOW THAT DOES FALL SINCE IT IS LATE APRIL AND
SURFACE TEMPERATURES WILL BE IN THE 30S FOR THE AREA UNDER THREAT
FROM SNOW. THE TEMPERATURES MIGHT BE WARM ENOUGH TO PREVENT THE
HEAVY ACCUMULATION THAT THE MODELS ARE OTHERWISE SUGGESTING.
NONETHELESS...THE WEATHER FOR THE ARROWHEAD WILL LIKELY BE A MESS
FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING DUE TO EITHER HEAVY
ACCUMULATING SNOW OR A MIXTURE OF RAIN AND SNOW. LOW VISIBILITIES
ARE LIKELY SINCE THE MAIN PCPN TYPE THAT DRIVERS SHOULD SEE IS
SNOW...EVEN IF MUCH OF IT MELTS ON THE ROAD. WE DECIDED TO ISSUE A
WINTER STORM WATCH FOR THE ARROWHEAD FOR THURSDAY AFTERNOON THROUGH
FRIDAY MORNING...WITH THE POTENTIAL FOR SEVERAL INCHES OR MORE. THE
HIGHEST AMOUNTS WILL LIKELY BE NEAR THE TIP OF THE ARROWHEAD...AND
NOT ON THE ROADS SINCE THE ROADS WILL LIKELY SEE SIGNIFICANT MELTING
OF THE SNOW. THE REST OF THE FORECAST AREA SHOULD MAINLY SEE LIGHT
TO MODERATE RAIN OR VERY LIGHT ACCUMULATIONS OF SNOW.

HIGH PRESSURE WILL BEGIN TO MOVE INTO THE NORTHLAND FRIDAY NIGHT.
THIS SHOULD PROVIDE DRY WEATHER FOR SATURDAY...EVEN IF SATURDAY WILL
BE SIGNIFICANTLY COOLER THAN NORMAL FOR THIS TIME OF YEAR.

THERE IS LESS CERTAINTY ABOUT EARLY NEXT WEEK. THE HIGH PRESSURE
COULD MAINTAIN THE COOL AND DRY WEATHER ACROSS THE NORTHLAND.
HOWEVER...A STRONG LOW PRESSURE SYSTEM WILL DEVELOP IN THE PLAINS
SUNDAY AND MONDAY...AND MOVE INTO THE MIDWEST TUESDAY.
HOWEVER...PCPN FROM THE INVERTED TROUGH IN THE NORTHERN PLAINS AND
FROM THE PARENTS LOW PRESSURE SYSTEM COULD MOVE INTO THE FORECAST
AREA. I KEPT THE LOW PCPN CHANCES FOR THIS SYSTEM LIMITED TO THE
WESTERN AND SOUTHERN FORECAST AREA...AND FORECASTED DRY WEATHER FOR
THE TWIN PORTS AREA. IF THE NORTHLAND DOES GET ANY PCPN...IT COULD
BE PERIODS OF LIGHT RAIN AND LIGHT SNOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CDT THU APR 24 2014

AN AREA OF FGEN/SHORTWAVE FORCED PRECIPITATION CONTINUED TO MOVE
NORTHEAST ACROSS THE NORTHLAND EARLY THIS MORNING. RAIN...ALONG WITH
SNOW/SLEET...WAS OCCURRING IN THIS BAND. CEILINGS WERE ALSO
LOWERING WITH SEVERAL SITES REPORTING IFR. WE EXPECT IFR/LIFR VSBYS AND
CEILINGS TO BECOME MORE COMMON AS THE MORNING PROGRESSES. THERE WILL
BE A BREAK IN THE PRECIP OVER KBRD...BUT IT WILL INCREASE AGAIN
THURSDAY MORNING. THE PRECIP INTENSITY WILL DECREASE ELSEWHERE
OVERNIGHT AS THIS BAND MOVES FURTHER NORTHEAST. RAIN AND SNOW WILL
BECOME MORE WIDESPREAD THROUGH THE DAY THURSDAY...THEN IT WILL
DIMINISH FROM THE SOUTHWEST BY EARLY EVENING.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  31  45  27  41 /  70  30  20  10
INL  32  45  26  46 /  80  40  10  10
BRD  33  54  32  51 /  30  20  10  10
HYR  33  51  28  49 /  60  30  10  10
ASX  32  46  27  42 /  80  30  20  10

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM NOON CDT TODAY THROUGH FRIDAY MORNING
     FOR MNZ012-020-021.

WI...NONE.
LS...NONE.
&&

$$

SHORT TERM...DAP
LONG TERM...GROCHOCINSKI
AVIATION...MELDE/CANNON






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