FXUS63 KDLH 150516
AFDDLH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
1116 PM CST MON DEC 14 2009
.DISCUSSION...
WE CANCELLED THE LAKE SNOW ADVISORY...AS SNOW SHOWERS HAVE NOT
FIRED BACK UP...AND SATELLITE STILL SHOWS FEW CLOUDS OVER FAR
WESTERN LAKE SUPERIOR. DRIER AIR AND BACKING WINDS WILL PREVENT
ANYTHING MORE THAN LIGHT SNOW SHOWERS FOR THE REST OF THE NIGHT.
AN AREA OF CLOUDS WERE MOVING THROUGH MINNESOTA LATE THIS EVENING
ASSOCIATED WITH A POTENT UPPER TROUGH. WE ADDED SOME FLURRIES TO
THE SOUTHERN HALF OUR CWA WHERE IT WAS PREVIOUSLY DRY. THERE WILL
BE SOME BRIEF VSBY RESTRICTIONS...TO ABOUT 2-3SM. A QUICK DUSTING
OF SNOW WILL BE POSSIBLE IS LOCALIZED AREAS.
&&
.AVIATION...06Z TAFS
MOST OF THE NORTHLAND WAS UNDER VFR CONDITIONS LATE THIS EVENING.
THE LAKE EFFECT SNOW SHOWERS ALONG THE SOUTH SHORE HAVE
DIMINISHED...AS DRIER AIR HAS MOVED IN...AND WINDS HAVE BACKED.
THERE IS A SHORTWAVE MOVING THROUGH NORTH DAKOTA AND NORTHWEST
ONTARIO LATE THIS EVENING. THAT WAVE WAS LEADING TO A DECK OF CLOUDS
WITH BASES VARYING FROM 5KFT TO 10KFT. THERE WAS ALSO A FEW POCKETS
OF LIGHT SNOW WITH MVFR CEILINGS/VSBYS. THOSE MVFR CONDITIONS WILL
MOST LIKELY BE BRIEF AND AFFECT THE KBRD TAF THROUGH ABOUT
09Z...KDLH BETWEEN 07Z AND 10Z...AND KHYR BETWEEN 08Z AND 12Z. THE
REST OF THE TAF PERIOD LOOKS LIKE VFR CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 927 PM CST MON DEC 14 2009/
DISCUSSION...
LAKE EFFECT SNOW SEEMS TO BE DIMINISHING THIS EVENING. SPOTTER AT
GILE REPORTED THE SNOW HAS ENDED FOR NOW...WITH AN ADDITIONAL 2.3
INCHES SINCE 6 PM. THE WEBCAM IN HURLEY SHOWS LITTLE SNOW ATTM.
WINDS HAVE BEEN SLOWLY BACKING...AND DRIER AIR HAS MOVED IN FROM
THE WEST. SATELLITE IMAGERY SHOWS FEW CLOUDS OVER FAR WESTERN LAKE
SUPERIOR WHERE IT HAS CLEARED OUT. WE MAY CANCEL THE ADVISORY
EARLY...BUT WILL WAIT FOR THE 04Z OR 10 PM OBSERVATIONS BEFORE
DOING SO.
FOR THE REST OF THE FORECAST...WE INCREASED CLOUD COVER BASED ON
INCOMING CLOUDS SEEN ON SATELLITE. THIS WILL CAUSE SHORT TERM TEMP
FLUCTUATIONS AS THE CLOUD PASSES THROUGH. THERE COULD BE SOME
FLURRIES AS WELL...AS SEEN IN UPSTREAM OBS OVER ND AND ON KMVX
RADAR.
WE DID DECREASE WINDS SOME INLAND. ONCE TEMPS DROP WAY OFF...AS
SEEN EARLIER AT KINL AND CURRENTLY OVER KCDD...THE WIND DROPS OFF
AS WELL. WE WILL KEEP THE WIND CHILL ADVISORY AS IS...BUT THERE
WON'T BE TOO MANY READINGS OF 35-40 BELOW ZERO...WITH MOST AREAS
25-35 BELOW LATE TONIGHT INTO TUESDAY MORNING.
