Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 062044
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
344 PM EST FRI MAR 6 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 342 PM EST FRI MAR 6 2015

WNW FLOW ALOFT BROUGHT A REALLY WEAK WAVE ALOFT OVER UPR MICHIGAN
TODAY. MAINLY A SMATTERING OF MID CLOUDS AND JUST NOW SOME FLURRIES
ARE STARTING TO FORM OVER EASTERN CWA. INCREASING LOW-LEVEL MOISTURE
AND LIFT BLO H85 PER RAP ALONG SFC TROUGH CROSSING THE EASTERN CWA
MAY INCREASE LGT SNOW BRIEFLY INTO EARLY EVENING TO EAST OF P53 AND
NORTH OF ERY. RADAR ECHOES PRETTY LIGHT THOUGH...SO FLURRIES ARE
PROBABLY ALL THAT MOST AREAS WILL SEE. ONLY OTHER ISSUE TODAY HAS
BEEN GUSTY SW WINDS OVER EAST HALF. ERY EVEN GUSTED OVER 40 MPH
BRIEFLY EARLY THIS AFTN WITH HAZE REPORTED ON THE AWOS WHICH IS LIKELY
BLSN. WEBCAMS OVER REST OF THE EAST INDICATE THAT IS FAIRLY LOCALIZED
THOUGH. WINDS HAVE DIMINISHED OVER THE WEST HALF AS LOW-LEVEL JET
HAS MOVED EAST OF THE AREA. AFTER THE LIGHT SNOW/FLURRIES IN THE EAST
EARLY...A QUIET EVENING EXPECTED AS THERE ARE NOT A LOT OF CLOUDS
IMMEDIATELY UPSTREAM IN WAKE OF THE WEAK TROUGH MOVING ACROSS THIS
AFTN. TEMPS SHOULD FALL OFF INTO THE TEENS. PERHAPS IF WINDS BECOME
CALM FOR A WHILE COULD SEE SINGLE DIGITS FOR THE COLDEST SPOTS IN THE
INTERIOR.

CHANGES OCCUR OVERNIGHT THROUGH AS SHORTWAVE DIGGING SOUTHEAST OVER
NORTHERN SASKATCHEWAN AND MANITOBA BRING DEEPENING SFC LOW TO
NORTHERN PART OF LK SUPERIOR BTWN 09Z-12Z SATURDAY. MID-HIGH CLOUDS
SHOULD INCREASE BY MIDNIGHT OVER THE WEST AND SPREAD OVER REST OF
THE AREA OVERNIGHT. PRECIP CURRENTLY OVER SOUTHERN PORTION OF
SASKATCHEWAN WILL EXPAND AS THE SHORTWAVE AND LOW GET CLOSER TO THE
AREA. SFC OBS ACTUALLY SHOW LGT LIQUID PRECIP OCCURRING OVER
SASKATCHEWAN THIS AFTN...BUT IT APPEARS THAT THE WARMER AIR ABOVE 0C
AT H85 GETS SHUNTED TO THE SOUTH BEFORE MAKING IT INTO UPR MICHIGAN.
ONLY EXPECTING SNOW LATE TONIGHT INTO SATURDAY MORNING. SOUNDINGS
SHOW MOST OF THE MOISTURE ADVECTION AND STRONGEST LIFT OCCURS H8-H7
WITH TEMPS WELL WITHIN THE DGZ. SLR/S SHOULD BE AT LEAST 15:1 IF NOT
MORE TOWARD 20:1 WHERE LIFT IS MAXIMIZED ON TEMPS -15C TO -18C.
MIXING RATIOS AHEAD OF THE LOW UP TO 2G/KG WOULD SUPPORT 4 INCHES OF
SNOW OVER 12 HOURS...BUT DURATION OF THE SNOW IN THIS CASE WILL BE 3-
5 HOURS AT THE MOST. MAYBE COULD SEE A COUPLE INCHES OF SNOW BUT
OVERALL SNOW AMOUNTS WILL BE AN INCH OR LESS...A LITTLE MORE IF THE
FLUFFIER SLR/S MATERIALIZE FOR THE DURATION OF THE SNOW.

IN WAKE OF THE SNOW...WHICH ENDS FM WEST TO EAST ON SATURDAY...IT IS
POSSIBLE THERE COULD BE SOME BRIEF FREEZING DRIZZLE BEFORE TEMPS AT
H9-H85 COOL SUFFICIENTLY FOR STRICTLY SNOW AS THE MID-LEVEL MOISTURE
WILL BE OUT OF THE PICTURE BY THAT TIME. BEST CHANCE FOR ANY PRECIP
AT ALL BTWN 15Z-21Z WOULD BE OVER HIGHER TERRAIN OF WESTERN UPR
MICHIGAN WITH NW WINDS THAT DEVELOP BEHIND THE SFC LOW. AT LEAST
LIGHT LAKE EFFECT COULD ALSO DEVELOP IN THE AFTN AS H85 THERMAL
TROUGH WITH H85 TEMPS DOWN TO -14C AND SUFFICIENT MOISTURE AFFECT
MAINLY WESTERN CWA. HIGH TEMPS SHOULD REACH UPR 20S TO LOWER 30S
MOST LOCATIONS BEFORE COOLER AIR WORKS IN LATE IN THE DAY.

.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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1253 PM EST FRI MAR 6 2015

SCT-BKN VFR CLOUDS THIS AFTN AND THROUGH MOST OF THE NIGHT. CLOUDS
LOWER TO MVFR OR LOWER VFR LATE TONIGHT INTO SATURDAY MORNING AS A
UPPER DISTURBANCE PRODUCES A 3-5 HOUR PERIOD OF LIGHT SNOW. VSBY MAY
DROP TO IFR AS THE SNOW MOVES THROUGH.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 342 PM EST FRI MAR 6 2015

NO GALES ARE EXPECTED THROUGH THE PERIOD. SOUTHWEST TO WEST WINDS TO
30 KTS AHEAD OF A SFC LOW PRESSURE SYSTEM AND TROUGH DIMINISH THIS
EVENING. EXPECT WEST TO NORTHWEST WINDS TO 30 KTS FOR SATURDAY
BEHIND THE DEPARTING LOW PRESSURE SYSTEM. WINDS DIMINISH LATER
SATURDAY THROUGH SUNDAY. ANOTHER ROUND OF SOUTHWEST TO WEST WINDS TO
30 KTS EXPECTED MONDAY AND TUESDAY AHEAD OF A COLD FRONT THAT DROPS
NORTH TO SOUTH ACROSS LAKE SUPERIOR BY WEDNESDAY MORNING. BEHIND
THAT FRONT...NORTHWEST WINDS SHOULD BE 25 KTS OR LESS ON WEDNESDAY.

LAKE SUPERIOR REMAINS MOSTLY ICE COVERED. ALREADY SEEING THE ICE
SHIFT AROUND THOUGH WITH THE STRONGER WINDS THAT OCCURRED SINCE
EARLY FRIDAY MORNING. EXPECT THE ICE COVERAGE TO DIMINISH SOME INTO
EARLY NEXT WEEK DUE TO THE STRONG AND SHIFTING WINDS AT TIMES AND
WITH DAYTIME TEMPERATURES RISING ABOVE FREEZING AT LEAST EARLY NEXT
WEEK.
&&

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

$$

SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...JLA
MARINE...JLA


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