Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 291103
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
603 AM EST MON DEC 29 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 455 AM EST MON DEC 29 2014

TODAY AND TONIGHT WILL BE MARKED BY PERSISTENT COOL NW FLOW...WITH
DAYTIME HIGHS FALLING ANOTHER 5F FROM WHAT WAS REALIZED SUNDAY. A
WEAK SFC TROUGH SET UP ACROSS THE CWA WILL CONTINUE TO BE ERODED FOR
ALL BUT FAR E UPPER MI/LAKE SUPERIOR AS VERY STRONG 1060-1062MB
ARCTIC HIGH PRESSURE OVER CENTRAL BRITISH COLUMBIA AND ALBERTA THIS
MORNING.

EXPECT TO SEE SOME TEMPORARY IMPROVING CONDITIONS LES WISE FROM
DAYBREAK THROUGH THE EARLY AFTERNOON HOURS AS THE INITIAL SHORTWAVE
SHIFTS A BIT FARTHER TO OUR N. A SECODARY TROUGH/SHORTWAVE IS
BRINGING HIGH CLOUDS TO THE S TIP OF THE CWA THIS MORNING.

PERSISTENT OFF AND ON LES WILL CONTINUE OUR HIGH POP/LOW QPF
SCENARIO...WITH ONLY A FEW HUNDREDTHS IF THAT EVERY 6 HOURS. 850MB
TEMPS WILL GENERALLY RUN -17 TO -20C THROUGH TONIGHT. BETTER
CONVERGENCE WITH THE LOSS OF DAYTIME HEATING...AND THE APPROACH OF
YET ANOTHER SHORTWAVE WILL HELP BRING A LITTLE BETTER CHANCE OF
ACCUMULATING SNOW TO THE NW WIND SNOWBELTS. A COUPLE OF LOCATIONS IN
ALGER COUNTY COULD GET CLOSE TO ADVISORY SNOW TONIGHT IN CONVERGENT
BANDS OF LES SET UP IN ONE PLACE LONG ENOUGH. OTHERWISE COUNTY
AVERAGE IS RIGHT AROUND 3IN. SIMILAR TO THIS MORNING...CLOUD COVER
WILL MAKE ALL THE DIFFERENCE IN HOW COLD IT WILL GET TONIGHT. EXPECT
INTERIOR W HALF TO FALL INTO THE SINGLE DIGITS BELOW ZERO AGAIN.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 603 AM EST MON DEC 29 2014

WATER VAPOR LOOP AND RUC ANALYSIS SHOWS STRONGLY AMPLIFIED PATTERN
TAKING SHAPE ACROSS NAMERICA WITH RIDGE OVER THE ERN PACIFIC INTO
WRN CANADA/ALASKA AND A BROAD DOWNSTREAM TROF OVER MUCH OF CENTRAL
AND ERN CANADA INTO THE ERN 2/3RDS OF THE CONUS. MODELS INDICATE
THAT THIS PATTERN WILL HOLD AT LEAST INTO MID WEEK ALLOWING FOR THE
BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S
INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER
AND LAST MONTH. THIS PATTERN WILL RESULT IN MUCH BELOW NORMAL TEMPS
OVER THE NEXT SEVERAL DAYS AND PERSISTENT LAKE EFFECT SNOW FOR THE
NW TO W WIND SNOW BELTS DOWNWIND OF LAKE SUPERIOR. MODELS DIFFER
WITH HANDLING OF CUT OFF LOW WHICH DEVELOPS OVER THE SW CONUS TOWARD
THE MIDDLE OF THE WEEK. BOTH THE ECMWF AND GEM-NH SHOW THE REMNANTS
OF THIS LOW EJECTING DUE E BY NEXT WEEKEND IN SRN BRANCH AND NOT
REALLY IMPACTING THE GREAT LAKES REGION. THE GFS MEANWHILE HAS THE
REMNANTS OF THE LOW EJECTING NE AND PHASING WITH NRN BRANCH AS IT
DEVELOPS A RAPIDLY DEEPENING STORM SYSTEM OVER THE CENTRAL/LOWER
GREAT LAKES BY NEXT SUNDAY. IT WILL BE WORTH MONITORING MODEL TRENDS
WITH THIS SYSTEM AS ANY TREND TOWARD THE 00Z GFS SOLN WOULD SIGNAL
PERHAPS A MUCH MORE SIGNIFICANT IMPACT ON OUR WEATHER FOR NEXT
WEEKEND.