PREV DISCUSSION... /ISSUED 604 PM CST MON DEC 14 2009/
UPDATE...
UPDATED GRIDS AND ISSUED A LAKE SNOW ADVISORY FOR ASHLAND AND IRON
COUNTIES. REPORTS OF 3-4 INCHES SINCE THIS AFTERNOON HAVE BEEN
REPORTED. COULD HAVE EVEN GONE WITH A WARNING...BUT WE DO EXPECT
THE SNOW TO DIMINISH AFTER 03Z AS WINDS BACK.
PREV DISCUSSION... /ISSUED 536 PM CST MON DEC 14 2009/
DISCUSSION...
WE UPDATED GRIDS AND FORECASTS TO INCREASE POPS OVER A PORTION OF
NORTHWEST WISCONSIN...ESPECIALLY THE LAKE SNOW BELT OF ASHLAND AND
IRON COUNTIES. WEBCAMS AND SURFACE OBS SHOW MODERATE SNOW AT
HURLEY. LAKE SNOW PARAMETERS LOOK GOOD EARLY THIS EVENING...THEN
WINDS ARE FORECAST TO BACK QUICKLY BETWEEN 00-03Z. DRIER AIR IS
ALSO MOVING IN. WE WILL MONITOR CONDITIONS...AND MAKE SOME CALLS
TO SPOTTERS.
AVIATION...OOZ TAFS
HIGH PRESSURE AND DRIER AIR WERE MOVING IN FROM THE WEST THIS
EVENING. VFR CEILINGS STILL COVERED MOST TAF SITES...WITH SOME LOW
MVFR OR IFR CONDITIONS ACROSS A PORTION OF THE SOUTH SHORE OF LAKE
SUPERIOR DOWN TO NEAR KPBH. THERE WAS AN AREA OF SNOW MOVING
THROUGH...WITH SOME LAKE EFFECT SNOW LINGERING THROUGH THE NIGHT.
MOST SITES WILL HOWEVER BE VFR.
PREV DISCUSSION... /ISSUED 302 PM CST MON DEC 14 2009/
DISCUSSION...
ANOTHER UPPER TROUGH...ASSOCIATED WITH A WAVY NORTHWEST FLOW...
WILL DROP THROUGH OUR AREA TUESDAY. CLOUDS ARE DISSIPATING FROM
WEST TO EAST...WITH AN ERODING BACK-EDGE MOVING THROUGH WESTERN MN
AT THIS TIME. A RADIATING ARCTIC AIR MASS SUGGESTS LOW TEMPERATURES
MORE IN LINE WITH THE MUCH COLDER MET FORECASTS. THE CORE OF THE
COLD AIR ALOFT PASSES...BUT SURFACE RIDGING AND THE LEADING EDGE
OF MID/HIGH CLOUDS WILL LIKELY NOT REACH OUR AREA BEFORE WEDNESDAY
MORNING. TEMPERATURES WILL BE MOSTLY OR COMPLETELY SUBZERO ACROSS
OUR AREA UNTIL THEN. AS THE SASKATCHEWAN SURFACE HIGH SLIPS TO OUR
SOUTH...RIDGING NORTH OF LAKE SUPERIOR SHOULD QUICKLY DIMINISH AND
WINDS WILL BACK...DRIVING LAKE CONVECTION MORE AND MORE OFFSHORE
TONIGHT AND KEEPING IT OFFSHORE TUESDAY AND TUESDAY NIGHT. GRADUAL
WARMING WILL FOLLOW...BUT WEAK SHORT WAVES WILL NOT RESULT IN MUCH
OR ANY PRECIPITATION THROUGH THURSDAY.
