Area Forecast Discussion
Issued by NWS Marquette, MI

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747
FXUS63 KMQT 102021
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
321 PM EST WED FEB 10 2016

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 320 PM EST WED FEB 10 2016

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE IN THE ROCKIES AND A
DEEP TROUGH IN THE EASTERN U.S. THIS MORNING WITH NW UPPER FLOW OVER
THE AREA ALLOWING COLD AIR TO SPILL ACROSS THE REGION. A SHORTWAVE
OVER THE ERN U.P. THIS MORNING WILL CONTINUE TO HEAD SOUTHEAST TO
THE LOWER GREAT LAKES BY THIS EVENING AND THIS REINFORCES THE TROUGH
OVER THE ERN U.S. AND ALSO THE COLD AIR ACROSS THE REGION. ANOTHER
SHORTWAVE THEN DIGS SE FROM NRN MANITOBA ON THU INTO CENTRAL
ONTARIO. NAM SHOWS MAJORITY OF ENERGY WITH THIS NEXT SYSTEM PASSING
BY TO THE NORTH AND EAST OF THE CWA WITH DEEPER MOISTURE STAYING
NORTH OF THE AREA.

PERSISTENCE HAS BEEN THE WAY TO GO WITH THIS FORECAST AND WILL
CONTINUE TO USE THAT TO BASE THE FORECAST AROUND. INVERSION HEIGHTS
OFF NAM BUFKIT SOUNDINGS ARE AT OR BELOW 4000 FEET NOW WITH BEST
OMEGA AND LIFT EXITING THE AREA WITH THE SHORTWAVE THAT MOVED
THROUGH THIS MORNING. 950 MB CONVERGENCE STRENGTHENS OVERNIGHT OFF
TO THE WEST AND ALSO ACROSS ALGER COUNTIES...BUT DRY AIR AT THE LOW
LEVELS AND DEW POINTS BELOW ZERO NORTH AND WEST OF LAKE SUPERIOR
APPEAR TO HAVE TAKEN THEIR TOLL ON LAKE EFFECT SNOW SHOWER INTENSITY
AND COVERAGE A BIT AS LAKE EFFECT BANDS HAVE BECOME SPLOTCHY AND
REFLECTIVITIES HAVE DECREASED ON THE KMQT RADAR THIS AFTERNOON. PLAN
IS TO LET ADVISORIES GO IN THE WEST WITH THE DRY AIR CUTTING DOWN
ACCUMULATIONS AND WITH LIGHTER WINDS NOT LETTING THE SNOW BLOW AND
DRIFT AROUND AS MUCH. FOR MARQUETTE COUNTY...PLAN IS TO CANCEL
WARNING AND GO WITH ADVISORY FOR THE ERN PART OF COUNTY FOR TONIGHT
INSTEAD AS BAND WILL CONTINUE TO AFFECT THE FAR ERN COUNTY OVERNIGHT
AND KEEP WARNING UP FOR ALGER COUNTY TONIGHT. WINDS GO WESTERLY ON
THU.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 530 AM EST WED FEB 10 2016

MODELS INDICATED THE AMPLIFIED PATTERN WITH INTRUSIONS OF VERY COLD
ARCTIC AIR INTO THE NRN LAKES WILL BECOME MORE ZONAL NEXT WEEK WITH
MILDER PACIFIC AIR AND ABOVE NORMAL TEMPERATURES RETURNING TO THE
REGION.

THURSDAY...WITH BACKING WINDS FROM NW TO W AHEAD OF THE NEXT CLIPPER
SHRTWV...LES WILL SHIFT INTO THE KEWEENAW AND NEAR LAKE SUPERIOR
EAST OR MUNISING. DESPITE 850 MB TEMPS AROUND -22C...INVERSION
HEIGHTS OF 4K-5K FT WILL LIMIT LES INTENSITY AND KEEP ADDITIONAL
ACCUMULATIONS TO 1 TO 2 INCHES NW AND FROM 2 TO 4 INCHES OVER THE NE
CWA. TEMPS WILL REBOUND SLIGHTLY WITH HIGHS FROM 12 TO 17.