BEGINNING TUE AND TUE NIGHT...THE COLDEST AIR WITH THE INITIAL SURGE
OF ARCTIC AIR WILL SETTLE OVER THE AREA  LATE TUE/TUE NIGHT WHEN
850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY
BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL
WILL RANGE FROM NEAR ZERO FAR WEST TO THE LOW TO MID TEENS EAST.
SUBZERO MIN TEMPS WILL BE THE RULE TUE NIGHT IN THE INTERIOR AWAY
FROM LAKE EFFECT CLOUDS/SNOW WITH TEMPS IN THE INTERIOR W HALF
SLIPPING TO -10F OR COLDER. WINDS BACKING MORE WESTERLY WILL RESULT
IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED
WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO
-30F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NUMEROUS
SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W
WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO EXPECT
LES OVERALL TO BE ON THE LIGHT SIDE (GENERALLY 1-4IN/12HRS).
HOWEVER...THERE COULD BE SOME LOCALLY HIGHER AMOUNTS EAST (PERHAPS
ADVISORY LVL) WHERE FETCH ACROSS THE LAKE IS MAXIMIZED..ALLOWING FOR
MORE LAKE MODERATION AND BETTER POSITIONING OF DGZ WITHIN
CONVECTIVE LAYER. SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE
WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION
HEIGHTS MAINLY TUE AFTERNOON WHICH COULD RESULT IN A SPIKE IN
LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY
OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS
IN THE SNOW BELTS FAVORED BY NW WINDS.

ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN
SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA
INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI.
HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL
LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES
GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER
HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE
EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. WOULD NOT BE
SURPRISED TO SEE BLIZZARD TO NEAR BLIZZARD CONDITIONS MET OVER
KEWEENAW IF LES COVERAGE REMAINS NUMEROUS OR GREATER...WHICH NAM
SNDGS SUGGEST A GOOD POTENTIAL FOR LES ENHANCEMENT WITH DEEPENING
MOISTURE PROFILE AND DEEP CONVECTION LAYER TROUGH DGZ...ESPECIALLY
LATE WED AFTERNOON INTO NEW YEARS EVE NIGHT. WILL HIGHLIGHT THIS
POTENTIAL IN HWO.

NEXT ARCTIC COLD FRONT ASSOCIATED WITH MANITOBA SHORTWAVE WILL
SWING ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A
TIME IN NW LAKE SUPERIOR SNOWBELTS AND PROBABLY BRINGING ISOLD/SCT
-SHSN TO THE REMAINDER OF THE AREA.

LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS
STILL DECENT MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES
RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS.
THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT
REGIME WILL ALLOW FOR MORE WIDESPREAD SNOW TO DEVELOP OVER THE NRN
PLAINS AND THEN SPREAD E INTO THE UPPER LAKES.

ON INTO SAT/SUN...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW
THAT WILL BE OVER THE SW STATES MIDWEEK AS STATED EARLIER IN
DISCUSSION. 00Z GFS SOLN OF DEVELOPING MORE PHASED DEEP STORM SYSTEM
OVER THE CENTRAL GREAT LAKES BY NEXT WEEKEND APPEARS TO BE SOMEWHAT
OF AN OUTLIER BASED ON PREVIOUS GFS RUNS AND THE REST OF THE MODEL
GUIDANCE. I AM MORE INCLINED TO LEAN TOWARD BLEND OF MORE CONSISTENT
00Z ECMWF AND GEM-NH SOLN WHICH KEEPS REMNANTS OF CLOSED LOW MUCH
FARTHER SOUTH. THIS SOLN WOULD SHOW NRN BRANCH REMAINING DOMINANT
OVER UPPER LAKES WITH A RETURN TO COLDER AIR (NEAR -20C AT 850 MB)
FOR NEXT WEEKEND BEHIND FRI/S SYSTEM ALLOWING FOR MORE PERIODS OF
LES FOR THE NW SNOWBELTS ALONG LAKE SUPERIOR. LOOKS LIKE NRN BRANCH
WILL REMAIN ACTIVE INTO EARLY NEXT WEEK AS WELL BRINGING PERIODIC
CLIPPER SYSTEMS THROUGH AREA REINFORCING ARCTIC AIRMASS IN
PLACE.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM EST SUN DEC 28 2014

NORTHWEST FLOW LAKE EFFECT WILL BE THE MAIN ITEM OF CONCERN. WITH A
STRONG INVERSION AROUND 3KFT ABOVE THE SURFACE...DON/T EXPECT THE
SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE
MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK
SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT
WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS
A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK
TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE
BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION
FOR KSAW...VFR WILL CONTINUE THROUGH THE PERIOD.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 455 AM EST MON DEC 29 2014

LOOK FOR A BETTER CHANCE OF FREEZING SPRAY AND STRONG WINDS TUESDAY
NIGHT THROUGH THURSDAY MORNING.

THE OVERALL PATTERN LOOKS LIKE THIS...A RIDGE ACROSS THE UPPER GREAT
LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE
INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK
FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS
WILL BE AS A HUDSON BAY LOW SWINGS A TROUGH ACROSS LAKE SUPERIOR.
THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A
REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-40KTS ARE
STILL ANTICIPATED /ALONG WITH THE POTENTIAL FOR HEAVY FREEZING
SPRAY/ LATE TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE
GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW
TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN
SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE
ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE
TRACKS ACROSS THE UPPER GREAT LAKES.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KF
LONG TERM...VOSS
AVIATION...07
MARINE...KF






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