EXTENDED...THURSDAY NIGHT THROUGH MONDAY...
WAA REGIME AND A FAST MOVING UPPER DISTURBANCE WILL HAVE SHIFTED OFF
TO THE EAST AT THE START OF THE PERIOD. UPPER LEVEL FLOW WILL THEN
VEER AND BECOME NW AND THEN N THROUGH THE REMAINDER OF THE EXTENDED.
THIS IS DUE TO THE FACT THAT A DEEP UPPER LEVEL LOW WILL GET BLOCKED
ALONG THE EASTERN US AND THEN...TO SIGNIFICANT DIFFERING DEGREES
BASED ON YOUR MODEL OF CHOICE...RETROGRADE BACK TO THE WEST THROUGH
SE CANADA. THE GFS AND GEM RETROGRADE THE UPPER LOW AND KEEP
SURFACE HIGH PRESSURE TUCKED OFF TO OUR WEST...WHILE THE ECMWF KEEPS
THE LOW MUCH FURTHER EAST AND KEEP WEAK HIGH PRESSURE OVER THE AREA.
THIS MAKES THE GFS/GEM A BIT WETTER THAN THE EURO...ESPECIALLY ON
THE SOUTH SHORE.
WHAT THIS ALL MEANS IS...WITH UPPER FLOW NORTHERLY...DISTURBANCES
MOVING AROUND THE BACK SIDE OF THE LOW...AND CAA IN PLACE...OFF AND
ON CHANCES OF LIGHT SNOW SHOWERS/FLURRIES WILL PERSIST AND WILL
DEPEND ON HOW MUCH THE LOW RETROGRADES. SURFACE-850 WINDS WILL
INVOLVE SOME FORM OF A NORTHERLY COMPONENT WHICH WILL KEEP THE FEED
OF COOL AIR OUT OF SOUTHERN CANADA...AND ALSO KEEP THE CHANCE OF
LAKE EFFECT SNOW SHOWERS ALONG THE SOUTH SHORE...THOUGH THE QUESTION
MARK WILL BE MOISTURE. THEREFORE...LITTLE CONFIDENCE TO DEVIATE
FROM ONGOING FCST TOO MUCH AT THIS TIME.
AVIATION...18Z TAF ISSUANCE...KHYR WILL SEE LINGERING MVFR
CONDITIONS IN -SN THROUGH AT LEAST 0Z. THERE WILL BE A WINDOW OF MVFR
AT KBRD WITH LIGHT SNOW SHOWERS PUSHING THROUGH CENTRAL MINNESOTA
THIS AFTERNOON AHEAD OF A WEAK MID LEVEL DISTURBANCE. THESE MAY ALSO
IMPACT KDLH LATER THIS AFTERNOON...BUT LOW CONFIDENCE ON THAT
OCCURRING...AND IT WILL BE BRIEF AT BEST. THE MAIN UPPER LEVEL WAVE
WILL THEN MOVE THROUGH OVERNIGHT...WITH LITTLE MORE THAN LOW VFR
CLOUD. OTHERWISE...VFR CONDITIONS WILL PREVAIL THROUGH TAF PERIOD
WITH MID LVL CLOUDS AROUND 6-8 KFT BEFORE CLEARING NEAR THE END OF
THE PERIOD.
&&
.POINT TEMPS/POPS...
DLH -9 2 -11 6 / 10 10 10 10
INL -20 -9 -21 3 / 10 10 10 20
BRD -14 -1 -13 9 / 10 10 10 10
HYR -10 4 -12 8 / 20 10 10 10
ASX -4 4 -12 10 / 50 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 11 AM CST TUESDAY FOR MNZ010>012-
018>021-025-026-033>038.
WI...WIND CHILL ADVISORY UNTIL 11 AM CST TUESDAY FOR WIZ001.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST TUESDAY FOR LSZ121-146>148.
&&
$$
MELDE/EOM/DONOFRIO
