Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 061034
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
534 AM EST FRI MAR 6 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM EST FRI MAR 6 2015

PRETTY QUIET NIGHT WITH NO PRECIP OBSERVED AND ONLY A FEW HIGH
CLOUDS OVER THE CWA. DO SEE VERY LIGHT PRECIP ON RADAR OVER NCENTRAL
MN ASSOCIATED SHORTWAVE CURRENTLY MOVING INTO NWRN MN...BUT NO
PRECIP OBSERVED BY SFC OBS YET. THE SHORTWAVE WILL SHIFT ACROSS THE
CWA TODAY...POSSIBLY PRODUCING SOME FLURRIES OR LIGHT SNOW SHOWERS
OVER THE WEST AND CENTRAL. SHOULD BE A LITTLE BETTER COVERAGE OVER
THE E AS LOW LEVEL MOISTURE WILL BE BETTER THERE AND SW FLOW OFF
LAKE MI SHOULD PROVIDE SOME ADDITIONAL FORCING. ADDITIONALLY...THE
KEWEENAW MAY SEE SOME ENHANCED SNOW OFF LAKE SUPERIOR WITH THE SW
WINDS. EXPECT TOTAL DAYTIME ACCUMULATIONS TO BE A HALF INCH OR
LESS...GREATEST OVER THE KEWEENAW AND EAST. IT WILL BE WARMER TODAY
WITH HIGHS IN THE 20S.

A MORE POTENT SHORTWAVE DIVES SE INTO THE AREA LATE
TONIGHT...BRINGING A 1008MB SFC LOW TO NWRN LAKE SUPERIOR (NEAR ISLE
ROYALE) BY 12Z SAT. SNOW WILL HAVE TO SATURATE THE DRY LOW
LEVELS...BUT SHOULD BE OBSERVED OVER MAINLY THE W HALF OF UPPER MI
BY 12Z SAT. HAVE JUST OVER AN INCH OF SNOW FROM IRONWOOD TO COPPER
HARBOR...WITH LESSER AMOUNTS TO THE E THROUGH 12Z SAT. MOST OF THIS
SNOW SHOULD FALL IN 2-3 HOURS PRIOR TO 12Z. PRECIP PROGRESSES E
AFTER 12Z (SEE LONG TERM DISCUSSION). TEMPS TONIGHT WILL BOTTOM OUT
IN THE TEENS TO LOW 20S...WARMEST W.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 532 AM EST FRI MAR 6 2015

A WARMER PATTERN WILL BE TAKING HOLD LATE THIS WEEKEND INTO NEXT
WEEK. THE VERY PERSISTENT TROF THAT HAS DOMINATED WEATHER OVER ERN
NAMERICA FOR MORE THAN A MONTH WILL BE WEAKENING AS POSITIVE HEIGHT
ANOMALIES OVER WRN NAMERICA/NE PACIFIC DIMINISH. THESE CHANGES WILL
RESULT IN A MORE ZONALLY ORIENTED FLOW TAKING SHAPE...ALLOWING
PACIFIC AIR TO SPREAD ACROSS THE CONUS. FOR UPPER MI...THIS MEANS
ABOVE NORMAL TEMPS WILL RETURN TO THE AREA FOR MUCH OF NEXT WEEK. A
SERIES OF DISTURBANCES WILL TRACK ALONG THE SRN EDGE OF THE
RETREATING ARCTIC AIR THRU THE WEEKEND...AND THEN NEXT WEEK...
DISTURBANCES WILL CONTINUE TO TRACK ACROSS SRN CANADA IN THE MORE
ZONALLY ORIENTED FLOW. AS FOR PCPN...DESPITE THE CHANGING PATTERN
WEATHER STILL LOOKS MAINLY DRY FOR UPPER MICHIGAN THROUGH MUCH OF
THE PERIOD.

BEGINNING SAT...A SHORTWAVE DROPPING SE THROUGH SCNTRL CANADA WILL
REACH THE UPPER LAKES SAT MORNING. MODELS SHOW A PERIOD OF DEEP
LAYER Q-VECT CONVERGENCE AND ISENTROPIC ASCENT BEST VIEWED ON THE
280-285K SFCS (700-850MB) WHICH SHOULD YIELD A SHORT PERIOD OF -SN
AT MOST LOCATIONS. MIXING RATIOS ADVECTING INTO THE AREA ARE 2G/KG
BUT THE PERIOD OF ISENTROPIC ASCENT IS SHORT-LIVED...AND MUCH OF THE
LIFT WILL GO INTO MOISTENING THE DRY LOW-LEVELS ALREADY IN PLACE.
SO...EXPECT MAYBE 3HRS OR SO OF STEADIER -SN SAT MORNING IN THE NW
AND ERN FCST AREA...CLOSER TO TRACK OF THE SHORTWAVE/BEST HEIGHT
FALLS. SNOW ACCUMULATIONS CLOSER TO AN INCH MAY OCCUR IN THOSE AREAS
SAT MORNING. ELSEWHERE...EXPECT ONLY PATCHY -SN/FLURRIES AND A
DUSTING OF ACCUMULATION. WITH 850MB TEMPS FALLING BACK TO -14C
BEHIND SHORTWAVE ON SAT...THERE COULD BE SOME LIGHT LES OFF THE OPEN
SPOTS IN THE LAKE SUPERIOR ICE COVER FOR THE NW SNOWBELTS.