THU NIGHT INTO FRI...A CLIPPER SHRTWV MOVING THROUGH NRN ONTARIO
WILL DRAG AN ARCTIC COLD FRONT INTO THE NRN LAKES WITH WINDS VEERING
FROM W TO NW...MAINLY AFTER 06Z/FRI. ALTHOUGH A HEAVIER SNOWBAND
ASSOCIATED WITH LOW LEVEL CONV ALONG THE FRONT WILL MOVE IN
OVERNIGHT...IT SHOULD MOVE THROUGH FAST ENOUGH TO LIMIT ACCUMULATIONS
TO AN INCH OR TWO. MODERATE TO OCNLY HEAVY LES FOR NW WIND SNOW BELTS
WILL DEVELOP FOR FRI AS INVERSION HEIGHTS CLIMB TO 6-8K FT WITH 850
MB TEMPS INTO THE -25C TO -30C RANGE. THE BEST CHANCE FOR MORE
SIGNFICANT ACCUMULATIONS WILL BE OVER THE EAST...DOWNSTREAM OF THE
LONGER FETCH. A LIMITING FACTOR WILL BE THE SHALLOW DGZ NEARTHE SFC
IN THE VERY COLD AIRMASS LEADING TO MAINLY SMALLER SNOWFLAKES AND
LOWER SLR VALUES. THE COMBINATION OF WINDS AND SMALLER SNOWFLAKES
THAT WILL BE EFFECTIVE IN REDUICING VSBY REQUIRE AN LES ADVY EVEN
WITH LOWER END SNOW AMOUNTS.

FRI NIGHT INTO SAT...MODERATE NW FLOW LES WILL CONTINUE. WIND CHILL
VALUES ACROSS MOST OF THE CWA ARE EXPECTED TO DROP TO ADVY LEVELS
(AROUND -25) WITH TEMPS FROM -5 TO -10 AND WINDS TO NEAR 10 MPH.
HIGHS SAT WILL REMAIN IN THE 4 TO 10 DEGREE RANGE.

SUN-TUE...WINDS SHIFTING TO THE SOUTH AHEAD OF A PLAINS SHRTWV AND
SFC TROUGH WILL BRING AN END TO THE LES BY SUN MORNING. THE
GFS/ECMWF WERE IN REASONABLE AGREEMENT BRINGING POTENTIAL FOR LIGHT
SNOW INTO UPPER MI LATE SUN INTO SUN NIGHT WITH A STRENGTHENING WAA
PATTERN. THERE IS MORE UNCERTAINTY EARLY NEXT WEEK WITH A FASTER WNW
FLOW DEVELOPING WITH THE POTENTIAL FOR EMBEDDED WEAK SHRTWVS THAT
COULD PRODUCE SOME LIGHT SNOW.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1159 AM EST WED FEB 10 2016

UNDER A NNW FLOW OF ARCTIC AIR ACROSS LAKE SUPERIOR...LAKE EFFECT
SNOW SHOWERS WILL BE THE RULE AT KIWD/KCMX/KSAW THRU MOST OF THIS
FCST PERIOD...AND TYPICAL FOR LAKE EFFECT SNOW...CONDITIONS WILL BE
HIGHLY VARIABLE. PREVAILING CONDITIONS WILL LIKELY BE IFR AT KCMX
AND KSAW THROUGH THIS EVENING WITH MVFR AT KIWD...BUT EXPECT BRIEF
PERIODS OF LIFR AND MVFR. DRIER AIR MOVING IN TONIGHT WILL ALLOW
CONDITIONS TO SLOWLY IMPROVE AT ALL TAF SITES AS SNOW SHOWERS SLOWLY
DIMINISH IN INTENSITY AND WINDS SHIFT MORE NORTHWESTERLY AND COULD
SEE SOME VFR CONDITIONS BY THU AFTERNOON AT KIWD AND LATE TONIGHT AT
KSAW AS WINDS BECOME WEST ENOUGH TO PUSH THE SNOW BANDS NORTH AND
EAST OF THOSE SITES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 320 PM EST WED FEB 10 2016

ANOTHER ROUND OF GALES ARE POSSIBLE THURSDAY NIGHT INTO FRIDAY NIGHT
ACROSS LAKE SUPERIOR AS NEXT SHOT OF COLD AIR MOVE IN AND PRESSURE
GRADIENT TIGHTENS UP AGAIN. FREEZING SPRAY WILL ALSO INCREASE WITH
THE HEAVIEST FREEZING SPRAY EXPECTED THROUGH TONIGHT AND AGAIN
THURSDAY NIGHT INTO SATURDAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
  LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ005.

  LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING
     FOR MIZ001>003-009.

  LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ006.

LAKE SUPERIOR...
  HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST THURSDAY FOR
     LSZ265>267.

LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...07
LONG TERM...JLB
AVIATION...07
MARINE...07



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