SAT NIGHT THRU SUN NIGHT...TWO MORE SHORTWAVES WILL DROP THRU THE
UPPER MISSISSIPPI VALLEY/WRN GREAT LAKES. INITIALLY...EXPECT MAINLY
DRY WX SAT NIGHT WITH PASSAGE OF SFC RIDGE AXIS/WSHFT TO THE SW THAT
WILL PUSH ANY REMAINING LIGHT LES OUT OVER LAKE SUPERIOR BY LATE SAT
NIGHT. LATE IN THE NIGHT...FOCUS OF WAA/ISENTROPIC ASCENT ASSOC WITH
THE PASSAGE OF THE FIRST SHORTWAVE WILL DEVELOP OFF TO THE SW IN SRN
MN/SW WI WHERE THE MAIN AREA OF -SN WILL DEVELOP. WITH THE SECOND
SHORTWAVE DUE TO ARRIVE SUN AFTN...ASSOC SHSN MAY BE ENHANCED BY
DIURNAL INSTABILITY. 850MB TEMPS -10 TO -12C PROBABLY WON`T BE
SUFFICIENTLY COLD TO GENERATE MUCH IF ANY LES SUN EVENING IN A
WESTERLY FLOW.

RETREATING FLOW TO THE N WILL THEN LEAD TO DRY WEATHER DOMINATING
MON THRU THU AS SHORTWAVES PASS BY TO THE N OF THE UPPER LAKES.
PERSISTENT WAA WILL CAUSE 850MB TEMPS OF -7 TO -10C MON MORNING TO
RISE TO 1 TO 4C BY TUE MORNING...BUT THEN TEMPS WL FALL TO -2C NORTH
TO 2C SOUTH BY WED MORNING AS A COLD FRONT BEGINS TO MOVE THROUGH
THE AREA. MODEL SNDGS INDICATE THAT THERE SHOULDN/T BE MUCH MORE
THAN MID/HIGH CLOUDS AT TIMES. SINCE SUNSHINE ON THE LOWER ALBEDO
FORESTED TERRAIN OF UPPER MI BY EARLY MARCH CAN SIGNIFICANTLY
DIMINISH THE INFLUENCE OF SNOW COVER ON DAYTIME HEATING...WILL
CONTINUE TO LEAN TOWARD THE WARMER SIDE OF ALL AVBL GUIDANCE FOR MON
THRU WED. MOST LOCATIONS WILL SEE HIGH TEMPS INTO THE 40S BY TUE
WITH THE WARMEST DAYS TUE AND WED. GIVEN EXPECTED PASSAGE OF COLD
FRONT...EXPECT THE N TO BE A LITTLE COOLER ON WED THAN TUE WHILE THE
S SHOULD REMAIN SIMILAR TO TUESDAYS TEMPS. IF TUE OR WED ENDS UP
MOSTLY SUNNY...COULD SEE SOME LOW 50S TEMPS IN THE INTERIOR...MAINLY
CLOSER TO THE WI BORDER. SFC HIGH PRES DROPPING TO THE NE AND E OF
LAKE SUPERIOR WILL LEAD TO A COOLER DAY ON THU IN AN ERLY FLOW...
ESPECIALLY OVER THE KEWEENAW PENINSULA AND NEAR LAKE MICHIGAN.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1226 AM EST FRI MAR 6 2015

EXPECT QUIET CONDITIONS OVERNIGHT...THEN CLOUDS WILL THICKEN LATE
TONIGHT AHEAD OF A WARM FRONT MOVING TOWARD THE AREA. CIGS SHOULD
REMAIN VFR OR POSSIBLY MVFR BY FRI AFTERNOON. SHARP INVERSION IN
PLACE INTO FRIDAY MORNING WITH THE FRONT IS EXPECTED TO BE
FAVORABLE FOR LOW-LEVEL WIND SHEAR INTO FRI MORNING.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 AM EST FRI MAR 6 2015

SW WINDS HAVE INCREASED AHEAD OF A LOW PRESSURE TROUGH CROSSING THE
REGION. EXPECT A FEW GALE GUSTS ARE THROUGH MID MORNING TODAY.
STRONGEST WINDS ON WESTERN AND NCENTRAL LAKE SUPERIOR. WINDS
DIMINISH TO LESS THAN 25KTS TONIGHT INTO SATURDAY BEHIND THE TROUGH.
WINDS DECREASE FURTHER SUNDAY AS A HIGH PRESSURE RIDGE CROSSES. SW
WINDS KICK UP AGAIN EARLY NEXT WEEK TO 25KTS AHEAD OF ANOTHER LOW
PRESSURE TROUGH THAT MOVES OVER LAKE SUPERIOR ON TUESDAY.

LAKE SUPERIOR REMAINS MOSTLY ICE COVERED. THE ICE MAY BEGIN TO SHIFT
AROUND AND/OR DIMINISH DUE TO THE STRONG AND SHIFTING WINDS AND ALSO
SINCE TEMPERATURES...AT LEAST FOR THE DAYTIME HOURS...ARE EXPECTED
TO BE ABOVE FREEZING SUNDAY THROUGH WEDNESDAY.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...VOSS
AVIATION...JLB
MARINE...TITUS


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